Parabens

What are Parabens and what dos it do?

Parabens are man-made chemicals often used in small amounts as preservatives in cosmetics, pharmaceuticals, foods, and beverages. Numerous studies has shown that parabens are linked to cancer. It also interfers with your hormone levels and can mimic estrogen, which can result in negative outcomes.  Common parabens are methylparaben, ethylparaben, propylparaben, and butylparaben.

How People Are Exposed to Parabens?

People can be exposed to parabens through touching, swallowing, or eating products that contain parabens. Many products, such as makeup, moisturizers, hair-care products, and shaving creams, contain parabens. Parabens in these products are absorbed through the skin. Parabens also can enter the body when pharmaceuticals, foods, and drinks containing parabens are swallowed or eaten. Parabens that enter the body are quickly excreted. Parabens are the most widely used preservative in cosmetics. An estimated 75 to 90 per cent of cosmetics contain parabens (typically at very low levels).

If you wouldn’t eat your moisturizer, you shouldn’t put it on you skin either – the chemicals will get absorbed into your system!

Health and Environmental Hazards of Parabens

Parabens easily penetrate the skin and are suspected of interfering with hormone function (endocrine disruption). Parabens can mimic estrogen (the primary female sex hormone). In one study, parabens were detected in human breast cancer tissues, raising questions about a possible association between parabens in cosmetics and cancer. Parabens may also interfere with male reproductive functions. In addition, studies indicate that methylparaben applied on the skin reacts with UVB leading to increased skin aging and DNA damage!

Parabens occur naturally at low levels in certain foods, such as barley, strawberries, currents, vanilla, carrots and onions, although a synthetic preparation derived from petrochemicals is used in cosmetics.

Important:

Parabens in foods are metabolized when eaten, making them less strongly estrogenic. In contrast, when applied to the skin and absorbed into the body, parabens in cosmetics bypass the metabolic process and enter the blood stream and body organs intact.

It has been estimated that women are exposed to 50 mg per day of parabens from cosmetics. More research is needed concerning the resulting levels of parabens in people. Studies conducted by the U.S. Centers for Disease Control and Prevention (CDC) did find four different parabens in human urine samples, indicating exposure despite the very low levels in products.

Related Ingredients

Methylparaben, butylparaben and propylparaben are some of the most common parabens in cosmetics. Other chemicals in this class generally have “paraben” in their names (e.g., isobutylparaben, ethylparaben, etc).

Resources

http://www.cdc.gov/biomonitoring/Parabens_FactSheet.html

http://www.dr-baumann-international.co.uk/science/The%20Dangers%20of%20Parabens.pdf

http://www.davidsuzuki.org/issues/downloads/Dirty-dozen-backgrounder.pdf

http://www.ncbi.nlm.nih.gov/pubmed/14745841

http://www.ncbi.nlm.nih.gov/pubmed/16938376

http://www.ncbi.nlm.nih.gov/pubmed/18656963

Legs cosmetic treatment, isolate on white background

Legs cosmetic treatment, isolate on white background

Fiber

What is fiber and what does it do?

Fiber is a substance found in plants. Dietary fiber is found in fruits, vegetables, and grains. It is an important part of a healthy diet.Dietary fiber adds bulk to your diet. Because it makes you feel full faster, it can be helpful in controlling weight. Fiber aids digestion, helps prevent constipation, and is sometimes used for the  treatment of diverticulosis, diabetes, and heart disease. However, if you have diverticulitis, some types of fiber can make your symptoms worse.

Food Sources

There are two forms of fiber: soluble and insoluble.

Soluble fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in oat bran, barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables. Soluble fiber has been scientifically proven to lower cholesterol, which can help prevent heart disease.

Insoluble fiber is found in foods such as wheat bran, vegetables, and whole grains. It appears to speed the passage of foods through the stomach and intestines and adds bulk to the stool.

You should eat 20 to 35 grams of fiber a day. To get more into your diet, eat different types of foods, such as fruits, vegetables, and grains.

Vegetables, Legumes, and Nuts

Vegetables are a major source of fiber:

  • Lettuce, Swiss chard, raw carrots, and spinach
  • Tender cooked vegetables, such as asparagus, beets, mushrooms, turnips, and pumpkin
  • Broccoli, artichokes, squashes, sweet potatoes, and string beans
  • Vegetable juices

You can also get more fiber by eating:

  • Legumes, such as lentils, black beans, split peas, kidney beans, lima beans, and chickpeas
  • Sunflower seeds, almonds, pistachios nuts, and pecans

Fruits

Fruits are another good source of fiber:

  • Apples and bananas
  • Peaches and pears
  • Tangerines, prunes, and berries
  • Figs and other dried fruits

Grains

Grains are another important source of dietary fiber:

  • Hot cereals, such as oatmeal, farina, and Cream of Wheat
  • Whole-grain breads (whole wheat or whole rye)
  • Brown rice
  • Popcorn
  • High-fiber cereals (such as bran, shredded wheat, Grape Nuts, Ry Krisp, and puffed wheat)
  • Whole-grain pastas

Peeling can reduce the amount of fiber in fruits and vegetables. Eating fiber-containing food is beneficial, whether it is cooked or raw.

 Side Effects

Eating a large amount of fiber in a short period of time can cause intestinal gas (flatulence), bloating, and abdominal cramps. This usually goes away once the natural bacteria in the digestive system get used to the increase in fiber in the diet. Adding fiber gradually to the diet, instead of all at one time, can help reduce gas or diarrhea.

Too much fiber may interfere with the absorption of minerals such as iron, zinc, magnesium, and calcium. However, this effect usually does not cause too much concern because high-fiber foods are typically rich in minerals.

Recommendations

The recommendation for older children, adolescents, and adults is 20 – 35 grams per day. Younger children will not be able to eat enough calories to achieve this, but it is a good idea to introduce whole grains, fresh fruits, and other high-fiber foods. Add fiber gradually over a period of a few weeks to avoid abdominal discomfort. Water aids the passage of fiber through the digestive system. Drink plenty of fluids (approximately 8 glasses of water or noncaloric fluid a day).

 Resources

http://www.nlm.nih.gov/medlineplus/ency/article/002470.htm

http://www.nlm.nih.gov/medlineplus/ency/patientinstructions/000193.htm

potatoes

Fats & Cholesterol

What are fats and what do they do?

Fats are a type of nutrient that you get from your diet. It is essential to eat some fats, though it is also harmful to eat too many.

The fats you eat give your body energy that it needs to work properly. During exercise, your body uses calories from carbohydrates you have eaten. But after 20 minutes, exercise then depends on calories from fat to keep you going.

You also need fat to keep your skin and hair healthy. Fat aso helps you absorb vitamins A, D, E, and K, the so-called fat-soluble vitamins. Fat also fills your fat cells and insulates your body to help keep you warm.

The fats your body gets from your food gives your body essential fatty acids called linoleic and linolenic acid. They are called “essential” because your body cannot make them itself, or work without them. Your body needs them for brain development, controlling inflammation, and blood clotting.

Fat has 9 calories per gram, more than 2 times the number of calories in carbohydrates and protein, which each have 4 calories per gram. That is why foods that are high in fat are called “fattening.”

All fats are made up of saturated and unsaturated fatty acids. Fats are called saturated or unsaturated depending on how much of each type of fatty acid they contain.

How much total dietary fat do I need?

  • Consume less than 10% of calories from saturated fats.
  • Replace solid fats with oils whenever possible.
  • Limit foods that contain synthetic sources of trans fatty acids (such as hydrogenated oils), and keep total trans fatty acid consumption as low as possible.
  • Eat fewer than 300 mg of dietary cholesterol per day.
  • Reduce intake of calories from solid fats.
Age Group Total Fat Limits
Children ages 2 to 3 30% to 40% of total calories
Children and adolescents ages 4 to 18 25% to 35% of total calories
Adults, ages 19 and older 20% to 35% of total calories

Types of Fat

Saturated fats raise your LDL (“bad”) cholesterol level. High LDL cholesterol puts you at risk for heart attack, stroke, and other major health problems. You should avoid or limit foods that are high in saturated fats.

  • Keep saturated fats to only 10% of your total daily calories.
  • Foods with a lot of saturated fats are animal products, such as butter, cheese, whole milk, ice cream, cream, and fatty meats.
  • Some vegetable oils — coconut, palm, and palm kernel oils — also contain saturated fats. These fats are solid at room temperature.
  • A diet high in saturated fat increases cholesterol build up in your arteries (blood vessels). Cholesterol is a soft, waxy substance that can cause clogged, or blocked, arteries.

Eating unsaturated fats instead of saturated fats can help lower your LDL cholesterol. Most vegetable oils that are liquid at room temperature have unsaturated fats. There are 2 kinds of unsaturated fats:

  • Mono-unsaturated fats, which include olive and canola oil
  • Polyunsaturated fats, which include safflower, sunflower, corn, and soy oil

Trans fatty acids are unhealthy fats that form when vegetable oil hardens in a process called hydrogenation. Hydrogenated fats, or “trans fats,” are often used to keep some foods fresh for a long time.

Trans fats are also used for cooking in some restaurants. They can raise LDL cholesterol levels in your blood. They can also lower your HDL (“good”) cholesterol levels.

  • Trans-fatty acids are found in fried foods, commercial baked goods (donuts, cookies, and crackers), processed foods, and some margarines.
  • You should avoid foods made with hydrogenated and partially hydrogenated oils (such as hard butter and margarine). They contain high levels of trans-fatty acids.

It is important to read nutrition labels on foods. This will help you know what kinds of fats, and how much, your food contains.

Cholesterol

Cholesterol is a fatty substance that’s found in animal-based foods such as meats, poultry, egg yolks, and whole milks. Do you remember the other type of fat that is found in animal-based products? That’s right — saturated fat.

Polyunsaturated Fats and Monounsaturated Fats

Most of the fat that you eat should come from unsaturated sources: polyunsaturated fats and monounsaturated fats. In general, nuts, vegetable oils, and fish are sources of unsaturated fats. The table below provides examples of specific types of unsaturated fats.

Monounsaturated Fat Sources Omega-6 Polyunsaturated Fat Sources Omega-3 Polyunsaturated Fat Sources
Nuts Vegetable oils Canola oil Olive oil High oleic safflower oil Sunflower oil Avocado Soybean oil Corn oil Safflower oil Soybean oil Canola oil Walnuts Flaxseed Fish: trout, herring, and salmon

Polyunsaturated fats can also be broken down into two types:

  • Omega-6 polyunsaturated fats — these fats provide an essential fatty acid that our bodies need, but can’t make.
  • Omega-3 polyunsaturated fats — these fats also provide an essential fatty acid that our bodies need. In addition, omega-3 fatty acids, particularly from fish sources, may have potential health benefits.

How do I control my polyunsaturated fat and monounsaturated fat intake?

In general, nuts, vegetable oils, and fish are sources of unsaturated fats. The table below provides examples of specific types of unsaturated fats.

Monounsaturated Fat Sources Omega-6 Polyunsaturated Fat Sources Omega-3 Polyunsaturated Fat Sources
Nuts Vegetable oils Canola oil Olive oil High oleic safflower oil Sunflower oil Avocado Soybean oil Corn oil Safflower oil Soybean oil Canola oil Walnuts Flaxseed Fish: trout, herring, and salmon

Below are tips for including appropriate amounts of unsaturated fats in your diet:

  • Replace solid fats used in cooking with liquid oils.
  • Remember any type of fat is high in calories. To avoid additional calories, substitute polyunsaturated and monounsaturated fats for saturated fats and trans fats rather than adding these fats to your diet.
  • Have an ounce of dry-roasted nuts as a snack. Nuts and seeds count as part of your meat and beans “allowance”.

Oils and Cooking

When you cook, solid margarine or butter are not the best choices. Butter is loaded with saturated fat, which can raise your cholesterol. It can also increase your chance of heart disease. Most margarines, on the other hand, have some saturated fat plus trans-fatty acids, which can also be bad for you. Both of these fats have their risks.

If you must use one or the other, some margarines may be better than butter.

What oils to use

As a general rule, try to use extra virgin oils in cooking and avoid margarine and dairy products. Also, low fat options are not very good for you – try to stay away from processed foods. An easy rule of thumb is to only go with foods (in this case oils) with only one ingredient (olive oil, flaxseed oil etc.) These foods are generally not processed.

  • Use olive / canola / sunflower / flaxseed oil instead of butter or margarine.
  • If you want margarine, go with the soft ones (tub or liquid) over harder stick forms.
  • Choose margarines with liquid vegetable oil as the first ingredient (they are ranked after amounts on the ingredients list).

What Not to Use When Cooking

  • Margarine, shortening, and cooking oils that have more than 2 grams of saturated fat per tablespoon (read the nutrition information labels).
  • Hydrogenated and partially hydrogenated fats (read the ingredients labels). These are high in saturated fats and trans-fatty acids.
  • Shortening or other fats made from animal sources, such as lard.

Resources

http://www.nlm.nih.gov/medlineplus/ency/patientinstructions/000104.htm

http://www.nlm.nih.gov/medlineplus/ency/patientinstructions/000095.htm

http://www.cdc.gov/nutrition/everyone/basics/fat/index.html

http://www.cdc.gov/nutrition/everyone/basics/fat/unsaturatedfat.html

http://www.cdc.gov/nutrition/everyone/basics/fat/cholesterol.html

Monounsaturated Fats

Monounsaturated Fats

Zinc

What is zinc and what does it do?

Zinc is a nutrient that people need to stay healthy. Zinc is found in cells throughout the body. It helps the immune system fight off invading bacteria and viruses. The body also needs zinc to make proteins and DNA, the geneticmaterial in all cells. During pregnancy, infancy, and childhood, the body needs zinc to grow and develop properly. Zinc also helps wounds heal and is important for proper senses of taste and smell.

How much zinc do I need?

The amount of zinc you need each day depends on your age. Average daily recommended amounts for different ages are listed below in milligrams (mg):

Life Stage Recommended Amount
Birth to 6 months 2 mg
Infants 7–12 months 3 mg
Children 1–3 years 3 mg
Children 4–8 years 5 mg
Children 9–13 years 8 mg
Teens 14–18 years (boys) 11 mg
Teens 14–18 years (girls) 9 mg
Adults (men) 11 mg
Adults (women) 8 mg
Pregnant teens 12 mg
Pregnant women 11 mg
Breastfeeding teens 13 mg
Breastfeeding women 12 mg

What foods provide zinc?

Zinc is found in a wide variety of foods. You can get recommended amounts of zinc by eating a variety of foods including the following:

  • Oysters, which are the best source of zinc.
  • Red meat, poultry, seafood such as crab and lobsters, and fortified food products
  • Beans, nuts, whole grains, and dairy products, which provide some zinc.

What kinds of zinc dietary supplements are available?

Zinc is present in almost all multivitamin/mineral dietary supplements. It is also available alone or combined with calcium, magnesium or other ingredients in dietary supplements. Dietary supplements can have several different forms of zinc including zinc gluconate, zinc sulfate and zinc acetate. It is not clear whether one form is better than the others.

Zinc is also present in some denture adhesive creams. Using large amounts of these products, well beyond recommended levels, could lead to excessive zinc intake and copper deficiency. This can cause neurological problems, including numbness and weakness in the arms and legs.

Am I getting enough zinc?

Most people in the Western world get enough zinc from the foods they eat.

However, certain groups of people are more likely than others to have trouble getting enough zinc:

  • People who have had gastrointestinal surgery, such as weight loss surgery, or who have digestive disorders, such as ulcerative colitis or Crohn’s disease. These conditions can both decrease the amount of zinc that the body absorbs and increase the amount lost in the urine.
  • Vegetarians because they do not eat meat, which is a good source of zinc. Also, the beans and grains they typically eat have compounds that keep zinc from being fully absorbed by the body. For this reason, vegetarians might need to eat as much as 50% more zinc than the recommended amounts.
  • Older infants who are breastfed because breast milk does not have enough zinc for infants over 6 months of age. Older infants who do not take formula should be given foods that have zinc such as pureed meats. Formula-fed infants get enough zinc from infant formula.
  • Alcoholics because alcoholic beverages decrease the amount of zinc that the body absorbs and increase the amount lost in the urine. Also, many alcoholics eat a limited amount and variety of food, so they may not get enough zinc.
  • People with sickle cell disease because they might need more zinc.

What happens if I don’t get enough zinc?

Zinc deficiency is rare in North America. It causes slow growth in infants and children, delayed sexual development in adolescents and impotence in men. Zinc deficiency also causes hair loss, diarrhea, eye and skin sores and loss of appetite. Weight loss, problems with wound healing, decreased ability to taste food, and lower alertness levels can also occur.

Many of these symptoms can be signs of problems other than zinc deficiency. If you have these symptoms, your doctor can help determine whether you might have a zinc deficiency.

What are some effects of zinc on health?

Scientists are studying zinc to learn about its effects on the immune system (the body’s defense system against bacteria, viruses, and other foreign invaders). Scientists are also researching possible connections between zinc and the health problems discussed below.

Immune system and wound healing

The body’s immune system needs zinc to do its job. Older people and children in developing countries who have low levels of zinc might have a higher risk of getting pneumonia and other infections. Zinc also helps the skin stay healthy. Some people who have skin ulcers might benefit from zinc dietary supplements, but only if they have low levels of zinc.

Diarrhea

Children in developing countries often die from diarrhea. Studies show that zinc dietary supplements help reduce the symptoms and duration of diarrhea in these children, many of whom are zinc deficient or otherwise malnourished. The World Health Organization and UNICEF recommend that children with diarrhea take zinc for 10–14 days (20 mg/day, or 10 mg/day for infants under 6 months). It is not clear whether zinc dietary supplements can help treatdiarrhea in children who get enough zinc, such as most children in the United States.

The common cold

Some studies suggest that zinc lozenges or syrup (but not zinc dietary supplements in pill form) help speed recovery from the common cold and reduce its symptoms if taken within 24 hours of coming down with a cold. However, more study is needed to determine the best dose and form of zinc, as well as how long it should be taken before zinc can be recommended as a treatment for the common cold.

Age-related macular degeneration (AMD)

AMD is an eye disease that gradually causes vision loss. Research suggests that zinc might help keep early AMD from worsening into advanced AMD. In a large study, older people with AMD who took a daily dietary supplement with 80 mg zinc, 500 mg vitamin C, 400 IU vitamin E, 15 mg beta-carotene, and 2 mg copper for about 6 years had a lower chance of developing advanced AMD and less vision loss than those who did not take the dietary supplement. In the same study, people at high risk of the disease who took dietary supplements containing only zinc also had a lower risk of getting advanced AMD than those who did not take zinc dietary supplements. More research is needed before doctors can recommend zinc dietary supplements for patients with AMD. However, people who have or are developing the disease might want to talk with their doctor about taking dietary supplements.

Can zinc be harmful?

Yes, if you get too much. Signs of too much zinc include nausea, vomiting, loss of appetite, stomach cramps, diarrhea, and headaches. When people take too much zinc for a long time, they sometimes have problems such as low copper levels, lower immunity, and low levels of HDL cholesterol (the “good” cholesterol).

The safe upper limits for zinc are listed below. These levels do not apply to people who are taking zinc for medical reasons under the care of a doctor:

Life Stage Upper Safe Limit
Birth to 6 months 4 mg
Infants 7–12 months 5 mg
Children 1–3 years 7 mg
Children 4–8 years 12 mg
Children 9–13 years 23 mg
Teens 14–18 years 34 mg
Adults 40 mg

 Are there any interactions with zinc that I should know about?

Yes. Zinc dietary supplements can interact or interfere with medicines that you take and, in some cases, medicines can lower zinc levels in the body. Here are several examples:

  • Taking a zinc dietary supplement along with quinolone or tetracycline antibiotics (such as Cipro®,Achromycin®, and Sumycin®) reduces the amount of both zinc and the antibiotic that the body absorbs. Taking the antibiotic at least 2 hours before or 4–6 hours after taking a zinc dietary supplement helps minimize this effect.
  • Zinc dietary supplements can reduce the amount of penicillamine (a drug used to treat rheumatoid arthritis) that the body absorbs. They also make penicillamine work less well. Taking zinc dietary supplements at least 2 hours before or after taking penicillamine helps minimize this effect.
  • Thiazide diuretics, such as chlorthalidone (brand name Hygroton®) and hydrochlorothiazide (brand namesEsidrix® and HydroDIURIL®) increase the amount of zinc lost in the urine. Taking thiazide diuretics for a long time could decrease the amount of zinc in the body.

Resources

http://ods.od.nih.gov/factsheets/Zinc-QuickFacts/

oysters

Protein

What is protein?

Proteins are complex organic compounds. The basic structure of protein is a chain of amino acids. They provide energy for the body. Brain cells, muscle, skin, hair and nails are just some of the body parts that are protein-based. Estimates suggest that about half of the human body’s dry weight is made up of protein. Many of the foods we eat contain protein, particularly flesh foods (chicken, beef, lamb and fish), and legumes like beans and lentils. These proteins are digested to release amino acids. In the body, amino acids are used to make new proteins, converted into hormones such as adrenalin or are used as an energy source.

What are amino acids?

Proteins are made up of chains of smaller building blocks called amino acids, which are chemically linked to each other. There are about 20 different amino acids that, in different combinations, make up the countless millions of proteins available in nature. A protein can consist of between 50 and tens of thousands of amino acids. There are two broad classes of amino acids: those that can be made by the human body (non-essential amino acids) and those that can only be supplied by food (essential amino acids).

In the diet, protein sources are labeled according to how many of the essential amino acids they provide:

  • A complete protein source is one that provides all of the essential amino acids. You may also hear these sources called high quality proteins. Animal-based foods; for example, meat, poultry, fish, milk, eggs, and cheese are considered complete protein sources.
  • An incomplete protein source is one that is low in one or more of the essential amino acids. Complementary proteins are two or more incomplete protein sources that together provide adequate amounts of all the essential amino acids.
  • Every function in the living cell depends on proteins.
  • Motion and locomotion of cells and organisms depends on contractile proteins. [Examples: Muscles]
  • The catalysis of all biochemical reactions is done by enzymes, which contain protein.
  • The structure of cells, and the extracellular matrix in which they are embedded, is largely made of protein. [Examples: Collagens] (Plants and many microbes depend more on carbohydrates, e.g., cellulose, for support, but these are synthesized by enzymes.)
  • The transport of materials in body fluids depends of proteins. [Blood]
  • The receptors for hormones and other signaling molecules are proteins.

How much protein you need

The amount of protein you need in your diet depends on your weight, age and health. As a rough guide, the recommended dietary intake (RDI) for protein (measured in grams per kilogram of bodyweight) is:

  • 0.75 g/kg for adult women
  • 0.84 g/kg for adult men
  • Around 1 g/kg for pregnant and breastfeeding women, and for men and women over 70 years.

So, for example, a 75 kg adult male would need 63 g of protein per day. It is recommended that 15 to 25 per cent of total energy intake per day is from protein sources.
The needs of children and adolescents also vary according to their age and weight. A full list of recommendations for dietary protein is available from the Australian Nutrient Reference Values (NRVs) website.
Most Australians eat far more protein than they actually need, so deficiencies are rare.

Sources of protein

Some sources of dietary protein include:

Beans (including soy)

  •  Tofu, ½ cup 20 grams protein
  • Soy milk, 1 cup – 6 -10 grams
  • Most beans (black, pinto, lentils, etc) about 7-10 grams protein per half cup of cooked beans
  • Soy beans, ½ cup cooked – 14 grams protein
  • Split peas, ½ cup cooked – 8 grams

 Nuts & Seeds

  • Peanut butter, 2 Tablespoons – 8 grams protein
  • Almonds, ¼ cup – 8 grams
  • Peanuts, ¼ cup – 9 grams
  • Cashews, ¼ cup – 5 grams
  • Pecans, ¼ cup – 2.5 grams
  • Sunflower seeds, ¼ cup – 6 grams
  • Pumpkin seeds, ¼ cup – 8 grams
  • Flax seeds – ¼ cup – 8 grams

Fish

  • Most fish fillets or steaks are about 22 grams of protein for 3 ½ oz (100 grams) of cooked fish, or 6 grams per ounce
  • Tuna, 6 oz can – 40 grams of protein

Meat

  • Steak, 6 oz – 42 grams
  • Most cuts of beef – 7 grams of protein per ounce
  • Chicken breast, 3.5 oz – 30 grams protein
  • Chicken thigh – 10 grams (for average size)
  • Drumstick – 11 grams
  • Wing – 6 grams
  • Chicken meat, cooked, 4 oz – 35 grams
  • Pork chop, average – 22 grams protein
  • Ham, 3 oz serving – 19 grams
  • Bacon, 1 slice – 3 grams
  • Egg, large – 6 grams protein

Recommended serves per day from the lean meat, poultry, fish, eggs, legumes and beans, and nuts and seeds food category:

  • 3 serves for adult men
  • 2½ serves for adult women
  • 2½ to 3½ serves for breastfeeding and pregnant women

A standard serving size is one of the following:

  • 65 g cooked lean red meats
  • 80 g cooked poultry
  • 100 g cooked fish fillet
  • 2 large eggs
  • 1 cup cooked dried beans, lentils, chickpeas, split peas or canned beans
  • 170 g tofu
  • 30 g nuts or seeds.

Adult men are recommended to consume 2½ serves of (mostly low-fat) dairy or alternatives per day and 2½ to 4 serves per day for adult women. A serve could include either:

  • 250 ml (1 cup) milk
  • 200 g (3/4 cup or 1 small carton) yogurt
  • 40 g (2 slices) hard cheese

Do athletes require more protein?

In the last 20 years, detailed research has enabled scientists to measure protein metabolism during exercise and recovery, and to monitor protein balance in athletes. Endurance athletes in heavy training require extra protein to cover a small proportion of the energy costs of their training and to assist in the repair and recovery process after exercise. Strength athletes, who are interested in gaining muscle size and function, require more protein in the early stages of very intensive resistance exercise. However, strength athlete’s muscles seem to adapt to the stress of resistance exercise, so that the protein requirements to maintain protein balance in very well-trained athletes are only marginally greater than those of generally active people. Athletes, who are growing, such as adolescents, have additional protein requirements. The table below summarizes protein requirements for different types of athletes or exercise activities. Since athletes come in various shapes and sizes, it is easier to keep track of these requirements by relating them to the size (body mass or BM) of the athlete.

Table : Estimated protein requirements for athletes

Group Protein intake (g/kg/day)
Sedentary men and women 0.8-1.0
Elite male endurance athletes 1.6
Moderate-intensity endurance athletes (a) 1.2
Recreational endurance athletes (b) 0.8-1.0
Football, power sports 1.4-1.7
Resistance athletes (early training) 1.5-1.7
Resistance athletes (steady state) 1.0-1.2
Female athletes ~15% lower than male athletes

(a) Exercising approximately four to five times per week for 45-60 min (b) Exercising four to five times per week for 30 min at <55% VO2peak

Source: Burke and Deakin, Clinical Sports Nutrition, 3rd Edition, McGraw-Hill Australia Pty Ltd, 2006

Nutritional value of protein

A protein’s nutritional value is measured by the quantity of essential amino acids it provides. Different foods contain different numbers and amounts of amino acids. Generally speaking:

  • Animal products (such as chicken, beef or fish) contain all of the essential amino acids.
  • Soy products and the seed of a leafy green called Amaranth (consumed in Asia and the Mediterranean) also contain all of the essential amino acids. However, plant proteins usually lack at least one amino acid.

People following a strict vegetarian or vegan diet need to choose a variety of protein sources from a combination of plant foods throughout the day to get an adequate mix of amino acids. For example, a meal containing cereals and legumes, such as baked beans on toast, provides all the essential amino acids found in a typical meat dish.

Digestion of proteins

A protein-rich food, such as meat, is broken down into individual proteins by the gastric juices in your stomach. Pancreatic enzymes released into the first portion of your small intestine (duodenum) split the proteins into their separate amino acids. The amino acids are absorbed by the small finger-like projections (villi) lining the intestine walls, and are taken to the liver via the bloodstream.

How amino acids are used

The human body uses amino acids in three main ways:

  • Protein synthesis – new proteins are created constantly. For example, as old, dead cells are sloughed off the skin surface, new ones are pushed up to replace them.
  • Precursors of other compounds – a range of substances are created using amino acids, (for example, the brain chemical (neurotransmitter) serotonin and the ‘fight or flight’ chemical adrenalin).
  • Energy – although carbohydrates are the body’s preferred fuel source, about 10 per cent of energy is obtained from protein.

Ammonia – a toxic byproduct of protein

One of the byproducts of protein metabolism is ammonia. In high levels, ammonia is extremely dangerous to the body and so is converted into urea. This water-soluble chemical is collected by the kidneys and eliminated from the body in our urine. The more protein we eat each day, in excess of our needs, the more work our kidneys must do to expel ammonia.

Amount of protein needed each day

Some people, such as growing children, pregnant women and breastfeeding mothers, need slightly more protein than the recommended daily intake (RDI). However, most Australians consume more than enough dietary protein, so deficiencies are rare.
From 50 years onwards, ageing is associated with loss of skeletal muscle, a condition known as sarcopenia, which, in the elderly is worsened by chronic illness, poor diet and inactivity. It is likely that protein intake at the upper end of the RDI range can maintain muscle mass and strength, which is vital for walking ability.
It is also important for the elderly to eat protein ‘effectively’, which means to consume high-quality protein foods, such as lean meats.

Strenuous exercise doesn’t mean you need extra protein

Contrary to popular belief, people who exercise vigorously or are trying to put on muscle mass do not need to consume extra protein. Studies show that weight-trainers who do not eat extra protein (either in food or protein powders) still gain muscle at the same rate as weight-trainers who supplement their diets with protein. A very high-protein diet can strain the kidneys and liver, and prompt excessive loss of the mineral calcium.

Timing of protein consumption

Soon after exercising (either resistance or aerobic), it is recommended consuming a high-quality protein source (such as a glass of milk or tub of yogurt) combined with a carbohydrate meal to help positive protein balance. Studies have shown this to be beneficial for maintaining protein balance even when following low to moderate aerobic exercise (such as walking), particularly for older adults.

Symptoms of protein deficiency

The human body cannot store protein, so it must be supplied on a daily basis from the foods we eat. Strict vegetarians who do not consume any animal products at all are at increased risk of protein deficiency if they do not eat a wide range of plant proteins.
Symptoms of protein deficiency include:

  • Wasting and shrinkage of muscle tissue
  • Oedema (build-up of fluids, particularly in the feet and ankles)
  • Anaemia (the blood’s inability to deliver sufficient oxygen to the cells, usually caused by dietary deficiencies such as lack of iron)
  • Slow growth (in children).

Very high protein diets are dangerous

Some weight trainers and bodybuilders believe that high protein diets lead to increased muscle mass. High protein diets promote intakes of protein of between 200 and 400 g per day, which equates to approximately 5 g/kg each day (more than five times the RDI). This belief is false. It is the stimulation of muscle tissue through exercise, not extra dietary protein, that leads to muscle growth.
The RDI for protein provides adequate protein to build and repair muscles even for body builders and athletes. Fad diets that favour very high protein and fat intake, combined with very low carbohydrate intake, may be harmful.
Some of the problems with very high protein diets (more than 35 per cent of total daily intake) include that:

  • They usually promote a very low intake of carbohydrates. Glucose, made when your body breaks down dietary carbohydrate, is your body’s preferred fuel source. If your body does not receive enough dietary carbohydrate, it will break down muscle tissue to make glucose. This causes muscle wastage, reduced metabolism and a build-up of ketones.
  • Fiber is largely a carbohydrate. Foods rich in carbohydrates (such as whole grains and legumes) are also rich in fiber. Avoiding these foods leads to an overall low-fiber intake, which can result in constipation, bowel disorders and increased risk of colon cancer.
  • There is evidence to suggest that the heart may not function as well if its main source of fuel is ketones.
  • High intake of animal products (which is usually recommended in such diets) can also be high in saturated fats and cholesterol, which is associated with a range of conditions including heart disease.
  • The liver and kidneys are put under strain because they have to detoxify and eliminate unusually high quantities of protein byproducts. Kidney problems may be exacerbated in people with diabetes.
  • There is an increased risk of developing gout and gall bladder colic.
  • Greater losses of body calcium may increase the risk of osteoporosis.
  • High protein diets can cause mild dehydration due to increased water loss through urine. Increased risk of dehydration puts the body under pressure.
  • Recent research shows that weight loss over one year is not greater on a high protein diet when compared to safer, low fat eating patterns.

Things to remember

  • Proteins are made up of chains of smaller chemicals called amino acids.
  • The human body cannot store amino acids, so it must be supplied daily from the foods we eat.
  • Very high protein diets combined with very low carbohydrate intakes are not recommended.

Resources

http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/protein?open

http://und.edu/student-life/dining/_files/docs/fact-sheets/protein.pdf

http://www.ausport.gov.au/ais/nutrition/factsheets/basics/protein_-_how_much

tofu

Carbohydrates

What are carbohydrates?

The term carbohydrate is synonymous with sports nutrition. The immediate impact of carbohydrate intake (or its absence) on daily training and competition performance has been widely researched and documented. Recent media attention directed at public health issues, however, has suggested low carbohydrate diets are beneficial for weight loss and other health benefits. In addition, different approaches to fuelling sports performance become an item of discussion among scientists or the locker room from time to time.

Carbohydrate is a key fuel source for exercise, especially during prolonged continuous or high-intensity exercise. The body stores carbohydrate as glycogen in the muscles and liver, however its storage capacity is limited. When these carbohydrate stores are inadequate to meet the fuel needs of an athlete’s training program, the results include fatigue (staleness), reduced ability to train hard, impaired competition performance, and a reduction in immune system function. For these reasons, active people are encouraged to plan carbohydrate intake around key training sessions and over the whole day according to their carbohydrate requirements as an exercise fuel.

Carbohydrates (or carbs) include:

  •  The sugars and starches which provide with an important source of energy (Calories) in our diets.
  • Dietary fibre.

All types of carbohydrate consist of individual sugar units. What makes them different is the number of sugar units they contain and how these are linked together.

  • A carbohydrate with one unit of sugar is called a simple sugar (monosaccharide). Examples include both fructose (fruit sugar) and glucose (the main form in which carbohydrate circulates in our body as blood sugar).
  • A carbohydrate with two units of sugar is called a disaccharide. Sucrose (table sugar) and lactose (milk sugar) are examples.
  • Complex carbohydrates, also known as polysaccharides have more than two units of sugar linked together. Starch, a complex carbohydrate found in cereal grains and some fruits and vegetables, is made of many units of glucose.
  • Some carbohydrates such as cellulose found in plant cell walls are known as non-starch polysaccharides (NSP). We cannot digest them but they are a major component of dietary fibre.

How  do  we  get  carbohydrates from the diet?

The main sources of carbohydrates in our diet are;

  • Foods made from cereal grains (e.g. bread, flour, rice, pasta, and breakfast cereal). These foods give us mainly complex or starchy carbohydrate.
  • Fruit and vegetables especially potatoes, root vegetables (e.g. carrots) and pulses (beans and lentils) contain a mix of starches and sugars.
  • Lactose which is found in milk.
  • Table sugar, honey, soft drinks and confectionery provide mainly simple carbohydrates.

We break down most carbohydrates in the gut and absorb them into our blood stream as   individual   sugar   units. We generally digest simple carbohydrates quickly giving a rapid rise in blood sugar levels. In contrast, complex carbohydrates (such as starch) need time to be broken down into their individual sugar units before they can be absorbed. The result is a much slower rise in our blood sugar levels. Once in the blood, the sugar is carried into cells such as the muscles and brain with the help of insulin, a hormone secreted by the pancreas. Here it provides a source of vital fuel, for example to help our muscles work and our brain cells to work properly. We convert any glucose the cells do not need immediately to glycogen (animal starch) and tuck it away as stored energy in the liver and muscles for use at a later date. Once these stores are full we convert any excess into body fat.

What happens if we don’t get enough carbohydrate?

Eating too little carbohydrate may lead to low blood sugar levels (hypoglycaemia) which can leave us feeling weak and light headed. It can also make it difficult to concentrate as the ability to think and learn comes from an adequate supply of fuel to the brain. Hypoglycaemia is a particular risk for some people with diabetes who are on tablets or insulin. It can also affect very active sports people, who may feel exhausted when their blood sugar and muscle glycogen stores run low.

If we eat too little carbohydrate, over time our body will begin to use up some stored fat but quickly moves on to burning its own protein tissue such as in the heart and muscles. A low intake of wholegrain cereals, fruit and vegetables rich in indigestible carbohydrate or NSP can also lead to bowel problems such as constipation.

Research shows that in the long term high carbohydrate diets are the most beneficial for health. Dietary guidelines advise that we should be getting about half of our energy intake from carbohydrate. We should eat more starchy foods (e.g. bread, rice, pasta, breakfast cereals, oats and chapattis) preferably in wholegrain forms.

How much carbohydrate should we eat?

Starchy foods are good source of energy and fibre but they also contain calcium, iron and B vitamins. About a third of the food we eat should be carbs. In practice this means making ‘starchy’ carbohydrate foods the base and bulk for each meal and snack. Sugary foods such as table sugar, soft drinks and sweets, generally contain few other nutrients and are recommended only on a more occasional basis.

Carbohydrate requirements are dependent on the fuel needs of the individuyal’s activity level. For athlete’s, getting the right amount of carbohydrates for their training and competition program, with parameters including the frequency, duration and intensity of the activity is vital. Since activity levels change from day to day, carbohydrate intake should fluctuate to reflect this. On high activity days, carbohydrate intake should be increased to match the increase in activity. This will help to maximise the outcomes from the training sessions and promote recovery between sessions.

 Aren’t carbohydrates fattening?

If we take in more food energy than we burn up, no matter what the source, the excess will be converted to fat. Since sugary foods taste good and can be high in calories (chocolate, cakes, ice cream, biscuits, puddings), it can be easy to consume too many calories from sweet foods and drinks.

Sometimes people mistakenly think starchy foods such as bread and potatoes are fattening. However weight for weight carbohydrates contain less than half the calories of fat and studies show they are much better at satisfying our hunger. Watch out for the added fats used for cooking and serving, because it is these that increase the calorie content (e.g. fried potatoes).

Can low-carbohydrate diets help with weight loss?

‘Low-carbohydrate’ diets which cut out most starchy foods are sometimes used for weight loss. In the short term they can lead to side effects such as constipation, headache, bad breath and nausea. In the longer term cutting out any food group can be bad for health because you risk missing out on vital nutrients. Low-carbohydrate diets tend to be higher in fat, and eating a high fat diet (especially one rich in saturated fat from foods such as meat, cheese, cream and butter) could increase the chances of developing heart disease. Low- carbohydrate diets may also restrict the amount of fruit, vegetables and fibre, all of  which  are  vital  for  good  health including reducing cancer risk.

It’s fair to say the jury is still out on how safe or effective low-carbohydrate diets really  are.  However  there  does  not seem  to  be  any  advantage  in  following  a  low- carbohydrate diet in terms of sustained weight loss.

Which foods are good sources of carbohydrate?

Many everyday foods and fluids contain carbohydrate, but have different features. For this reason, carbohydrate-containing foods and fluids are often divided into categories for comparison. Previously, carbohydrates were classified as either simple or complex, and more recently, the terms low and high glycemic index (GI) are being used (more on GI below). From a sports nutrition point of view, it is more helpful to classify carbohydrates as nutrient-dense, energy-dense or high-fat.

Category Description Examples Use for athletes
Nutrient-dense carbohydrate Foods and fluids that are rich sources of other nutrients including protein, vitamins, minerals, fibre and antioxidants in addition to carbohydrate Breads and cereals, grains (e.g. pasta, rice), fruit, starchy vegetables e.g. potato, corn), legumes and low-fat dairy products Everyday food that should form the base of an athlete’s diet. Helps to meet other nutrient targets.
Nutrient poor carbohydrate Foods and fluids that contain carbohydrate but minimal or no other nutrients Soft drink, energy drinks, lollies, carbohydrate gels, sports drink and cordial. Shouldn’t be a major part of the everyday diet but may provide a compact carbohydrate source around training.
High-fat carbohydrate Foods that contain carbohydrate but are high in fat Pastries, cakes, chips (hot and crisps) and chocolate ‘Sometimes’ foods best not consumed around training sessions

What does the Glycemic Index of carbohydrates mean?

Different  carbohydrate-containing  foods  are  digested and absorbed at different rates. The Glycaemic Index (GI) is the classification used to identify which carbohydrates are quickly broken down to glucose (high GI) and which are slowly broken down (low GI).

Examples of medium and low GI carbohydrate foods include:

  •  Wholegrain and seeded bread
  • Pasta, basmati rice
  • Oats and muesli
  • Beans and pulses
  • Most fruit and vegetables including sweet potatoes and new boiled potatoes in their skins
  • Milk and yogurt (try to avoid too much dairy)

Resources

http://www.devon.gov.uk/carbohydratefactsheet.pdf

http://www.ausport.gov.au/ais/nutrition/factsheets/basics/carbohydrate__how_much

brown rice

Omega 3 & Omega 6

What is Omega-3 and Omega-6 fatty acids & their known functions?

There are two major classes of polyunsaturated fatty acids (PUFAs): the omega-3 and the omega-6 fatty acids. They are distinguished by their chemical structure. Only the fatty acids alpha-linolenic acid (ALA) and linoleic acid (LA) must come from the diet because they cannot be made by the body. ALA, an omega-3 fatty acid, is converted in the body to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA also occur naturally in some foods. LA, an omega-6 fatty acid, is converted in the body to arachidonic acid (AA). Both EPA and DHA are metabolized through the same biochemical pathways as AA. Studies show that omega-3 fatty acids in general decrease triglyceride and very-low-density lipoprotein blood levels in hyperlipidemic individuals but may increase or have no effect on low-density lipoprotein (LDL) levels.

Both AA and EPA are further metabolized to produce hormone-like agents called eicosanoids, which include prostaglandins, thromboxanes, and leukotrienes. Eicosanoids regulate fundamental physiological processes such as cell division and growth, blood clotting, muscle activity, secretion of digestive juices and hormones, and movement of substances like calcium into and out of cells. However, AA and EPA lead to the production of different subgroups of eicosanoids with sometimes opposing effects. Eicosanoids formed from AA (particularly the series-2 prostaglandins and series-4 leukotrienes) are released in the body in response to injury, infection, stress, or certain diseases. They increase platelet aggregation and enhance vasoconstriction and the synthesis of substances involved with the inflammatory process. Eicosanoids derived from EPA (particularly the series-3 prostaglandins), in contrast, decrease excessive series-2 prostaglandin production. As a result, adequate production of EPA-derived series-3 prostaglandins may help protect individuals against heart attacks and strokes as well as certain inflammatory diseases such as arthritis, systemic lupus erythematosus, and asthma.

The omega-3 fatty acid DHA, while not involved in eicosanoid formation, is the major polyunsaturated fatty acid found in the brain and is important for brain development and function. Synapses are rich in DHA, which suggests that this fatty acid is involved in signal transmission along neurons. DHA is also required to produce one member of a family of compounds called resolvins that participate in the body’s response to inflammation in the brain. The DHA-derived resolvin in particular helps to reduce inflammation brought about by ischemic insults (reductions in blood flow). (EPA also helps to temper inflammatory responses by decreasing production of proinflammatory compounds such as cytokines.)

Most Western diets provide at least 10 times more omega-6 than omega-3 fatty acids. There is now general scientific agreement that individuals should consume more omega-3 and fewer omega-6 fatty acids for good health. It is not known, however, whether a desirable ratio of omega-6 to omega-3 fatty acids exists for the diet or to what extent high intakes of omega-6 fatty acids interfere with any benefits of omega-3 fatty acid consumption.

What foods contains Omega 3 (ALA – alpha-linolenic acid)?

  • Leafy green vegetables
  • Nuts
  • Vegetable oils such as canola and soy, and especially in flaxseed and flaxseed oil.
  • Good sources of EPA and DHA are fish (both finfish and shellfish and their oils and eggs) and organ meats.

What foods contains Omega 6 (LA – linolenic acid)?

  • Meat
  • Vegetable oils (e.g., safflower, sunflower, corn, soy)
  • Processed foods made with these oils.

The Institute of Medicine has established Adequate Intakes for ALA and LA (1.1-1.6 g/day and 11-17 g/day, respectively, for adults) but not for EPA and DHA.

Products available

Omega-3 fatty acids are found in a variety of dietary supplements. For example, products containing flaxseed oil provide ALA, fish-oil supplements provide EPA and DHA, and algal oils provide a vegetarian source of DHA.

Omega-3 fatty acids for cardiovascular health and disease

Epidemiological studies first published in the late 1970s noted relatively low cardiovascular mortality in populations such as Eskimos with high fish consumption. The apparent health benefits of fish are explained, at least in part, by the EPA and DHA they contain.

The three reports by the Tufts EPC focused on different areas of research concerning this relationship between omega-3 fatty acids and cardiovascular health and disease and involved systematic reviews of the available scientific-medical literature.

Cardiovascular risk factors and intermediate markers of CVD

Overall, strong evidence showed that fish-oil supplements had a substantial and beneficial effect on triglycerides that was greater with larger intakes of fish oil; most studies reported a net decrease of about 10-33%. There is also evidence of a very small beneficial effect of fish oils on blood pressure and possible beneficial effects on coronary artery restenosis after angioplasty, exercise capacity in patients with coronary atherosclerosis, and heart rate variability (particularly in patients with recent myocardial infarctions).

Cardiovascular disease

Overall, evidence from both the primary and secondary prevention studies supports the hypothesis that consumption of omega-3 fatty acids, fish, and fish oil reduces all-cause mortality and various CVD outcomes such as sudden death, cardiac death, and myocardial infarction. The evidence is strongest for fish or fish oil whereas the potential effects of ALA are largely unknown and the relative effects of ALA versus fish oil are not well defined. In the only RCT that directly compared ALA and fish oil, both treatments reduced CVD outcome.

The lessons to be drawn from all these studies to date regarding use of omega-3 fatty acids for preventing and treating CVD are not completely clear. Because the studies involved a variety of methods of estimating fish or omega-3 fatty acid intake, background diets, background risk for heart disease, settings, and methods for reporting results, the validity of applying the results of studies conducted outside the United States to the U.S. population is uncertain. Furthermore, dietary intervention trials are limited by the multiple and complex dietary changes in the trials that make it difficult to distinguish among components and determine which specific components or combinations of these diets are most beneficial. For example, the different types of fish consumed and the method of food preparation may cause different effects.

Omega-3 fatty acids for asthma

Basic research suggests that omega-3 fatty acids may affect asthma because they influence substances that are part of the inflammatory process involved with asthma, such as the series-2 prostaglandin PGE2.

Whether omega-3 fatty acids are effective in the primary prevention of asthma is unknown. Four observational studies in children support a positive association for dietary patterns that include all fish or oily fish, but a prospective study of adult nurses found no association between asthma onset and dietary fish intake.

Omega-3 fatty acids for other diseases

The RAND EPC conducted a comprehensive search of published and unpublished scientific-medical literature on the health effects of omega-3 fatty acids in type II diabetes and metabolic syndrome, inflammatory bowel disease, rheumatoid arthritis, renal disease, systemic lupus erythematosus, and bone density/osteoporosis.

Type II diabetes and metabolic syndrome

Eighteen of the 34 RCTs whose subjects had type II diabetes or metabolic syndrome provided sufficient statistics to be included in a meta-analysis. The analysis found that omega-3 fatty acids had a favorable effect on triglyceride levels when compared with placebo but had no effect on total, LDL, or HDL cholesterol; fasting blood sugar; or glycosylated hemoglobin. A qualitative analysis of 4 studies concluded that omega-3 fatty acids had no effect on plasma insulin or insulin resistance in subjects with either disorder.

Inflammatory bowel disease (Crohn’s disease and ulcerative colitis)
In the 13 studies that reported outcomes in patients with inflammatory bowel disease, omega-3 fatty acids had variable effects on assessment scores (clinical, sigmoidoscopic, and histologic), induced remission, and relapse rates.

Rheumatoid arthritis

A meta-analysis of nine studies of patients with rheumatoid arthritis concluded that omega-3 fatty acids had no effect on patients’ reports of pain and disease severity, swollen joint count, or erythrocyte sedimentation rate (a measure of disease activity). However, an earlier meta-analysis found that the omega-3 fatty acids produced a statistically significant improvement in tender joint count as compared with placebo. A qualitative analysis of seven studies that assessed the effect of omega-3 fatty acids on anti-inflammatory drug or corticosteroid requirements found that six demonstrated reduced requirements. Overall, omega-3 fatty acids appear to reduce tender joint counts in individuals with rheumatoid arthritis and may reduce requirements for corticosteroids.

Omega-3 fatty acids and cognitive function, dementia, and neurological diseases

Omega-3 fatty acids appear to be important in brain development and function. Their effects on cognitive function in normal aging, incidence and treatment of dementia, incidence of several neurological diseases, and progression of multiple sclerosis were evaluated. A comprehensive search of the published and unpublished scientific-medical literature identified 12 studies that met inclusion criteria.

Multiple sclerosis and other neurological diseases

The quantity and strength of evidence for the effects of omega-3 fatty acids on cognitive function and decline, dementia, and neurological diseases vary greatly. Given the overall small number of studies and generally poor quality of clinical trials, substantive conclusions about the value of these compounds for these conditions cannot be drawn.

Omega-3 fatty acids for organ transplantation

Several laboratory, animal, and human studies suggest that omega-3 fatty acids from fish oil may improve outcomes in organ transplantation (e.g., decrease rejection; reduce hyperlipidemia, hypertension, and blood viscosity; and decrease the toxicity of the immunosuppressive agent cyclosporin A).

Resources

http://ods.od.nih.gov/factsheets/Omega3FattyAcidsandHealth-HealthProfessional/

Mixed Nuts

Chromium

What is Chromium?

Chromium is a mineral that humans require in trace amounts, although its mechanisms of action in the body and the amounts needed for optimal health are not well defined. It is found primarily in two forms: 1) trivalent (chromium 3+), which is biologically active and found in food, and 2) hexavalent (chromium 6+), a toxic form that results from industrial pollution. This fact sheet focuses exclusively on trivalent (3+) chromium.

Chromium is known to enhance the action of insulin, a hormone critical to the metabolism and storage of carbohydrate, fat, and protein in the body. In 1957, a compound in brewers’ yeast was found to prevent an age-related decline in the ability of rats to maintain normal levels of sugar (glucose) in their blood. Chromium was identified as the active ingredient in this so-called “glucose tolerance factor” in 1959.

Chromium also appears to be directly involved in carbohydrate, fat, and protein metabolism, but more research is needed to determine the full range of its roles in the body. The challenges to meeting this goal include:

  • Defining the types of individuals who respond to chromium supplementation;
  • Evaluating the chromium content of foods and its bioavailability;
  • Determining if a clinically relevant chromium-deficiency state exists in humans due to inadequate dietary intakes; and
  • Developing valid and reliable measures of chromium status.

What foods provide chromium?

Chromium is widely distributed in the food supply, but most foods provide only small amounts (less than 2 micrograms [mcg] per serving). Meat and whole-grain products, as well as some fruits, vegetables, and spices are relatively good sources. In contrast, foods high in simple sugars (like sucrose and fructose) are low in chromium.

Dietary intakes of chromium cannot be reliably determined because the content of the mineral in foods is substantially affected by agricultural and manufacturing processes and perhaps by contamination with chromium when the foods are analyzed. Therefore, Table 1, and food-composition databases generally, provide approximate values of chromium in foods that should only serve as a guide.

Table 1: Selected food sources of chromium
Food Chromium (mcg)
Broccoli, ½ cup 11
Grape juice, 1 cup 8
English muffin, whole wheat, 1 4
Potatoes, mashed, 1 cup 3
Garlic, dried, 1 teaspoon 3
Basil, dried, 1 tablespoon 2
Beef cubes, 3 ounces 2
Orange juice, 1 cup 2
Turkey breast, 3 ounces 2
Whole wheat bread, 2 slices 2
Red wine, 5 ounces 1–13
Apple, unpeeled, 1 medium 1
Banana, 1 medium 1
Green beans, ½ cup 1

What are recommended intakes of chromium?

Recommended chromium intakes are provided in the Dietary Reference Intakes (DRIs) developed by the Institute of Medicine of the National Academy of Sciences. Dietary Reference Intakes is the general term for a set of reference values to plan and assess the nutrient intakes of healthy people. These values include the Recommended Dietary Allowance (RDA) and the Adequate Intake (AI). The RDA is the average daily intake that meets a nutrient requirement of nearly all (97 to 98%) healthy individuals. An AI is established when there is insufficient research to establish an RDA; it is generally set at a level that healthy people typically consume.

In 1989, the National Academy of Sciences established an “estimated safe and adequate daily dietary intake” range for chromium. For adults and adolescents that range was 50 to 200 mcg. In 2001, DRIs for chromium were established. The research base was insufficient to establish RDAs, so AIs were developed based on average intakes of chromium from food as found in several studies. Chromium AIs are provided in Table 2.

Table 2: Adequate Intakes (AIs) for chromium
Age Infants and children
(mcg/day)
Males
(mcg/day)
Females
(mcg/day)
Pregnancy
(mcg/day)
Lactation
(mcg/day)
0 to 6 months 0.2
7 to 12 months 5.5
1 to 3 years 11
4 to 8 years 15
9 to 13 years 25 21
14 to 18 years 35 24 29 44
19 to 50 years 35 25 30 45
>50 years 30 20

mcg = micrograms

Adult women in the United States consume about 23 to 29 mcg of chromium per day from food, which meets their AIs unless they’re pregnant or lactating. In contrast, adult men average 39 to 54 mcg per day, which exceeds their AIs.

The average amount of chromium in the breast milk of healthy, well-nourished mothers is 0.24 mcg per quart, so infants exclusively fed breast milk obtain about 0.2 mcg (based on an estimated consumption of 0.82 quarts per day). Infant formula provides about 0.5 mcg of chromium per quart. No studies have compared how well infants absorb and utilize chromium from human milk and formula.

What affects chromium levels in the body?

Absorption of chromium from the intestinal tract is low, ranging from less than 0.4% to 2.5% of the amount consumed, and the remainder is excreted in the feces. Enhancing the mineral’s absorption are vitamin C (found in fruits and vegetables and their juices) and the B vitamin niacin (found in meats, poultry, fish, and grain products). Absorbed chromium is stored in the liver, spleen, soft tissue, and bone.

The body’s chromium content may be reduced under several conditions. Diets high in simple sugars (comprising more than 35% of calories) can increase chromium excretion in the urine. Infection, acute exercise, pregnancy and lactation, and stressful states (such as physical trauma) increase chromium losses and can lead to deficiency, especially if chromium intakes are already low.

When can a chromium deficiency occur?

Chromium has been found to correct glucose intolerance and insulin resistance in deficient animals, two indicators that the body is failing to properly control blood-sugar levels and which are precursors of type 2 diabetes. However, reports of actual chromium deficiency in humans are rare. Three hospitalized patients who were fed intravenously showed signs of diabetes (including weight loss, neuropathy, and impaired glucose tolerance) until chromium was added to their feeding solution. The chromium, added at doses of 150 to 250 mcg/day for up to two weeks, corrected their diabetes symptoms. Chromium is now routinely added to intravenous solutions.

Who may need extra chromium?

There are reports of significant age-related decreases in the chromium concentrations of hair, sweat and blood, which might suggest that older people are more vulnerable to chromium depletion than younger adults. One cannot be sure, however, as chromium status is difficult to determine. That’s because blood, urine, and hair levels do not necessarily reflect body stores. Furthermore, no chromium-specific enzyme or other biochemical marker has been found to reliably assess a person’s chromium status.

There is considerable interest in the possibility that supplemental chromium may help to treat impaired glucose tolerance and type 2 diabetes, but the research to date is inconclusive. No large, randomized, controlled clinical trials testing this hypothesis have been reported in the United States. Nevertheless, this is an active area of research.

What are some current issues and controversies about chromium?

Chromium has long been of interest for its possible connection to various health conditions. Among the most active areas of chromium research are its use in supplement form to treat diabetes, lower blood lipid levels, promote weight loss, and improve body composition.

Type 2 diabetes and glucose intolerance

In type 2 diabetes, the pancreas is usually producing enough insulin but, for unknown reasons, the body cannot use the insulin effectively. The disease typically occurs, in part, because the cells comprising muscle and other tissues become resistant to insulin’s action, especially among the obese. Insulin permits the entry of glucose into most cells, where this sugar is used for energy, stored in the liver and muscles (as glycogen), and converted to fat when present in excess. Insulin resistance leads to higher than normal levels of glucose in the blood (hyperglycemia).

Chromium deficiency impairs the body’s ability to use glucose to meet its energy needs and raises insulin requirements. It has therefore been suggested that chromium supplements might help to control type 2 diabetes or the glucose and insulin responses in persons at high risk of developing the disease. A review of randomized controlled clinical trials evaluated this hypothesis. This meta-analysis assessed the effects of chromium supplements on three markers of diabetes in the blood: glucose, insulin, and glycated hemoglobin (which provides a measure of long-term glucose levels; also known as hemoglobin A1C). It summarized data from 15 trials on 618 participants, of which 425 were in good health or had impaired glucose tolerance and 193 had type 2 diabetes. Chromium supplementation had no effect on glucose or insulin concentrations in the non-diabetic subjects nor did it reduce these levels in subjects with diabetes, except in one study. However, that study, conducted in China (in which 155 diabetics were given either 200 or 1,000 mcg/day of chromium or a placebo) might simply show the benefits of supplementation in a chromium-deficient population.

Overall, the value of chromium supplements for diabetics is inconclusive and controversia. Randomized controlled clinical trials in well-defined, at-risk populations where dietary intakes are known are necessary to determine the effects of chromium on markers of diabetes.

Lipid metabolism

The effects of chromium supplementation on blood lipid levels in humans are also inconclusive [1,8,37]. In some studies, 150 to 1,000 mcg/day has decreased total and low-density-lipoprotein (LDL or “bad”) cholesterol and triglyceride levels and increased concentrations of apolipoprotein A (a component of high-density-lipoprotein cholesterol known as HDL or “good” cholesterol) in subjects with atherosclerosis or elevated cholesterol or among those taking a beta-blocker drug. These findings are consistent with the results of earlier studies.

However, chromium supplements have shown no favorable effects on blood lipids in other studies. The mixed research findings may be due to difficulties in determining the chromium status of subjects at the start of the trials and the researchers’ failure to control for dietary factors that influence blood lipid levels.

Body weight and composition
Chromium supplements are sometimes claimed to reduce body fat and increase lean (muscle) mass. Yet a recent review of 24 studies that examined the effects of 200 to 1,000 mcg/day of chromium (in the form of chromium picolinate) on body mass or composition found no significant benefits. Another recent review of randomized, controlled clinical trials did find supplements of chromium picolinate to help with weight loss when compared to placebos, but the differences were small and of debatable clinical relevance. In several studies, chromium’s effects on body weight and composition may be called into question because the researchers failed to adequately control for the participants’ food intakes. Furthermore, most studies included only a small number of subjects and were of short duration.

What are the health risks of too much chromium?

Few serious adverse effects have been linked to high intakes of chromium, so the Institute of Medicine has not established a Tolerable Upper Intake Level (UL) for this mineral. A UL is the maximum daily intake of a nutrient that is unlikely to cause adverse health effects. It is one of the values (together with the RDA and AI) that comprise the Dietary Reference Intakes (DRIs) for each nutrient.

Chromium and medication interactions

Certain medications may interact with chromium, especially when taken on a regular basis (see Table 3). Before taking dietary supplements, check with your doctor or other qualified healthcare provider, especially if you take prescription or over-the-counter medications.

Table 3: Interactions between chromium and medications [14,52-54]
Medications Nature of interaction
  • Antacids
  • Corticosteroids
  • H2 blockers (such as cimetidine, famotidine, nizatidine, and rantidine)
  • Proton-pump inhibitors (such as omeprazole, lansoprazole, rabeprazole, pantoprazole, and esomeprazole)
These medications alter stomach acidity and may impair chromium absorption or enhance excretion
  • Beta-blockers (such as atenolol or propanolol)
  • Corticosteroids
  • Insulin
  • Nicotinic acid
  • Nonsteroidal anti-inflammatory drugs (NSAIDS)
  • Prostaglandin inhibitors (such as ibuprofen, indomethacin, naproxen, piroxicam, and aspirin)
These medications may have their effects enhanced if taken together with chromium or they may increase chromium absorption

Supplemental sources of chromium

Chromium is a widely used supplement. Chromium is sold as a single-ingredient supplement as well as in combination formulas, particularly those marketed for weight loss and performance enhancement.

The safety and efficacy of chromium supplements need more investigation. Please consult with a doctor or other trained healthcare professional before taking any dietary supplements.

Chromium supplements are available as chromium chloride, chromium nicotinate, chromium picolinate, high-chromium yeast, and chromium citrate. Chromium chloride in particular appears to have poor bioavailability. However, given the limited data on chromium absorption in humans, it is not clear which forms are best to take.

The Dietary Guidelines for Americans describes a healthy diet as one that:

  • Emphasizes a variety of fruits, vegetables,  whole grains and dairy (try and avoid too much dairy)
  • Whole grain products and certain fruits and vegetables like broccoli, potatoes, grape juice, and oranges are sources of chromium.
  • Includes lean meats, poultry, fish, beans, eggs, and nuts.
    Lean beef, oysters, eggs, and turkey are sources of chromium.
  • Is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars.
  • Stays within your daily calorie needs.

Resources

http://ods.od.nih.gov/factsheets/Chromium-HealthProfessional/

Iodine

What is iodine and what does it do?

Iodine is a mineral found in some foods. The body needs iodine to make thyroid hormones. These hormones control the body’s metabolism and many other important functions. The body also needs thyroid hormones for proper bone and brain development during pregnancy and infancy. Getting enough iodine is important for everyone, especially infants and women who are pregnant.

How much iodine do I need?

The amount of iodine you need each day depends on your age. Average daily recommended amounts are listed below in micrograms (mcg).

Life Stage Recommended Amount
Birth to 6 months 110 mcg
Infants 7–12 months 130 mcg
Children 1–8 years 90 mcg
Children 9–13 years 120 mcg
Teens 14–18 years 150 mcg
Adults 150 mcg
Pregnant teens and women 220 mcg
Breastfeeding teens and women 290 mcg

 What foods provide iodine?

Iodine is found naturally in some foods and is also added to salt that is labeled as “iodized”. You can get recommended amounts of iodine by eating a variety of foods, including the following:

  • Fish (such as cod and tuna), seaweed, shrimp, and other seafood, which are generally rich in iodine.
  • Dairy products (such as milk, yogurt, and cheese) and products made from grains (like breads and cereals), which are the major sources of iodine in American diets.
  • Fruits and vegetables, which contain iodine, although the amount depends on the iodine in the soil where they grew and in any fertilizer that was used.
  • Iodized salt, which is readily available in the United States and many other countries. Processed foods, however, such as canned soups, almost never contain iodized salt.

What kinds of iodine dietary supplements are available?

Iodine is available in dietary supplements, usually in the form of potassium iodide or sodium iodide. Many multivitamin-mineral supplements contain iodine. Dietary supplements of iodine-containing kelp (a seaweed) are also available. However, for a healthy person with a nutritious and balanced diet, it should not be necessary to take supplements with iodine.

Am I getting enough iodine?

Most people get enough iodine from foods and beverages. However, certain groups of people are more likely than others to have trouble getting enough iodine:

  • People who do not use iodized salt. Adding iodine to salt is the most widely used strategy to control iodinedeficiency. Currently, about 70% of households worldwide use iodized salt.
  • Pregnant women. Women who are pregnant need about 50% more iodine than other women to provide enough iodine for their baby. Surveys show that many pregnant women in the United States may not get quite enough iodine, although experts do not know whether this affects their babies.
  • People living in regions with iodine-deficient soils who eat mostly local foods. These soils produce crops that have low iodine levels. Among the regions with the most iodine-poor soil are mountainous areas, such as the Himalayas, the Alps, and the Andes regions, as well as river valleys in South and Southeast Asia.
  • People who get marginal amounts of iodine and who also eat foods containing goitrogens. Goitrogens are substances that interfere with the way the body uses iodine. They are present in some plant foods includingsoy, and cruciferous vegetables such as cabbage, broccoli, cauliflower and Brussels sprouts. For most people in the United States who get adequate amounts of iodine, eating reasonable amounts of foods containing goitrogens is not a concern.

What happens if I don’t get enough iodine?

Iodine deficiency is uncommon in the western world. People who don’t get enough iodine cannot make sufficient amounts of thyroid hormone. This can cause many problems. In pregnant women, severe iodine deficiency can permanently harm the fetus by causing stunted growth, mental retardation, and delayed sexual development. Less severe iodine deficiency can cause lower-than-average IQ in infants and children and decrease adults’ ability to work and think clearly. Goiter, an enlarged thyroid gland, is often the first visible sign of iodine deficiency.

What are some effects of iodine on health?

Scientists are studying iodine to understand how it affects health. Here are some examples of what this research has shown.

Fetal and infant development

Women who are pregnant or breastfeeding need to get enough iodine for their babies to grow and develop properly. Breastfed infants get iodine from breast milk. However, the iodine content of breast milk depends on how much iodine the mother gets.

To make adequate amounts of iodine available for proper fetal and infant development, several national and international groups recommend that pregnant and breastfeeding women and infants take iodine supplements. In the United States and Canada, the American Thyroid Association recommends that pregnant and breastfeeding women take prenatal vitamin/mineral supplements containing iodine (150 mcg/day). However, only about half the prenatal multivitamins sold in the United States contain iodine.

Cognitive function during childhood

Severe iodine deficiency during childhood has harmful effects on the development of the brain and nervous system. The effects of mild iodine deficiency during childhood are more difficult to measure, but mild iodine deficiency might cause subtle problems with neurological development.

Giving iodine supplements to children with mild iodine deficiency improves their reasoning abilities and overall cognitive function. In children living in iodine-deficient areas, iodine supplements seem to improve both physical and mental development. More study is needed to fully understand the effects of mild iodine deficiency and of iodine supplements on cognitive function.

Fibrocystic breast disease

Although not harmful, fibrocystic breast disease causes lumpy, painful breasts. It mainly affects women of reproductive age but can also occur during menopause. Very high doses of iodine supplements might reduce the pain and other symptoms of fibrocystic breast disease, but more study is necessary to confirm this. Check with yourhealth care provider before taking iodine for this condition, especially because iodine can be unsafe at high doses.

Radiation-induced thyroid cancer

Nuclear accidents can release radioactive iodine into the environment, increasing the risk of thyroid cancer in people who are exposed to the radioactive iodine, especially children. People with iodine deficiency who are exposed to radioactive iodine are especially at risk of developing thyroid cancer. The U.S. Food and Drug Administration has approved potassium iodide as a thyroid-blocking agent to reduce the risk of thyroid cancer in radiation emergencies.

Can iodine be harmful?

Yes, if you get too much. Getting high levels of iodine can cause some of the same symptoms as iodine deficiency, including goiter (an enlarged thyroid gland). High iodine intakes can also cause thyroid gland inflammation and thyroid cancer. Getting a very large dose of iodine (several grams, for example) can cause burning of the mouth, throat, and stomach; fever; stomach pain; nausea; vomiting; diarrhea; weak pulse; and coma.

The safe upper limits for iodine are listed below. These levels do not apply to people who are taking iodine for medical reasons under the care of a doctor.

Life Stage Upper Safe Limit
Birth to 12 months: Not established
Children 1–3 years: 200 mcg
Children 4–8 years: 300 mcg
Children 9–13 years: 600 mcg
Teens 14–18 years: 900 mcg
Adults: 1,100 mcg

Are there any interactions with iodine that I should know about?

Yes. Iodine supplements can interact or interfere with medicines that you take. Here are several examples:

  • Iodine supplements might interact with anti-thyroid medications such as methimazole (Tapazole®), used totreat hyperthyroidism. Taking high doses of iodine with anti-thyroid medications could cause your body to produce too little thyroid hormone.
  • Taking potassium iodide with medicines for high blood pressure known as ACE inhibitors could raise the amount of potassium in your blood to an unsafe level. ACE inhibitors include benazepril (Lotensin®), lisinopril (Prinivil® and Zestril®), and fosinopril (Monopril®).
  • The amount of potassium in your blood can also get too high if you take potassium iodide with potassium-sparing diuretics, such as spironolactone (Aldactone®) and amiloride (Midamor®).

Resources

http://ods.od.nih.gov/factsheets/Iodine-QuickFacts/

Magnesium

What is Magnesium and it’s functions?

Magnesium is an essential mineral for human nutrition and serves several important functions:

  • Contraction and relaxation of muscles
  • Function of certain enzymes in the body
  • Production and transport of energy
  • Production of protein

Food Sources

Most dietary magnesium comes from vegetables, such as dark green, leafy vegetables. Other foods that are good sources of magnesium:

  • Fruits or vegetables (such as bananas, dried apricots, and avocados)
  • Nuts (such as almonds and cashews)
  • Peas and beans (legumes), seeds
  • Soy products (such as soy flour and tofu)
  • Whole grains (such as brown rice and millet)

Approximately 30% to 40% of the dietary magnesium consumed is typically absorbed by the body.

Selected Food Sources of Magnesium
Food Milligrams
(mg) per
serving
Percent
DV*
Almonds, dry roasted, 1 ounce 80 20
Spinach, boiled, ½ cup 78 20
Cashews, dry roasted, 1 ounce 74 19
Peanuts, oil roasted, ¼ cup 63 16
Cereal, shredded wheat, 2 large biscuits 61 15
Soymilk, plain or vanilla, 1 cup 61 15
Black beans, cooked, ½ cup 60 15
Edamame, shelled, cooked, ½ cup 50 13
Peanut butter, smooth, 2 tablespoons 49 12
Bread, whole wheat, 2 slices 46 12
Avocado, cubed, 1 cup 44 15
Potato, baked with skin, 3.5 ounces 43 11
Rice, brown, cooked, ½ cup 42 11
Yogurt, plain, low fat, 8 ounces 42 11
Breakfast cereals, fortified with 10% of the DV for magnesium 40 10
Oatmeal, instant, 1 packet 36 9
Kidney beans, canned, ½ cup 35 9
Banana, 1 medium 32 8
Salmon, Atlantic, farmed, cooked, 3 ounces 26 7
Milk, 1 cup 24–27 6–7
Halibut, cooked, 3 ounces 24 6
Raisins, ½ cup 23 6
Chicken breast, roasted, 3 ounces 22 6
Beef, ground, 90% lean, pan broiled, 3 ounces 20 5
Broccoli, chopped and cooked, ½ cup 12 3
Rice, white, cooked, ½ cup 10 3
Apple, 1 medium 9 2
Carrot, raw, 1 medium 7 2

Side Effects of too Much Magnesium

Side effects from increased magnesium intake are not common because the body removes excess amounts. Magnesium excess almost always occurs only when magnesium is supplemented as a medication.

Lack of magnesium (deficiency) is rare. The symptoms include:

  • Hyperexcitability
  • Muscle weakness
  • Sleepiness

Deficiency of magnesium can occur in people who abuse alcohol or in those who absorb less magnesium due to:

  • Burns
  • Certain medications
  • Low blood levels of calcium
  • Problems absorbing nutrients from the intestinal tract (malabsorption)
  • Surgery

Symptoms due to a lack of magnesium have three categories.

Early symptoms:

  • Anorexia
  • Apathy
  • Confusion
  • Fatigue
  • Insomnia
  • Irritability
  • Muscle twitching
  • Poor memory
  • Reduced ability to learn

Moderate deficiency symptoms:

  • Heart (cardiovascular) changes
  • Rapid heartbeat

Severe deficiency:

  • Continued muscle contraction
  • Delirium
  • Numbness
  • Seeing or hearing things that aren’t there (hallucinations)
  • Tingling

Recommendations

These are the recommended daily requirements of magnesium:

  • Children
    • 1 – 3 years old: 80 milligrams
    • 4 – 8 years old: 130 milligrams
    • 9 – 13 years old: 240 milligrams
    • 14 – 18 years old (boys): 410 milligrams
    • 14 – 18 years old (girls): 360 milligrams
  • Adult females: 310 – 320 milligrams
  • Pregnancy: 350 – 400 milligrams
  • Breastfeeding women: 310 – 360 milligrams
  • Adult males: 400 – 420 milligrams

Magnesium and Health

Habitually low intakes of magnesium induce changes in biochemical pathways that can increase the risk of illness over time. This section focuses on four diseases and disorders in which magnesium might be involved: hypertension and cardiovascular disease, type 2 diabetes, osteoporosis, and migraine headaches.

Hypertension and cardiovascular disease

Hypertension is a major risk factor for heart disease and stroke. Studies to date, however, have found that magnesium supplementation lowers blood pressure, at best, to only a small extent. A meta-analysis of 12 clinical trials found that magnesium supplementation for 8–26 weeks in 545 hypertensive participants resulted in only a small reduction (2.2 mmHg) in diastolic blood pressure. The dose of magnesium ranged from approximately 243 to 973 mg/day. A diet containing more magnesium because of added fruits and vegetables, more low-fat or non-fat dairy products, and less fat overall has proven to lower systolic and diastolic blood pressure by an average of 5.5 and 3.0 mmHg, respectively.

Several prospective studies have examined associations between magnesium intakes and heart disease.  A systematic review and meta-analysis of prospective studies found that higher serum levels of magnesium were significantly associated with a lower risk of cardiovascular disease, and higher dietary magnesium intakes (up to approximately 250 mg/day) were associated with a significantly lower risk of ischemic heart disease caused by a reduced blood supply to the heart muscle.

Higher magnesium intakes might reduce the risk of stroke. In a meta-analysis of 7 prospective trials with a total of 241,378 participants, an additional 100 mg/day magnesium in the diet was associated with an 8% decreased risk of total stroke, especially ischemic rather than hemorrhagic stroke.

Type 2 diabetes

Diets with higher amounts of magnesium are associated with a significantly lower risk of diabetes, possibly because of the important role of magnesium in glucose metabolism. Hypomagnesemia might worsen insulin resistance, a condition that often precedes diabetes, or it might be a consequence of insulin resistance. Diabetes leads to increased urinary losses of magnesium, and the subsequent magnesium inadequacy might impair insulin secretion and action, thereby worsening diabetes control.

Most investigations of magnesium intake and risk of type 2 diabetes have been prospective cohort studies. In 2008, the American Diabetes Association stated in its nutrition recommendations for people with diabetes, “Health care providers should focus on nutrition counseling rather than micronutrient supplementation in order to reach metabolic control of their patients.

Osteoporosis

Magnesium is involved in bone formation and influences the activities of osteoblasts and osteoclasts. Magnesium also affects the concentrations of both parathyroid hormone and the active form of vitamin D, which are major regulators of bone homeostasis. Several population-based studies have found positive associations between magnesium intake and bone mineral density in both men and women. Other research has found that women with osteoporosis have lower serum magnesium levels than women with osteopenia and those who do not have osteoporosis or osteopenia. These and other findings indicate that magnesium deficiency might be a risk factor for osteoporosis.

Migraine headaches

Magnesium deficiency is related to factors that promote headaches, including neurotransmitter release and vasoconstriction. People who experience migraine headaches have lower levels of serum and tissue magnesium than those who do not.

However, research on the use of magnesium supplements to prevent or reduce symptoms of migraine headaches is limited.

In their evidence-based guideline update, the American Academy of Neurology and the American Headache Society concluded that magnesium therapy is “probably effective” for migraine prevention. Because the typical dose of magnesium used for migraine prevention exceeds the UL (upper limit), this treatment should be used only under the direction and supervision of a healthcare provider.

Resources

http://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/

http://www.nlm.nih.gov/medlineplus/ency/article/002423.htm