Following on from previous research with mice that demonstrated that a diet rich in methionine could increase the risk of developing Alzheimer's Disease through its effect on homocysteine levels, a new study has found that these effects were reversible if the mice then switched to a healthier diet. The mice, after five months on a methionine-rich diet, were divided into two groups, with one group continuing the diet and the second switching to the healthy diet for an additional two months. The cognitive impairment, and the build-up in amyloid plaques, was completely reversed after two months.

Methionine is an amino acid typically found in red meats, fish, beans, eggs, garlic, lentils, onions, yogurt and seeds. I note, however, that most of the items in this list are usually considered healthy! Fish, in particular, has been shown in a number of studies to reduce the risk of Alzheimer’s. The point is that methionine in itself is an essential amino acid and necessary for a healthy brain, but this indicates that, as with many foods, moderation is important. Clearly a balance is required; equally clearly, we still haven’t quite worked out the ‘perfect’ Alzheimer’s-prevention diet. Nevertheless, this study is welcome in demonstrating that diet can have such an effect on the brain, and adds to our knowledge of what makes a good diet for staving off dementia.