IBD: A low-calorie plant diet relieves inflammation, repairs gut
Repeated cycles of a low-calorie, plant-based diet have shown promise as a treatment for inflammatory bowel disease.
Scientists at the University of Southern California in Los Angeles recently tested what they describe as the "fasting-mimicking" diet on a mouse model of inflammatory bowel disease (IBD).
In a study paper that now features in the journal Cell Reports, they describe how, compared with water-only fasting, periodic 4-day cycles of the fasting-mimicking diet "partially reversed" hallmarks of IBD in the mice.
They saw that the diet reduced inflammation and increased populations of stem cells in the mice's intestines. Stem cells are essential for tissue repair and regeneration.
In addition, the team observed that these effects appeared, in part, to be due to an increase in beneficial gut bacteria.
Results from humans also showed that the diet reduced markers of inflammation and associated immune cells.
Taking these results together, the researchers conclude that a low-calorie, plant-based, fasting-mimicking diet has potential as an effective treatment for IBD.
Corresponding study author Valter Longo, a professor of biological sciences, says that their investigation is the first IBD study to bring together "two worlds of research."
"The first [world]," he explains, "is about what you should eat every day, and many studies point to a diet rich in vegetables, nuts, and olive oil. The second is fasting and its effects on inflammation, regeneration, and aging."
He and his colleagues suggest that the reason that water-based fasting does not seem to be as effective as the fasting-mimicking diet could be because while fasting produces many of the desired effects, the body still needs essential nutrients to do the rest.
IBD and gut inflammation
The term IBD mainly covers two conditions, Crohn's disease and ulcerative colitis, whose principal feature is long-term inflammation of the intestines. The protracted inflammation eventually damages the tissue of the gut.
The main difference between these conditions is that Crohn's disease can occur anywhere in the gut between the mouth and the anus, while ulcerative colitis affects the colon and rectum.
According to 2015 survey data in a Centers for Disease Control and Prevention (CDC) study, about 3 million adults in the United States have reported ever having had a diagnosis of IBD.
This figure suggests that at least 1.3 percent of the U.S. adult population has IBD, which often occurs with other illnesses and results in poor quality of life and "complications requiring hospitalizations and surgical procedures."
The main symptoms of IBD are abdominal pain and diarrhea. People with ulcerative colitis can also experience bleeding through the anus.
The risk factors for IBD include "genetic predisposition and factors that alter gut microbiota, such as antibiotics," note the study authors.
For a while, experts thought that IBD was a "classic autoimmune" disease, wherein the immune system attacks the tissue of the gut as if it were a threat similar to that of disease-causing viruses and bacteria.
More recently, however, other explanations about the origins of IBD have emerged, and there is a growing view that Crohn's disease and ulcerative colitis are "complex barrier disorders."
