Book on fertility and diet stirs buzz, skepticism

December 24, 2007|Judy Foreman

Researchers at the Harvard School of Public Health have created a buzz with their new - and controversial - book, "The Fertility Diet."

The book doesn't actually come right out and claim that the new Harvard diet is a cure for infertility. But that's the message desperate couples could be forgiven for getting, given its title, some of the authors' public statements, the intense media hype, and, of course, the clout of almost anything with the Harvard imprimatur. That's why some critics are upset.

The book, by epidemiologists Drs. Walter Willett and Jorge Chavarro and writer Patrick J. Skerrett, is based on the authors' research, published in the November issue of "Obstetrics and Gynecology."

In that paper, the authors reported on 17,544 women participating in the Nurses' Health Study who recorded their diets and their quests to get pregnant in biennial questionnaires.

The study found that women had a lower risk of infertility due to anovulation - the failure to produce a viable egg every month - if they ate a diet that emphasized monounsaturated fats like olive oil over trans fats often found in baked goods; vegetable proteins such as in beans and nuts rather than animal sources such as red meat; whole grains instead of refined carbohydrates that cause too rapid a rise of blood sugar and insulin; some whole milk, a little ice cream or other high-fat dairy products daily; multivitamins containing folic acid; and iron from plants and supplements.

The study is groundbreaking because it "is one of the first times that anyone has shown that what you eat and drink can impact the reproductive system," said Alice Domar, a psychologist who heads the Domar Center for Mind/Body Health at Boston IVF, one of the country's largest infertility centers.

But it's a huge leap to go from a statistical correlation to actually giving advice. The authors veer toward prescription when they say in their book, "We have discovered 10 simple changes that offer a powerful boost in fertility for women with ovulation-related infertility." Ditto, in a cover story they wrote for the Dec. 10 issue of Newsweek, when they said their recommendations are aimed at preventing and "reversing" infertility - a conclusion Willett defended in an interview.

Observational studies like the Nurses' Health Study do not prove that a behavior causes or prevents a health problem, only that it might do so. To prove that diet affects fertility, researchers would have to take a group of women with diagnosed infertility and randomly put half on a special diet and half on a regular diet and compare conception rates.