Sign Up Now For
HEALTHbeat
Our FREE E-mail Newsletter

In each issue of HEALTHbeat:

  • Get trusted advice from the doctors at Harvard Medical School
  • Learn tips for living a healthy lifestyle
  • Stay up-to-date on the latest developments in health
  • Receive special offers on health books and reports
  • Plus, receive your FREE Bonus Report, Living to 100: What's the secret?

[ Maybe Later ] [ No Thanks ]

Check out these newly released Special Health Reports from Harvard Medical School
Learn How

New Releases

You can't buy good health but you can buy good health information. Check out these newly released Special Health Reports from Harvard Medical School:

Listing of vitamins Home > Welcome Newsweek readers > Listing of vitamins

Listing of vitamins

Vitamin (common names) Benefits Recommended amount (daily RDA* or daily AI**) Upper limit (UL) per day Good food sources Did you know?
VITAMIN A (Retinol, retinal, and retinoic acid — three active forms of vitamin A in the body — are retinoids, "preformed" vitamin A. Beta carotene can easily be converted to vitamin A as needed.) Essential for vision Lycopene may lower prostate cancer riskKeeps tissues and skin healthyPlays an important role in bone growthDiets rich in the carotenoids alpha carotene and lycopene seem to lower lung cancer riskCarotenoids act as antioxidantsFoods rich in the carotenoids lutein and zeaxanthin may protect against cataracts M: 900 mcg (3,000 IU)W: 700 mcg (2,333 IU)Some supplements report vitamin A in international units (IU’s). 3,000 mcg (about 10,000 IU) Sources of retinoids: beef, liver, eggs, shrimp, fish, fortified milk, cheddar cheese, Swiss cheese

Sources of beta carotene:
sweet potatoes, carrots, pumpkins, squash, spinach, mangoes, turnip greens
Many people get too much preformed vitamin A from food and supplements.Large amounts of supplemental vitamin A (but not beta carotene) can be harmful to bones.
THIAMIN (vitamin B1) Helps convert food into energyNeeded for healthy skin, hair, muscles, and brain M: 1.2 mg, W: 1.1 mg Not known Pork chops, ham, soymilk, watermelons, acorn squash Most nutritious foods have some thiamin.
RIBOFLAVIN (vitamin B2) Helps convert food into energyNeeded for healthy skin, hair, blood, and brain M: 1.3 mg, W: 1.1 mg Not known Milk, yogurt, cheese, whole and enriched grains and cereals, liver Most Americans get enough of this nutrient.
NIACIN (vitamin B3, nicotinic acid) Helps convert food into energyEssential for healthy skin, blood cells, brain, and nervous system M: 16 mg, W: 14 mg 35 mg Meat, poultry, fish, fortified and whole grains, mushrooms, potatoes, peanut butter Niacin occurs naturally in food and can also be made by your body from the amino acid tryptophan, with the help of B6.
PANTOTHENIC ACID (vitamin B5) Helps convert food into energyHelps make lipids (fats), neurotransmitters, steroid hormones, and hemoglobin M: 5 mg, W: 5 mg Not known Wide variety of nutritious foods, including chicken, whole grains, broccoli, mushrooms, avocados, tomato products Deficiency causes burning feet and other neurologic symptoms.
VITAMIN B6 (pyridoxal, pyridoxine, pyridoxamine) Aids in lowering homocysteine levels and may reduce the risk of heart diseaseHelps convert tryptophan to niacin and serotonin, a neurotransmitter that plays key roles in sleep, appetite, and moodsHelps make red blood cells Influences cognitive abilities and immune function 31–50: M: 1.3 mg, W: 1.3 mg51+: M: 1.7 mg, W: 1.5 mg 100 mg Meat, fish, poultry, legumes, tofu and other soy products, potatoes, noncitrus fruits such as bananas and watermelons Many people don’t get enough of this nutrient.
Vitamin B12 (cobalamin) Aids in lowering homocysteine levels and may lower the risk of heart diseaseAssists in making new cells and breaking down some fatty acids and amino acidsProtects nerve cells and encourages their normal growth Helps make red blood cells M: 2.4 mcg, W: 2.4 mcg Not known Meat, poultry, fish, milk, cheese, eggs, fortified cereals, fortified soymilk Some people, particularly older adults, are deficient in vitamin B12 because they have trouble absorbing this vitamin from food. A lack of vitamin B12 can cause memory loss, dementia, and numbness in the arms and legs.
BIOTIN Helps convert food into energy and synthesize glucoseHelps make and break down some fatty acidsNeeded for healthy bones and hair M: 30 mcg, W: 30 mcg Not known Many foods, including whole grains, organ meats, egg yolks, soybeans, and fish Your body needs very little biotin. Some is made by bacteria in the gastrointestinal tract. However, it’s not clear how much of this the body absorbs.
VITAMIN C (ascorbic acid) Foods rich in vitamin C may lower the risk for some cancers, including those of the mouth, esophagus, stomach, and breastLong-term use of supplemental vitamin C may protect against cataractsHelps make collagen, a connective tissue that knits together wounds and supports blood vessel wallsHelps make the neurotransmitters serotonin and norepinephrine Acts as an antioxidant, neutralizing unstable molecules that can damage cellsBolsters the immune system M: 90 mg, W: 75 mg Smokers: Add 35 mg 2,000 mg Fruits and fruit juices (especially citrus), potatoes, broccoli, bell peppers, spinach, strawberries, tomatoes, Brussels sprouts Evidence that vitamin C helps reduce colds has not been convincing.
CHOLINE Helps make and release the neurotransmitter acetylcholine, which aids in many nerve and brain activitiesPlays a role in metabolizing and transporting fats M: 550 mg, W: 425 mg 3,500 mg Many foods, especially milk, eggs, liver, and peanuts No rmally the body makes small amounts of choline. But experts don’t know whether this amount is enough at certain ages.
VITAMIN D (calciferol) Helps maintain normal blood levels of calcium and phosphorus, which strengthen bonesHelps form teeth and bonesSupplements can reduce the number of non-spinal fractures 31–50: 5 mcg (200 IU) 51–70: 10 mcg (400 IU) 71+: 15 mcg (600 IU) 50 mcg (2,000 IU) Fortified milk or margarine, fortified cereals, fatty fish Many people don’t get enough of this nutrient.While the body uses sunlight to make vitamin D, it cannot make enough if you live in northern climes or don’t spend much time in the sun.
VITAMIN E (alpha-tocopherol) Acts as an antioxidant, neutralizing unstable molecules that can damage cellsProtects vitamin A and certain lipids from damageDiets rich in vitamin E may help prevent Alzheimer’s diseaseSupplements may protect against prostate cancer M: 15 mg, W: 15 mg (15 mg equals about 22 IU from natural sources of vitamin E and 33 IU from synthetic vitamin E) 1,000 mg (nearly 1,500 IU natural vitamin E; 2,200 IU synthetic) Wide variety of foods, including vegetable oils, salad dressings and margarines made with vegetable oils, wheat germ, leafy green vegetables, whole grains, nuts Vitamin E does not prevent wrinkles or slow other aging processes.
FOLIC ACID (folate, folacin) Vital for new cell creationHelps prevent brain and spine birth defects when taken early in pregnancy; should be taken regularly by all women of child-bearing age since women may not know they are pregnant in the first weeks of pregnancyCan lower levels of homocysteine and may reduce heart disease risk May reduce risk for colon cancerOffsets breast cancer risk among women who consume alcohol M: 400 mcg, W: 400 mcg 1,000 mcg Fortified grains and cereals, asparagus, okra, spinach, turnip greens, broccoli, legumes like black-eyed peas and chickpeas, orange juice, tomato juice Many people don’t get enough of this nutrient.Occasionally, folic acid masks a B12 deficiency, which can lead to severe neurological complications. That’s not a reason to avoid folic acid; just be sure to get enough B12.
VITAMIN K (phylloquinone, menadione) Activates proteins and calcium essential to blood clottingMay help prevent hip fractures M: 120 mcg, W: 90 mcg Not known Cabbage, liver, eggs, milk, spinach, broccoli, sprouts, kale, collards, and other green vegetables Intestinal bacteria make a form of vitamin K that accounts for half your requirements.If you take an anticoagulant, keep your vitamin K intake consistent.
Mineral (common names) Benefits Recommended amount (daily RDA* or daily AI**) Upper limit (UL) per day Good food sources Did you know?
CALCIUM Builds and protects bones and teethHelps with muscle contractions and relaxation, blood clotting, and nerve impulse transmissionPlays a role in hormone secretion and enzyme activationHelps maintain healthy blood pressure 31–50: M: 1,000 mg, W: 1,000 mg 51+: M: 1,200 mg, W: 1,200 mg 2,500 mg Yogurt, cheese, milk, tofu, sardines, salmon, fortified juices, leafy green vegetables, such as broccoli and kale (but not spinach or Swiss chard, which have binders that lessen absorption) Adults absorb roughly 30% of calcium ingested, but this can vary depending on the source.Diets very high in calcium may increase the risk of prostate cancer.
CHLORIDE Balances fluids in the bodyA component of stomach acid, essential to digestion Food and Nutrition Board 1989 guidelines: M: 750 mg, W: 750 mg Not known Salt (sodium chloride), soy sauce, processed foods New recommendations (DRIs) for chloride are under development by the Institute of Medicine.
CHROMIUM Enhances the activity of insulin, helps maintain normal blood glucose levels, and is needed to free energy from glucose 31–50: M: 35 mcg, W: 25 mcg 51+: M: 30 mcg, W: 20 mcg Not known Meat, poultry, fish, some cereals, nuts, cheese Unrefined foods such as brewer’s yeast, nuts, and cheeses are the best sources of chromium.
COPPER Plays an important role in iron metabolismHelps make red blood cells M: 900 mcg, W: 900 mcg 10,000 mcg Liver, shellfish, nuts, seeds, whole-grain products, beans, prunes More than half of the copper in foods is absorbed.
FLUORIDE Encourages strong bone formationKeeps dental cavities from starting or worsening M: 4 mg, W: 3 mg 10 mg Water that is fluoridated, toothpaste with fluoride, marine fish, teas Harmful to children in excessive amounts.
IODINE Part of thyroid hormone, which helps set body temperature and influences nerve and muscle function, reproduction, and growthPrevents goiter and a congenital thyroid disorder M: 150 mcg, W: 150 mcg 1,100 mcg Iodized salt, processed foods, seafood To prevent iodine deficiencies, some countries add iodine to salt, bread, or drinking water.
IRON Helps hemoglobin in red blood cells and myoglobin in muscle cells ferry oxygen throughout the bodyNeeded for chemical reactions in the body and for making amino acids, collagen, neurotransmitters, and hormones 31–50: M: 8 mg, W: 18 mg 51+: M: 8 mg, W: 8 mg 45 mg Red meat, poultry, eggs, fruits, green vegetables, fortified bread and grain products Many women of childbearing age don’t get enough iron.Women who do not menstruate probably need the same amount of iron as men.Because iron is harder to absorb from plants, experts suggest vegetarians get twice the recommended amount (assuming the source is food).
MAGNESIUM Needed for many chemical reactions in the body Works with calcium in muscle contraction, blood clotting, and regulation of blood pressureHelps build bones and teeth 31+: M: 420 mg, W: 320 mg 350 mg (Note: This upper limit applies to supplements and medicines, such as laxatives, not to dietary magnesium.) Green vegetables such as spinach and broccoli, legumes, cashews, sunflower seeds and other seeds, halibut, whole-wheat bread, milk The majority of magnesium in the body is found in bones. If your blood levels are low, your body may tap into these reserves to correct the problem.
MANGANESE Helps form bonesHelps metabolize amino acids, cholesterol, and carbohydrates M: 2.3 mg, W: 1.8 mg 11 mg Nuts, legumes, whole grains, tea If you take supplements or have manganese in your drinking water, be careful not to exceed the upper limit. Those with liver damage or whose diets supply abundant manganese should be especially vigilant.
MOLYBDENUM Part of several enzymes, one of which helps ward off a form of severe neurological damage in infants that can lead to early death M: 45 mcg, W: 45 mcg 2,000 mcg Legumes, nuts, grain products, milk Molybdenum deficiencies are rare.
PHOSPHORUS Helps build and protect bones and teethPart of DNA and RNAHelps convert food into energyPart of phospholipids, which carry lipids in blood and help shuttle nutrients into and out of cells M: 700 mg, W: 700 mg 31–70: 4,000 mg 71+: 3,000 mg Wide variety of foods, including milk and dairy products, meat, fish, poultry, eggs, liver, green peas, broccoli, potatoes, almonds Certain drugs bind with phosphorus, making it unavailable and causing bone loss, weakness, and pain.
POTASSIUM Balances fluids in the bodyHelps maintain steady heartbeat and send nerve impulses Needed for muscle contractions A diet rich in potassium seems to lower blood pressureGetting enough potassium from your diet may benefit bones Food and Nutrition Board 1989 guidelines: M: 2,000 mg, W: 2,000 mg Not known Meat, milk, fruits, vegetables, grains, legumes New recommendations (DRIs) for potassium are under development by the Institute of Medicine.Food sources do not cause toxicity, but high-dose supplements might.
< b>SELENIUM Acts as an antioxidant, neutralizing unstable molecules that can damage cellsHelps regulate thyroid hormone activity M: 55 mcg, W: 55 mcg 400 mcg Organ meats, seafood, walnuts, sometimes plants (depends on soil content), grain products Researchers are investigating whether selenium may help reduce the risk of developing cancer.
SODIUM Balances fluids in the bodyHelps send nerve impulses Needed for muscle contractionsImpacts blood pressure; even modest reductions in salt consumption can lower blood pressure Food and Nutrition Board 1989 guidelines: M: 500 mg, W: 500 mg Not determined Salt, soy sauce, processed foods, vegetables While experts recommend that people limit sodium intake to 2,400 mg, most Americans consume 4,000–6,000 mg a day.New recommendations (DRIs) for sodium are being developed by the Institute of Medicine.
SULFUR Helps form bridges that shape and stabilize some protein structuresNeeded for healthy hair, skin, and nails Unknown Unknown Protein-rich foods, such as meats, fish, poultry, nuts, legumes Sulfur is a component of thiamin and certain amino acids. There is no recommended amount for sulfur. Deficiencies occur only with a severe lack of protein.
ZINC Helps form many enzymes and proteins and create new cellsFrees vitamin A from storage in the liverNeeded for immune system, taste, smell, and wound healingWhen taken with certain antioxidants, zinc may delay the progression of age-related macular degeneration M: 11 mg, W: 8 mg 40 mg Red meat, poultry, oysters and some other seafood, fortified cereals, beans, nuts Because vegetarians absorb less zinc, experts suggest that they get twice the recommended requirement of zinc from plant foods.
*Recommended dietary allowance **Adequate intake