Glutamate (neurotransmitter)
Glutamate is a major constituent of a wide variety of proteins; consequently it is one of the most abundant amino acids in the human body. Under ordinary conditions enough is obtained from the diet that there is no need for any to be synthesized. Nevertheless, glutamate is formally classified as a non-essential amino acid, because it can be synthesized from alpha-Ketoglutaric acid, which is produced as part of the citric acid cycle by a series of reactions whose starting point is citrate. Glutamate cannot cross the blood-brain barrier unassisted, but it is actively transported into the nervous system by a high affinity transport system, which maintains its concentration in brain fluids at a fairly constant level.
Nutrition and cognition
Foods that are rich in omega-3 fatty acids have been shown to decrease risk of getting Alzheimer's disease. Omega-3 fatty acids, primarily docosahexaenoic acid (DHA), which is the most prevalent omega-3 fatty acid found in neurons, have been studied extensively for use in possible prevention and therapy of Alzheimer's disease. Some studies (cross-sectional) suggest that reduced intake or low brain levels of DHA are associated with earlier development of cognitive deficits or development of dementia, including Alzheimer's disease. Several clinical trials suggest that omega-3 fatty acid supplementation does not have significant effects in the treatment of Alzheimer's disease—which in turn may suggest that the protective benefits of omega-3 fatty acid supplementation could depend on the scope of the disease and other confounding factors. A diet that is rich in antioxidants will also help get rid of free radicals in the body, which could be a cause for Alzheimer's. The buildup of Beta Amyloid plaques, a marker highly associated with Alzheimer's disease, generates cell damaging free radicals. Therefore, the role of antioxidants as protectants against Alzheimer's disease has become a hot topic of study. Simple dietary modification, towards fewer highly processed carbohydrates and relatively more fats ad cholesterol, is likely a protective measure against Alzheimer's disease.