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Vitamins/Minerals 101: Why Take Vitamins & Minerals?

Vitamins / Minerals 101: Why Take Vitamins / Minerals?


Do you need vitamin and mineral supplements? Find out with this beginner's guide.

Why are They Needed? Human bodies cannot function without protein, carbohydrates (sugars and starches) and fats—or the nutrients we call vitamins and minerals.

Because vitamins and minerals are not evenly distributed among foods, people need to eat a well-balanced diet, high in "nutrient-dense" fruits, vegetables, nuts, seeds, and whole grains.

However, few people eat the kind of varied, plant-rich diet needed to provide optimal—or even minimal—levels of all vitamins and minerals. And, modern farming techniques drain the soil of nutrients, making our fruits and vegetables less nutritious. (This is one reason for the popularity of produce grown in nutrient-rich organically cultivated soils.) The facts speak for themselves:

  1. In the most recent USDA survey, more than 80 percent of women and more than 70 percent of men consumed less than two-thirds of the RDA for one or more nutrients. People are eating almost 20 percent more vegetables than they did 25 years ago. But 25 percent of the vegetables consumed in the U.S. are artery clogging French fries, according to a study reported in the journal Cancer.
  2. While there is no clear evidence that daily multi-vitamins extend the life spans of healthy people, there is considerable evidence that they can reduce the risks of specific diseases—thereby increasing "health span."
    Americans and western Europeans are commonly considered the best-fed people in the world. But this characterization is accurate only in reference to caloric intake. In fact, most are overfed and undernourished, eating too much fat, sugar, refined flour, and empty-calorie" foods.
  3. A recent report on children's eating habits indicates that "low nutrient-density foods"—including cake, cookies, donuts, and sugary fruit drinks—are major components of U.S. children's diets, and notes "this compromises intakes of more nutritious foods and may impede compliance with current dietary guidelines.
  4. Americans rank 17th in terms of life expectancy— or that they are spending billions of dollars each year to treat illnesses directly related to poor nutrition. The $666 billion spent to treat disease in 1990 represented an expenditure of $2,566 per year for every man, woman, and child.

Benefits and uses: Proof that multivitamin-mineral supplements protect health continues to accumulate:
Taking a multi-vitamin pill for 15 years of more may reduce the risk of colon cancer by 75 percent, according to a study of 80,000 U.S. nurses.

Daily doses of multivitamin supplements have been found to cut fetal deaths, low birth weight, and pre-term births by 40 percent. After years of foot-dragging in the face of persuasive evidence, in 1997 the U.S.FDA finally agreed that women who intend to become pregnant should be getting 400 mcg of supplemental folic acid (a B vitamin) per day, to reduce the risk of severe birth defects. The only way to ensure this intake level is to consume vitamin supplements or folate-fortified foods.

Studies show that women with the highest intake of folate and vitamin B6 may cut their heart disease risk in half compared to women with the lowest intake. Men and women taking levels of Vitamin E higher than can be obtained from food have lower rates of heart disease than those who ingest low doses do. (Over 800,000 Americans die of heart disease every year.)

Daily multivitamin supplements have been found to boost immune response by up to 60% in older people; Vitamin E supplementation has also been found to boost immune response in the elderly. One clinical trial indicates that nutritional supplements could halve the rate of infectious diseases among elderly persons.
Elderly users of both vitamin E and vitamin C supplements were found to have a 42 percent decreased risk of mortality compared to non- users.

Researchers estimate that regular use of vitamin supplements, including vitamin C and vitamin E could delay the onset of cataracts by at least ten years.

Many studies indicate that increased intake of vitamins A, C, E, and other nutrients, in excess of the RDA, reduce the risk of cancer, which causes 500,000 American deaths each year.

Daily requirements: The best way to get your vitamins and minerals is through food. The only problem is, it's nearly impossible to get the optimal amounts of vitamins and minerals from your diet, no matter how good it is. And "optimal doesn't mean the RDAs. The RDAs (Recommended Daily Allowances) were created as guidelines to vitamin and mineral requirements for healthy people, the average amount adequate to prevent deficiency diseases. They do not represent the amounts most researchers now believe are needed to achieve optimal health and help prevent a variety of diseases.

Vitamins and Minerals Average RDA for Men Average RDA for Women* Estimated Optimal Adult Intake Maximum Safe Intake for Healthy Adults†††
Vitamin A 5,000 IU 4,000 IU 10,000 IU 25,000 IU††
Thiamin 1.5 mg 1.1 mg to 1.5 mg 100-300 mg No known limit
Riboflavin 1.7 mg 1.3-1.7 mg 100-300 mg No known limit
Niacin 19 mg 15-19 mg 50-100 mg# No known limit
Vitamin B6 2.0 mg 1.6-2.0 mg 50-300 mg 500 mg
Folate (folic acid) 200 mcg 180-400 mcg 400 mcg No known limit
Vitamin B12 2.0 mcg 1.6-2.4 mcg 5-100 mcg No known limit
Biotin 30-100 mcg** 30-100 mcg** 300 mcg No known limit
Pantothenic acid 4-7 mg** 4-7 mg** 10-300 mg No known limit
Vitamin C 60 mg 60-85 mg 100-2,000 mg# No known limit
Vitamin D 200-400 IU (5-10 mcg) 200-400 IU (5-10 mcg) 400 IU (10 mcg) 15,000 IU (375 mcg)
Vitamin E 10 IU 8-11 IU 200-600 IU No known limit
Vitamin K 80 mcg** 65 mcg** 100 mcg 500 mcg
Calcium 1,000-1,200 mg 1,000-1,200 mg 1,200 mg# 2,500 mg
Chromium 50-200 mcg** 50-200 mcg** 50-200 mcg 200 mcg
Copper 1.5-3.0 mg** 1.5-3.0 mg** 3.0 mg 3.0 mg
Iodine 150 mcg 150-187 mcg 150 mcg 2.0 mg
Iron 10 mg 15-22 mg 18 mg 50-100 mg
Magnesium 420 mg 320-360 mg 600 mg No known limit
Manganese 2.0-5.0 mg** 2.0-5.0- mg** 10 mg No known limit
Molybdenum 75-250 mcg** 75-250 mcg** 250 mcg 500 mcg
Phosphorous 800 mg 800-1,200 mg 1,200 mg No known limit
Potassium 2,000 mg† 2,000 mg† 3,500 mg 15,000 mg
Selenium 70 mcg 55-70 mcg 200 mcg 200 mcg
Zinc 15 mg 12-17 mg 30 mg 500 mg

*Lower number in the range is the RDA; higher number is the average of the recommended daily allowances for pregnant and nursing women. Women attempting to conceive should take 400 mcg of Folate daily.
**Estimated safe and adequate daily intake; there is no RDA.
†Estimated minimum requirement; there is no RDA.
††Estimated optimal intake based on research showing reduction of disease risk or risk factors for disease. Pregnant women, women attempting pregnancy, or women at risk of unplanned pregnancy must not exceed the RDAs. †††

These upper limits apply only to completely healthy adults who are not pregnant or taking prescription drugs. When a nutrient is marked as "no limit, this should not be taken as license to consume more than the Optimal Adult Intake. Extreme excesses of any one vitamin or mineral can interfere with absorption or use of others (e.g., zinc and copper must be consumed in proper balance). Some individuals may suffer adverse reactions, and there is no benefit to exceeding the Optimal Adult Intake, except to treat or prevent specific disease conditions under expert medical guidance, (e,g, mega--dose niacin for elevated serum cholesterol). # May cause discomfort or minor side effects at intake levels above the Optimal Adult Intake.

Deficiency risk factors: It is an accepted scientific fact that people have different nutritional needs based on genetics, weight, gender, age, health status, physical activity, and ability to absorb various nutrients. In particular, the RDAs are inadequate for the elderly and people who are ill, immune compromised, or on medication. The elderly are particularly at risk—and indeed many studies indicate that they often don't get the nutrients they need—because they not only absorb nutrients less easily but also consume fewer calories and thus fewer nutrients from food.

Then there are environmental factors. Pollution robs us of vital nutrients and increases our exposure to dangerous toxins, and physical or mental stress (which affects practically everyone these days) also weakens immunity and ups our nutritional needs.

Unfortunately, while our need for vitamins and minerals is only increasing, the nutritional content of our food is decreasing. Even if you eat the full complement of fresh produce, you may be getting far fewer vitamins and minerals than you imagine. Over-farming, over- fertilization, and reduced crop rotation all deplete fruits and vegetables of vital nutrients, as do food processing, refinement, storage, and cooking.

Optimal intake: All nutrients are crucial to good health, although some are needed in larger amounts. Well-formulated multi-vitamin and mineral supplements usually include balanced levels of nutrients at dosages that provide at least the RDA for all age groups. But higher levels of individual nutrients are believed to help prevent specific conditions. Calcium, for example, has been shown to help prevent brittle bones and osteoporosis when taken at levels beyond than the RDA.

Antioxidants such as vitamins A, C, and E, beta-carotene, zinc, copper, manganese, and selenium may provide significant protection from conditions ranging from wrinkles to heart disease and cancer. The amounts of these nutrients needed to provide preventive benefits is often beyond the intake levels obtainable from all but the most ideal diets.

Safety: Talk to your health practitioner before using supplements if you are pregnant or nursing or have an existing health condition. And remember, while more can sometimes be better, that's not always the case. Pay close attention to dosage recommendations and safe amounts for all supplements. Most multi-vitamin/mineral supplements—even high-potency formulas—contain amounts that fall well within the safe dosage range for all but pregnant or lactating women.

No pill or powder can replace the nutritional goodness of whole foods such as fruits, vegetables, and fiber-rich grains, which offer health-promoting, disease-preventive fatty acids and phytochemicals. Supplements are intended, as the name indicates, to supplement a wholesome diet and to fill in the inevitable gaps. But as more and more studies show, they can do much more than that. Nutritional supplements may be our best medicine—the key to a whole new level of wellness.

References

Ali N. Nutritionally at-risk groups in the community. Nurs Times 1998 May 20-26;94(20):68-9.
Berdanier, C. Advanced Nutrition: Micronutrients. CRC Press, 1998.
Block, G. Vitamin C and cancer prevention, American Journal of Clinical Nutrition, 1991 supplement.
Bonn D. Vitamin E may reduce prostate-cancer incidence. Lancet 1998 Mar 28;351(9107):961.
Brown NA, Bron AJ, Harding JJ, Dewar HM. Nutrition supplements and the eye. Eye 1998;12 ( Pt 1):127-33.
Cambridge Heart Antioxidant Study, The Lancet, 1996.
Chandra K. Effect of vitamin and trace-element supplementation on immune responses and infection in elderly subjects. The Lancet 1992 Nov 7;340(8828):1124-7.
Clark, L. C. et al. Effects of selenium supplementation for cancer prevention, Journal of the American Medical Association, 1996.
Gey KF. Vitamins E plus C and interacting conutrients required for optimal health. A critical and constructive review of epidemiology and supplementation data regarding cardiovascular disease and cancer. Biofactors 1998;7(1-2):113-74.
Giovannucci, E, et al. Multivitamin use, folate, and colon cancer in women in the Nurses' Health Study. Annals of Internal Medicine, 1998;129:517-524.
Hercberg S. [Antioxidant micronutrients and chronic degenerative pathology: the role of complementary nutritional doses]. Bull Mem Acad R Med Belg 1997;152(10-11):379-85; discussion 385-7. [Article in French]
Locksmith GJ, Duff P. Preventing neural tube defects: the importance of periconceptional folic acid supplements. Obstet Gynecol 1998 Jun;91(6):1027-34.
Losonczy, K.G., et al. Vitamin E and vitamin C supplement use. American Journal of Clinical Nutrition, 1996.
Mindell, E. Vitamin Bible, Warner Books.
Oakley GP Jr. Eat right and take a multivitamin. N Engl J Med 1998 Apr 9;338(15):1060-1.
Rimm, Eric, ScD. Nurses' Health Study, Journal of the American Medical Association, 1998.
Robertson, J., et al. A possible role for vitamins C and E in cataract prevention. American Journal of Clinical Nutrition, 1991 supplement.
Tufts University Diet & Nutrition Letter, Vol. 12, No. 9 Nov. 1994.
United States Department of Agriculture survey, 1987-88.
White, E. Relationship between vitamin and calcium supplement use and colon cancer. Cancer Epidemiology: Biomarkers and Prevention, 1997.


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