Vitamin supplements have scientific support

By William B. Patterson, MD, MPH, FACOEM

(Editor’s note: With so many employees taking herbs and vitamin supplements on their own these days, it’s important for them to have sound medical advice. Below is an article on vitamins written by Occupational Health Management editorial advisory board member William B. Patterson.)

Many patients have asked me about the evidence for vitamin supplementation in improving health or preventing medical problems. My opinion is that the scientific data supporting the benefits of vitamin supplementation is strong. For example, in prospective studies, the use of a multivitamin has been associated with a lower risk of heart disease, colon cancer, and breast cancer, particularly among regular users of alcohol.

These comments and recommendations are based on published scientific research and reflect the approach of using the available evidence to weight the likelihood of benefit against the likelihood of harm. With the exception of excess intake of vitamin A, there is no meaningful risk associated with any of the following recommendations.

Good evidence supports regular supplements with vitamin E. For example, in healthy elderly individuals, 200 mg per day of vitamin E provides enhancement of immune function. There also is substantial evidence that vitamin E supplements reduce the risk of cancer and/or cardiovascular disease, especially in large groups of individuals without known cardiac disease.

High levels of vitamin C intake have been associated with a reduced risk of osteoarthritis-related knee pain and substantial reduction in the progression of established osteoarthritis. One study has shown improved cognitive abilities in older persons taking supplements of vitamin A and C. In at least one study, subjects with vitamin C intake more 50 mg per day had a lower death rate from all cardiovascular diseases.

Research also demonstrates the importance of daily vitamin D, which is not found in some multivitamin and mineral preparations. Vitamin D is especially important for bone strength and may decrease the risk of other medical problems. Higher intakes of vitamin D are associated with lower risk of osteoarthritis, improved bone mineral density, and reduced risk of fractures. Individuals with low exposure to sunlight and low milk intake commonly do not receive enough vitamin D. Many authorities recommend 400 IU daily for all adults and 800 IU daily for older adults and adults with other medical problems.

There is substantial evidence that folic acid (folate) reduces the risk of most cardiovascular disease and stroke, and most experts recommend 400 mcg per day. There is also very good evidence that 0.4 mg (400 mcg) of folic acid reduces the risk of colon cancer. Folic acid is better absorbed in vitamin form than in foods. Most individuals in the United States still consume less than 400 mcg of folic acid per day from their diet. Folate is especially important in women of childbearing age since it substantially prevents neural tube abnormalities, a serious birth defect.

Because 10%-30% of individuals older than 60 cannot absorb vitamin B12 in food, they should take vitamin supplements that contain B12. Crystalline B12, the form in vitamins, is absorbed well. Some specialists in aging also recommend vitamin B6 supplementation. In the Nurses’ Health Study, women who regularly took multivitamins had a reduced risk of cardiac disease, which appeared to be related to a substantial degree to folate and vitamin B6. The recommended dose of B6 is 3 mg/day. People who reduce their red meat consumption without increasing legumes may not obtain enough B6 from their diet.

Many individuals do not obtain enough calcium, especially middle-aged and postmenopausal women. Calcium prevents osteoporosis (weak and brittle bones) and probably reduces the risk of colon cancer. An intake of at least 1,000 mg per day is recommended for adults 19-50 depending on your age, sex, physical activity, diet, and other factors. The recommendation is 1,200 mg per day for everyone older than 50 years. Calcium citrate is generally better absorbed than calcium gluconate, and taking supplements in doses of 500 mg or less with meals probably improves absorption. Oral calcium supplements in women (and perhaps in men) have the added benefit of raising HDL (good) cholesterol. Good sources of calcium in the diet include milk, yogurt, most hard cheeses, tofu, and calcium supplemented foods.

There is substantial evidence that one low-dose aspirin daily (80 mg or 160 mg) reduces the risk of cardiovascular disease and colon cancer and may have other benefits. Using enteric-coated aspirin will reduce the risk of stomach side effects.

In a French study of nursing home patients, supplemental zinc (20 mg) and selenium (100 mcg) improved immune response and substantially reduced the frequency of respiratory tract infections. There is a substantial body of evidence suggesting that selenium has a cancer protective effect, especially of prostate cancer. In a Dutch study, daily consumption of nutrient rich fruits and dairy foods increased bone mass and density. Zinc also may help to prevent macular degeneration, which occurs in the elderly.

Elderly individuals with a limited diet should strongly consider multivitamin and mineral supplementation. In one randomized study of elderly people, a multivitamin-multimineral combination reduced the number of days due to illness by half.

Other micronutrients that may have beneficial health effects include potassium, magnesium, and chromium. There is good evidence on the value of chromium piconolate in building lean muscle mass. Men and postmenopausal women should not take vitamins that contain iron, which may act as an oxidant and possibly accumulate in the body.

In summary, I recommend the following vitamins for most adults concerned with being as healthy as they can. Compared to most prescriptions and many other aspects of health, the annual costs are very reasonable. They will not make up for inattention to basic health habits such as exercise, not smoking, weight control, and general medical care. They will promote better health. The available evidence suggests that generic preparations from mainstream pharmacy chains are bioavailable, and there is no benefit in purchasing brand name or "natural" vitamin preparations.

  • A good multivitamin/mineral preparation (such as a generic Centrum) should contain many of the recommendations noted above, including vitamin D, folic acid, vitamin B6, vitamin B12, vitamin A, and several minerals.
  • vitamin E (400 units);
  • one low-dose aspirin;
  • calcium supplements (if not obtained via diet);
  • consider: zinc, magnesium, potassium, chromium picconolate, and other micronutrients based on your dietary and exercise habits;
  • consider vitamin C (250 mg-500 mg).

For more information, contact:

William B. Patterson, MD, MPH, FACOEM, Occupational Health + Rehabilitation Inc., 175 Derby St., Suite 36, Hingham, MA 02043. Telephone: (978) 657-3826. FAX: (978) 657-5705.