Recommendations on use of supplements by healthy individuals

The increasing popularity and use of nutritional supplements has put a greater demand on conventional physicians to provide insight into their appropriate use. A recent review article in the New England Journal of Medicine​ explored current data on different nutritional therapies and provided recommendations concerning which supplements may be appropriate for healthy individuals.

Although there are many supplements available, only a handful of key nutrients were addressed in this report. The authors stated that supplementing with folic acid can produce substantial benefits for many people.

Folic acid reduces the risk of spinal cord defects in fetuses, lowers blood levels of homocysteine (a risk factor for heart disease), and may prevent breast and colon cancer. The recommended level of intake suggested by the authors was at least 400 mcg per day, but higher amounts may be necessary for certain individuals.

Vitamin B6 deficiency may be a problem for those who eat a diet low in red meat and legumes, since these foods are rich sources of vitamin B6. Although the authors don't recommend a specific amount, 50 mg of supplemental vitamin B6 per day has been used in various clinical trials and has not been associated with significant side effects.

Taking additional vitamin B12 may help those with high homocysteine levels, or the elderly, who may have inadequate vitamin B12 stores. The recommended amount of vitamin B12 is not specified, but up to 1,000 mcg per day appears to be safe.

For people living in higher latitudes, taking additional vitamin D may help prevent osteoporosis and bone fractures. Since few foods contain significant amounts of vitamin D, taking 400 IU per day may help, although some individuals may need as much as 800 IU per day. The authors feel that taking up to 2,000 IU of vitamin D per day is safe.

Vitamin E is recommended in the amount of 400 IU per day for middle-aged to older people to prevent heart disease. Daily multivitamins may protect against heart disease and colon and breast cancer, and may also help improve immune function. Multivitamins typically contain 100% of the recommended dietary allowance (RDA) of the primary nutrients in the body and some may contain other minerals or amino acids. The authors recommend taking an amount that is equivalent to the RDA for each nutrient.

Two nutrients the authors don't recommend taking on a regular basis are vitamins A and C. They argue that neither have substantial scientific basis for preventing disease and in the case of vitamin A, may actually be toxic. However, the authors appear to have overlooked research suggesting that supplemental vitamin C may protect against the development of colds, cataracts, and macular degeneration.

It is important to bear in mind that these guidelines apply only to healthy adults and the amounts mentioned may be inadequate for other groups, such as the elderly, pregnant women and immune-compromised people, to name a few. The authors also point out that using a supplement is not an adequate replacement for a good diet or a healthy lifestyle.