Soja en het geheugen*
Een Engelse studie onder ruim 700 oudere Indonesiërs blijkt dat verschillende sojaproducten zoals
tofu slecht kunnen zijn voor het geheugen van oudere mensen (+ 65 jaar) terwijl daarentegen gefermenteerde sojaproducten zoals
tempeh juist goed zijn voor het geheugen. Het is niet onmogelijk dat deze uitkomst alleen zou kunnen gelden voor deze bevolkingsgroep doch eerder onderzoek onder Japanse
Amerikanen gaf eenzelfde beeld.
High Tofu Intake Linked To Higher Memory Loss
People who eat high levels of some soy products, including tofu and other so-called superfoods, may be at an increased risk of memory loss.
Loughborough and Oxford scientists, funded by the Alzheimer's Research Trust, worked with Indonesian colleagues to investigate the effects of high soy consumption in 719 elderly Indonesians living in urban and rural regions of Java.
The researchers' findings, to be published in Dementias and Geriatric Cognitive Disorders later this month, include evidence that a high consumption of tofu is associated with worse memory, particularly among the over 68s.
Lead researcher, Professor Eef Hogervorst of Loughborough University, said, "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 ageing brain is.
"They have similar effects to oestrogen which may offer neuroprotection to the middle-aged and young but not to over 65s for whom it could heighten risk of dementia and lower memory function."
Intriguingly, the researchers also found that consuming tempe, a fermented soy product made from whole soy bean, is associated with better
memory.
Prof Hogervorst said the beneficial effect of tempe might be related to its high levels of 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."
Prof Hogervorst said future studies would investigate how folate or folic acid combined with phytoestrogens protects against memory dysfunction in the
elderly.
Prof Hogervorst cautioned that the effects of tempe and tofu were most apparent in elderly Javanese people, so it is not clear how the findings relate to soy intake among all ethnic groups. An earlier study found that older Japanese American men were also at increased risk of dementia with high tofu consumption.
Rebecca Wood, Chief Executive of the Alzheimer's Research Trust said, "This study adds to our understanding of Alzheimer's disease. Further research is needed to understand the full potential, and risks, of these 'superfoods'.
"This kind of research into the causes of Alzheimer's could lead scientists to new ways of preventing this devastating disease. As over half a million people have Alzheimer's in the UK today, there is a desperate need to find a new prevention or
cure."
The Alzheimer's Research Trust provides free information on Alzheimer's disease and related dementias: phone 01223 843899 or visit http://www.alzheimers-research.org.uk. The charity relies solely on public donations to fund its research.
"High Tofu Intake Is Associated with Worse Memory in Elderly Indonesian Men and Women"
Vol. 26, No. 1 of the journal Dementia and Geriatric Cognitive Disorders
E. Hogervorst, A. Yesufu, P. Kreager, T. Sadjimim, T.B. Rahardjo.
Click here to view Abstract online
(Augustus
2008)
Deze uitkomst is niet vreemd, wetenschappers adviseren al langer alleen gefermenteerde sojaproducten te nuttigen.