Researchers suggest gut damage due to high-sugar diet

UT Southwestern researchers fed mice a solution of water with a 10 percent concentration of various dietary sugars – glucose, fructose, and sucrose – for seven days

Researchers at UT Southwestern in the US fed mice with diets high in sugar and observed that the mice developed worse colitis, a type of inflammatory bowel disease (IBD). Researchers examining their large intestines found more of the bacteria that can damage the gut’s protective mucus layer.

This new study points to sugar – particularly the glucose found in high fructose corn syrup developed by the food industry in the 1960s and then increasingly used to sweeten soft drinks and other foods – as a prime suspect.

UT Southwestern researchers fed mice a solution of water with a 10 percent concentration of various dietary sugars – glucose, fructose, and sucrose – for seven days. They found that mice that were either genetically predisposed to develop colitis, or those given a chemical that induces colitis, developed more severe symptoms if they were first given sugar.

The researchers then used gene-sequencing techniques to identify the types and prevalence of bacteria found in the large intestines of mice before and after receiving their sugar regimen. After being given sugar treatments for seven days, those fed sucrose, fructose, and – especially – glucose showed significant changes in the microbial population inside the gut, according to the study.

Bacteria known to produce mucus-degrading enzymes, such as Akkermansia, were found in greater numbers, while some other types of bugs considered good bacteria and commonly found in the gut, such as Lactobacillus, became less abundant.  

After finding changes in the gut microbiota in sugar-fed mice, the researchers fed feces from the sugar-treated mice to other mice. Those mice developed worse colitis, suggesting that glucose-induced susceptibility to colitis can be transmitted along with the destructive intestinal microbiota from affected animals.

The researchers now plan to study whether and how high sugar intake affects the development of other inflammatory diseases such as obesity, fatty liver disease, and neurodegenerative diseases like Alzheimer’s.