quinta-feira, 22 de março de 2018

Dietary fiber protects against obesity and metabolic syndrome, study finds

Date: January 22, 2018 Source: Georgia State University Summary: Consumption of dietary fiber can prevent obesity, metabolic syndrome and adverse changes in the intestine by promoting growth of 'good' bacteria in the colon, according to a new study.

Consumption of dietary fiber can prevent obesity, metabolic syndrome and adverse changes in the intestine by promoting growth of "good" bacteria in the colon, according to a study led by Georgia State University.

The researchers found 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 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.

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. Studies have found 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.

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. The findings are published in the journal Cell Host & Microbe.

"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. "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."

For four weeks, the researchers 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.

They discovered 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). The researchers found insoluble cellulose fiber only modestly reduced obesity and dysglycemia.

Supplementing the high-fat diet with inulin restored gut microbiota. However, inulin didn't restore the microbiota levels to those of mice fed a chow diet. A distinct difference in microbiota levels remained between mice fed a high-fat diet versus those fed a chow diet. Enrichment of high-fat diets with cellulose had a mild effect on microbiota levels.

In addition, the researchers 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.

Story Source:

Materials provided by Georgia State University. Note: Content may be edited for style and length.

Journal Reference:
Jun Zou, Benoit Chassaing, Vishal Singh, Michael Pellizzon, Matthew Ricci, Michael D. Fythe, Matam Vijay Kumar, Andrew T. Gewirtz. Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health. Cell Host & Microbe, 2018; 23 (1): 41 DOI: 10.1016/j.chom.2017.11.003

Cite This Page:
Georgia State University. "Dietary fiber protects against obesity and metabolic syndrome, study finds." ScienceDaily. ScienceDaily, 22 January 2018. <www.sciencedaily.com/releases/2018/01/180122184723.htm>.

Vitamin D supplements could ease painful IBS symptoms

Date: January 25, 2018 Source: University of Sheffield Summary: New research finds high prevalence of vitamin D deficiency in IBS patients – regardless of their ethnicit.

Vitamin D supplements could help to ease painful Irritable Bowel Syndrome (IBS) symptoms, a new study from the University of Sheffield has found.

Scientists from the University's Department of Oncology and Metabolism reviewed and integrated all available research on vitamin D and IBS -- a condition which affects two in 10 people in the UK.

The study showed a high prevalence of vitamin D deficiency in IBS patients -- regardless of their ethnicity.

The Sheffield team also assessed the possible benefits of vitamin D supplements on IBS symptoms. Whilst they believe more research still needs to be conducted, their findings suggested supplements may help to ease symptoms which can include abdominal pain, bloating, diarrhea and constipation. Vitamin D was shown to have the most benefit on quality of life in IBS.

Lead author of the study, Dr Bernard Corfe, said: "The study provides an insight into the condition and, importantly, a new way to try to manage it.

"It is evident from the findings that all people with IBS should have their vitamin D levels tested and a large majority of them would benefit from supplements.

"IBS is a poorly understood condition which impacts severely on the quality of life of sufferers. There is no single known cause and likewise no single known cure."

IBS is a debilitating functional disorder of the gastrointestinal (GI) tract. Little is known about why and how the condition develops, although it is known that diet and stress can make symptoms worse.

The symptoms often cause embarrassment for patients meaning many live with the condition undiagnosed.

IBS accounts for 10 per cent of visits to GP surgeries and the condition has a significant and escalating burden on society as a consequence of lost work days and time spent on regular hospital appointments.

Vitamin D is essential for general wellbeing, including bone health, immune function, mental health as well as gut health. Vitamin D inadequacy can be remedied relatively easily with supplements if diagnosed.

Low vitamin D status has already been associated with the risk of colorectal cancer and has been implicated in inflammatory bowel disease.

The new study is published today (Thursday 25 January 2018) in the European Journal of Clinical Nutrition.

The University of Sheffield's Department of Oncology and Metabolism conducts world-class research from basic clinical and translational cancer research to life course research and basic level biology through to diseases such as diabetes and osteoporosis.

Story Source:

Materials provided by University of Sheffield. Note: Content may be edited for style and length.

Journal Reference:
Claire E. Williams, Elizabeth A. Williams, Bernard M. Corfe. Vitamin D status in irritable bowel syndrome and the impact of supplementation on symptoms: what do we know and what do we need to know? European Journal of Clinical Nutrition, 2018; DOI: 10.1038/s41430-017-0064-z

Cite This Page:
University of Sheffield. "Vitamin D supplements could ease painful IBS symptoms." ScienceDaily. ScienceDaily, 25 January 2018. <www.sciencedaily.com/releases/2018/01/180125110806.htm>.