Vitamins: Why They’re Vital
The National Academy of Sciences last week recommended that large segments of the population take vitamins because even people who eat well may not be getting all the nutrients they need from food alone.
In particular, the academy cited folic acid for women of child-bearing age--to reduce the risk of serious birth defects--and vitamin B12 for older Americans in their fight against anemia.
Here is a guide to the vitamins, from A to K:
Vitamin A
* What It’s for: Tissue maintenance. Healthy skin, hair and mucous membranes. Helps us see in dim light. Essential for normal growth and reproduction.
* Some Good Sources: Liver; deep yellow, orange and dark green vegetables and fruits (including carrots, broccoli, spinach, cantaloupe, sweet potatoes); cheese; milk; and fortified margarine.
* Signs of Severe Deficiency: Night blindness; dry, scaling skin; poor immune response.
* Signs of Extreme Excess: Damage to liver, kidney and bone; headache; irritability; vomiting; hair loss; blurred vision; yellow skin.
Vitamin B1 (Thiamine)
* What It’s for: Helps body release energy from carbohydrates during metabolism. Health of nerves and muscles, including heart. Helps prevent fatigue and irritability.
* Some Good Sources: Pork, whole grains, dried beans and peas, sunflower seeds, nuts.
* Signs of Severe Deficiency: Beriberi (nerve changes, sometimes edema, heart failure).
* Signs of Extreme Excess: None known.
Vitamin B2 (Riboflavin)
* What It’s for: Helps body release energy from protein, fat and carbohydrates during metabolism. Good vision. Healthy hair, skin, nails. Necessary for normal cell growth.
* Some Good Sources: Liver and other organ meats, poultry, brewer’s yeast, fish, dried peas, beans, nuts, sunflower seeds, cheese, eggs, yogurt, milk, whole grains, green leafy vegetables, nori seaweed.
* Signs of Severe Deficiency: Skin lesions.
* Signs of Extreme Excess: None known.
Vitamin B3 (Niacin)
* What It’s for: Energy metabolism. Important for healthy skin and digestive tract tissue. Stimulates circulation. (Caution: If taken by itself, may cause flushing.)
* Some Good Sources: Liver and other organ meats, veal, pork, poultry, fish, nuts, brewer’s yeast, dried beans, dried fruit, leafy greens, whole grains, milk, eggs.
* Signs of Severe Deficiency: Pellagra (sensitivity to light; fatigue; loss of appetite; skin eruptions; and sore, red tongue).
* Signs of Extreme Excess: Flushing of face, neck and hands; liver damage.
Pantothenic acid
* What It’s for: Supports adrenal glands to increase production of hormones to counteract stress. Important for healthy skin and nerves.
* Some Good Sources: Nuts, beans, seeds, dark green leafy vegetables, poultry, dried fruit, milk.
* Signs of Severe Deficiency: Fatigue, sleep disturbance, nausea.
* Signs of Extreme Excess: None known.
Vitamin B6
* What It’s for: Helps body use protein to build body tissue and aids in metabolism of fat. Facilitates release of glycogen from liver and muscles. Helps in red-blood cell production, fluid-balance regulation.
* Some Good Sources: Sunflower seeds, beans, poultry, liver, nuts, leafy green vegetables, bananas, dried fruit.
* Signs of Severe Deficiency: Nervous and muscular disorders.
* Signs of Extreme Excess: Unstable gait, numb feet, poor hand coordination, abnormal brain function.
Vitamin B12
* What It’s for: Important in formation of red-blood cells and building genetic material. Stimulates growth in children. Helps functioning of nervous system, and in metabolizing protein and fat in body.
* Some Good Sources: Animal protein foods, including meat, fish, shellfish, poultry, milk, yogurt, eggs.
* Signs of Severe Deficiency: Pernicious anemia (weight loss, weakness, pale skin), confusion, moodiness, memory loss, depression.
* Signs of Extreme Excess: None known.
Biotin
* What It’s For: Used in energy metabolism.
* Some Good Sources: Widely distributed in foods, especially eggs.
* Signs of Severe Deficiency: Dermatitis, depression, muscular pain.
* Signs of Extreme Excess: None known.
Folate (folic acid, folacin)
* What It’s for: Helps form red-blood cells. Assists in breakdown and utilization of protein. Essential during pregnancy for its importance in cell division.
* Some Good Sources: Dark green leafy vegetables, nuts, beans, whole-grain products, fruit, fruit juices, liver.
* Signs of Severe Deficiency: Anemia, gastrointestinal disturbances.
* Signs of Extreme Excess: Masks Vitamin B12 deficiency.
Vitamin C
* What It’s for: Essential for connective tissue found in skin, cartilage, bones and teeth. Helps heal wounds. Antioxidant. Stimulates immune system. Aids in absorption of iron.
* Some Good Sources: Citrus fruits, berries, melons, dark green vegetables, cauliflower, tomatoes, green and red peppers, cabbage and potatoes.
* Signs of Severe Deficiency: Scurvy (bleeding gums, weakness), delayed wound healing, impaired immune response.
* Signs of Extreme Excess: Gastrointestinal upsets, confounds certain lab tests; poor immune response.
Vitamin D
* What It’s for: Helps regulate calcium metabolism and bone calcification. Called the “sunshine vitamin” because it’s manufactured in human skin when in contact with ultraviolet light. Wintertime, clouds and smog reduce body’s production.
* Some Good Sources: Fortified and full-fat dairy products, tuna, salmon, cod liver oil
* Signs of Severe Deficiency: Rickets in children, bone softening in adults.
* Signs of Extreme Excess: Gastrointestinal upset; cerebral, cardiovascular and kidney damage; lethargy.
Vitamin E
* What It’s for: Antioxidant to prevent cell-membrane damage.
* Some Good Sources: Vegetable oils and their products, nuts, seeds, fish, wheat germ, whole-grain products, green leafy vegetables.
* Signs of Severe Deficiency: Anemia.
* Signs of Extreme Excess: Perhaps fatal in premature infants given intravenous solution.
Vitamin K
* What It’s for: Necessary for normal blood clotting.
* Some Good Sources: Dark green leafy vegetables, cabbage, cauliflower.
* Signs of Severe Deficiency: Severe bleeding on injury; internal hemorrhaging.
* Signs of Extreme Excess: Liver damage, anemia (from synthetic forms).
*
Sources: National Center for Nutrition and Dietetics of the American Dietetic Assn., Chicago; Food and Nutrition Board, National Academy of Sciences, Washington, D.C.; U.S. Department of Agriculture / Human Nutrition Information Service, Hyattsville, Md.; Food and Drug Administration, Washington, D.C.; California Medical Group, Santa Monica; “The Real Vitamin & Mineral Book,” Second Edition, Shari Lieberman and Nancy Bruning, (Avery Publishing Group, 1997).
