IDO (indoleamine 2,3-dioxygenase) activity reflects the rate at which the amino acid tryptophan is converted into kynurenine. This pathway is regulated by immune and inflammatory signals, particularly cytokines such as interferon-γ. An increased IDO activity (low tryptophan/kynurenine ratio) may indicate immune activation, chronic inflammation, or oxidative stress. Balanced IDO activity suggests normal immune regulation and adequate tryptophan availability for serotonin and melatonin synthesis.
IDO (indoleamine 2,3-dioxygenase) activity reflects how actively the amino acid tryptophan is converted into kynurenine. This pathway is closely linked to immune regulation and inflammation, as it is stimulated by cytokines such as interferon-γ.
Higher IDO activity (corresponding to a lower tryptophan/kynurenine ratio) may indicate immune activation, chronic inflammation, infection, or oxidative stress. It suggests that tryptophan is being redirected from serotonin synthesis toward immune-related metabolic pathways.
Low IDO activity (a higher tryptophan/kynurenine ratio) may reflect reduced immune stimulation or low inflammatory signaling. It can also suggest adequate tryptophan availability for serotonin and melatonin production.
Supporting balanced immune and inflammatory function is key. Adequate antioxidant intake, stress reduction, and maintaining healthy gut and immune function may help normalize IDO activity. Ensuring sufficient dietary tryptophan and cofactors such as B vitamins and magnesium supports optimal tryptophan metabolism.