It is evident from the scientific literature that environmental factors affect cognition. Exercise for example, may play a significant role in the modulation of brain function. In particular exercise has been shown from animal studies and those of older humans to be able to nodulate the relational memories formed in the hippocampus. Relational memories are those that are required to bind together the experiences of the past, giving them a spatial and temporal context through provision of information about objects, people or places. In this regard, the hippocampus shows considerable plasticity in its efficiency for this process, based on the environmental conditions the subject is exposed to. Damage to parts of the brain through hostile environmental conditions could therefore significantly impair memory and lead to detrimental cognitive outcomes. High levels of oxidative stress, hormonal imbalances and metabolic disturbances may all contribute to memory decline, and exercise may be protective of this process to some extent.
Diet also appears to influence the relational memory. In this regard, omega-3 fatty acids may be particularly influential. The association between omega-3 fatty acids and hippocampal-related relational memory have been investigated by researchers in children between the ages of 7 and 9 years1. The children completed a youth-adolescent frequent food questionnaire and then performed a series of memory tasks designed to test hippocampal-dependent relational memory. The results of the study showed that there was a positive association between the hippocampal-dependent relational memory and the intake of omega-3 fatty acids, when adjusted for the body weight of the subjects. In addition, the researchers identified an inverse association between the hippocampal-dependent relational memory and the intake of saturated fatty acids. Further, measures of eye movement such as preferentially viewing target stimuli, a measure of hippocampal-dependent memory, were inversely associated with added sucrose intake.
These results suggest that omega-3 fatty acids, saturated fatty acids and sugar may all influence cognitive ability with regards memory. These dietary components were chosen by the researchers because they are related to the typical Western diet. In particular, the typical Western diet contains too much saturated fat and added sugar and too little omega-3 fat. The deficiencies of omega-3 fatty acids in the population of developed nations is well reported and has been linked to poor cognitive outcomes. In particular, docosahexaenoic acid (DHA, C22:6 (n-3)), an omega-3 fatty acid found in fish, may be of paramount importance to the development of the brain and central nervous system in the growing foetus and infant. The results of this study add weight to the contention that deficiencies of omega-3 fats during early development may negatively affect cognitive performance, a situation compounded by the addition of excessive saturated fat and added sugars to the diet.
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