Advances in Nutrition review finds “it would be a lost opportunity in not providing dietary guidance as part of the management of inflammatory bowel disease.”

According to the Global Burden of Disease Study 2017, “inflammatory bowel disease is on the rise worldwide, with some seven million people currently having the diagnosis, taking a toll on patients’ health as well as being a growing economic burden to society.” For some people, inflammatory bowel disease is a mild, manageable illness. For others, it can be a debilitating condition, leading to life-threatening complications.

Inflammatory bowel disease is an umbrella term that includes several disorders characterized by chronic inflammation of the tissues in the digestive tract, often with cycles of remission and relapse. The two most common forms of inflammatory bowel disease are Crohn’s disease and ulcerative colitis, but there are also less common forms such as microscopic colitis.

In the past decade, researchers have made substantial progress in understanding the causes underlying the onset and progression of inflammatory bowel disease. It is now understood to be rooted in a set of interactions between genetic, microbial, and environmental factors. Many researchers also believe that the recent increase in cases is connected to the modern Western lifestyle and diet.

Inflammatory bowel disease is typically treated pharmaceutically via long-term use of immunosuppressive, anti-inflammatory, biological, and immunomodulatory medications. These treatments can help many patients manage their symptoms; however, not all patients respond well. Moreover, there are no current pharmaceutical treatments that can prevent the onset of inflammatory bowel disease.

While research has led to improved pharmaceutical treatments, less is known about how diet may affect both the onset and progression of inflammatory bowel disease. In response, the authors of Diet, Food, and Nutritional Exposures and Inflammatory Bowel Disease or Progression of Disease: An Umbrella Review analyzed the evidence to better understand the interplay between dietary factors and inflammatory bowel disease, with the goal of supporting the development of effective dietary strategies to prevent disease onset as well as alleviate symptoms. Their review was published in Advances in Nutrition: An International Review Journal, a publication of the American Society for Nutrition.

To conduct their research, the authors performed a comprehensive search for relevant systematic reviews and meta-analyses that explored diet and its association with the incidence, progression, and remission of inflammatory bowel disease. Their search eventually led them to 47 systematic reviews and meta-analyses that met their criteria.

Following their analyses, the authors concluded that “a high intake of fruits and vegetables are both strongly associated with reduced incidence of ulcerative colitis and Crohn’s disease.” In addition, they noted that “Mediterranean, vegetarian, and semi-vegetarian diets are associated with reduced incidence and progression of inflammatory bowel disease.” In contrast, the evidence led the authors to conclude that “dietary patterns high in meat, ultra-processed food, dietary fats, and refined sugars are associated with increased incidence of inflammatory bowel disease, ulcerative colitis, and Crohn’s disease.”

Interestingly, there were some differences in the association of diet and ulcerative colitis compared to diet and Crohn’s disease. For example, the authors found that an increased intake of dietary fiber was associated with a lower risk of Crohn’s disease, but it did not appear to be clearly associated with ulcerative colitis.

Many of the associations that were found between diet and inflammatory bowel disease have been mirrored by studies on inflammatory markers, microbiota, and other disease mechanisms, increasing the level of certainty that the authors’ findings were not just associative, but also causal. Given “the strong associations with both incidence and progression to disease of several dietary factors,” the authors concluded that “it would be a lost opportunity in not providing dietary guidance as part of the management of inflammatory bowel disease.”

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