Heraief E, Burckhardt P, Mauron C, Wurtman J J, Wurtman R J
J Neural Transm. 1983;57(3):187-95. doi: 10.1007/BF01245117.
We measured plasma concentrations of tryptophan (Trp) and the other large neutral amino acids (LNAA) in 6 control and 7 obese subjects before and after they consumed a low-carbohydrate "protein-sparing modified fast" (PSMF) diet; LNAA levels in control subjects were also assessed after supplemental oral Trp. Consumption of the PSMF diet by non-obese subjects, or obesity per se, caused major reductions in the ratio of the plasma Trp concentration to the summed plasma concentrations of the other LNAA (i.e., the "plasma Trp ratio"), and may thus have diminished brain serotonin synthesis. Administration of even 2 g of supplemental Trp did not elevate the plasma Trp ratio beyond the normal range observed previously in subjects consuming carbohydrate-containing meals.
我们测量了6名对照受试者和7名肥胖受试者在食用低碳水化合物“蛋白质节省型改良禁食”（PSMF）饮食前后血浆中色氨酸（Trp）和其他大中性氨基酸（LNAA）的浓度；还评估了补充口服色氨酸后对照受试者的LNAA水平。非肥胖受试者食用PSMF饮食或肥胖本身会导致血浆色氨酸浓度与其他LNAA血浆总浓度之比（即“血浆色氨酸比率”）大幅降低，因此可能会减少大脑中血清素的合成。即使给予2克补充色氨酸，血浆色氨酸比率也不会升高到之前食用含碳水化合物餐食的受试者所观察到的正常范围之外。
