In a recent issue of The New England Journal of Medecine, Drs. Walter C. Willett and Meir J. Stampfer review the evidence for and against using various vitamin supplements to prevent disease.
Most people could probably benefit from taking a multivitamin, say researchers at the Harvard School of Public Health, but regular vitamin intake cannot remove the health effects of a poor diet and a sedentary lifestyle.
"Taking a multivitamin is particularly important for women who may become pregnant, people who drink one or two alcoholic beverages daily and urban residents who may not be able to afford to eat enough fruits and vegetables" .
"Substantial data suggest that higher intakes of folic acid, vitamin B6, vitamin B12 and vitamin D will benefit many people, and a multivitamin will ensure an adequate intake of other vitamins for which the evidence of benefit is indirect," they write.
Elderly people should also take a multivitamin, the report indicates, because they tend to have a difficult time absorbing vitamin B12 and to be deficient in vitamin D. And vegans might also want to consider a multivitamin because they may lack vitamin B12, the researchers suggest.
Willett and Stampfer highlight the benefits of folic acid for women of child-bearing age, because the nutrient can prevent them from having a child with neural tube defects.
"We also believe that vitamin E supplements are reasonable for most middle-aged and older Americans who are at increased risk for heart disease," the team adds.
But the authors emphasize that a vitamin pill is no substitute for a healthy diet because foods contain additional important components, such as fiber and essential fatty acids.
Furthermore, "a vitamin supplement cannot begin to compensate for the massive risks associated with smoking, obesity or inactivity," the doctors warn.
"Given the greater likelihood of benefit than harm, and considering the low cost, we conclude that a daily multivitamin that does not exceed the recommended daily allowance (RDA) of its component vitamins makes sense for most adults," the researchers write.