A study published Jan. 7 in The Journal of the National Cancer Institute claims that antioxidant vitamins C, E and beta carotene have no effect in preventing cancer. The study, conducted by Jennifer Lin and colleagues at Harvard Medical School, tracked 7,600 women over an eight-year period. The women either suffered from heart disease or were at high risk, 80 percent of the study group was overweight or obese, and the average age at the time the study began was 60 years.
Critics of the study—a secondary analysis of data originally intended to measure the link between antioxidants and heart disease—criticized both the methodology and the outcome, warning that consumers may get faulty information about vitamins and health.
"We think the study was clearly designed to fail," said Gretchen DeBeau, executive director of the American Association for Health Freedom, an alternative medicine advocacy organization based in Washington, D.C. "They used vitamins well below the therapeutic dose for health benefits, and conducted the study on a sick subset of the population. I don't know if they had ulterior motives, but I'm concerned about folks getting the wrong message. In conjunction with a healthy lifestyle and diet, antioxidants really do help prevent cancer, and their benefits are countless."
A more measured response came from the Council for Responsible Nutrition, a Washington, D.C.-based trade organization representing the dietary supplements industry. "These are nutrients, not drugs," said Andrew Shao, CRN's vice president of scientific and regulatory affairs. "They have real but subtle effects over a very long period of time, and they're one set of tools among many you incorporate to avoid disease. You can't wait until you're 60 and expect that they will prevent cancer."
There is clinical precedent for the selection of dose, he said, but it's impossible to know the ideal dose for a given population. "The results of this trial may not be representative of the general population," Shao said. "Unfortunately, the message taken away from black-and-white press coverage is that these things don't work. In fact, they've been shown to be beneficial in a number of areas."
The study's primary focus, on the link between antioxidants and heart disease, was published last year. It also found no evidence of antioxidant benefits. "The first study also seemed designed to fail," DeBeau said. "We noted in our press release that it was funded by big pharma."