Omega-3 fatty acids are a family of fats that occur naturally; three of them, α-linolenic acid (ALA), eicosapentaenoic acid, and docosahexaenoic acid (DHA), are important components of the human diet. Some recent studies have concluded that being deficient omega-3 fatty acids may affect brain physiology and increase the risk of cognitive decline. Superficially, this claim makes sense. After all, DHA is abundant in the brain and is involved in numerous critical functions. ALA, or something that it’s converted into once consumed, exhibits a potent anti-inflammatory effect in the brain. Finally, DHA might be able to enhance learning and memory processes in the brain.
Dietary intake of omega-3’s, mainly from fish, have been claimed to either slow, or have no effect upon, cognitive decline and the incidence of dementia. The problem is that thus far all of the clinical trials have either included too few patients or were conducted for quite brief periods of time. Thus, the results tended to be rather variable and potentially misleading. Over time, as the studies became more sophisticated and involved more and more patients for longer periods of time, the effects of omega-3s became far less apparent.