Compiled by George Carter, Jen Curry and Anya Romanowski, M.S., R.D., C.D.N.
Spring 2002
This article is part of TheBody.com's archive. Because it contains information that may no longer be accurate, this article should only be considered a historical document.
Nutrient
Functions in the Body/Benefits
Dietary Sources
Maximum Daily Dose/Toxicities
Fat Soluble Vitamins
Vitamin A Retinol, beta-carotene and various other carotenoids
Helps maintain good vision (necessary for night vision), resistance to infections, and supports growth and repair of body tissues. Also maintains integrity of white and red blood cells, and epithelial lining. Used to treat acne.
Yellow and orange fruits: mango, cantaloupe, papaya, apricots.
5,000 IU is probably best (in beta-carotene form); max/day 20,000 IU.
Stop immediately if you experience nausea and vomiting, blurred vision, or bone pain. A harmless orange coloring of the palms and the face may develop with excessive intake of beta-carotene.
Vitamin D Cholecalciferol, ergocalciferol
Regulates absorption of calcium and phosphorus for bone health.
Formed in skin when exposed to sunlight. Also found in dairy products, egg yolks, fish liver oils, tuna, mackerel, herring, sardines, oysters, yeast.
800-1,200 IU.
Don't give kids more than 1000 IU; excess doses may result in hypercalcemia, which can damage the kidneys and weaken the bones.
Vitamin E Tocopherols, tocotrienols
Antioxidant. Helps maintain cell membranes, red blood cell integrity, protects vitamin A and fatty acids from oxidation. Used to treat anemia and may help manage claudication (cramping pain caused by low blood supply to affected muscles).
Found primarily in vegetable oils, but also butter, avocados, eggs, nuts, whole grain cereals, wheat germ.
Fat malabsorption can lead to vitamin E deficiency.
1,200 IU; such high amounts may interfere with vitamin K activity and increase the risk of uncontrolled bleeding.
Important to know what type of tocopherol you're getting in a supplement.
Vitamin K
Helps make factors that promote blood clotting. Used in hemorrhagic disorders.
Gut produces some. Diet generally supplies remaining need. Some stored in liver. Green, leafy vegetables are the best source, followed by liver and other animal foods.
Fat malabsorption can lead to vitamin K deficiency.
80 mcg; phylloquinone is essentially non-toxic; otherwise, take care with use, especially in children.
Water Soluble Vitamins
Vitamin B1 Thiamin
Helps metabolize carbohydrates, maintain appetite and normal digestion. Essential for nervous tissue function. May be part of a regimen to offset mitochondrial toxicity.
Found in many foods: whole grain cereals, peas, beans, peanuts, legumes, brewer's yeast, wheat germ.
Alcohol, malnutrition, diarrhea, and malabsorption contribute to vitamin B1 deficiency.
Very safe. One German study used 320 mg/day for neuropathy with no side effects.
Vitamin B2 Riboflavin
Helps body break down amino acids, regulates energy, growth, hormones, and formation of red blood cells. Supports cellular breathing. Prevents red, cracked lips and burning tongue. May help with high lactate or lactic acidosis.
B vitamin complexes can include from 50-100 mg/day of riboflavin. Standard multivitamins contain 3 mg.
Vitamin B3 Niacin, nicotinic acid, niacinamide
Important for fat synthesis, protein and carbohydrate breakdown, tissue respiration, health of skin, tongue, digestive system. Higher doses may help manage cholesterol.
Niacin: Standard formulations of multivitamins can contain 20-30 mg. B-complex supplements contain 100 mg, some have up to 200 mg. Supplementation at this dose can cause flushing or itching. Higher doses are sometimes used to treat high LDL cholesterol but can cause liver damage, high blood sugar, vomiting, diarrhea, and low blood pressure. This should be done only with a physician's supervision.
Niacinamide: A non-itchy, no-flush form of B3. 250 mg is probably a safe daily dose. Higher doses may be tolerated. Niacinamide isn?t associated with causing low blood pressure and doesn?t work to treat high cholesterol.
Vitamin B5 Panthothenic Acid
Helps body metabolize carbohydrates, fats, and make steroids.
Offsets deficiency-related dermatitis and "burning foot" syndrome.
Eggs, chicken, avocados, soybeans, whole grains.
Deficiency is uncommon due to its widespread availability in foods.
10 mg included in most supplements.
B vitamin complexes can include from 5-75 mg.
Vitamin B6 Pyridoxine, pyridoxal, other forms
Various classes of enzymes (e.g., aminotransferases) depend on B6 for their activity. Often prescribed to offset the depletion caused by the TB drug, Isoniazid.
250 mg; more than this may worsen or cause neuropathy; high doses probably are best taken with a B-complex; more data needed.
Vitamin B12 Cobalamin
Red blood cell health and development, treat pernicious anemia, used in management of neuropathy.
Liver, kidney, dairy, eggs.
B12 is synthesized by intestinal bacteria. Many people use acidophilus supplements to help maintain intestinal flora.
1,000 mcg; non-toxic.
Absorption of B12 is more complicated than other B vitamins. The body can make and recycle some B12 from what comes in, but absorption of this vitamin can be disrupted in both the stomach and the intestines. If absorption is a problem, B12 may need to be administered by injection.
Biotin
Deficiency can result in hair loss, dermatitis. Biotinyl proteins are critical for fat, carbohydrate and amino acid metabolism.
Yeast, liver, kidney, eggs, milk, fish, nuts.
No known toxicity.
B complex vitamins can contain from 30 to 100 mcg of biotin.
Vitamin C (ascorbic acid; also may be found bound to minerals such as in calcium ascorbate)
Essential element in collagen formation. Important for wound healing, bone fractures, and resistance to infections. Strengthens blood vessels. Helps body absorb non-heme iron when the two are ingested together.
Abundant in most fresh fruits (esp. citrus) and vegetables.
No toxic limit. However, if you take too much too fast (greater than a 2,000 mg dose), you may have diarrhea. Ascorbate forms are easier on the intestine; raise dosage slowly.
Folic acid Folate, folacin
Essential for blood cell formation, protein metabolism, and prevention of neural tube defects.
Very non-toxic, particularly if taken with adequate B12. High dosages may mask a vitamin B12 deficiency.
Selected Minerals
Boron
Bone health, prevention of osteoporosis, reduces magnesium excretion.
Fruits, vegetables.
3 mg/day is a suggested dose; take with multi containing manganese, calcium and riboflavin.
Calcium (and phosphate)
Necessary for strong bone structure, teeth, muscle tissue. Regulates heartbeat, nerve function. Plasma levels affected by thyroid, parathyroid glands.
Green leafy vegetables, fortified orange juice, dairy products. Sardines, salmon with bones, tofu. Alcohol, soda (colas) and caffeine deplete calcium stores in body. Need vitamin D to make use of calcium in the body.
Overdose unlikely unless you are magnesium deficient; iron and zinc absorption may be impaired with high calcium intake. High intake may cause constipation. Daily intake need varies depending on age, gender, and health. Talk with your doctor about the right dose for you.
Chromium
Glucose metabolism. Deficiency results in glucose intolerance.
Certain foods, like grains, contain phytates, which may inhibit iron absorption.
Vegetarians may not get enough iron from their diet.
30 mg/day max; avoid extra if you have liver disease or hemochromatosis; excess can cause bloody diarrhea, vomiting, acidosis, darkened stools, abdominal pain.
Non-heme (plant sources) iron absorbed poorly.
Magnesium
Important for parathyroid hormone release, muscle contraction, bone formation, blood pressure control.
Deficiency occurs with malabsorption/alcoholism/ kidney disorders and may result in lowered calcium and potassium levels.
Nuts, legumes, unmilled grains, beans, green leafy vegetables, avocados, bananas.
Trace element supplements can contain from 100-500 mg. Higher doses (up to 1000 mg) may also have benefit, but more data needed.
Supplementation may be problematic if you have kidney trouble; first signs of excess are low blood pressure, nausea and vomiting.
Manganese
Involved in the formation of bone, as well as in enzymes involved in amino acid, cholesterol, and carbohydrate metabolism.
10 mg. Higher doses can interfere with iron absorption.
Molybdenum
Important in a variety of enzyme systems (e.g., oxidases). Mobilization of iron from storage, growth and development.
Milk, beans, whole grain breads and cereals, nuts, legumes (depending on soil content).
75-250 mcg; it's not clear what the limit is but this is generally a safe and adequate range. A high incidence of gout-like syndrome has been associated with dietary intakes of 10-15 mg/day.
Phosphate
Bone health.
See calcium entry.
Maintains acid-base balance.
Don't supplement if you eat meat or drink sodas. Abundant in all animal foods: meat, fish, poultry, eggs, and milk.
500 mg. High consumption of phosphate may affect calcium levels.
Potassium (electrolyte)
Along with sodium and chloride, referred to as electrolytes. Maintains fluid balance, blood pressure, cell integrity, muscle contractions, and nerve impulse transmission. Sodium/potassium ratios out of balance result in muscle and heart weakness, diarrhea.
Fruits and juices (a banana has about 450 mg), green leafy vegetables, meats.
2,000 mg. High doses are used in people with kidney disease; excessive doses can be problematic.
Selenium
Antioxidant properties protect body tissues against oxidative damage caused by radiation, pollution and normal body reactions.
Red blood cell health.
Deficiency results in growth failure, and hepatic necrosis.
Seafood, kidney, liver, selected grains.
Keshan's syndrome occurs in regions with selenium-depleted soils.
600 mcg max; 200-400 mcg per day is probably more than enough; reduce dose if you get a "garlic" breath/taste.
Zinc
Maintaining immune function; wound repair.
Deficiency results in anorexia, growth retardation, lowered testosterone levels, hair loss, and impaired taste.
Meat, liver, eggs, seafood (oysters), whole grains (but the form is less absorbable).
40 mg. Be sure to take copper if taking 50-150 mg and only under guidance of healthcare provider. High consumption of zinc may impair immune function.
IU = International Units; mg = milligrams; mcg = micrograms; g = grams.
This article is part of TheBody.com's archive. Because it contains information that may no longer be accurate, this article should only be considered a historical document.
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