Terms and Abbreviations to Know How to Read This Guide What About Multivitamins? Supplement Guide

Water-Soluble Vitamins
Water-soluble vitamins are readily absorbed into the blood and travel freely through the body. Because they are used up quickly and excesses are excreted and not stored (except for vitamin B-12, which remains stored in the liver for about five years), you need to get a sufficient amount of these vitamins every day.

Vitamin C
Other names: Ascorbic acid, L-ascorbic acid, calcium ascorbate, sodium ascorbate and C-complex. 
Why: Builds and maintains collagen and connective tissue; helps form red blood cells; enhances iron and folic acid absorption; acts as an antioxidant; aids wound healing.
How much: RDA = 90 mg daily for men; 75 mg for women; smokers and people with arthritis should aim for 110 mg daily.
Deficiency: Weight loss, fatigue, slower healing times and repeated infections and colds. 
Foods: Peppers (especially sweet red ones), orange juice, pineapple and other citrus fruits, strawberries, papaya, broccoli, Brussels sprouts and kiwi. 
Supplements: Daily intake of 200 mg is frequently recommended for all adults, because many experts think the RDA for vitamin C is too low. A supplement can help boost intake if diet falls short. Taking more than 200 mg daily won't benefit you because excesses are excreted. Natural and synthetic vitamin C react the same in the body. Additional ingredients, such as rose hips or bioflavonoids, have not been shown to improve benefit. 
Too much: UL of vitamin C is 2,000 mg daily. Excessive amounts can lead to diarrhea, nausea and risk of kidney stones. 
Interactions: Anticoagulant or blood-thinning medication, oral contraceptives, hormone supplements and iron supplements. Regular use of nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, antibiotics or steroids increases the need for vitamin C. 
Research note: People who took at least 152 mg vitamin C daily reduced the progression of knee osteoarthritis (OA) by half and had less pain. Scientists think vitamin C helps people with OA and rheumatoid arthritis (RA) because it promotes the formation of collagen, which is weakened by OA, and gets rid of free radicals, which can damage cartilage and cause inflammation.

Vitamin B-1
Other names: Thiamine, thiamin, thiamin hydrochloride and thiamin nitrate.
Why: Converts sugar to energy and is essential for normal functioning of the heart, brain, nervous system and muscles.
How much: RDA = 1.2 mg for men; 1.1 mg for women.
Deficiency: Effects of low levels not known.
Foods: Pork, fortified cereal, sunflower seeds, whole wheat, brown rice, fish, lentils, peas and beans. Pasta, bread and rice are enriched with thiamine.
Supplements: Multivitamins generally provide 100% or more of the DV. 
Too much: No known symptoms. B vitamins may cause an allergic reaction resulting in flushing, itching or swelling. 
Interactions: Drinking excessive amounts of coffee, tea (regular or decaffeinated) or alcohol with foods high in vitamin B-1 decreases absorption of this vitamin. Oral contraceptives, antibiotics, sulfa drugs, regular use of antacids and some diuretics may interfere with thiamine's absorption. 

Vitamin B-2
Other names: Riboflavin.
Why: Promotes healthy development; helps produce skin and red blood cells; helps the body convert sugar to energy.
How much: RDA = 1.3 mg daily for men; 1.1 mg daily for women.
Deficiency: Rare; symptoms can include dry, cracked skin and sensitivity to light. 
Foods: Beef, beef liver, milk, cheese, eggs, almonds, fortified cereals and grains. Riboflavin is easily destroyed by light.
Supplements: Generally contained in B-complex or multivitamins, which provide 100% or more of the DV for riboflavin. 
Too much: UL not determined. High doses are believed harmless, but may turn urine bright orange or yellow.
Interactions: None known.

Vitamin B-3
Other names: Niacin, nicotinic acid and nicotinamide.
Why: Helps with producing energy from food (sugars and fats); keeps skin, nerves and digestive system healthy.
How much: RDA = 16 mg for men; 14 mg for women. 
Deficiency: Effects of low levels not known.
Foods: Chicken, tuna, turkey, fish, beef, fortified cereals, enriched grains and peanut butter. 
Supplements: Typically in B-complex and multivitamins, which generally provide 100% or more of the DV. 
Too much: UL = 35 mg, though some doctors prescribe higher doses as a treatment to reduce cholesterol and triglyceride levels. Flushing of the face, neck and ears; itching, nausea and headache; can aggravate gout. More serious effects include peptic ulcers, diabetes and liver damage.
Interactions: Alcohol (with nicotinic acid), cholesterol-lowering drugs, gout medication and oral contraceptives. Pregnant women should avoid taking high doses of nicotinic acid. Take with food to avoid stomach upset.

Vitamin B-6
Other names: Pyridoxine, pyridoxal, pyridoxamine and pyridoxine hydrochloride. 
Why: Participates in more than 100 chemical reactions in the body; needed for formation of amino acids, red blood cells and antibodies; important for nerve and brain function and energy production. 
How much: RDA = 1.3 mg for all adults up to age 50; over age 50, 1.7 mg for women, 1.5 mg for men.
Deficiency: Effects of low levels not known.
Foods: Bananas, fortified cereal, salmon, beans, potatoes, chicken and peanut butter. 
Supplements: Found in multivitamins, B-complex and vitamin B-6 supplements; do not exceed a total intake higher than 100% of the DV.
Too much: UL = 100 mg. Long-term high doses of B-6 can lead to nerve damage, resulting in pain and numbness of the extremities.
Interactions: Oral contraceptives, hormone replacement therapy and medications for tuberculosis and Parkinson's disease.
Research note: In an Arthritis Foundation-funded study, researchers at Tufts University in Boston found that low blood levels of vitamin B-6 decreased as the activity, severity and pain of RA increased. Researchers suggest that inflammation may decrease the level of vitamin B-6.

Vitamin B-12
Other names: Cobalamin, cyanocobalamin and methylcobalamin.
Why: Helps make red blood cells, nerve cells and genetic material; converts folate to its active form. 
How much: RDA = 2.4 mcg.
Deficiency: Because vitamin B-12 converts folate to its active form, too little B-12 can lead to a folate deficiency, resulting in pernicious anemia - malformed red blood cells - causing fatigue, weakness, nausea, loss of appetite and weight loss. 
Foods: Beef, lamb, pork, eggs, chicken, fish, milk and cheese. Fortified foods such as cereal, pasta and bread contain synthetic versions. 
Supplements: Recommended for strict vegetarians and those with a malabsorption disease. Because vitamin B-12 absorption declines with age, it is also advised for people older than 50. Most multivitamins and B-complex supplements contain 100% or more of the DV. 
Too much: UL not determined; negative side-effects not known. 
Interactions: Antacids, drugs for indigestion and reflux disease and cholesterol-lowering medication.
Research note: A study of 3,000 adults age 26 to 83 found almost 40 percent fell in the low-to-normal range for vitamin B-12 blood levels. Because participants ate plenty of meat, poultry and fish, these findings support a case for getting more of your B-12 from fortified cereals and/or supplements. Studies show that low blood levels have been linked to heart disease, cancer, decreased folate levels, neural tube defect, Alzheimer's disease and depression. 

Folate
Other names: Folate (natural), folic acid and folacin (synthetic).
Why: Promotes healthy cell growth and reproduction, formation of DNA; regulates homocysteine levels.
How much: RDA = 400 mcg for adults; 600 mcg for pregnant women. At least half of this intake (200 mcg) should come from the folic acid found in fortified foods and supplements. 
Deficiency: In pregnant women, low levels increase the risk of neural tube defects in their babies. Increased risk for certain cancers and heart disease; increases the toxic effects of methotrexate.
Foods: Spinach, kale, collards, turnip greens, asparagus, broccoli, black- eyed peas, lentils, peas, baked beans, oranges, orange juice, brown rice and fortified breads, cereals and grains.
Supplements: Multivitamins and B-complex vitamin supplements generally provide 100% of the DV. 
Too much: UL = 1,000 mcg daily, or 1 mg. Doses higher than 1,500 mcg (1.5 mg) may cause minor discomfort such as nausea, appetite loss and gas; and can mask a vitamin B-12 deficiency, resulting in nerve and brain damage. Folic acid may be prescribed at levels higher than the UL for people taking methotrexate.
Interactions: Alcohol, anticonvulsive medications, cholesterol-lowering drugs and methotrexate. 
Research note: A study has shown that folic acid supplementation may actually decrease the effectiveness of methotrexate, particularly in patients who are negative for rheumatoid factor or who have a milder form of RA.