Western Diet, Not High BMI, May Fuel Irritable Bowel Disease

Eating a typical Western diet, which is high in sugar and fat, may cause major changes to gut immune cells that pave the way for irritable bowel disease (IBD), a chronic condition that can be painful and have a negative effect on one's life. The study involved mice, including some with genetic mutations that caused them to overeat.

The Western diet is commonly high in salt, sugar, and fat, with excessive meat consumption and too much processed foods. This diet's potential impact on health has been studied extensively and associated with things like increased risk of cancer and heart disease. The same diet may also put one at risk of developing IBD.

The new research comes from Washington University School of Medicine, where researchers found that both humans and mice fed a diet high in fat and sugar had abnormal gut immune cells called Paneth cells. The abnormality puts the gastrointestinal tract at increased risk of inflammation, the key element of inflammatory bowel diseases.

The study found that the higher a person's BMI, the more damaged their Paneth cells were. However, further exploration of this using mice found that BMI isn't the driving factor behind this dysfunction, but rather a diet high in fat and sugar, the overconsumption of which is the leading cause of obesity in humans.

Overeating a healthy diet didn't result in abnormal Paneth cells in high BMI mice, but it did lead to the damaged cells in mice who were overfed a diet where 40-percent of the calories came from sugar and fat. The good news is that the Paneth cells returned to normal in mice who were put back on their healthy diet after only four weeks.