Diet-derived tryptophan influences immune system via gut microbiome
A recent Science study deciphers a specific nutrition / microbiome / metabolite / immunity axis and establishes a link with one bacterial species.
It was shown that Lactobacillus reuteri, part of the normal gut microbiome, may stimulate a more tolerant, less inflammatory gut immune system.
The combination of L. reuteri and a diet rich in tryptophan (protein-rich) showed to promote tolerance-promoting immune cells. When the researchers doubled the amount of tryptophan in the mice’s feed, they found 50 percent more of such cells rose. Consistently, when tryptophan levels were halved, the number of tolerance-promoting immune cells dropped by half.
We humans have the same tolerance-promoting cells as mice, and also accommodate L. reuteri in our gastrointestinal tracts. Hence, these findings in mice might suggest a way to tilt the gut immune system away from inflammation, bringing potentially relief for people living with inflammatory bowel disease.
Lactobacillus reuteri induces gut intraepithelial CD4(+)CD8αα(+) T cells. Science (2017). Cervantes-Barragan, L., Chai, J. N., Tianero, M. D., Di Luccia, B., Ahern, P. P., Merriman, J., et al.