The question of why the Western population is increasingly suffering from inflammatory bowel diseases, which include Crohn’s disease and ulcerative colitis, is increasingly concerned about the medical community. It looks like it has to do with our diet, sugar consumption in particular.

“Colitis is a major public health problem in the US and other Western countries,” says Hasan Zaki, professor of pathology at the University of Texas Southwestern Medical Center, who led the study published in the journal Science Translational Medicine.

The colitis and Crohn’s disease can cause persistent diarrhea, abdominal pain and rectal bleeding. The number of American adults suffering from these diseases rose from two million in 1999 to three million in 2015, according to the Centers for Disease Control and Prevention. Also, the disease is beginning to appear in children.

Because the prevalence of the disease is much higher in Western countries, researchers consider the Western diet high in fat, sugar, and animal protein as a possible risk factor. Saturated fats have already confirmed their role in colon inflammation, but the role of sugar has yet to be studied.

According to the recent study, mice fed high-sugar diets developed worse colitis and had more bacteria in the large intestine that could damage the protective mucus layer of the intestine.

During the experiment, the University of Texas scientists fed mice a water solution containing 10% concentration of various sugars – glucose, fructose, and sucrose – for seven days. Mice that were genetically predisposed to developing colitis, or given a chemical that induces colitis, developed more severe symptoms if they also consumed sugar.

The researchers then used genetic sequencing techniques to identify the types and prevalence of the bacteria that were found in the large intestines of the mice before and after receiving their sugar diet. After seven days of consuming sugar, those who were fed sucrose, fructose and, especially, glucose, showed significant changes in the microbiota within the gut, according to the study.

Bacteria that produce mucus-degrading enzymes, such as Akkermansia, were found in greater numbers, while other types of good bacteria, such as Lactobacillus, became less abundant. The protective mucus layer in the large intestine also thinned.

Although glucose had a greater effect, “the three sugars profoundly altered the composition of the gut microbiota,” the study concludes. These data suggest that the ingestion of simple sugars predisposes to colitis and accelerates its pathogenesis by modulating the intestinal microbiota in mice.