A handful of walnuts or half a piece of salmon a day may protect against Alzheimer’s disease. Diets rich in foods like this, containing brain-boosting omega-3 fatty acids, were linked to lower levels of a protein related to Alzheimer’s disease.
Researchers interviewed over 1,200 elderly people about their diet, and determined their intake of various nutrients, such as vitamins B12, C, D and E, beta carotene and fatty acids.
A year after the dietary survey, blood tests showed that people with the most omega-3 fatty acids in their diet had the lowest levels of the protein beta-amyloid in their blood. None of the other nutrients were linked to lower levels of this protein.
Autopsies have shown that people with Alzheimer’s disease have deposits of beta-amyloid in their brains. Studies also suggest that high levels of this protein in the blood may predict Alzheimer’s, even before memory loss starts.
The study, published in the journal Neurology, found that beta-amyloid levels decreased by 20 to 30 percent for each additional gram of omega-3 fatty acids in the diet, the amount found in that handful of walnuts or piece of salmon. Another food that contains omega-3 fatty acids, flaxseeds, have 1.6 grams per tablespoon.
It is too soon, though, to prescribe salmon for the prevention of Alzheimer’s disease, but study author Nikolaos Scarmeas, MD, told WebMD, "This adds to the evidence that diet may play a role in [memory] decline. We know that omega-3 helps protect against heart disease. Now there is emerging evidence that it may protect the brain as well as the heart.”