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. 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 indicates the extent to which the amino acid tryptophan is converted into kynurenine. This pathway is closely associated with 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 towards immune-related metabolic pathways.
Low IDO activity (a higher tryptophan/kynurenine ratio) may indicate reduced immune activation or low inflammatory signalling. It can also suggest sufficient tryptophan availability for the production of serotonin and melatonin.
Supporting balanced immune and inflammatory function is essential. Adequate antioxidant intake, stress reduction, and maintaining healthy gut and immune function may help normalise IDO activity. Ensuring sufficient dietary tryptophan and cofactors such as B vitamins and magnesium supports optimal tryptophan metabolism.