Think tofu, and you probably think of open-toed sandals, beards and tasteless health foods for the sort of people who insist on treating their bodies like temples.
Think again. A new study suggests that the soya bean product with the consistency of warm rubber may not be so healthy after all. In fact, research shows that middle-aged people who eat tofu regularly are more prone to signs of mental deterioration and even brain shrinkage.
The study, published in the latest issue of the Journal of the American College of Nutrition, showed that eating tofu two or more times a week affected brain function, leading to poor attention and memory as well as brain atrophy, or shrinkage.
In Britain, sales of tofu total more than £4m a year. The protein is added to many meat products as well as being eaten alone.
The Vegetarian Society dismissed the report's findings, saying that tofu was a recognised health food and had many proven health benefits.
"It is madness for people to stop eating tofu or soya products as they have many proven health benefits such as protecting people against prostate or breast cancer," said spokeswoman, Sam Calvert.
"This research does not show a causal link, and it would be almost impossible for people to stop eating soya as it is in a wide variety of foods," she said.
The scientists who conducted the research believe that the link between tofu consumption and decline of brain function could be connected to the level of isoflavones present in the food. These chemicals, which increase the levels of oestrogen in the body, may also impact on an enzyme that affects the part of the brain that controls learning, they said.
Dr Lou White, of the Hawaii Centre for Health Research, and lead author of the study, who tested more than 4,000 people, said: "Both men and women eating the most tofu were up to twice as likely to show some signs of impaired mental function later in life than those who rarely ate tofu."