A new study on elderly Indonesians found that those who ate tofu daily had weaker memory function than those who ate it rarely. This led to headlines circling the world today (for example, “Eating Soy Linked to Memory Loss” and “Tofu May Raise Risk of Dementia“) which generalize these findings to all tofu, and implicitly or explicitly, all soy products. However, that’s not what the research actually says.
First, the researchers who found that Indonesian elders eating tofu daily had worse memories (by about 20%) also found that eating tempeh (another Indonesian soy product) improved memory. Therefore, soybeans are not themselves the source of the memory loss. It’s something about the tofu, and perhaps something specific about the tofu eaten in Indonesia, that is the issue.
Is there anything about Indonesian tofu that might be a problem? In fact, it turns out that formaldehyde is used there as a preservative in tofu. Formaldehyde damages brain cells.
Was this information noted in the articles that circled the globe this morning? In most, it was left out completely, while in a few it appears only several paragraphs down into the text. Interestingly, the best article I’ve seen was in the Jakarta Post, the major newspaper in the capital of Indonesia.
Hogervorst said tofu’s associations with a worsening memory might be attributed to formaldehyde contents in the soy product.
“The culprit may be formaldehyde but we need further study to confirm this.”
Formaldehyde had killed brain cells of rats in a study, she said.
Further nutrients that can reduce the risk of dementia include vitamin B12 and anti-oxidants, but Hogervorst said these were more effective if consumed as part of the diet and not as tablets.
Active people with a higher education were less likely to develop dementia, while smokers and drinkers were in a high risk category, she said.
“Besides those factors, diseases or illnesses like diabetes mellitus, high blood pressure, high LDL-cholesterol, obesity and cardiovascular disease are among things negatively affecting the brain,” she said.
So, the bottom line is that tofu consumed in Indonesia, in which formaldehyde is present, is associated with memory loss in the elderly. The lead scientist says further studies are needed to clarify this possible chain of causation. Soy products such as tempeh do not harm memory, and in fact appear to improve it.
Since there is no evidence that North American or European tofu contains formaldehyde (apparently formaldehyde-laden tofu is tough on the outside and brittle on the inside), this study’s findings are likely irrelevant for those outside Indonesia.
You wouldn’t know that if you only read the headlines.
