The Grapevine

Metabolism And Gut Bacteria: What You Need To Know

Diabetes, heart disease and gastrointestinal problems have been strongly associated with obesity from time immemorial. The factors and risks that influence obesity are varied from person to person. However, one aspect of the disease has not got as much attention - gut health. Even the ancient Greek physician, Hippocrates, believed that all diseases originate from the gut, which is why studying the link is crucial to find better treatment for obesity.   

The link to the gut microbiome was for the first time studied comprehensively by researchers at Beth Israel Deaconess Medical Center (BIDMC). The human gut microbiome is a collective term used to refer to 1,000 odd bacteria inhabiting the gut, belonging to 160 bacteria species. This surprisingly has more of an impact on metabolism and obesity than one would imagine. 

Why is this? Diversity in the gut bacteria becomes compromised with a high intake of sugar, unhealthy and processed food with additives, which is the usual diet of obese individuals. This is why diets with an abundance of fiber are good for overall health since they improve the condition of the digestive tract because it increases the good bacteria.    

People who suffer from obesity have harmful bacteria in the gut that outnumber the good bacteria. In terms of the diversity, the bacteria is not varied for people who are overweight  In the past, several studies have proven that obese individuals show a 40 percent decrease in bacterial diversity in the gut. And that metabolic defect could even be cured by taking probiotic supplements. 

What The Study Said

The researchers of the latest study confirmed the aforementioned association in a press release. “Our research confirms a positive association between obesity and chronic diarrhea and reveals for the first time that this relationship is not driven by confounding factors such as diet or physical activity level,” Sarah Ballou, Ph.D., corresponding author and a health psychologist in the Division of Gastroenterology, Hepatology, and Nutrition at BIDMC, said.

Chronic diarrhea is an important sign of an unhealthy gut and indigestion that does not occur if the body is correctly digesting the food. A body with good metabolism would be absorbing the nutrients and utilizing the energy as opposed to storing it in the form of fat. This is why chronic diarrhea is being used by the researchers as a marker to understand both metabolism and gut health. 

Metabolism Speed Metabolism is controlled by different areas of the body that change the speed at which food is processed. Photo courtesy of Flickr, Dylan Luder

In 2009-2010, the Centers for Disease Control and Prevention (CDC) developed a program to examine the nutritional levels and food habits of U.S. citizens, called the National Health and Nutrition Examination Survey (NHANES).  

Responses to questionnaires on bowel health were given by 5,126 patients, 20 years and older, without a history of any health problem concerned with the bowel region (celiac disease, colon cancer, and irritable bowel syndrome). 

Their responses were compared to the bowel habits of people of various sizes: obese, underweight, normal weight and extremely obese. The researchers cancelled out factors that could influence bowel movements such as diabetes, demography, food habits and unhealthy use of laxatives. They were then able to independently assess whether obesity and diarrhea were linked. 

The researchers said that 8.5 percent of the respondents of the survey who were obese and 11.5 percent of severely obese people had a 60 percent higher chance of suffering from chronic diarrhea. This was in comparison to 4.5 percent of people with normal weight. “Stepwise regression revealed that severe obesity was independently associated with an increased risk of diarrhea,” the authors said.

The reason behind this connection has not yet been established. However, the researchers suspect obesity and chronic low-grade inflammation (leading to diarrhea)  could be linked. For physicians to get more clarity on how to treat poor bowel functioning, more research is needed on the reasons behind why obesity triggers inflammation. 

“The treatment of obesity and obesity-related medical conditions requires multidisciplinary management. Clinicians should be aware of the relationship between obesity and diarrhea, especially considering the potential negative impacts altered bowel habits can have on quality of life," Anthony Lembo, MD, senior author and a gastroenterologist in the Division of Gastroenterology, Hepatology, and Nutrition at BIDMC, said in the press release.