According to researchers at Loughborough University, soy products, which are a major alternative protein source to meat for many people, contain phytoestrogens which actually heighten the risk of memory loss.
"Oestrogens - and probably phytoestrogens - tended to promote growth among cells, not necessarily a good thing in the ageing brain," lead researcher Prof Eef Hogervorst said.
They have based their findings on an analysis of 719 elderly people living in the Java region of Indonesia. The researchers found that those who consumed tofu - at least once a day - developed memory loss, it was worse among those over 68 years of age, according to the journal 'Dementias and Geriatric Cognitive Disorders.'
The latest study also found that eating tempe, a fermented soy product made from the whole soy bean, was associated with better memory. Professor Hogervorst said the beneficial effect of tempe might be related to the fact that it contains high levels of the vitamin folate, which is known to reduce dementia risk.
“It may be that that the interaction between high levels of both folate and phytoestrogens protects against cognitive impairment,” she was quoted by the BBC.