Scientists investigated the effects of high soy consumption in 719 elderly Indonesians living in urban and rural parts of Java.
Subjects had their memories measured using a word learning test sensitive to dementia and soy consumption was measured using a food frequency questionnaire.
There was a negative association between high tofu consumption and performance in memory tests.
Lead researcher, professor Eef Hogervorst of Loughborough University, said: ‘Soy products are rich in micronutrients called phytoestrogens but it is not entirely clear what their effect on the ageing bran is.
‘They have similar effects to oestrogen, which may offer neuroprotection to the middle-aegd and young but not to over-65s for whom it could heighten the risk of dementia and lower memory function.’
Dementia and Geriatric Cognitive Disorders (2008)