Just when you thought you couldn’t be more confused > Tofu may raise the risk of dementia … or not?Just when you thought you were doing everything right, along comes a study reported on by the BBC that says eating high levels of soy products — Tofu included — “may raise the risk of memory loss”. The study was conducted with 719 Indonesians who were living in urban and rural regions of Java. It was found that if they ate tofu at least once a day that, particularly among those over 68, memory worsened.
The study was featured in the journal Dementias and Geriatric Cognitive Disorders and was led by The Loughborough University.
According to the BBC report. “Soy products are a major alternative protein source to meat for many people in the developing world … but soy consumption is also on the increase in the west, where it is often promoted as a ‘superfood’.” The latest study suggests phytoestrogens – in high quantity – may actually heighten the risk of dementia.
Lead researcher Professor Eef Hogervorst said previous research had linked oestrogen therapy to a doubling of dementia risk in the over-65s. She said oestrogens – and probably phytoestrogens – tended to promote growth among cells, not necessarily a good thing in the ageing brain.
Alternatively, high doses of oestrogens might promote the damage caused to cells by particles known as free radicals.
Soy products are rich in micronutrients called phytoestrogens, which mimic the impact of the female sex hormone oestrogen. There is some evidence that they may protect the brains of younger and middle-aged people from damage – but their effect on the ageing brain is less clear. The latest study suggests phytoestrogens – in high quantity – may actually heighten the risk of dementia.
“A third theory is that damage is caused not by the tofu, but by formaldehyde, which is sometimes used in Indonesia as a preservative … However, previous research has also linked high tofu consumption to an increased risk of dementia in older Japanese American men.”
Professor David Smith, of the University of Oxford … “There seems to be something happening in the brain as we age which makes it react to oestrogens in the opposite way to what we would expect.” 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 also stressed that there was no suggestion that eating tofu in moderation posed a problem.
“Rebecca Wood, of the Alzheimer’s Research Trust, which funded the study, said more research was needed to pin down the potential risks and benefits of so-called superfoods …”
