Liver metabolism of an essential amino acid may play a key role in gut health (Tryptophan)

Medical Xpress / Pennsylvania State University / iScience ^ | Feb. 2, 2026 | Katie Bohn / Ethan W. Morgan et al

[ConservativeMind]

Many biological processes exhibit daytime differences governed by rhythmic exposure to sunlight, termed circadian rhythms. Researchers recently found, in mice, that a protein critical to intestinal barrier function—helping the gut absorb nutrients while blocking harmful pathogens—is rhythmically controlled by nighttime liver metabolism of the molecule tryptophan.

In this study, researchers found that when tryptophan—an amino acid needed to synthesize vital proteins—is ingested, it travels to the liver. There, tryptophan produces metabolites—molecular byproducts of metabolism—that activate a protein called the aryl hydrocarbon receptor (Ah receptor), which then works to improve barrier function in the gut.

Gary Perdew, said that the findings provide clues as to how diet can be used to improve intestinal barrier function.

"Ingesting tryptophan kickstarts this process that results in better barrier function in the gut, suggesting that protein is a really important part of your diet," he said, explaining that, even though this work was conducted in mice, the Ah receptor is abundant in humans. "We also observed that this process increases during waking hours, indicating it might be even more important to have protein at breakfast."

The Ah receptor is found in many types of tissues in the human body, the researchers said, but it is more plentiful in the lungs, liver, skin and intestinal tract.

Previous research from the team found that when Ah receptor is blocked in the intestinal tract, negative effects followed, including altered transit time of food in the small intestine and decreased amounts of protective mucus.

For this study, the researchers fed the mice on a schedule meant to mimic how humans usually eat.

"This, in turn, leads to an increase in Ah receptor activity," Perdew said. "And based on our previous findings of the role of the Ah receptor, this would likely lead to enhanced barrier tissue function."

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TOPICS: Health/Medicine
KEYWORDS: gitract; liver; livermetabolism; tryptophan

[ConservativeMind]

Tryptophan eaten at meals is converted by the liver into substances that maintain a healthy gut barrier (and appears to help other barriers, as well).

[ConservativeMind]

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[Mark]

bkmk

[fso301]

I’ve heard the tryptophan supplements cause vivid strange dreams

[posterchild]

Years ago when I used the ‘nicotine patch’ I had strange vivid dreams. Some found them disturbing but I loved them. I’ll have to eat more turkey!

[MayflowerMadam]

I had bizarre dreams, and obsessive-type recurring videos in loops, when I had Covid.

[sauropod]

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[Irish Eyes]

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