Eating more ultra-processed foods may be linked to a higher risk of developing Crohn’s disease, according to a new review of scientific studies.
Researchers analyzed more than a decade of data on how these foods relate to inflammatory bowel disease, or IBD. The findings were published in the journal Nutrients.
The review looked at population studies, lab experiments, and dietary trials. It found a consistent pattern: people who ate more ultra-processed foods had a higher chance of developing Crohn’s disease. The same link was much weaker for ulcerative colitis, another form of IBD.
This suggests that Crohn’s disease may be especially sensitive to diet.
How ultra-processed foods affect the gut
Ultra-processed foods are industrial products made from refined ingredients and additives. These include emulsifiers, artificial sweeteners, thickeners, and colorants. They are designed to improve taste, texture, and shelf life.
Lab studies offer clues about why these foods may harm the gut. Some emulsifiers appear to thin the protective mucus layer in the intestines. This makes it easier for bacteria to touch intestinal tissue directly. Other additives change the gut microbiome, reducing helpful bacteria and increasing inflammatory ones.
Some additives may also increase intestinal permeability, often called “leaky gut.” This allows bacterial fragments to enter the bloodstream and trigger immune responses. Over time, this low-level immune activity may lead to the chronic inflammation seen in Crohn’s disease.
The review notes that these changes do not happen overnight. But daily exposure to ultra-processed foods may slowly make the gut more vulnerable.
What this means for people with and without IBD
The research does not prove that ultra-processed foods cause Crohn’s disease. Most of the evidence is observational. But the link between population data, biological mechanisms, and clinical outcomes is strong.
For people already living with IBD, eating more ultra-processed foods has been tied to worse disease activity and higher chances of relapse. Diets that cut out these foods, such as the Crohn’s Disease Exclusion Diet, have helped some patients reach remission, especially children.
Even for people without IBD, the findings matter. The same gut changes linked to Crohn’s disease, such as microbiome disruption and chronic inflammation, are also tied to metabolic disease, immune problems, and mental health conditions.
Globally, nearly five million people now live with IBD. Rates are rising fastest in countries where ultra-processed foods make up a large part of the diet. Genetics alone cannot explain this shift, which points to environmental factors like diet.
The review’s authors say the message is becoming clearer: as diets move away from natural foods, the gut may pay the price.
