A single Hawaii study hasBy Helen Altonn
linked consumption of tofu with
loss of mental ability
People who like tofu shouldn't quit eating it because of a study showing it may have adverse effects on aging and the brain, some researchers say.
"It's premature," said Dr. Brian F. Issell, interim director of prevention and control programs at the Cancer Research Center of Hawaii.
He said a dietary study by Dr. Lon White of the Pacific Health Research Institute showing a statistical connection between tofu and accelerated brain aging and Alzheimer's disease "is an important study. He's done good work."
But while it "gives clues," Issell said a lot more work must be done to determine if frequent eating of tofu is associated with loss of mental ability and brain weight as one ages.
"Soy seems to be associated with health in other areas -- heart and cancer," he pointed out.
White also said more study is needed on tofu and brain aging, and he hopes to get a National Institutes of Health grant to continue the project.
'There are so many things
people do in terms of lifestyle.
Looking at select things may
have nothing to do with
a causal effect.' Brian F. Issell
INTERIM DIRECTOR OF PREVENTION
AND CONTROL PROGRAMS, CANCER
RESEARCH CENTER OF HAWAII
"There could be other things people who are eating tofu do as well that haven't been tested," Issell said. "There are so many things people do in terms of lifestyle. Looking at select things may have nothing to do with a causal effect."
White and his colleagues have been studying aging and diseases in a group of Japanese-American men in the Honolulu Heart Program. The project began in 1965 with 8,006 Hawaii men who volunteered for medical research; more than 3,600 are still living and participating in the study.
White discussed results of the dietary study at a recent conference sponsored by soybean firms in Washington and attended by scientists from around the world.
Local reports of the findings have affected tofu sales, said Paul Uyehara, whose family operates the Aloha Tofu Factory.
But recommendations on what people should eat can't be based on one study, said Dr. Gertraud Maskarinec, assistant researcher at the Cancer Research Center of Hawaii.
She said she eats tofu.
"There are so many effects of tofu," she said. "If one is not so wonderful, it doesn't speak against tofu per se, and that speaks for most foods."
Maskarinec also attended the mainland symposium, which focused on the role of soy products in prevention and treatment of diseases.
Like Issell, she said White's study "is really very good. There is no problem with the study. The problem is, it is one study."
Maskarinec is conducting research on the effects of estrogens on breast cancer.
"What we know about breast cancer points to the idea that women with higher estrogen levels, the level you make in your body seems to be a risk for that," she said.
Women who live in places such as China and Japan with low breast cancer risks also have lower estrogen levels, she said.
Controlled studies in the United States have produced similar findings, she said. "So, for a lot of reasons, we think estrogen has to do with breast cancer risk."
Estrogens in soy and other plants act like weak estrogens and sometimes like anti-estrogens, so people have been studying those effects, Maskarinec said.
She is questioning, "What happens if women who don't eat tofu start eating a reasonable amount every day, and what happens to their estrogen levels?"