Fiber-rich Diets Help Fight Obesity and Metabolic Syndrome

Highlights

• Including fiber-rich foods in the daily diet can prevent obesity, metabolic syndrome and adverse changes in the intestine.
• A high-fat diet which is a risk factor for //metabolic syndrome, reduces the production of epithelial cells lining the intestine and causes gut bacteria to invade intestinal epithelial cells.
• Fermentable fiber inulin restores the expression of the protein interleukin-22 (IL-22), which prevents gut microbiota from invading epithelial cells

Consumption of dietary fiber found in whole grains, vegetables, legumes, and fruits, can prevent obesity, metabolic syndrome and adverse changes in the intestine. Enriching the diet of mice with the fermentable fiber inulin prevented metabolic syndrome that is induced by a high-fat diet, and they identified specifically how this occurs in the body.

Metabolic Syndrome - What is it?

Metabolic syndrome is a cluster of conditions closely linked to obesity that includes increased blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol or triglyceride levels. When these conditions occur together, they increase a person's risk of heart disease, stroke, and diabetes.

Fiber Alters Gut Microbes

Obesity and metabolic syndrome are associated with alterations in gut microbiota, the microorganism population that lives in the intestine. Modern changes in dietary habits, particularly the consumption of processed foods lacking fiber, are believed to affect microbiota and contribute to the increase of chronic inflammatory disease, including metabolic syndrome.

A high-fat diet destroys gut microbiota, reduces the production of epithelial cells lining the intestine and causes gut bacteria to invade intestinal epithelial cells.

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This study found the fermentable fiber inulin restored gut health and protected mice against metabolic syndrome induced by a high-fat diet by restoring gut microbiota levels, increasing the production of intestinal epithelial cells and restoring expression of the protein interleukin-22 (IL-22), which prevented gut microbiota from invading epithelial cells.

"We found that manipulating dietary fiber content, particularly by adding fermentable fiber, guards against metabolic syndrome," said Dr. Andrew Gewirtz, professor in the Institute for Biomedical Sciences at Georgia State.

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"This study revealed the specific mechanism used to restore gut health and suppress obesity and metabolic syndrome is the induction of IL-22 expression. These results contribute to the understanding of the mechanisms that underlie diet-induced obesity and offer insight into how fermentable fibers might promote better health."

Fiber Reverses Effect of High-fat Diet

For four weeks, the research team fed mice either a grain-based rodent chow, a high-fat diet (high fat and low fiber content with 5 percent cellulose as a source of fiber) or a high-fat diet supplemented with fiber (either fermentable inulin fiber or insoluble cellulose fiber). The high-fat diet is linked to an increase in obesity and conditions associated with metabolic syndrome.

• A diet supplemented with inulin reduced weight gain and noticeably reduced obesity induced by a high-fat diet, which was accompanied by a reduction in the size of fat cells.
• Dietary enrichment with inulin also markedly lowered cholesterol levels and largely prevented dysglycemia (abnormal blood sugar levels). Insoluble cellulose fiber only modestly reduced obesity and dysglycemia.
• Supplementing the high-fat diet with inulin restored gut microbiota. Enrichment of high-fat diets with cellulose had a mild effect on microbiota levels.

In addition, the research team found switching mice from a grain-based chow diet to a high-fat diet resulted in a loss of colon mass, which they believe contributes to low-grade inflammation and metabolic syndrome. When they switched mice back to a chow diet, the colon mass was fully restored.

Fiber-rich Foods

Whole grains such as buckwheat, white millet, oat bran, wheat bran, legumes such as whole green grams, split bengal gram, Black eyed peas. Dried figs, apricots, dates, sapota, peas, broccoli, drumstick.

Dietary Fiber Has Other Benefits Also

• Foods rich in dietary fiber have a low glycemic index. Thus these foods take longer to convert into simple sugars and the rise in the blood sugar level is gradual. This also prevents sudden surges in insulin levels and deposition of fat.
 
• Fiber has the added benefit of improving heart health and reducing the risk of heart ailments by lowering LDL (bad) cholesterol and total cholesterol levels.
• Soluble fiber balances intestinal pH and stimulates intestinal fermentation. This helps to reduce the risk of colorectal cancer.
• Insoluble fiber enables the food to pass quickly through the digestive system thus facilitating regularity in motions. It also adds bulk to the stool which alleviates constipation. 
• Diet rich in fiber makes you feel full faster and last longer. This helps reduce appetite. So if you are looking at reducing or maintaining your weight, include lot of fiber in your diet.

A high fiber diet and good water intake are the first and foremost for a healthy and stress-free body. Most of us sometimes tend to eat only 5g to 10g of fiber in a day against the recommended amount of 25g to 30g per day. 

Reference

1. Jun Zou, Benoit Chassaing, Vishal Singh, Matam Vijay Kumar, Michael Pellizzon, Matthew Ricci, Michael D. Fythe. 'Dietary fiber protects against obesity and metabolic syndrome, study finds.' Cell Host & Microbe (2018).

Source-Medindia