According to background information in the study, which was published in the Feb. 9 issue of Archives of Internal Medicine, half of Americans regularly use dietary supplements, to the tune of $20 billion a year.
Many people believe multivitamins will prevent chronic conditions such as cancer and heart disease. Yet "convincing scientific data . . . are lacking," the researchers stated.
Two exceptions are folic acid use in women of childbearing age to prevent neural tube defects in babies, and avoiding beta carotene supplements if you're a smoker.
These researchers looked at 161,808 postmenopausal women participating in the government-sponsored Women's Health Initiative who were followed for about eight years. Some 41.5 percent of participants reported using multivitamins.
There appeared to be no association between multivitamin use and risk of breast, colorectal, endometrial, lung or ovarian cancers; cardiovascular disease; or overall death.
"There was some hint that stress vitamins, which are mostly high doses of B vitamins, may have been protective for some forms of cardiovascular disease," Wassertheil-Smoller said.
And the study does come with other caveats, Wassertheil-Smoller said.
"Most of the women in the study probably did eat a fairly decent diet, meaning we don't yet necessarily know how vitamins affect women eating poorly," sh
All rights reserved