(NaturalNews) Regularly eating high levels of tofu may increase the risk of the memory loss associated with dementia, according to a new study conducted by researchers from Loughborough University in the United Kingdom, and published in the journal Dementias and Geriatric Cognitive Disorders.
Researchers investigated the connection between memory loss and diet for 719 elderly urban and rural residents of Java, Indonesia. The found that those who ate tofu at least once per day performed significantly worse on memory tests than those who ate tofu less frequently. The effect was particularly strong among those over the age of 68.
Lead researcher Eef Hogervorst has suggested several possible explanations, most of which hinge on the fact that soy products are known to contain high levels of estrogen-mimicking plant compounds called phytoestrogens.
Prior research has found that women over the age of 65 who receive hormone therapy may double their risk of dementia. This may occur because estrogen promotes cell growth, which may actually do damage to the aging brain, Hogervorst said. Alternately, high levels of estrogen might enhance the cell-damaging effects of free radicals.
Hogervorst also noted that much of tofu consumed by study participants might have been preserved with formaldehyde, a common practice in Indonesia. Formaldehyde has been strongly linked to various forms of cell damage, and might be responsible for the memory effects observed.
Prior research has found that older Japanese-American men who consumed high levels of tofu are also at an elevated risk for dementia, however.
In contrast to the effects of tofu, Hogervorst and colleagues found that eating of the fermented soy product tempeh was correlated with improved performance on memory tests. This effect may be due to the high levels of folate in tempeh, Hogervorst said.
She emphasized that it is only in high levels that tofu appears to damaging the brain, and that moderate consumption should be safe.