Gender differences in tryptophan (TRP) breakdown in obese individuals have been previously reported. This could be both contributory to, as well as a consequence of, gender differences in mood changes among obese people. To exclude the potential effect of depression on TRP breakdown and its levels in obesity, we replicated analyses in psychiatrically healthy individuals. In 1000 participants, plasma kynurenine (KYN), TRP, and the KYN/TRP ratio were compared between overweight/obese and normal-weight individuals using analysis of covariance, with adjustment for age and gender. Bivariate post hoc tests were also conducted. There were no significant relationships between KYN, TRP, or the KYN/TRP ratio and overall overweight/obese status. However, a significant gender by weight category interaction was identified for TRP only, with overweight/obese women having lower TRP than overweight/obese men (p=0.02). No gender differences in TRP were found in non-obese participants. Our study in psychiatrically healthy individuals suggested that lower TRP levels in obese women were not secondary to depression, strengthening the possibility that TRP levels could mediate depression in vulnerable women. Thus experimental manipulations of TRP levels could be used to advance theoretical knowledge, prevention, and clinical control of depression in obese women.

中文翻译：

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在精神健康的个体中，超重的女性而非男性的色氨酸水平较低

先前已报道过肥胖个体中色氨酸 (TRP) 分解的性别差异。这可能既是肥胖人群情绪变化性别差异的原因，也是其结果。为了排除抑郁症对 TRP 分解及其肥胖水平的潜在影响，我们在精神健康的个体中重复了分析。在 1000 名参与者中，使用协方差分析比较了超重/肥胖和正常体重个体之间的血浆犬尿氨酸 (KYN)、TRP 和 KYN/TRP 比率，并调整了年龄和性别。还进行了双变量事后检验。KYN、TRP 或 KYN/TRP 比率与总体超重/肥胖状态之间没有显着关系。然而，仅在 TRP 中发现了显着的性别与体重类别的交互作用，超重/肥胖女性的 TRP 低于超重/肥胖男性（p=0.02）。在非肥胖参与者中未发现 TRP 的性别差异。我们对精神健康个体的研究表明，肥胖女性较低的 TRP 水平并非继发于抑郁症，这加强了 TRP 水平可以介导弱势女性抑郁症的可能性。因此，TRP 水平的实验操作可用于提高肥胖女性抑郁症的理论知识、预防和临床控制。加强 TRP 水平可以调节脆弱女性抑郁症的可能性。因此，TRP 水平的实验操作可用于提高肥胖女性抑郁症的理论知识、预防和临床控制。加强 TRP 水平可以调节脆弱女性抑郁症的可能性。因此，TRP 水平的实验操作可用于提高肥胖女性抑郁症的理论知识、预防和临床控制。