Pregnant Women With Gestational Diabetes Mellitus and High Consumption of Tryptophan-Rich Foods Show Increased Levels of 6-Sulfatoxymelatonin in Urine.

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with metabolic and inflammatory alterations that may influence melatonin metabolism. This study evaluated associations between dietary intake of tryptophan-rich foods, urinary 6-sulfatoxymelatonin, and serum tumor necrosis factor-alpha (TNF-α) levels in pregnant women with GDM.

METHODS

A cross-sectional study included 34 women with GDM and 18 with normal-risk pregnancies. Dietary habits were assessed using a validated food frequency questionnaire (FFQ). Serum TNF-α and first-morning urinary 6-sulfatoxymelatonin levels were measured by ELISA. Associations were evaluated using generalized linear models (GLMs), adjusting for maternal age, body mass index (BMI), gestational age, and sleep quality.

RESULTS

Women with GDM reported a significantly higher frequency of consumption of tryptophan-rich foods, particularly milk and dairy products (p < 0.01) and fruits (p < 0.05). The GDM group also exhibited higher urinary 6-sulfatoxymelatonin (p = 0.002) and serum TNF-α levels (p = 0.023). In multivariable models, GDM remained significantly associated with higher urinary 6-sulfatoxymelatonin levels, whereas TNF-α concentrations were primarily associated with maternal characteristics and interaction effects.

CONCLUSIONS

GDM was associated with higher urinary 6-sulfatoxymelatonin and TNF-α levels despite greater reported intake of tryptophan-rich foods. These findings highlight associations between dietary precursors, melatonin metabolism, and inflammatory markers in hyperglycemic pregnancy and underscore the need for longitudinal studies to clarify underlying mechanisms.