Eating oily fish high in omega-3 fatty acids (think in terms of mackerel, herring, lake trout, sardines, albacore tuna, and, again, salmon) is also good for your heart—which, in turn, protects brain health.

Low levels of these vitamins have another side effect: both B12 and folate are essential for converting the amino acid homocysteine. When B12 and folate levels are too low, homocysteine isn’t converted and blood levels of this amino acid rise. The result is an increased risk of heart attack, stroke, and inflammation of the blood vessels.