From previous studies, scientists knew that certain diets, such as low-calorie diets, enhance the activity of intestinal stem cells. A new study by a team from MIT has identified for the first time a substance that enhances the regenerative properties of intestinal tissue—the amino acid cysteine.
The findings are based on experiments with mouse models fed a diet containing one of 20 different amino acids. For each group, they measured the effect of the diet on intestinal stem cell regeneration. Of all the diets, cysteine had the most pronounced effect on stem and progenitor cells.
It turned out that cysteine triggered a cascade of reactions leading to the activation of immune CD8+ T lymphocytes and the proliferation of the cytokine IL-22. IL-22 plays an important role in regulating stem cell regeneration, primarily in the small intestine.
Interestingly, a cysteine-rich diet has been shown to be effective in restoring the gut after chemotherapy.
Scientists are continuing experiments to study the amino acid's effect on other tissue regeneration mechanisms. They are also testing the properties of other amino acids. If successful, dietary modifications could prove a simple and effective way to restore intestinal tissue and possibly other organs.
What is cysteine and which foods contain it in the highest amounts?
Cysteine is a sulfur-containing amino acid that is not completely essential: the body can synthesize it from methionine and serine, but when there is a deficiency of these amino acids or an increased need (stress, illness, intense exercise), cysteine becomes conditionally essential.
Rich in cysteine and its precursors (primarily methionine):
Animal products
Eggs (especially egg whites);
Meat and poultry (chicken, turkey, pork, beef);
Fish and seafood (salmon, tuna, shrimp);
Dairy products (cottage cheese, cheese, milk, yogurt, whey protein).
Plant-based products
Legumes (lentils, beans, chickpeas, soybeans);
Nuts and seeds (sunflower seeds, sesame seeds, flax seeds, walnuts);
Whole grains (oats, wheat, corn, rice);
Onions and garlic (rich in organic sulfur compounds that stimulate cysteine synthesis).
Whey protein (the basis of sports supplements) contains especially a lot of cysteine.
The WHO and FAO recommend ~13 mg of methionine/cysteine per kg of body weight per day for adults. This means that a 70 kg person requires approximately 900 mg of these amino acids per day. This is easily achieved with a normal diet: for example, 100 g of chicken contains approximately 220–240 mg of cysteine, an egg ~250 mg, and 100 g of sunflower seeds ~450 mg. Therefore, with a balanced diet, additional cysteine intake is not required, except in special cases (certain liver and respiratory diseases, or high oxidative stress—in which case N-acetylcysteine is prescribed as a supplement).
In another study, researchers previously found that the amino acid glutamine plays a key role in fighting cancer. Glutamine delivery resulted in a significant reduction in tumor growth.
