Can One A Day multivitamins prevent disease?

Can a multivitamin really prevent various diseases? Bayer claims that its One A Day multivitamins  "support" breast, heart, eye, and joint health, as well as physical energy, immunity, healthy blood pressure, bone strength, and metabolism.

But the Center for Science in the Public Interest (CSPI) says that claim has never been proven and that it will sue Bayer unless it removes the claims from its packaging and advertising. 

The non-profit consumer group quotes literature from Bayer that recommends women conduct breast self-exams, get annual mammograms and eat a healthy diet to reduce their chances of getting breast cancer.

Bayer's final tip? "Take One A Day Women's multivitamins formulated with a high level of vitamin D to support breast health."

Inconclusive evidence

But CSPI says the evidence that vitamin D plays a role in preventing breast cancer is inconclusive and, even if it weren't, supplement manufacturers are prohibited from making disease-prevention claims altogether.

"Bayer is literally putting One A Day multivitamins on a par with mammograms," said CSPI litigation director Steve Gardner. "Bayer is saying: 'Take these pills and you'll reduce your risk of breast cancer.' And elsewhere, when the company says it 'supports breast health,' it knows full well that cancer is far and away the top breast health issue for women."

Labels and marketing copy for several One A Day multivitamins also claim that the product is formulated to "support heart health" or "support healthy blood pressure," basing such claims on the presence of vitamins B, C, and E. But in the same way consumers interpret "supports breast health" as "prevents breast cancer," consumers interpret these claims to mean that the pills prevent heart disease or lower blood pressure, according to CSPI. There is inconclusive evidence that those particular nutrients do either.

It's not the first time Bayer's claims have been challenged. In 2007, the company paid a $3.2 million fine as part of a consent decree reached with the Federal Trade Commission and the Department of Justice over weight-loss claims on One A Day.

In October 2009, CSPI filed suit against Bayer over its claims that One A Day Men's multivitamins with selenium might reduce the risk of prostate cancer. In fact, the largest prostate cancer prevention trial ever conducted was abandoned once it became clear that selenium was no more effective at reducing prostate cancer risk than a placebo. In October 2010, Bayer settled a suit brought by several states, accusing Bayer of deceptively leveraging fear of prostate cancer in order to market One A Day to men.

"By positioning One A Day as a preventive for breast cancer, heart disease, and other conditions, Bayer is thumbing its nose at the Food and Drug Administration, the Federal Trade Commission, and a dozen or so state attorneys general-continuing a decade-long spree of irresponsible and sometimes felonious behavior," Gardner said. "There's nothing wrong with selling-or taking-a daily multivitamin. But you can't sell something you can't deliver."