Chitin may be good for the metabolism

Summary: a polysaccharide against obesity

Ingesting chitin, found in arthropods (insects, crustaceans) and fungi modifies the body's metabolism and may help combat obesity.

Chitin and its anti-obesity potential

Chitin (β-1,4-poly-N-acetylglucosamine) is a natural polysaccharide found in insects, crustaceans such as shrimp, crabs and lobsters and also in mushrooms.

A A polysaccharide is a very large molecule made up of smaller simple sugars like glucose. Polysaccharides are also called a glycans.

Chitin is a natural dietary fiber and when ingested (eating insects isn't common in Western societies, but forms part of the dietary habits of other cultures such as the Chinese or even Mexican).

Researchers at the Washington University School of Medicine, St. Louis, MO, USA. published a study involving mice (1) showing that chitin may be beneficial for the metabolism.

Eating chitin activates the immune system and this in turn has been linked to a leaner body with lower body fat, less propensity to put on weight and a therefore resistance to obesity.

The team found that ingesting chitin causes the stomach to stretch and this triggers type 2 immune responses that result in the output of enzymes called chitinases that break down the tough polysaccharide.

Chitin also altered the microbiome in the mice's gut, enriching it with Bacteroidetes phyla and reducing the Firmicutes bacteria.

Interestingly obese people tend to have a higher Firmicutes to Bacteroidetes ratio in their intestines than normal-weight people; the chitin may help to revert this ratio (2).

The scientists fed mice a high-fat diet and added chitin. Some mice lacked the ability to produce chitinases to break down chitin; these gained the least amount of weight, had the lowest body fat measurements and resisted obesity, compared with mice that didn't eat chitin (only ate a high-fat diet) and a third group with mice e that ate chitin but could break it down. This third group also benefited metabolically.

Research will continue, and explore if chitin could be added to human diets to help control obesity.

References and Further Reading

(1) Do-Hyun Kim, Yilin Wang, Haerin Jung, Rachael L. Field, Xinya Zhang, Ta-Chiang Liu, Changqing Ma, James S. Fraser, Jonathan R. Brestoff, Steven J. Van Dyken. (2023). A type 2 immune circuit in the stomach controls mammalian adaptation to dietary chitin. Science, 2023; 381 (6662): 1092 DOI: 10.1126/science.add5649.

(3) Magne F, Gotteland M, Gauthier L, Zazueta A, Pesoa S, Navarrete P, Balamurugan R. (2020). The Firmicutes⁄Bacteroidetes Ratio: A Relevant Marker of Gut Dysbiosis in Obese Patients?. Nutrients. 2020 May 19;12(5):1474. doi: 10.3390/nu12051474. PMID: 32438689