The Vitamins You Need

Conventional wisdom has long held that people don't need to supplement their diet if they consume one that meets the RDAs-- recommended dietary allowances -- and other guidelines for vitamin and mineral intakes developed by health agencies of the federal government. Problem is, overwhelming evidence shows that most people don't come close to meeting those nutritional requirements. Surveys report that only nine percent of Americans eat five daily servings of fresh fruits and vegetables -- the amount recommended for obtaining a minimum level of nutrients believed necessary to prevent illness. And average daily calcium consumption in the United States is estimated to be far below the recommended amount.

According to a review of national data by experts at the University of California, Berkeley, people often make food choices that are nutritionally poor: For example, they are more likely to select French fries than broccoli as a vegetable serving, and will opt for a soft drink rather than a glass of skim milk as a beverage. Do you do that? Not only may these and other foods contribute too much fat and sugar to your diet, but they can also result in less-than-optimal intakes of vitamins, minerals, and disease-fighting phytochemicals. The result: Many American diets contain half the recommended amounts of magnesium and folic acid. Also, vitamins A, C, and B6, as well as iron and zinc, are other nutrients that surveys show are at notably low levels in the American diet.

Even with the best nutritional planning, it is difficult to maintain a diet that meets the RDAs for all nutrients. For example, vegetarians, who as a group are healthier than meat eaters (and who tend to avoid junk foods lacking in vitamins and minerals), still may be deficient in some nutrients, such as iron, calcium, and vitamin B12. And most people who want to maintain a healthy low-fat diet will have a problem obtaining the recommended amounts of vitamin E from their food alone, because so many of the food sources for vitamin E are high in fat. Another complication is that a balanced diet may not contain the more specialized substances -- fish oils, soy isoflavones, or alpha-lipoic acid -- that researchers think may promote health. For generally healthy people who cannot always eat a well-balanced diet every day, a supplement can fill in these nutritional gaps or boost the nutrients they consume from adequate to optimal. Check out the chart on the following pages to learn the types of vitamins and minerals you should take, depending upon your eating habits.

The Vitamins You Need

This chart shows the vitamins and minerals that should be in a basic daily supplement formula, and the amounts of each that can help you obtain preventive benefits. (The RDA, short for recommended dietary allowance, is the amount of a nutrient needed to prevent a deficiency in 97 to 98 percent of a population, as determined by the Food and Nutrition Board of the National Research Council.)

The more nutrients you get from foods, the fewer you need from a supplement, so use the chart with these guidelines.

If your diet is nutritionally excellent, take the amounts recommended in column A. These levels are sufficient if you regularly eat foods low in fat, get five to six generous servings of fruit and vegetables every day, and have meat, chicken, or fish several times a week in small portions.

If your diet is basically sound, take the amounts recommended in column B. They are intended for someone who usually eats three meals a day, with at least one or two servings of fruits and vegetables, and who doesn't gorge on fatty foods -- but skips a lunch or breakfast in an average week and may grab one or two fast-food meals.

If your diet is poor, take the amounts recommended in column C in consultation with your doctor. These levels are for someone who skips meals, skimps on fruits, vegetables, and grains (the foods that are considered the richest sources of vitamins and minerals), and normally eats a slice of pizza or a deli sandwich and a diet cola for lunch.

Vitamins	RDA	A - Excellent Diet	B - Sound Diet	C - Poor Diet +
B1 (Thiamin)	1.2 mg	1.5-30 mg	30-60 mg	60-100 mg
B2 (Riboflavin)	1.3 mg	1.7-30 mg	30-60 mg	60-100 mg
B3 (Niacin)	16 mg	20-30 mg	30-50 mg	50-100 mg
B5 (Pantothenic acid)	5 mg	10-60 mg	60-100 mg	100-200 mg
B6	1.7 mg	2-25 mg	25-60 mg	60-100 mg
B12	2.4 mcg	6-100 mcg	100-400 mcg	400-800 mcg
Beta-carotene	*	5,000-10,000 IU	10,000-15,000 IU	15,000-25,000 IU
Biotin	30 mcg	30-100 mcg	100-400 mcg	400-600 mcg
Folic acid	400 mcg	400 mcg	400-600 mcg	600-800 mcg
Vitamin A	3,000 IU	2,500 IU	2,500 IU	2,500 IU
Vitamin C	90 mg	60-300 mg	300-600 mg	600-900 mg
Vitamin D	600 IU	400 IU	400 IU	400 IU
Vitamin E	22 IU	30-200 IU	200-300 IU	300-400 IU

Minerals	RDA	A - Excellent Diet	B - Sound Diet	C - Poor Diet +
Boron	*	100 mcg-1 mg	1-2 mg	2-4 mg
Calcium	1,300 mg	50-150 mg	150-200 mg	200-300 mg
Chromium	35 mcg	50-65 mcg	65-100 mcg	100-200 mcg
Copper	0.9 mg	1 mg	1-1.5 mg	1.5-2 mg
Iron	# 18 mg	5-10 mg	10-18 mg	18 mg
Magnesium	420 mg	100 mg	100-200 mg	200-300 mg
Manganese	2.3 mg	3-5 mg	5-10 mg	10-11 mg
Molybdenum	45 mcg	25-65 mcg	65-100 mcg	100-200 mcg
Potassium	*	30-80 mg	80-100 mg	100 mg
Selenium	55 mcg	20-100 mcg	100-200 mcg	200 mcg
Vanadium	*	10-50 mcg	50-100 mcg	100 mcg
Zinc	11 mg	15 mg	15-20 mg	20-30 mg

Consult a doctor about the appropriateness of taking supplements and their potential interactions with medications.

* No RDA is established for these nutrients.

# Iron recommendations apply only to younger women; men and postmenopausal women should not choose a supplement containing iron.

+ Data on adverse effects of high intakes is limited. Consult your doctor before taking dosages in this column.