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Vitamins & Minerals
 
Open/Close text Vitamin and Mineral Supplements

The American public has a keen and rapidly increasing interest in the role of diet and nutrition on health disease avoidance and treatment, aging and performance. In America, over 66% of the population uses vitamins and nutritional supplements, 43% on a daily basis.  In 1997, American's spent more than $11.5 billion on over-the counter (OTC), mail order and non-prescribed nutritional supplements and vitamins. Sales in this industry are exploding. Unfortunately, it is often difficult to sort out legitimate information about these products from the hype, misleading claims and outright fraud. 

This article will outline available scientific information about some commonly used products, discuss potential risks and benefits, provide links to sources of legitimate information and describe FAA policy for use of these products by pilots.  Multiple links to specific vitamin and mineral documents from the FDA's Center for Food Science and Applied Nutrition and the Merck Manual Section on Nutrition are imbedded in the text below.  Also see the Dietary Supplements Resource List from the USDA Food and Nutrition Information Center, an excellent comprehensive list of web resources, books, publications and consumer information.

Most government and medical organizations state in their position papers that optimum intake of vitamins and minerals should come from food sources.  Supplementation is indicated in some groups of people who have increased needs or do not follow good dietary practices.  Further research needs to be completed prior to making definite recommendations for additional supplementation.   Research in many areas is currently being conducted.  Toxic effects are possible from inappropriate supplementation.  Current federal regulations prohibit dietary supplement manufacturers from making unproven claims for disease prevention or cure. The U.S. Preventive Services Task Force: Recommendations and Rationale paper "Routine Vitamin Supplementation to Prevent Cancer and Cardiovascular Disease: Recommendations and Rationale"  recommends against the routine use of vitamin supplements for prevention of heart disease and cancer.

A growing body of nutritionists and preventive medicine proponents question the philosophy of delaying supplementation for years while awaiting definitive proof by rigorous scientific studies, primarily because there is little funding available for fully researching some potential health effects of supplements.  The primary reason funding is sparse is that, unlike new drugs made by pharmaceutical companies, the supplements can not be patented and there is no economic incentive to conduct the expensive and time consuming research. 

The US public is using nutritional supplements, usually without consultation with physicians, in very large percentages.   Other countries, particularly Germany, have researched, regulated and used supplements and herbal products as a standard part of their health care system.   Medical training in the US has covered nutrition extensively in curricula, although considerably more information is now available for students and the practicing physician.  Until a consensus is reached through scientific study, the consumer should beware of both inappropriate claims of benefit from supplements and overly cautious warnings of potential harm.

Open/Close text Definitions

The distinction between medications, vitamins, minerals, nutritional supplements, medicinal herbs and performance enhancing compounds is blurred. The terms are often used interchangeably. They can be confused with homeopathic medicine, which purports use of herbs in very small amounts to achieve therapeutic effects.   Scientific evidence to date does not support this method of use as beneficial. Science definitely supports the use of vitamins and minerals in the treatment of specific diseases and in the prevention of others.  Current research is directed at determining relationships between these compounds and medical conditions, determining the optimum dose of each compound for individuals and how these nutrients work together.

"Vitamins" are compounds found in foods naturally and manufactured synthetically. They are called organic compounds because they all contain carbon, oxygen and hydrogen atoms.  Both the natural forms and synthetic forms have nutritional value, though sometimes not equally. The Food and Drug Administration sets Recommended Daily Allowances (RDA) for many vitamins and minerals. The RDA's were initially listed as a minimum amount of a nutrient taken in daily by a healthy person without additional needs to avoid overt disease.  New guidelines were developed by the Institute of Medicine of the National Academy of Sciences for these nutrients.  Another useful recommendation for optimum nutrient levels is the development of Dietary Reference Intakes (DRI).   

A press release from the Institute of Medicine states "Our understanding of the relationship between nutrition and chronic disease has progressed to the point where we can now begin to recommend intakes that are thought to help people achieve measurable physical indicators of good health," said Vernon Young, chair of the IOM's Standing Committee on Dietary Reference Intakes and professor of nutritional biochemistry, Massachusetts Institute of Technology, Cambridge. "The new DRIs represent a major leap forward in nutrition science -- from a primary concern for the prevention of deficiency to an emphasis on beneficial effects of healthy eating."

"Minerals" are naturally derived compounds, often electrically charged and bound to other compounds, which play key roles in all aspects of the body's function.  Minerals are single elements that do not include carbon, oxygen or hydrogen, but are frequently bound to organic molecules.   Excessively high or low concentrations of minerals can cause disease or death.  Minerals interact with vitamins to support the biochemical actions in our cells and organs.

"Nutritional supplements" are compounds derived from plants and synthetically produced that are not regulated by the FDA. The Dietary Supplement and Health Education Act of 1994 legally defined what could and could not be called a "nutritional supplement".  Most nutritional supplements are sold to enhance wellness or alleviate symptoms.  Manufacturer's are restricted from claiming therapeutic benefits in the prevention or treatment of disease. Consequently, most of the products are sold as food additives, foods or nutritional supplements and are not listed in The United States Pharmacopoeia (USP).  Recent efforts by the FDA may lead to increasing regulation or monitoring of these products.   Manufacturers may voluntarily comply with the FDA Good Manufacturing Practices for quality control.

"Performance enhancers" or "ergogenic aids" are also not regulated by the FDA.  They are designed to boost performance, usually in athletic endeavors.   Like some medications, many performance enhancers are banned by a variety of national and international amateur and professional sports governing bodies.  Some of these compounds are steroid or protein building blocks while others may mask the discomfort of athletic efforts.

Herbs are plant-derived products generally used in a natural or dried form of the plant. They may contain several chemicals naturally found in the plant. Although used as medicines in the past, often for hundreds of years, the purity and concentration of these "supplements" and herbs are no longer regulated or monitored.  Funding for research on these compounds has been sparse because their production can not be patented and there is little economic incentive for expensive studies. Given this vacuum of reliable information, consumers must be cautious in their use.  Recent consumer interest has sparked federally funded research efforts in the area of herbal medications.

Open/Close text FAA Policy

The FAA does not restrict or require reporting the use of these "nutritional supplements", vitamins, minerals or OTC performance enhancers by pilots or controllers. The prudent pilot/controller who elects to use such agents should ground test them for several days before performing duty to ensure there are no unexpected side effects. Many products initially thought to be safe have later proven harmful or even fatal in some people. Frequently, the underlying medical condition an individual is using these medications for must be reported on the FAA Airman's Medical Application Form 8500-8.  Self treatment of medical diseases may be dangerous. However, a proactive approach to optimum wellness and health promotion is in everyone's long-term interest.
Open/Close text Vitamins and Minerals

Vitamins and minerals play essential roles in nearly all of the body's physiological processes. The quantity of each vitamin and mineral required in the average healthy individual is difficult to predict exactly. The National Academy of Science issued Recommended Daily Allowances (RDA's) for many of these in 1980. The RDA is set by determining the Estimated Average Requirement (EAR) for a nutrient that would be adequate for 50% of the population and adding 2 standard deviations to this requirement to yield the RDA.  Thus, the RDA should provide adequate nutrition to about 97% of the population.

Individuals with certain disease states may require significantly higher levels of a particular nutrient because of increased need, utilization, or excretion. The Institute of Medicine of the National Academy of Sciences is undertaking a reclassification of dietary recommendations.  Increased recommended optimum dosages are predicted for many vitamins and minerals, as was done for Vitamin A in January 2001.  See the summary of the IOM - Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001) for a clear explanation of how these levels are determined.  The Tufts University Health & Nutrition Letter states that up to 25% of American's in their 60's and older are malnourished with "subclinical deficiencies that have a direct impact on body function" according to Jeffrey Blumberg, Ph.D., from Tufts University.

Nutrient labels and recommended amounts are specified in several different formats. Dietary Reference Intakes (DRI?s) are developed by the National Research Council?s (Institute Of Medicine) Food and Nutrition Board.  For each specific nutrient, the DRI vary by age, sex and reproductive status. They are designed for healthy people. Those with chronic illnesses or acute disease may require more of a specific nutrient than the DRI.  For further information, see the IOM page on Frequently Asked Questions About DRIs and IOM - Dietary Reference Intakes: Applications in Dietary Assessment (2000).

The Recommended Daily Allowances (RDA?s) were initially set as the lowest amount of daily intake of a nutrient to avoid overt disease in healthy people. These frequently equaled the highest DRI for all groups. A recent movement to revise the RDA?s to provide health benefits is underway. The RDA?s for calcium were recently revised upwards to indicate levels required to minimize osteoporosis. Previous levels reflected amounts necessary to avoid the disease rickets.

Many nutrients are stored in the body, particularly the fat soluble vitamins. Excessive intake of these compounds may be harmful. The "mega-vitamin" enthusiasm, also known as "orthomolecular medicine," of recent years emphasizing that huge doses of vitamins are more beneficial than the RDA levels may be counterproductive. On the other hand, intakes higher than the current RDA's are beneficial in some circumstances, according to recent research.  Water soluble vitamins tend to be rapidly eliminated in the urine. Extremely high doses of these will not result in a proportional improvement in health, but will make very expensive urine.   Some fat soluble vitamins which are stored in the body have very high tolerances before any ill effects.  The National Research Council?s (Institute Of Medicine) Food and Nutrition Board has recently published a report on Upper Reference Levels of Nutrients addressing maximum safe levels of vitamins and minerals

Open/Close text NOAEL?s and LOAEL?s

How can someone interested in taking vitamin and mineral supplements determine what levels can safely be taken?  The No Observed Adverse Effect Level (NOAEL) and the Lowest Observed Adverse Effect Level (LOAEL) give good approximations for the concerned consumer. Dr. John Hancock in the American Journal of Clinical Nutrition (1997; 66:427-437) published these levels based on currently available scientific studies.   The Council for Responsible Nutrition also has published a chart of the NOAEL and LOAELs.

The NOAEL represents a safe level for long term human ingestion by mouth for individual vitamins and minerals. Long-term intake of levels below the NOAEL (both from food sources and supplements) have not been associated with any ill effects.

The LOAEL is calculated for vitamins and minerals that may have adverse effects from oral intake if ingestion at these levels for extended periods of time. The LOAEL is not representative of a toxic level or of harm with short-term use at these levels. It is merely an indicator of the need for a safety margin with specific vitamins or minerals.

Detection of some vitamin and mineral deficiencies is easily done with blood testing. However, many do not have easily measured or well defined "normal" levels in the blood. The detection of deficiency may be dependent on recognizing certain signs or symptoms in moderate or severe deficiency states.

The American Cancer Society has published 2002 Guidelines for Nutrition and Physical Activity for the Prevention of Cancer.  This document gives excellent advice of proven, postulated, unproven and harmful interventions for many types of cancer.  Of note, moderate regular physical activity is beneficial for nearly every type of cancer.  Not all nutrients have been shown to be beneficial, and the American Cancer Society recommends obtaining nutrients through natural foods rather than from nutritional supplements.

Open/Close text Vitamin A (Retinol, Retinoic Acid) and Beta Carotene

Vitamin A is a fat-soluble compound derived from vegetables containing carotene, which is converted to vitamin A in the body with zinc. Vitamin A is found in liver and eggs. Carotenes, also know as carotinoids or provitamin A, are vitamin A precursors or building blocks.   Dark green leafy vegetables and those with red or yellow colors are the best sources. 

The RDA for for vitamin A in healthy adults was 5000 International Units (IU) per day for men and 4000 IU/day for women. This is also expressed in micrograms of Retinol Equivalents and is near 1000 RE micrograms daily. The January 2001 recommendations doubled the RDA's to 700 micrograms in women and 900 micrograms in men (See below). Vitamin A is essential for normal night vision, as is zinc. Vitamin A deficiency may also cause dryness and cracking of the skin. Skin preparations of vitamin A (Retin-A) have recently been developed for treatment of acne and fine wrinkles of aging. Vitamin A may have a role in preventing bladder cancer. New research indicates Vitamin A may be important in gene expression and have a role in cancer prevention.  This may be through enhanced function of the immune system.   See the new IOM - Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001).

Some researchers have suggested dosages in the range of 25,000 IU of beta carotene and mixed carotinoids for its antioxidant properties.  Vitamin A toxicity occurs with prolonged daily intakes of over 50,000 IU per day of vitamin A.  Side effects include abnormal liver function, headache, dizziness, increased risk of cancer in smokers and yellow skin. High dosages, greater than 10,000 IU, in early pregnancy may cause birth defects. Plant sources of vitamin A precursors, primarily beta-carotene and mixed carotinoids, do not cause toxicity. The carotenes are gaining popularity as nutritional supplements because of their strong anti-oxidant properties and absence of any known toxicity.   Despite the absence of known toxicity, a controlled trial of beta carotene plus 25,000 IU of vitamin A (Beta Carotene and Retinol Efficacy Trial) showed an increase in risk of death from all causes and a slight increase risk of death for cardiovascular causes in users.  Note that the doses used in this study were above the LOAEL for vitamin A. See the Update on Vitamin Supplements for the Prevention of Coronary Disease and Stroke AFP Sep 15, 2000. 

Dr. Ken Cooper in his book, The Antioxidant Revolution, recommends a minimum of 25,000 IU of beta carotene daily.   The NOEAL for vitamin A is 10,000 IU per day and the LOEAL is 21,600 IU.   The NOEAL for beta carotene is 25 mg (about 41,400 IU) per day and there is no LOEAL for beta-carotene.

Open/Close text Vitamin B1 (Thiamin)

As with most of the B vitamins (thiamin, riboflavin, niacin, biotin, pantothenic acid, folate, pyridoxine and B12), thiamin plays an important role in mental function and the peripheral nerves ability to function. Heart function is also affected by thiamin. B1 is now found in enriched flour and breads sold in the U.S.. The B vitamins are water soluble and do not accumulate in the body. The most common cause of thiamin deficiency and dependency is alcoholism, which may lead to severe mental disorder called Korsakoff's encephalopathy. Often, magnesium deficiency accompanies thiamin deficiency. Other manifestations of thiamin deficiency (called beriberi) include loss of sensation, burning and tingling in the hands and feet, fatigue, weakness of the arms and legs and heart failure. The RDA is 1.0 - 1.5 mg/day.  Deficiency states may require replacement by injection and prolonged oral supplementation.  There is no toxicity to oral thiamin. See the Institute of Medicine?s recommendations for new intake levels.  Some nutritionists are recommending 50-100 mg per day.  The NOEAL for vitamin B-1 (thiamin) is 50 mg per day and no LOEAL is established.
Open/Close text Vitamin B2 (Riboflavin)

Riboflavin is an essential compound in energy production at the cell level. It is found in dairy products, enriched grains, organ meats, beans, green leafy vegetables and broccoli. Riboflavin deficiencies are manifest by irritation and cracking of the skin, particularly of the mouth.  An anemia (low red blood cell count) can also occur with riboflavin deficiency.  Riboflavin is also important in regenerating glutathione, a key antioxidant. The RDA of riboflavin is 1.7 mg/d for men and 1.3 mg/d for non-pregnant women. Oral doses of riboflavin are generally non-toxic.  Nutritionists recommend 5-10 mg per day as an optimum dose. See the Institute of Medicine?s recommendations for new intake levels.  The NOEAL for vitamin B-2 is 200 mg per day and no LOEAL is established.
Open/Close text Niacin (Vitamin B3)

Niacin, or nicotinic acid, is a mineral that has recently been highlighted for its protective role in heart disease by improving cholesterol profiles. It is very effective in reducing LDL cholesterol and triglycerides. It may also increase the desirable HDL cholesterol.   In the past, deficiencies of niacin caused pellagra and manifested as skin inflammation, cracking of the tongue, diarrhea and confusion (dermatitis, diarrhea and dementia). Niacin is found in most foods. 

High amounts of niacin are found in organ meats (liver, brain, kidney), eggs, fish, peanuts, beans and most whole grains. The body converts the amino acid tryptophan into niacin.  High amounts of crystalline niacin, or those dosages used to treat elevated cholesterol, cause a burning, itching and flushing sensation in the skin about 30 minutes after taking it and lasting for about 15 minutes. This sensation may be reduced by taking a single aspirin 30 minutes prior to taking niacin. The "timed release" forms of niacin are designed to avoid the flushing sensation, but may cause long term liver damage. An article in the Journal of the American Medical Association in 1994 recommended restricting the use of the sustained release forms of niacin.  Niacin has been shown to lower LDL cholesterol and lipoprotein A levels while raising the favorable HDL cholesterol.

Dosages of 1500 mg and higher are used to treat cholesterol elevations.  The RDA is 13-19 mg.  Dietary supplements of 100-200 mg of niacin may be tolerated with minimal flushing and beneficial effects on cholesterol levels.  Niacinomide, a different form of niacin, recently has been explored as a supplement to increase insulin sensitivity in diabetes. See the Institute of Medicine?s recommendations for new intake levels.  The NOEAL for nicotinic acid is 500 mg per day and the LOEAL is 1000 mg. The NOEAL for nicotinamide is 1,500 per day and the LOEAL is 3000 mg.

Open/Close text Pantothenic Acid (Vitamin B5, Pantothene)

Pantothenic acid is an essential B vitamin that is a precursor (building block) of coenzyme A (CoA) and of acyl carrier protein (ACP).  These two compounds are critical for the use of fats, proteins and carbohydrates in energy production.  They also are important in the production of red blood cells, adrenal (stress) hormones and nerve transmitters. Food sources include yeast, nuts, grains, beans and rice.  There is no RDA for pantothenic acid, but the Estimated Safe and Adequate Intake is 4-7 mg per day.  Deficiencies are rare.  Symptoms of deficiency include depression, fatigue and "burning feet syndrome."  Pantothene (not pantothenic acid) has been used to lower cholesterol and triglycerides, while pantothenic acid may be effective in relieving some symptoms of rheumatoid arthritis.  This supplement is expensive, particularly when taken in dosages of 500-1000 mg per day for the above conditions.  The Standard American Diet provides 5-10 mg per day.  The NOEAL for panothenic acid (vitamin B-5) is 1,000 mcg (1 mg) per day and no LOEAL is established.
Open/Close text Vitamin B6 (Pyridoxine)

Pyridoxine is an essential component of over one hundred reactions in the body.  Pyridoxine plays a role in brain function and emotional states through its interaction with brain neurotransmitters.  It also contributes to red blood cell production and the avoidance of anemia.  Essential cofactors for pyridoxine use in the body include riboflavin and magnesium. 

Pyridoxine is an essential component in the lowering of blood homocysteine levels, which can cause arteriosclerosis and heart disease. Deficiencies may lead to several conditions.  Certain medications may lower pyridoxine levels. These include hydralazene for high blood pressure, INH for tuberculosis and birth control pills.  People being treated for Parkinson's disease and on birth control pills may find improved moods with adequate intake of pyridoxine. Pyridoxine may aid in decreasing the formulation of oxalate stones in the urine and in improving glucose tolerance. It has even been advocated as a protective factor against mosquitoes.  Foods rich in B-6 include yeast, sunflower seeds, wheat germ, white meats, bananas and grains.

Although there is a wide margin of safety with this medication, chronic excess amounts may cause nerve problems. The RDA is 2.0 mg. Vitamin B-6 is one of the only water soluble vitamins that has any toxicity associated with it.  The liver only processes up to 50 mg per day and dosages as low as 200 mg per day over very long term have caused reversible nerve problems. Deficiency states may cause greasy rashes, anemia, weakness of the arms and legs, depression, seizures, anemia and glucose intolerance.  See the Institute of Medicine?s recommendations for new intake levels.  The NOEAL for vitamin B-6 (pyridoxine) is 200 mg per day and the LOEAL is 500 mg.

Open/Close text Vitamin B12

Vitamin B12 absorption in the stomach requires the presence of a compound known as intrinsic factor. Abnormalities of the stomach cause a lack of intrinsic factor and subsequently, a deficiency of B12.  People with intrinsic factor deficiency, which can be measured, require injections of B12 to replace deficiencies. The risk of intrinsic factor deficiency increases with age.  An excellent article on Vitamin B12 Deficiency and its complications is found in American Family Physician

Those with normal intrinsic factor may use oral supplements.  One study in JAMA in 1991 stated that oral supplementation is adequate to treat all forms of B12 deficiency.  Animal meats and cheeses are the prime sources of this nutrient.  Deficiencies of B12 lead to pernicious anemia, decrease white blood cells and platelets, cracking of the tongue, hostility, forgetfulness, paranoia, nerve damage, uncoordination and visual impairment.  There can be permanent damage to the brain, spinal cord and nerves.  B12 is closely related to folic acid and work together in several key enzyme processes. 

Perhaps the most important is the regulation of homocysteine levels, as homocysteine elevations are associated with atherosclerosis and heart disease.  The RDA is 2+ micrograms/day. Standard American diets usually are adequate without supplementation if intrinsic factor is present. However, a study published in the American Journal of Clinical Nutrition (71:514, 2000)  following the Framingham cohort found that 39% of adults from age 26 to 83 showed dangerously low levels of B12 in their blood.  Oral dosages for deficiency states are 1,000 micrograms per day. Toxicity is not a problem. 

See the Institute of Medicine?s recommendations for new intake levels.  The NOEAL for vitamin B12 is 3,000 mcg (3 mg) per day and no LOEAL is established.

Open/Close text Folate (Folic Acid)

Folate?s actions are very similar to B12 . The major effects of deficiency are anemia, fatigue, mental changes and painful changes in the tongue.  Folate has recently been identified as an important nutrient in pregnant women to decrease birth defects of the spinal cord and brain.  The April 9, 1998 issue of the New England Journal of Medicine contained two articles and an editorial on the benefits of folate in reducing homocysteine levels as a protective factor in heart disease. Also see an article in American Family Physician Update on Vitamin Supplements for the Prevention of Coronary Disease and Stroke.   Good source of folate include fortified grain products, citrus products green vegetables and beans.

The RDA is 0.2-0.4 mg, (200-400 mcg).  The FDA currently limits nutritional supplements to no more than 400 mcg per daily dose.  Pregnant women should get at least 1 mg (1000 mcg) per day to prevent spinal cord birth defects.  Approximately three fourths of Americans do not get the RDA in their diet.  Supplementing with folic acid should be done with caution in people who may have a vitamin B12 deficiency.  The folate will correct the macrocytic (large cells) anemia, but will not protect against the nerve damage associated with B12 deficiencies.  See the Institute of Medicine?s recommendations for new intake levels.  The NOEAL for folic acid is 1,000 mcg (1 mg) per day and no LOEAL is established.

Open/Close text Biotin (Vitamin B-7)

Biotin is a B vitamin that is produced naturally in the intestines from primarily vegetable sources.  Deficiency is rare but is associated with hair loss, hair thinning, seborrhea, dandruff and red, cracking rashes around the mucus membranes of the eyes, mouth, nose and anus.  Severe deficiencies for those on prolonged intravenous feeding may lead to mental disturbances.  There is no RDA for biotin, but the estimated safe and adequate dietary intake for adults is 30-100 mg per day.  There is no known toxicity of excess biotin.  The NOEAL for biotin (vitamin B-7) is 2,500 mcg (2.5 mg) per day and no LOEAL is established.
Open/Close text Vitamin C (Ascorbic Acid)

Vitamin C is an extremely important water-soluble antioxidant found in many fruits and vegetables, particularly citrus fruits and bell/yellow peppers.  It is also found in the Acerola plant, also known as Rose Hips. Vitamin C levels drop quickly when fruits and vegetables are left standing or uncovered. 

Deficiencies of vitamin C cause wound breakdown, skin changes and scurvy with bone bleeding, joint swelling, bruising and painful sores in the mouth.  British sailors recognized this relationship and took limes on their expeditions to prevent scurvy, hence the name "Limeys". Smokers tend to have low levels of vitamin C, as do regular aspirin users.

Thousands of articles have been written about the reported benefits of Vitamin C.  Linus Pauling, the Nobel prize winning scientist, advocated taking mega doses (several grams daily) of vitamin C to prevent the common cold or speed recovery. Although several studies have shown possible benefits, but others have not supported his claims. Tissue saturation levels and white blood cell vitamin C levels increase minimally with levels above 200 mg per day. A National Institutes of Health study on vitamin C demonstrated that tissue levels of vitamin C were only 30% saturated at the RDA intake of 60 mg/day. Higher intake levels increased saturation levels:  72% for 100 mg per day; 86% at 200 mg per day; 91% at 400 mg per day; and 100% at 1,000 mg per day.  Pregnant women, smokers, people with stomach ulcers and those facing physical stress, such as infections, trauma and surgery, may require higher daily amounts.  Vitamin C is useful in aiding absorption of iron and in making the urine more acidic, which may reduce urinary tract infections. 

In April 2000, the Institute of Medicine Food and Nutrition Board recommended raising the DRI for vitamin C to 90 mg for men and 75 mg for women.  Smokers should take an additional 35 mg daily.   The maximum daily amount recommended by the IOM is 2,000 mg

Vitamin C also has significant antioxidant properties, particularly when combined with vitamins A and E and selenium.  These properties may give some protection against cancer and heart disease.  Its effects on the immune system, primarily by increasing tissue glutathione levels in white blood cells, augment the antioxidant properties.  Vitamin C is also critical in the skin healing and wound repair process through its effects on production of collagen.  Vitamin C has also been shown to reduce the risk of cataract formation and Age Related Macular Degeneration, a major cause of loss of vision in adults. Vitamin C works together with Vitamin E in reducing the oxidizing effects of LDL cholesterol and reducing damage to the intima of blood vessels.  The list of potential benefits of vitamin C on various medical conditions is long.  Research on this vitamin is exploding, but there is no universal agreement on many of the purported benefits.  As a supplement and antioxidant, it is very inexpensive. 

All forms of vitamin C are beneficial and there is no need to use "special formulations."  Relatively neutral sources on nutrition recommend getting 200-350 mg per day of vitamin C from 5 -9 servings of fruit and vegetables per day, a difficult task for many people.  Many nutrition researchers and advocates recommend 500 mg to 2000 mg per day as a minimum dose.  Potential side effects of high does include diarrhea, gas and possible increased risk of calcium oxalate kidney stones.  In the absence of gout or previous kidney stones, this does not seem to be a concern.  Overall, vitamin C may considered a very inexpensive,  powerful antioxidant with many other potential benefits and few risks.  See Dr. Kenneth Cooper's book,  The Antioxidant Revolution,  and Dr. Michael Murray's book, The Encyclopedia of Nutritional Supplements, for very detailed and well referenced discussions.  The NOEAL for vitamin C is 1,000 per day and no LOEAL is established.

Open/Close text Vitamin D (Calciferol, Calciferdiol, Calcifertriol)

Vitamin D is a fat soluble vitamin stored in the body and plays a critical component in bone healing and formation. It regulates calcium levels in the blood by increasing absorption of calcium from the intestine and moving calcium back and forth between the bones and blood.   Vitamin D3 is produced in the skin when exposed to ultraviolet light.  Only 30 minutes of exposure to sunlight per day is required for adequate vitamin D production.  Dietary sources include fortified milk products and fatty fish. Deficiencies in Vitamin D lead rickets (poor bone formation in childhood) and osteomalacia (increase bone brittleness in adults). People with lactose intolerance and those taking some anti-seizure medications and chronic steroids are prone to vitamin D deficiency.  Severe deficiencies may result in spasm of the muscles and of the voice box (larynx).

The RDA is 400 IU in children and 200 IU in healthy adults. Adults who remain indoors and who are older may require up to 800 IU per day.  Vitamin D, together with calcium and vitamin C are important nutrients in slowing the onset of osteoporosis, or bone loss in the elderly, particularly women.  For a discussion of potential toxicity and the treatment of osteoporosis, see The Integrative Medicine Consult article on Vitamin D, Osteoporosis and Hypercalcemia.  Vitamin D has some use in treating psoriasis and may be associated with lower risks of cancer of the prostate, colon and breast.  Toxicity occurs with daily intakes of over 5,000 IU.   The manifestations of toxicity include weakness, vomiting and diarrhea, bone loss, kidney stones and calcium deposits in the muscles. The Institute of Medicine of the National Academy of Sciences is considering higher recommendations than the current RDAs.  The NOEAL for vitamin D is 800 IU per day and the LOEAL is 2,000 IU.

Open/Close text Vitamin E (Tocopherol)

Vitamin E is a very important antioxidant in the body which is found in eight different forms.  The most active form is alpha-tocopherol, although beta, delta and gamma forms also have antioxidant properties. Deficiencies of vitamin E, a fat soluble vitamin, are rare in people with a normal diet and GI function.  The natural form of vitamin E is d-alpha tocopherol, while the synthetic form is dl-alpha tocopherol.  Research supports better absorption and utilization (11/2 times) of the natural form. Vitamin E is the most active lipid (fat) phase antioxidant and is primarily found in the cell membrane where it protects against cellular and DNA damage from free radicals. 

Vitamin E is used to treat claudication (atherosclerosis of the legs), cysts of the breasts, and sickle cell disease complications. Recent research supports use of vitamin E to help prevent coronary artery disease (atherosclerosis of the arteries of the heart). The RDA is 30 mg/day, but the dosages of 400-800 mg per day may be required for coronary artery disease and stroke prevention.  Dr. Kenneth Cooper recommends dosages of at least 400 mg per day as an antioxidant.  Dosages up to 3200 mg per day have not been shown to be harmful.  See potential toxicities described in the Merck Manual.  Also see Institute of Medicine Food and Nutrition Board recommended raising the DRI for vitamin E, but note there is an error in the second paragraph reversing the doses for the "d" form and the "dl" form of alpha-tocopherol.

A study published in the January 20, 2000 New England Journal of Medicine of 10,000 people over age 55 did not show a difference in outcomes for cardiovascular disease over a four and a half year observation period.  A review in American Family Physician, Update on Vitamin Supplements for the Prevention of Coronary Disease and Stroke, states vitamin E use in doses of 100-800 IU per day may be beneficial, although scientific evidence in its' role in the prevention of coronary artery disease is lacking.  No significant side effects were noted from use of 400 IU per day.

Vitamin E prolongs bleeding time and should not be used by anyone on anticoagulant medication or with bleeding problems.  Those taking aspirin should consult their physician before taking large dosages of vitamin E.  People more likely to get free radical damage (air pollution, smoking, radiation exposure, heavy physical exercise, chemotherapy) may benefit the most from vitamin E supplementation.   Vitamin E may also reduce the risk of cataracts and premature aging.  People with intestinal disturbance and poor fat absorption, such as those with cystic fibrosis, celiac disease, sprue, stomach removal, sickle cell and thalessemia should take extra amounts of vitamin E and other fat soluble vitamins.  Water soluble forms of this vitamin are sold at much higher prices than the fat soluble form, but offer no advantages.   The NOEAL for vitamin E is 1200 IU per day and no LOEAL is established.

Open/Close text Vitamin K

Vitamin K is an important element in the proper clotting of blood. Premature infants are often deficient and require injections at birth. Vitamin K deficiency is relatively rare as most dark green vegetables have more than one day?s requirements. It is also found in poly- and mono- unsaturated oils. Deficiencies would manifest as bleeding into the skin and gastrointestinal tract. Toxicity in adults is rare. The RDA was 60-80 mcg. The IOM paper below established Adequate Intake levels of 120 micrograms daily for men and 90 micrograms daily for women. The Standard American Diet (SAD) usually contains at least this amount daily.  Vitamin K interferes with the anti-clotting action of some medications, such as warfarin or coumadin.   Vitamin E in dosages above 600 IU daily may interfere with vitamin K.  The NOEAL for vitamin K is 30 mcg per day and no LOEAL is established.  See the 2001 IOM - Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (2001)
Open/Close text Choline

Choline, like inositol, is an essential nutrient sometimes known as an "unofficial B vitamin."  Free choline is found in vegetables, grains and soy while phosphotidylcholine is found in lecithin of grains, beans and egg yolks.   Choline aids in the transport of fats out of the liver as a "methyl donor".  It is also a key component in neurotransmitters of the brain and in the coating of nerve cells. Choline is found in cell membranes.  In Germany, it is used to lower cholesterol and in people with liver disease.  Dosages near 500-1000 mg are used.  There is no RDA for choline.  High amounts (5,000-10,000 mg) may cause gastrointestinal discomfort and a "fishy" odor.
Open/Close text Inositol

Another "unofficial B vitamin", inositol is very similar to choline in that it is found in the cell membranes in a phosphotidal form.  It is found in the diet in citrus fruit, grains, nuts and legumes, all high fiber foods.  The bacteria of the gut free inositol from foods, so it is not considered an essential nutrient.  It assists in mobilizing fat from the liver, a "lipotropic effect".  Inositol is also used in brain and nerve function.  Some researchers have advocated its use in depression and panic attacks and in nerve damage caused by diabetes.  There are no known side effects and dosages of 1,000 mg per day are safe.
Open/Close text Minerals - Boron

Boron is a trace mineral with a similar function in the body as calcium.   There is no established minimum amount of boron.  Dietary sources include fruits, vegetable and beans which provide 1.5 to 7.0 mg per day.  Intakes of 1-3 mg per day are adequate.  Boron, as sodium tetraborate decahydrate, may also be useful in minimizing symptoms of arthritis, but scientific evidence is sparse.  Studies showing improvement in arthritis used dosages of 6-10 mg daily.  Death has occurred in doses of 18 grams in adults.  Generally the kidneys can excrete excess amounts.   See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Calcium

Calcium has several important functions in the body.  Calcium is the major structural component of the bones and teeth.  It also is found in small amounts in the blood and cells where it functions in muscle contraction and as a coenzyme in many biochemical reactions.  The parathyroid hormone plays a critical role in regulating  levels of calcium.  Because the bones contain so much calcium, blood levels of calcium do not reflect whether the body has depleted or adequate amounts.  Bone formation requires adequate intake of both vitamin D and calcium.  Chelated calcium, primarily calcium citrate, will enhance the absorption of calcium from the intestines, while oxalates found in spinach and teas will inhibit absorption.  Calcium carbonate is absorbed in much lower amounts that the citrate form.  Milk products are the primary source of dietary calcium, although hard tofu, green leafy vegetables and fish with edible bones such as salmon also have significant amounts.  An 8 oz. glass of milk or a 6 oz. yogurt contains approximately 300 mg of calcium. Some antacid tablets also contain calcium in large amounts. Chronic calcium deficiency leads to osteoporosis with thinning of the bones and increased risk for fractures, particularly in older females. Adolescents require 1200-1500 mg of calcium per day as do women who are breast feeding. The RDA for most adults is 1000 mg although the Institute of Medicine is reviewing the adequacy of this amount currently.  Older adults require at least 1,200 mg daily.  Many Americans have inadequate dietary intakes of calcium.  Risk factors for osteoporosis include thinness, inactivity or non-weight bearing activity, female, many children, breastfeeding, fair skin and postmenopausal.  Astronauts lose a significant amount of bone density during space flights because of the weightless state, while weight bearing activity improves bone density.  Toxicity with calcium is rare.   Once thought to contribute to kidney stones, most researchers now do not believe that oral calcium intake contributes to stone formation.  See Optimal Calcium Intake (National Institutes of Health Consensus Development Conference Statement, June 6-8, 1994).  The NOEAL for calcium is 1,500 mg per day and the LOEAL is over 2,500 mg.
Open/Close text Minerals - Chromium

Chromium plays an important role in control of blood sugar and in lowering cholesterol. For this reason, it has new popularity as a heart disease prevention supplement and in preventing diabetes. As the active component in Glucose Tolerance Factor, chromium increases the effectiveness of insulin.  It improves uptake of blood glucose into the cells and modulates swings in blood sugar.  It is found mostly in vegetables and grains. 

Chromium may improve fat utilization in the body, while increasing lean muscle mass.   One study showed a dose response relationship (the more chromium ingested, the more pronounced the effect) with chromium picolinate at 200 and 400 mcg daily for weight loss and increased muscle mass.  Other studies do not support increase in lean muscle mass with resistive (weight) training.  All forms of chromium seem to have a modest effect in lowering total cholesterol while slightly raising HDL cholesterol. 

Small amounts of chromium are found in grains, fruits and vegetables.  The average daily intake for Americans is 25-35 micrograms daily, while the Estimated Safe and Adequate Daily Dietary Intake is 50-200 mcg.  There is almost no toxicity with chromium, with the possible exception of more vivid dreams.  Given the large margin of safety, inadequate daily intake and potential benefits in reducing the risk of diabetes and heart disease, supplementation may be very beneficial.  The NOEAL for chromium III is 1,000 mcg (1 mg) per day and no LOEAL is established.  See the 2001 IOM - Dietary Reference Intakes.

Open/Close text Minerals - Copper

Copper is an essential element in several enzyme reactions.  It is closely related in function to iron and is important in preventing iron deficiency anemia.  It also functions in wound healing and may have a role in lowering cholesterol.  Copper is found in shellfish, nuts and grains.  A significant source of copper is drinking water from copper pipes.  Copper absorption is decreased by vitamin C, zinc and iron.  Too much zinc lowers copper levels.   Both minerals are essential and a ratio of 10:1 zinc:copper is ideal if using supplements.  The average dietary intake of copper is about 1000 micrograms, just above the RDA of 900 micrograms.  Amounts less than that may be harmful.  the Estimated Safe and Adequate Intake in adults is 1.5-3.0 mg daily.  Excess supplementation (10 mg) produces nausea and 30 mg may induce vomiting.  If supplementing with copper, a daily amount of 3 mg with 30 mg of zinc may be optimum.  The NOEAL for copper is 9 mg per day and no LOEAL is established.  See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Iodine

Iodine deficiency once was common in the United States until it was added to salt (iodized salt). The mineral is found in seafood, kelp and in some drinking water. Iodine is a critical component in the thyroid hormone, thyroxin. Deficiency in adults results in an enlargement of the thyroid gland as it tries to make more thyroxin. Physical signs and symptoms include, weight gain, loss of energy, fatigue, low blood pressure, hair loss and a greasy, doughy skin. Treatment with oral iodine is curative if the cause f the hypothyroidism is iodine deficiency. Pregnant women with iodine deficiency have mentally slowed children, a condition called "cretinism" in severe cases. Iodine in children may have an effect on IQ. Iodine may decrease breast tenderness in fibrocystic breast disease. The RDA is 150 mcg.  The average American daily intake is about 600 micrograms.   Supplementation is not required unless a person is on a salt-free and no seafood diet.   The NOEAL for iodine is 1,000 mcg (1 mg) per day and no LOEAL is established.  See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Iron

Iron is both an essential element in red blood cell formation and a potentially deadly toxin. Iron is critical in the formation of hemoglobin, the oxygen carrying component of blood. It also is important in muscle function, cell reproduction and glucose production. The primary food source of iron is red meat, although grains and dark green leafy vegetables also contain iron.  Iron is best absorbed if digested with vitamin C.   Iron is stored in the liver, spleen and bone marrow. Deficiencies in iron are most often seen in menstruating women or those with chronic blood loss. They manifest as decreased exercise tolerance, fatigue, anemia, increased risk for hypoxia, itching, loss of stomach acid and pica (craving to eat ice or dirt). Children with iron deficiency may have a reduced attention span and learning difficulties.  Deficiencies may also contribute to Restless Legs Syndrome or akathesia.  Toxicity manifests by a variety of liver damage and skin conditions. Very high iron intake may be rapidly fatal, particularly in children. Accidental overdose of iron supplements by children is the leading cause of pediatric poisoning deaths in the US.  Overdoses of iron can also cause hemachromatosis, a chronic liver disease treated by frequent blood donations.  The new RDA's 8 mg for men and 18 mg pre-menopausal females, while adolescents and menstruating females have an RDA of 18 mg of elemental iron. Men and older women should not take supplements greater than 10 mg daily because of the risk of iron toxicity and liver damage.  Pregnant women have an RDA of 27 mg intake daily.  Calcium, magnesium and zinc can decrease iron absorption.  The NOEAL for iron is 65 mg per day and the LOEAL is 100 mg.  See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Magnesium

The role of magnesium in muscle function and electrical activity of the heart is critical. It also has important effects in mental function, particularly in alcoholics with thiamin deficiencies. Overall, magnesium is involved in over 300 functions in humans. Deficiencies manifest as numbness, tingling, twitching, impaired memory, high blood pressure and weakness. Severe deficiencies can cause serious irregularities of the heart rate and convulsions. Pregnant women with toxemia of pregnancy are treated with high doses of magnesium. Magnesium is sometimes used to treat acute heart attacks, cardiac rhythm problems and congestive heart failure. 

Magnesium supplementation lowered blood pressure in several studies. It may also have an antioxidant effect and decrease kidney stone formation. The American Diabetes Association 1993 consensus statement on magnesium stated that magnesium deficiency may play a role in increased insulin resistance, carbohydrate intolerance and hypertension.   The panel did not make magnesium supplementation recommendations for diabetics. The list of conditions associated with low magnesium levels in the tissues is long, but measuring magnesium levels in the blood will only reveal very serious deficiencies.  

Refined foods and meats have almost no magnesium, while beans, whole grains and green leafy vegetables are good sources.  American diets average 150-300 mg daily.   The RDA is 300-400 mg. Sources of magnesium include beans, grains and nuts.   Some nutritional experts recommend optimum doses of magnesium be based on body weight.  Baseline recommendations are 30 mg daily per 10 pounds of body weight and higher in some disease states.

Open/Close text Minerals - Manganese

Manganese is present in many enzymes, particularly those involved in tissue healing and in the free radical scavenger, superoxide dismutase, the most important antioxidant.  Low manganese levels have also been associated with seizures in animals.  Nuts and grains are the best food sources of manganese.  There is no RDA for manganese and the Estimated Safe and Desirable Daily Intake (2-5 mg) may be too low.  Doses of 10 mg per day for a lifetime are safe and supplements in epilepsy, strains and sprains of 15-30 mg may be effective.  The NOEAL for manganese is 10 mg per day and no LOEAL is established.  See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Molybdenum

Molybdenum is a component of enzymes involved in sulfite and alcohol detoxification and uric acid formation.  Grains and legumes (beans) are good sources and the American diet usually has up to 500 mcg daily.  The RDA for molybdenum is 45 mcg and the Estimated Safe and Adequate dose is 75-250 mcg per day.  Molybdenum may help fluoride in cavity prevention and is useful in treating a rare disease of copper metabolism called Wilson's disease.  Molybdenum has few toxic effects other than increased risk of gout due to uric acid formation in doses above 10 mg per day (20 times the ESADDI).  No supplementation is required.  The NOEAL for molybdenum is 350 mcg (0.35 mg) per day and no LOEAL is established.  See the 2001 IOM - Dietary Reference Intakes
Open/Close text Minerals - Potassium

Potassium is found in every cell of the body, particularly the muscles, and is critical to the electrical balance of cell function in conjunction with sodium and chloride.  Because both sodium and potassium hold a single positive electrical charge, an increase in the body of one causes a decrease in the other, primarily by excretion in the urine.  High sodium levels are associated with high blood pressure.  High blood pressure is often treated with diuretics that cause potassium loss from the kidneys and sodium restriction.  People under this treatment should take in potassium rich foods to replace lost potassium and enhance sodium excretion.  Sweat also has high concentrations of potassium.  Significant amounts of potassium are found in diarrhea.   Therefore,  athletes and people with intestinal illnesses should consume foods high in potassium.  Almost all foods contain some potassium, though bananas, fruits and potatoes have very high levels.  Low levels of potassium manifest as weakness and fatigue because of its role in glycogen use as a fuel for muscles.  Adults should consume 2 to 5 grams of potassium per day, higher if exercising or with a GI illness.   Some medications, including digoxin, potassium sparing diuretics and ACE inhibitors for high blood pressure, make potassium supplementation dangerous.  Otherwise, if kidney function is normal, the body can process nearly unlimited amounts of potassium.   Non-food supplements are not indicated.
Open/Close text Minerals - Selenium

Selenium has important antioxidant properties, particularly in its relationship with vitamin E.  It is also involved in the production of thyroid hormone.  The antioxidant properties of selenium give it great potential in lowering the risk of cancer, enhancing immune function, decreasing the risk of cardiovascular disease and reducing inflammatory responses.  Cataract formation is related to low levels of a selenium dependent enzyme, glutathione peroxidase, in the fluid of the eye.  A landmark trial of people in the Southeastern US, a selenium deficient area, showed that individuals supplemented with 200 mcg of selenium daily halved their risk of getting prostate, colon and lung cancer.

The Committee on Diet and Health of the Food and Nutrition Board (which develops RDA's) and the National Research Council both conclude that selenium in the diet protects against a wide variety of cancers.  Meat, fish, grains and Brazil nuts have large amounts of selenium.   The RDA's for selenium are 55-70 mcg for women and men.  Some researchers recommend dosages of 50-200 mcg daily for antioxidant effects.  The most biologically useful forms of selenium are selenomethionine and selenium rich yeast.  Sodium selenite is much less active.  Toxicity with selenium can occur at dosages as low as 900 mcg daily.  Toxic effects include birth defects, hair loss, skin cracking, vomiting, anxiety and depression.  The NOEAL for selenium is 200 mcg (0.35 mg) per day and the LOEAL is 910 mcg.  See the 2001 IOM - Dietary Reference Intakes.

Open/Close text Minerals - Silicon

Silicon deficiency in humans is not reported.  Grains rich in fiber are the best sources of silicon, while animal products contain little silicon.  Silicon is essential in an enzyme of cartilage formation and may have a role in bone formation.  There are no RDA's for silicon and the average requirement is estimated at 2-5 mg.  Doses below 50 mg are probably safe.  Supplementation is not required.  See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Vanadium

Vanadium is characterized as an essential nutrient and reportedly improves insulin action.   For this reason, it has been popular for body builders, although no scientific support for this function exists.  Very little dietary vanadium is absorbed.   The Estimated Safe and Adequate Dietary Daily Intake is 100 mcg and no RDA exists.   High daily intake of vanadium can cause gastrointestinal upset, and there has been some association of high levels with manic depressive illness.  Supplementation is not recommended.   See the 2001 IOM - Dietary Reference Intakes.
Open/Close text Minerals - Zinc

Zinc deficiency is relatively common. It is primarily found in red meats, fish and shellfish. Childhood zinc deficiencies lead to numerous skin and bone problems. Loss of taste and smell are some of the earlier signs of zinc deficiency, as is decreased sex drive and fertility. Zinc is also critical for wound and burn healing, as well as ulcers of the skin. Zinc lozenges have recently been advertised to minimize symptoms of colds, flu and prostate problems. The RDA is 8 mg for women and 11 mg for men. Red and white meats are excellent sources of zinc, but plants have little usable zinc. Zinc may also have anti-oxidant properties and may be a factor in reducing the progression of Alzheimer?s disease.  The NOEAL for zinc is 30 mg per day and the LOEAL is 60 mg.  See the 2001 IOM - Dietary Reference Intakes.
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