The body's internal clock may influence sleep patterns by maintaining glutamine balance in the gut.

The intestinal epithelial clock helps set the daily sleep-wake cycle by timing glutamine absorption.

This mechanistic circadian study in intestinal epithelial cells linked BMAL1-driven rhythmic SLC6A19 expression and active-phase glutamine absorption to higher hypothalamic glutamatergic activity, more wakefulness, and less sleep, and linked rest-phase glutamine elevation from REV-ERBalpha deficiency to reduced sleep.

The evidence is mechanism-focused and based on intestinal clock perturbations and glutamine timing rather than direct clinical evidence in human sleep disorders.