More regulation of supplements is needed

This “large, well-designed, and well-conducted” trial adds to the existing evidence that certain supplements can be harmful, and the findings concur with those of other recent observational studies.

“The belief that antioxidant supplements are beneficial seems likely to have resulted from a collective error. Perhaps oxidative stress is one of our life spans,” they suggested.

Indeed, the shift in the use of dietary supplementation for prevention of deficiency to use for promoting wellness and prevention of disease — with many consumers believing that supplements are safe for use without the supervision of their physician — is problematic.

“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,” they said.

Rather, there are likely risks with both insufficient and too-large intake, they added.

“Therefore, we believe that politicians and regulatory authorities should wake up to their responsibility to allow only safe products on the market,” they said, also nothing that in a well-nourished population, the use of vitamin and mineral supplements as a preventive measure should not be recommended.

A possible exception based on these and other findings is with vitamin D3 supplementation, particularly when there is insufficient vitamin D supply from the sun and diet; this may apply to older women, and perhaps older men. The matter of calcium supplementation may require further study.