Diet high in sugar triggers intestinal inflammation

Diet high in sugar triggers intestinal inflammation
Diet high in sugar triggers intestinal inflammation

In mice that were given glucose and fructose, an increase in the number of mucolytic bacteria was found in the intestines, which contributed to the destruction of the mucous membrane of this organ. As a result, these rodents developed colitis.


Inflammatory bowel disease (IBD) is a multiple disease characterized by chronic inflammation of the gastrointestinal tract. Although the etiology of these diseases is largely unknown, the so-called Western diet and lifestyle seems to be associated with an increased risk of developing them.

The authors of the new study, at the Southwestern Medical Center in Dallas, Texas, examined how a high-sugar diet affects colitis, an inflammatory disease of the lining of the colon that causes diarrhea, abdominal pain and rectal bleeding. According to statistics from the US Centers for Disease Control and Prevention, the number of American adults with IBD (including Crohn's disease) has increased from two million in 1999 to three million in 2015. In addition, colitis is becoming increasingly common among children, although historically they have not suffered from it.

“The prevalence of inflammatory bowel disease in Western countries indicates that Western diets are a possible risk factor for IBD. The high sugar content associated with many noncommunicable diseases is a hallmark of the Western diet, but its role in IBD remains unknown. We studied the effect of simple sugars such as glucose and fructose on the pathogenesis of colitis in mice,”reads an article published in the journal Science Translational Medicine.

For seven days, the researchers fed the mice with a 10% solution of various sugars - glucose and fructose. As a result, the scientists found that rodents that had a genetic predisposition to colitis or were injected with a chemical that causes colitis developed more severe symptoms if they were given sugar first.

“Short-term consumption of glucose or high-glucose fructose did not induce inflammatory responses in healthy gut, but markedly altered the composition of the gut microbiota. In particular, the number of bacteria that destroy the protective layer of mucus, Akkermansia muciniphila and Bacteroides fragilis, has increased. Accordingly, mucolytic enzymes of bacterial origin were enriched, resulting in erosion of the mucous layer of the colon. No exacerbation of sugar-induced colitis was observed when mice were treated with antibiotics or kept in a microbial-free environment. This suggests that altered microbiota plays a critical role in the pathogenesis of sugar-induced colitis. Overall, our data suggest that consumption of simple sugars predisposes to colitis and enhances its pathogenesis by modulating the gut microbiota,”the doctors explained.

After the researchers found changes in the gut microbiota in mice that had been fed sugar, they decided to feed their feces to another group of rodents. As a result, these animals developed more severe colitis: apparently, the predisposition to this disease caused by glucose can be transmitted along with disturbed intestinal microbiota from diseased rodents.

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