The authors found that use of most supplements was not associated with reduced total mortality in older women, and many supplements appeared associated with increased mortality risk. After adjustment, use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc and copper, were all associated with increased risk of death in the study population. Conversely, calcium supplements appear to reduce risk of mortality. The association between supplement intake and mortality risk was strongest with iron, and the authors found a dose-response relationship as increased risk of mortality was seen at progressively lower doses as women aged throughout the study.
Less is more.....
"Dietary supplementation has shifted from preventing deficiency to trying to promote wellness and prevent disease," the authors write. "Until recently, the available data regarding the adverse effects of dietary supplements has been limited and grossly underreported. We think the paradigm 'the more the better' is wrong. One should consider the likely U-shaped relationship between micronutrient status and health."
"We cannot recommend the use of vitamin and mineral supplements as a preventive measure, at least not in a well-nourished population," the authors conclude. "Older women (and perhaps men) may benefit from intake of vitamin D3 supplements, especially if they have insufficient vitamin D supply from the sun and from their diet. The issue of whether to use calcium supplements may require further study."