It is thought that a carbohydrate-rich or a high-glycemic-index meal can affect sleep through its effects on tryptophan (an essential amino acid) levels.[1] More specifically, high-glycemic-index carbohydrates cause a rise in insulin levels, which drive circulating large neutral amino acids (LNAAs)[2] into muscles. Because LNAAs compete with tryptophan for transport across the blood-brain barrier, lower levels of blood LNAAs result in a higher tryptophan-to-LNAA ratio, so more tryptophan can travel to the brain. More tryptophan entering the brain leads to greater production of serotonin,[3] and, finally, to the secretion of melatonin (a sleep-inducing hormone), resulting in sleepiness.
References
- ^Wurtman RJ, Wurtman JJ, Regan MM, McDermott JM, Tsay RH, Breu JJEffects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratiosAm J Clin Nutr.(2003 Jan)
- ^Berry EM, Growdon JH, Wurtman JJ, Caballero B, Wurtman RJA balanced carbohydrate: protein diet in the management of Parkinson's diseaseNeurology.(1991 Aug)
- ^Zimmermann RC, McDougle CJ, Schumacher M, Olcese J, Heninger GR, Price LHUrinary 6-hydroxymelatonin sulfate as a measure of melatonin secretion during acute tryptophan depletionPsychoneuroendocrinology.(1993)