Tofu-Rich Diet May Help Women With Lung Cancer Live Longer

Chinese study found eating high amounts before diagnosis boosted survival rates

By Mary Brophy Marcus

HealthDay Reporter

TUESDAY, March 26 (HealthDay News) -- Eating tofu and other soy foods may help women who develop lung cancer increase their odds of living longer.

A study of women from Shanghai, China, published in the March 25 issue of the Journal of Clinical Oncology, links high soy consumption before a lung cancer diagnosis with longer survival.

"This is the first study to suggest an association between soy food consumption and lung cancer survival," said study author Dr. Gong Yang, a research associate professor of medicine in the division of epidemiology at Vanderbilt University Medical Center, in Nashville.

Eating soy products in small amounts in the years preceding a lung cancer diagnosis didn't seem to pose a benefit, though.

Lung cancer is the leading cause of death among women in the world. It forms in the tissues of the lungs, usually in the cells that line the air passageways. The five-year survival rate is poor compared to breast cancer; it is estimated that by 2012, lung cancer will cause twice as many deaths as breast cancer, Yang said.

Cigarette smoking is the top cause of the disease in the United States, according to the U.S. Centers for Disease Control and Prevention, but in the study, most of the women from China were nonsmokers.

One expert noted another difference between the two populations of women that does not bode well for Chinese women.

"Far more never-smoking women in Asia get lung cancer than in the United States," said Dr. Jyoti Patel, an associate professor of medicine at the Robert H. Lurie Comprehensive Cancer Center at the Northwestern University Feinberg School of Medicine, in Chicago. "We're not sure why this is, but they may have a predilection for developing mutations ... that cause lung cancer to grow."

The study participants were part of a larger observational study called the Shanghai Women's Health Study, which tracked the incidence of cancer in about 75,000 women. Diet information was collected, including how much soy food -- such as soy milk, tofu, fresh and dry soybeans, and soy sprouts -- women ate.

The authors reported that about 450 women were diagnosed with lung cancer during the study. They were divided into three groups according to the amount of soy food they had eaten before their lung cancer diagnosis. The highest intake levels of tofu were equal to about 4 ounces a day, while the lowest soy consumers ate less than 2 ounces daily.

During the study, more than 300 of the lung cancer patients died, Yang said. Sixty percent of the women in the highest soy-eating group and 50 percent in the low soy consumer group were alive twelve months after diagnosis. A patient's risk of death decreased with increasing soy intake, but leveled off at 4 ounces of daily tofu consumption.

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