Unscientific, Deceptive, and a Disservice to American Women

Published March 1, 1999

NBC health correspondent Dr. Bob Arnot’s book, The Breast Cancer Prevention Diet: The Powerful Foods, Supplements, and Drugs That Can Save Your Life was published in October 1998. Taking its cue from the 12–step programs used by Alcoholics Anonymous and other organizations, the book offers 12 steps and an array of diet plans designed both for women who wish to prevent breast cancer and for women already diagnosed with the disease.

Arnot’s book comes at a time when American women’s consciousness of–and concern about–breast cancer may be at an all-time high. He taps into women’s fears of the disease by mislabeling breast cancer “an epidemic,” and then goes on to appeal to his readers’ notions of feminism by asserting that by following his diet, women can “grasp that sense of control and hope that this disease can be prevented and its intensity diminished.”

“Dr. Bob,” as he is called, is familiar to and trusted by millions of television viewers. His position as chief medical correspondent for NBC News and the Today show gives him the sort of credibility and exposure that allow him to exert a powerful influence on the public. A 1997 study by the National Health Council found that 40 percent of American adults consider television, more than any other media outlet, their “principal source of health information.” That study also found that Americans trust the health information on TV news shows almost as much as they trust their doctors.

The basic premise of Arnot’s book is that certain foods inhibit or stimulate the development of breast cancer. Arnot does not claim outright that his diet can “cure” breast cancer, but his argument strongly suggests that such a diet can treat and decrease the size of existing tumors.

One advertisement for Arnot’s book describes it as a “runaway best seller” and urges women: “Don’t wait to save your life.” That urgent plea may sound extreme–just another example of advertising hyperbole–but, in fact, Arnot does claim that his diet offers a life-saving effect to women at risk for breast cancer (meaning, of course, all women).

Arnot bases his diet on laboratory work done with animals and on preliminary human studies. In so doing, Arnot endorses imprudent approaches to preliminary findings and advocates abandoning the time-tested methods of scientific inquiry. Regardless of the potential of diet as a preventive measure against breast cancer, the benefits suggested so far cannot be extrapolated to humans without further research.

Many of the dietary interventions for breast cancer prescribed by Arnot do indeed represent scientific hypotheses worthy of further study. Potential benefits for some of the nutritional recommendations made in The Breast Cancer Prevention Diet appear promising, although none has undergone sufficient scrutiny and testing to conclude that their use “can save your life.”

Arnot claims that by eating the “right” combination of foods, women can dramatically decrease their risk of breast cancer. Among his “prescriptions,” Arnot recommends that women eat large doses of soy products and flaxseed for their estrogen-blocking effects–effects supposedly similar to those of tamoxifen and raloxifene, two drugs that currently are undergoing rigorous study for safety and efficacy in the prevention of breast cancer. According to The Breast Cancer Prevention Diet, the ultimate benefit of Arnot’s proposal is that foods can act as drugs and so can be used as a form of chemoprevention–but without any of the drugs’ adverse side effects.

When counseling health practitioners about the dangers of using dubious remedies, medical sages for centuries have warned, primum non nocere: “first, do no harm.” Arnot maintains that “you cannot err with a healthy diet.” But by making unfounded “life-saving” claims, The Breast Cancer Prevention Diet is offering something other than a healthy diet. Trusting Arnot’s version of science and adhering to his diet could cause real harm.

Arnot’s message that his diet allows women to “take control” of their breast cancer risk, and his claim that his diet offers effects comparable to those of drugs “without the side effects,” may confuse women and cause them to neglect well-established recommendations–such as routine physician evaluations and mammography–for early, potentially life-saving breast cancer detection. Arnot’s suggestion that following his diet may shrink breast tumors may encourage women who feel a lump to attempt to treat themselves with this diet rather than seeking reliable medical evaluation.

Arnot’s message may lead women suffering from breast cancer to feel personally responsible for their condition–to feel guilty because they did not follow the diet (“If only I had eaten the ‘right’ foods, I wouldn’t be ill.”). Arnot downplays the role of genetics and unknown factors in the development of breast cancer. (Indeed, most breast cancers are sporadic and not secondary to known risk factors.) The diet plans Arnot recommends with little or no scientific foundation require major lifestyle changes–changes that could disrupt already-healthy eating habits for the entire family, especially children.

Arnot’s book is alarmist. It promotes exaggerated perceptions of risk and undermines confidence in well-established scientific methods for breast cancer prevention and study. Those methods include regular mammography screening for women over age 40, regular breast self- examination, avoidance of obesity, regular exercise, and regular medical check-ups.

The scientists of the American Council on Science and Health and other leading health professionals–many of them scientists whose work is referred to in The Breast Cancer Prevention Diet–are gravely disturbed by the irresponsible and unfounded claims propagated in this book. In an effort to offer a sounder and more balanced viewpoint, ACSH has issued a peer–reviewed report refuting the arguments set forth in Arnot’s book. You can find the full ACSH report on the Internet at www.acsh.org/publications/reports/Arnot98_page1.html.

Elizabeth Whelan Sc.D., M.P.H., is president of the American Council on Science and Health, New York City. She can be reached by e-mail at [email protected]. John Morgan and Shalu Sharma are with the School of Public Health at Loma Linda University. Alicia Lukachko serves on the staff of the American Council on Science and Health.