title: Breakfast meal composition influences plasma tryptophan to large neutral amino acid ratios of healthy lean young men.
abstract: The effect of a carbohydrate, a 20% protein, or a carbohydrate +0.3% tryptophan TRP breakfast on plasma large neutral amino acid ratios was studied in 6 healthy men. The carbohydrate-rich meal produced shifts in plasma amino acid concentrations such that plasma TRP/LNAA ratios increased from 0.13 to 0.15 (p less than 0.04) and the protein meal decreased the ratio from 0.14 to 0.11 (p less than 0.04) after 1 hour. Addition of 0.3% TRP to the carbohydrate-rich meal increased plasma TRP/LNAA ratios more than 2-fold. The TRP containing meal was thus the only one likely to influence brain 5-HT synthesis, although the difference between the plasma TRP/LNAA ratios after carbohydrate and protein breakfasts suggests that the brain may distinguish, by synthesizing more or less 5-HT, the composition of breakfast meals.
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000097:blood*; D001921:Brain / Q000378:metabolism*; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D006801:Humans; D007737:Kynurenine / Q000097:blood; D008297:Male; D008875:Middle Aged; D012701:Serotonin / Q000096:biosynthesis*; D013997:Time Factors; D014364:Tryptophan / Q000008:administration & dosage / Q000097:blood
chemical_list: D000596:Amino Acids; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D012701:Serotonin; D007737:Kynurenine; D014364:Tryptophan