International Business Department           Liu Bojia           September 1, 2023

  Whenever we consume food, the pancreas in the body begins to release insulin, which helps absorb free sugar into the muscles and liver for storage. But chronic overconsumption of high-sugar foods not only overwhelms the pancreas, it also causes the body to develop insulin resistance.

  As the name suggests, insulin resistance means that cells no longer follow the "orders" of insulin. When this happens, sugar leaves the bloodstream in large quantities, and the pancreas continues to tell itself that there is still work to be done, but it can only continue to secrete large quantities of ineffective insulin until it is exhausted.

  Most obese, pre-diabetic patients develop insulin resistance and subsequently type 2 diabetes. If insulin resistance can be solved, it will lead to entirely new therapies for obesity and diabetes.

  Today, a brand new paper in Nature shows us a new perspective, as the authors no longer focus solely on the pancreas, but mention that the myriad of gut microbes that we have symbiotically in our bodies have a key role to play. According to the paper, gut microbes have specialized glucose metabolism mechanisms that help us break down undigested carbohydrates, and about 10% of the body's energy absorption comes from microbial glucose metabolism. A growing body of research also points to these tiny organisms in the process of obesity and diabetes.

  To clearly demonstrate the connection, scientists at the RIKEN Research Institute in Japan analyzed data from more than 300 volunteers who regularly participated in annual health screenings, which included metabolome fitness as well as stool samples. Data from those volunteers diagnosed with diabetes were eventually eliminated to prevent interference with the accuracy of the results.

  One intuitive result the researchers observed from these data comparisons was that people who were already insulin resistant would have an excess of carbohydrates in their feces. Most of these were in the form of simple sugars, such as glucose, fructose and galactose. In addition to this, some short-chain amino acids produced by sugar fermentation can be detected in the feces of this group of people.

  The researchers also observed excess monosaccharides in the feces of obese and pre-diabetic people. This suggests that there is a potential link between these symptoms.

  But why do these groups of people have abnormal levels of simple sugars in their feces? The researchers examined their fecal microbes meticulously, and the data found that when a person's microflora is dominated by bacteria from the Trichoderma (Lachnospiraceae) family, often they are more likely to be insulin-resistant, and to have more carbohydrates in their feces.

  But the opposite is true: the more bacteria of the Bacteroidales family there are, the lower the level of insulin resistance of the individual. The two types of bacteria form completely different gut microenvironments. In separate tests, the researchers confirmed that Bacteroidales can consume sugars that appear in the feces of insulin-resistant individuals.

  This gives this group of bacteria the potential to treat insulin resistance and obesity, the authors tried breeding a group of obese mice on a high-fat diet, and after they exhibited insulin resistance, the authors treated them with specific Bacteroidetes. After a period of time, the mice showed a reduction in all obesity-related symptoms, insulin resistance was no longer evident, and the trend of weight gain slowed down.

  In addition to this, they additionally observed a decrease in the serum levels of HDL-C and lipocalin in the mice, which are beneficial for the body's metabolism.

  The authors emphasize that understanding these connections could allow us to diagnose diabetes risk through gut microbes in the future. And while some probiotic supplements now may not address the two types of bacteria in the study, some future products could consider more beneficial bacteria and fewer others with potentially negative effects. They believe that supplementation with specific anabolic bacteria could be a solution to insulin resistance, but it still needs to be validated in clinical trials before it can be officially used.