Our bodies follow daily cycles based on light and darkness, called circadian rhythms. These rhythms affect many processes, including how our bodies absorb nutrients.
In a new study from Penn State, researchers found that a protein that helps the gut work properly is controlled by the way the liver processes a nutrient at night.
The nutrient in question is tryptophan, an amino acid that comes from protein-rich foods like meat, eggs, and dairy. Once we eat tryptophan, it travels to the liver. There, it is broken down into smaller substances called metabolites.
These metabolites turn on a special protein in the body called the aryl hydrocarbon receptor, or Ah receptor. When activated, the Ah receptor helps the gut create a stronger barrier. This barrier keeps harmful germs out while allowing nutrients to be absorbed.
Professor Gary Perdew, the lead researcher, said this shows that what we eat—especially when we eat protein—can make a big difference in gut health. Although the study was done in mice, humans also have high levels of the Ah receptor, especially in areas like the gut, liver, lungs, and skin.
Past research by the same team showed that when the Ah receptor is blocked in the gut, it leads to problems. Food moves too fast through the small intestine, and there is less protective mucus in the gut. That earlier study also found that eating vegetables like broccoli can activate the Ah receptor and improve gut health.
This new study adds another piece to the puzzle. The researchers guessed that there must be ways the body naturally activates the Ah receptor without depending only on food. They were right—tryptophan from a normal diet can trigger this helpful process.
To study this, the team fed mice at night when they are naturally more active and allowed them to fast during the day, just like how humans fast overnight and eat breakfast in the morning. Every four hours, the scientists took samples from the mice to see what was happening inside their bodies.
They found that during the animals’ active eating times, the liver made more tryptophan metabolites. These then activated the Ah receptor, which likely helped improve the strength of the gut’s protective barrier.
This means eating protein earlier in the day might give your gut a healthy boost. Since the body seems to rely on the timing of food intake to create these helpful changes, breakfast may be an especially important time to eat protein.
This research gives us a better understanding of how diet and timing affect gut health. It also shows that the body has built-in systems to protect itself, which can be supported by eating the right foods at the right times.
If you care about gut health, please read studies about how probiotics can protect gut health, and Mycoprotein in diet may reduce risk of bowel cancer and improve gut health.
For more health information, please see recent studies about how food additives could affect gut health, and the best foods for gut health.
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