Eating more ultra-processed foods may increase the risk of developing Crohn’s disease, according to a new review of research published in the journal Nutrients.
Nearly five million people worldwide live with inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis. Rates are rising fastest in countries where ultra-processed foods make up a large part of the diet. Researchers have been looking at environmental factors, with diet emerging as a major suspect.
The review analyzed more than a decade of research, including population data, lab experiments, and dietary studies. Across large observational studies, people who ate more ultra-processed foods had a higher risk of developing Crohn’s disease. The link was much weaker for ulcerative colitis, suggesting Crohn’s may be especially sensitive to diet.
Ultra-processed foods are industrial formulations made from refined ingredients and additives such as emulsifiers, artificial sweeteners, thickeners, and colorants. Mechanistic studies offer clues about why these foods may stress the gut. Some emulsifiers appear to thin the protective mucus layer in the gut, making it easier for bacteria to contact intestinal tissue. Others change the gut microbiome, reducing beneficial microbes and increasing inflammatory ones.
Certain additives may also increase intestinal permeability, sometimes called “leaky gut.” This allows bacterial fragments to enter the bloodstream and activate immune responses. Over time, this low-grade immune activation may contribute to the chronic inflammation seen in Crohn’s disease.
The research does not prove that ultra-processed foods directly cause Crohn’s disease. Most evidence is observational. But when population data aligns with biological mechanisms and clinical outcomes, the pattern becomes harder to ignore.
For people already living with IBD, higher intake of ultra-processed foods has been linked to greater disease activity and higher relapse risk. Dietary approaches that reduce ultra-processed foods, such as the Crohn’s Disease Exclusion Diet, have been shown to induce remission, especially in children.
Even for people without IBD, the same gut changes linked to Crohn’s disease—microbiome disruption, barrier breakdown, and chronic inflammation—are also tied to metabolic disease, immune dysfunction, and mental health conditions.
The review does not call for avoiding all ultra-processed foods. Instead, it supports being more aware of how often these foods make up the bulk of a diet. Centering meals around whole or minimally processed foods when possible, paying attention to ingredient lists with long strings of additives, and building a small rotation of simple meals at home are practical steps that align with the science.
Ultra-processed foods may actively shape the gut in ways that increase vulnerability to disease, particularly Crohn’s. While scientists continue to study cause and effect, the message is becoming clearer: the more diets move away from foods in their natural form, the more the gut may pay the price.
