A western diet usually contains high sugar foods, pre-packaged foods, butter, candy, fried foods, high-fat dairy products, etc. While knowingly or unknowingly we consume these foods almost every day, we ignore the harmful effects of it. Recently, a research conducted by Washington University School of Medicine in St. Louis and Cleveland Clinic found that a Western diet weakens the immune system in the gut, potentially increasing the risk of infection and inflammatory bowel disease. The study was conducted in mice and humans. It found that a high-sugar, high-fat diet damages Paneth cells, which are immune cells in the gut that help keep inflammation in check. When Paneth cells are not working usually, the gut immune system becomes overly vulnerable to inflammation, increasing the risk of inflammatory bowel disease and eroding effective control of disease-causing microbes.
According to Ta-Chiang Liu, MD, PhD, associate professor of pathology and immunology at Washington University- "Inflammatory bowel disease has historically been a problem primarily in Western countries such as the U.S., but it's becoming more common globally as more and more people adopt Western lifestyles" Adding to that he also said "Our research showed that long-term consumption of a Western-style diet high in fat and sugar impairs the function of immune cells in the gut in ways that could promote inflammatory bowel disease or increase the risk of intestinal infections."
The research examined a database containing demographic and clinical information on 400 people and an assessment of each individual's Paneth cells. The researchers discovered that having a high body mass index (BMI) was linked to Paneth cells that appeared abnormal under a microscope. The worse a person's Paneth cells looked, the higher was their BMI.
Infection that attacks the gut area
To better clarify their findings, the researchers studied two strains of mice that are genetically predisposed to obesity. These mice regularly over ate because they have mutations that prevent them from feeling full even when fed a regular diet. Surprisingly, the researchers discovered that the obese mice had Paneth cells that appeared normal.
Obesity in people is frequently the result of a high-fat, high-sugar diet. As a result, the scientists fed normal mice a diet containing 40% fat or sugar, similar to the typical Western diet. After two months on this diet, the mice were obese, and their Paneth cells were noticeably abnormal. Later, when the mice were put back on the healthy mouse diet, their paneth cells returned to normal.
Ta-Chiang Liu, also said "In people, obesity doesn't occur overnight or even in eight weeks. People have a suboptimal lifestyle for 20, 30 years before they become obese. It's possible that if you have a Western diet for so long, you cross a point of no return, and your Paneth cells don't recover even if you change your diet. We'd need to do more research before we can say whether this process is reversible in people."
Further research revealed that a molecule known as deoxycholic acid, a secondary bile acid formed as a by-product of gut bacteria metabolism, links a Western diet and Paneth cell dysfunction. Bile acid increases the formation of two immune molecules that inhibit Paneth cell function: farnesoid X receptor and type 1 interferon.