Consumption of soluble dietary fiber favors renewal of intestinal epithelial cells

A high-fiber diet is known to have several health benefits. Scientific studies point to protection against such diseases as cancer and diabetes. However, exactly how fiber interacts with the intestines and the microorganisms that colonize them – the gut microbiota – is poorly understood.

These images show more cells undergoing cell division (red) in the group fed an inulin-rich diet (right) than the group that did not ingest this soluble fiber. Photo: Renan Corrêa

A study conducted by Brazilian researchers shows that a diet containing suitable amounts of inulin, a soluble fiber abundant in chicory roots, for example, can influence even the length and other macroscopic characteristics of the intestines.

This beneficial action is possible only in the presence of bacteria that digest the fiber, however. Positive alterations in immunity are among the healthy interactions.

The findings include new evidence of the importance of dietary fiber and contribute to the medical understanding of inflammatory bowel disease.

“In mice that ingested a 10% inulin diet, the gut was larger than in mice that consumed only insoluble fiber [cellulose]. When we analyzed their intestinal tissue, we found more epithelial stem cell proliferation in the animals fed an inulin-rich diet. The epithelium is the layer that separates gut contents from other organs,” said Renan Oliveira Corrêa, first author of the article.

Genes associated with lipid and fatty acid metabolism were less expressed in the mice that consumed inulin.

This modulation was compatible with effects described by other research groups in studies showing that inulin consumption lowers lipid levels in the bloodstream and reduces hepatic steatosis (fatty liver disease).

The inulin-rich diet also increased expression of genes associated with gut epithelial cell differentiation, a process essential to growth of the organ and substitution of dead cells.

This led to an increase in the number of goblet cells, specialized epithelial cells that secrete mucins, which are significant components of the mucus that protects the human gut from harmful bacteria. Their abundance shows that the organ is in a healthy condition. (André Julião/Agência FAPESP)

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