Three amino acids are discussed in Part 38, which begins with an essential amino acid, threonine. In animal studies it is important for maintaining gut function, and also has a role in immune function. The amino acid tryptophan is a precursor of serotonin. It was first shown to be instrumental in promoting fatigue in rats, and this has since been confirmed in humans. It has mainly come to prominence in sports studies because of attempts to counteract its fatiguing effects by the use of branched chain amino acids (BCAA). Recently there has been some interest in the soporific effects of tryptophan, which were first observed in the 1960s. The third amino acid discussed is tyrosine: its increase across the blood-brain barrier can promote an increase in dopamine and norepinephrine.
© Copyright 2012 British Journal of Sports Medicine. BMJ Publishing Group Ltd of the BMA. Alle Rechte vorbehalten.