Scientists Identify Healthy Food Compound That May Worsen Inflammatory Bowel Disease

Healthy foods such as spinach, almonds and sweet potatoes may have an unexpected effect in people with inflammatory bowel disease (IBD), with new research suggesting that oxalate could worsen intestinal inflammation.

Published in Cellular and Molecular Gastroenterology and Hepatology, the study from the UNC School of Medicine examined people with IBD, including Crohn’s disease and ulcerative colitis, along with mice and laboratory-grown cells.

Oxalate is a natural compound found in plant foods. Normally, the gut helps process and remove much of it through stool. Researchers found that two proteins involved in moving oxalate through the intestine were present at lower levels in intestinal tissue from people with IBD.

The researchers also found that people with Crohn’s disease had higher amounts of oxalate in their stool than people without IBD, even though both groups reported eating similar amounts of plant-based foods. This suggests that the difference may be related to how the gut handles oxalate, rather than simply how much a person eats.

Animal experiments provided further clues. Mice given extra dietary oxalate developed more severe colitis, while genetically susceptible mice developed intestinal inflammation sooner and more severely. In laboratory experiments, oxalate also increased inflammatory activity in immune cells involved in gut protection.

The study found another potential clue in Crohn’s disease. Lower activity of the oxalate transporter was associated with stricturing disease, a more severe form that can narrow the intestine through scar tissue.

However, the findings do not mean people with IBD should eliminate plant foods. Plant-based diets can provide important fibre, vitamins and other nutrients. The researchers say more studies are needed before recommendations about oxalate intake change.

REFERENCE: Anna C. Salvador, et al.; Dietary Oxalate and Intestinal Inflammation: Evidence From Experimental Colitis and Inflammatory Bowel Disease Patient Cohorts. Cellular and Molecular Gastroenterology and Hepatology, 2026; 101861 DOI: 10.1016/j.jcmgh.2026.101861