A Diet Lacking In Tryptophan Alters Gut Microbiota, Increases Inflammation

With age, a diet lacking in the essential amino acid tryptophan — which has a key role in our mood, energy level, and immune response — makes the gut microbiome less protective and increases inflammation body-wide, investigators report.

In a normally reciprocal relationship that appears to go awry with age, sufficient tryptophan, which we consume in foods like milk, turkey, chicken, and oats, helps keep our microbiota healthy.

A healthy microbiota, in turn, helps ensure that tryptophan mainly results in good things for us like producing the neurotransmitter serotonin, which reduces depression risk, and melatonin, which aids a good night’s sleep, says Dr. Sadanand Fulzele, an aging researcher in the Medical College of Georgia Department of Medicine.

But in aged mice, just eight weeks on a low-tryptophan diet results in some unhealthy changes in the trillions of bacteria that comprise the gut microbiota and higher levels of systemic inflammation, they report in the International Journal of Molecular Sciences.