A new study from MIT has found that a diet rich in the amino acid cysteine may help the small intestine heal and even reverse damage caused by treatments like radiation or chemotherapy.
The study, done in mice, showed that cysteine helps activate immune pathways that support the growth of new intestinal tissue.
This research could be helpful for cancer patients, who often experience gut damage from radiation or chemotherapy. If future studies show similar effects in humans, adding more cysteine to the diet—either through food or supplements—might help speed up recovery of the intestinal lining.
Cysteine is an amino acid found in many protein-rich foods, such as meat, dairy, beans, and nuts. It also has antioxidant properties, but this study is the first to show that it can help stem cells in the gut to regenerate.
The study was led by Professor Omer Yilmaz from MIT’s Koch Institute for Integrative Cancer Research and postdoctoral researcher Fangtao Chi. Their findings were published in the journal Nature.
In their experiments, researchers fed mice diets high in each of 20 different amino acids to see which one helped gut tissue the most. Cysteine had the strongest impact, boosting the activity of intestinal stem cells and progenitor cells, which are responsible for creating new tissue.
The researchers discovered that when intestinal cells absorb cysteine from food, they convert it into a compound called CoA.
This CoA is then released into the lining of the intestine, where it is taken up by immune cells known as CD8 T cells. These T cells then start multiplying and release a chemical called IL-22, which plays a key role in helping stem cells regenerate.
Interestingly, CD8 T cells were not previously known to release IL-22. But this study showed that after a cysteine-rich diet, these immune cells increased in number and were ready to help the intestine heal.
Most of this effect was seen in the small intestine, likely because that’s where most protein from food is absorbed. The body can make some cysteine by converting another amino acid called methionine, but that process spreads cysteine throughout the body instead of concentrating it in the gut.
In this study, a cysteine-rich diet helped mice recover from radiation damage in the intestines. In separate unpublished research, the diet also helped repair damage caused by a chemotherapy drug called 5-fluorouracil, which is used to treat colon and pancreatic cancers.
The team is now exploring whether cysteine could also help regenerate other parts of the body, such as hair follicles, and plans to study other amino acids that might influence how cells grow and repair tissues.
This research shows that a simple dietary change could have powerful effects on tissue repair and recovery, especially for people undergoing harsh medical treatments.
The study is published in Nature.
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