The old wives' tale about fish being brain food may be true, according to Dr. John A. Boockvar, an assistant professor of brain surgery at Cornell University's Weill Medical College. "Unless it's fish that has a lot of mercury, it's not going to harm you, and we know it improves brain functioning," he told "The New York Times." Researchers have found that fatty acids and amino acids in some types of fish may improve the health of your brain, making it function better.
Omega-3 Fatty Acids
When you eat fat, your body takes omega-3 fatty acids out of it and uses them to build brain-cell membranes. One such compound is alpha-linolenic acid, or ALA, the omega-3 fatty acid found in salmon, sardines, mackerel and trout, according to the Franklin Institute. Because your body uses ALA to produce docosahexaenoic acid, or DHA, a more complex fatty acid that builds up your brain-cell walls, eating these types of cold-water fish may be beneficial to your brain's health.
According to Ernst Schaefer, M.D., of Tufts University, people tend to make less DHA as they age, a factor that may decrease their cognitive abilities. After a 9-year study of 900 elderly people, Schaefer found that those who consumed three servings of fish per week had a significantly lower risk of developing conditions such as Alzheimer's disease and dementia than those who did not. A DHA deficiency may also impair the mental ability of younger people. Upon comparing rats with an adequate DHA intake to rats without it, researchers from the National Institute on Alcohol Abuse and Alcoholism concluded that rats deficient in DHA showed deficits in higher-order learning.
Protein and Amino Acids
Your brain needs amino acids to construct the neurotransmitters that enable it to communicate with the rest of your body. According to Harvard University's Center for Health and the Global Environment, fish provides a high-quality source of protein that contains an abundance of essential amino acids. They are called essential because your body cannot make them itself, so you must supply them through food. Your brain may benefit from fish's high-protein content as well. Researchers at the National Academy of Sciences found that giving branched-chain amino acids, which are found in fish protein, helped brain-injured mice perform better at learning tasks.
Vitamin D, a nutrient not found naturally in many foods other than fish, is crucial for proper brain development and function. A study published in the "Journal of Neurology, Neurosurgery and Psychiatry" compared more than 3,000 European men aged 40 to 79 and found that those with higher vitamin D levels were better able to process information during a neuropsychological test. They were also able to think more quickly than the men with lower intakes of this nutrient. Vitamin D also helps your body absorb the calcium you take in, promoting the healthy function of brain nerves.