Experts at England's Loughborough and Oxford Universities researched the impact of soy consumption in 719 senior citizens on the Indonesian island of Java, the Daily Mail reported Saturday.
Researchers determined people who ate soy at least twice a day had 20 percent less memory function that those who ate it significantly less.
"Soy consumption is on the increase in the West and is often promoted as a 'superfood.' Soy products are rich in micronutrients called phytoestrogens, but it is not entirely clear what their effect on the aging brain is," said Professor Eef Hogervorst of Loughborough University.
Hogervorst said vegetarians and elderly women seemed to be highly susceptible to potential memory loss from soy consumption.