Topic 3. Nutrition and the brain

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The brain and body are constantly exchanging to ensure that the former receives information on the energy status and metabolic requirements of the latter. Most nutrients influence the brain’s metabolic signal pathways. The constant interaction between the peripheral nervous system and the brain is controlled by the somatic, autonomic and neurohumoral pathways which are involved in the contribution, expenditure and storage of energy reserves. Brain cells are sensitive and responsive not only to fluctuations in blood sugar concentration, but also to metabolites that provide information on the body’s metabolic status. The constant interaction between the peripheral system and the brain is also present during prolonged exercise. In this context, disruptions to the supply of neurotransmitter precursors might be responsible for the occurrence of fatigue. The “central fatigue” theory is mainly based on an increase in the concentration of the neurotransmitter serotonin (5-HT). According to the scientific literature, physical performance would be little influenced, if at all, by the intake of tryptophan (TRP) or branched chain amino acid (BCAA) substrates. In contrast, the beneficial effect of carbohydrate intake during prolonged exercise is unquestionable and could be related to the increase (or maintaining of) the supply of substrates to the brain. Numerous studies indicate that hypoglycemia affects brain function and cognitive performance. The positive effect of glucose intake on athletic performance is clearly illustrated by several investigations using a carbohydrate mouth rinse compared to a placebo. Studies have clearly shown an improvement in performance even when the carbohydrate drink was not ingested. Interestingly, research has shown that a mouth rince activates multiple areas of the brain involved in the control of reward, emotion and motor output.