Data linking brain agingBy Helen Altonn
and two-plus servings a
week concerns isle firms
A Hawaii study showing tofu might have some adverse health effects "kind of shocked" Yoshiya Ikoma, vice president of Nishimoto Trading Co.
"Everybody is thinking tofu is healthy, good for his or her bodies, all the way since eating," he said.
Nishimoto Trading Co. brings in an average of 1,600 cases a month of Mori-nu tofu, which can be stored unrefrigerated without spoiling. Every case has 24 boxes, each 12.3 ounces.
"It's a lot of tofu," said Ikoma, noting the company has been selling the product for about eight years, with an increase of 15 to 20 percent a year.
He said research showing a statistical link between two or more servings of tofu a week to increased brain aging is the first negative thing he has heard about tofu.
Ikoma doesn't believe the average person who enjoys tofu eats two servings a week. "For myself, it's once a week. If Japanese, Oriental, people eat twice a week, I think I can do two or three times more business."
Tofu (bean curd) is just one of several hundred soybean products, Ikoma noted. Among other popular items are soy sauce, miso, soybean paste and fried soybeans.
Tofu and miso were among 27 foods and drinks included in a dietary study of Japanese-American men between 1965 and 1993.
Comparing dietary findings and cognitive brain function, Dr. Lon White of the Pacific Health Research Institute and his colleagues found those men who ate more tofu tended to have brain impairment and faster brain aging.
The project began with 8,006 men born from 1900 to 1919. About 3,600 are still living.
Although protein and fats in tofu and other soy products are nutritious, White said molecules known as isoflavones made by the soy plant are drugs that may pose health risks.
He speculated that soy plant estrogens interfere with normal estrogen-related mechanisms, which protect the brain from effects of aging. White reported results of the study at a recent conference in Washington sponsored by soybean growing and processing companies.
The industry is looking to increased sales because of favorable regulatory decisions and scientific findings that soy could help prevent and treat chronic diseases.
The Food and Drug Administration said last month that it would allow soy-based manufacturers to label their products with the claim that they may reduce heart disease.
The FDA said it concluded that soy protein might lower blood cholesterol levels.
But scientists emphasized at the conference that findings about the health benefits of soy products are preliminary and that more research is needed.
C. Alan Titchenal, a vegetarian who eats tofu and teaches nutrition, science and exercise at the University of Hawaii, said White's study is "a little red flag popping up for people."
"It may prove to be just one study and not be a big issue, but it could be," he said. With nutrition, he said, "everybody wants foods to be good or bad -- two food groups -- and nutrition isn't that simple."
He said some foods that people put on their "bad" list have redeeming qualities, whereas some of the foods considered "good" sometimes have a downside if overdone.
"I think maybe that's what's going on here, too," Titchenal said. "I don't think the study says everyone should stop eating tofu or soy products, but I think the study says we shouldn't be going out and buying some of those soy isoflavone pills and things like that."
While White's study showed a statistically significant effect on the Japanese-American men who ate the most tofu, Titchenal said, "it's hard to tell how biologically significant it would be in the population at large without more research."
Figures aren't available on how much tofu is consumed in Hawaii, but it is clearly a large volume. About eight local companies make tofu, and about six others import the product from San Francisco and Los Angeles, said Paul Uyehara, whose family operates the Aloha Tofu Factory.
The Uyeharas' company --the largest tofu producer in Hawaii --makes 3,000 to 5,000 packages daily, Sunday through Friday. The largest is 20 ounces.
The family operation not only serves the local population, but the tourism industry, Uyehara said.
So far, he said, everything he has heard about tofu has been positive, and he hopes more studies are done before it is determined that it has negative health effects.
Ikoma expressed concern about consumer reaction to the study. "I hope it doesn't hurt business in the future," he said.
As for himself, he added: "I will continue to eat tofu. I love it."