Food & diet

Do fibers protect against obesity and metabolic syndrome?

July 3, 2018

The consumption of dietary fibers can prevent obesity, metabolic syndrome and intestinal disorders by promoting the growth of “good” bacteria in the colon. A study conducted by Georgia State University reports this finding and we comment it together with Dr. Martina Mura, dietitian at Humanitas.


Prevention through food

In laboratory experiments, researchers discovered that enriching the diet with fermentable inulin fiber prevents the metabolic syndrome induced by a diet rich in fat and specifically identified how this occurs in the body. Metabolic syndrome is a set of conditions closely related to obesity that include increased blood pressure, high blood sugar levels, excess body fat around the waist and abnormal levels of cholesterol or triglycerides. When these conditions occur together, they increase the risk of heart disease, stroke and diabetes.


“The effect of inulin on humans has been evaluated in many clinical studies, in which the positive action on plasma glucose and lipid profile is confirmed, effects that are not observed with other fibers, for example non-fermentable cellulose fibers – said Dr. Mura – For these characteristics a diet rich in soluble fibers and inulin is recommended in individuals with metabolic syndrome or individuals at risk. Inulin is a prebiotic, soluble fiber of the FOS (fructo-oligosaccharide) family. It is mainly found in some plants: artichokes, Jerusalem artichoke root, onions, garlic, asparagus, bananas, chicory, dandelion and some cereals such as rye. It has a mild laxative effect, but if taken in high doses (>10g/day) it can cause abdominal pain, diarrhea, and meteorism. Therefore, people with low fiber tolerance or who suffer from irritable bowel syndrome should use it with care, under the strict supervision of a specialist doctor.

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The results are published in the journal Cell Host & Microbe

Obesity and metabolic syndrome are also associated with alterations in the intestinal microbiota, the population of microorganisms that live in the intestine. Changes in dietary habits, in particular the consumption of processed fiber-free foods, affect the microbiota and contribute to the increase in chronic inflammatory diseases, including metabolic syndrome. “Studies have found that a diet rich in fat impoverishes and alters the balance of the microbiota at the expense of beneficial strains – explained Mura – Thus increases the proliferation of pathogens and loses unity in the intestinal barrier itself, leading to infiltration, which stimulates the inflammatory response. It has also been discovered by laboratory tests that fermentable inulin restores intestinal health and protects against the metabolic syndrome induced by a diet rich in fat by restoring levels of intestinal microbiota, increasing the production of intestinal epithelial cells and restoring the expression of the interleukin-22 protein (IL-22), which has prevented the intestinal microbiota from invading epithelial cells.


“A varied diet rich in fiber is certainly a very important factor in maintaining a healthy, rich and diversified microbiota, but do not forget that other elements affect intestinal health: – concluded the dietitian – the use and abuse of drugs, psychophysical stress, sedentary lifestyle, irregular and hectic life rhythms.

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