Tofu-Rich Diet May Help Women With Lung Cancer
Chinese study found eating high amounts before diagnosis boosted survival rates
"Patients with the highest soy food intake had better overall survival compared with those with the lowest intake," said Yang, who described the association as "linear."
What is in soybeans that might have cancer-slowing properties? It contains isoflavones that can act like selective estrogen modulators (SERMS), similar to the breast-cancer-fighting drug tamoxifen, Patel said.
"These SERMS may have a protective effect in lung cancer because we know that estrogen receptors are present in lung cancer and are important in lung development," Patel said.
Elisabetta Politi, nutrition director at the Duke Diet and Fitness Center in Durham, N.C., said the study is promising, but it raises a lot of questions too: Does the age at which soy is consumed play a role in how well it fights cancer later? Are certain soy foods better than others at fighting cancer? Would the results translate to a non-Chinese population?
"Maybe soy is important to eat before puberty," Politi said, noting that some studies suggest breast cancer risk is linked to earlier puberty. She said most American women don't eat soy before puberty, though. "It's not a typical staple in the American diet."
The new research also only collected information on soy intake before a lung cancer diagnosis, Politi said. People who already have lung cancer may wonder if adding tofu or soymilk to their daily diets could help.
Politi said she thinks it's too early to recommend boosting soy intake specifically for lung cancer survival reasons but she encourages people to try adding it to their diets.
"It's a good source of vegetable protein. I call it the miracle bean because it has about 30 percent of calories from protein, 30 percent from fat and 30 percent from carbohydrates. It's also high in fiber and often fortified with calcium. It's very nutritious," Politi said. "I do think soy in moderation is part of a healthy plant-based diet and I would recommend it, but not in high consumption for breakfast, lunch, snack and dinner."
The study authors also said it is premature to make any dietary recommendation on the basis of this single study, which did not prove a cause-and-effect relationship between soy and increased survival.
"Further investigation is warranted to confirm or refute this finding," Yang said. "We'd like to test this in other populations, too, like smokers or postmenopausal estrogen users, to answer the question of whether eating soy after diagnosis has a similar effect."
The research was supported by the U.S. National Cancer Institute and conducted by investigators at Vanderbilt University in collaboration with the Shanghai Cancer Institute and U.S. National Cancer Institute.