Urinary glutamate enrichment was not detected ... To our knowledge, this is the first multistable isotope study quantifying the metabolism of arginine in enterally fed human preterm infants.

More information: Joeri Bordes et al, Sex-specific fear acquisition following early life stress is linked to amygdala and hippocampal purine and glutamate metabolism, Communications Biology (2024).

It's possible that obesity and dietary patterns that are high in saturated fats cause changes in glutamate and GABA metabolism and neurotransmission, as has been shown in animal studies.