Well, then. A common assertion is that heavy consumption of turkey meat results in drowsiness, due to high levels of tryptophan contained in turkey. [...] [I]ngestion of a meal rich in carbohydrates triggers release of insulin. Insulin in turn stimulates the uptake of large neutral branched-chain amino acids (BCAA), but not tryptophan (an aromatic amino acid) into muscle, increasing the ratio of tryptophan to BCAA in the blood stream. The resulting increased ratio of tryptophan to BCAA in the blood reduces competition at the large neutral amino acid transporter (which transports both BCAA and aromatic amino acids), resulting in the uptake of tryptophan across the blood–brain barrier into the cerebrospinal fluid (CSF). Once in the CSF, tryptophan is converted into serotonin in the raphe nuclei by the normal enzymatic pathway. The resultant serotonin is further metabolised into melatonin by the pineal gland. Hence, this data suggests that feast-induced drowsiness— or postprandial somnolence — may be the result of a heavy meal rich in carbohydrates, which, via an indirect mechanism, increases the production of sleep-promoting melatonin in the brain.
Posted on: Fri, 28 Nov 2014 03:36:42 +0000