UNC study links oxalate in spinach, almonds to IBD inflammation

September 12, 2026 at 05:00 AM2 min

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Researchers at the UNC School of Medicine found that people with inflammatory bowel disease have lower levels of two oxalate-transporting proteins, SLC26A2 and SLC26A3, in intestinal tissue. Crohn's disease patients had higher stool oxalate than healthy controls despite similar plant-based diets, according to a study published August 13, 2026 in Cellular and Molecular Gastroenterology and Hepatology.

Key Facts

The study was published August 13, 2026 in Cellular and Molecular Gastroenterology and Hepatology.
Two oxalate transporter proteins, SLC26A2 and SLC26A3, were consistently lower in intestinal tissue from patients with ulcerative colitis and Crohn's disease.
Crohn's disease patients had significantly higher stool oxalate levels than people without IBD despite similar plant-based food intake.
The study used DNA metabarcoding for the first time to evaluate diet in an IBD population.

Oxalate Transport Disruption

Oxalate is a natural compound found in all plant foods, and in a healthy digestive system most dietary oxalate passes through the body and is eliminated in stool. Researchers found that two transporter proteins involved in moving oxalate out of the gut, SLC26A2 and SLC26A3, were consistently present at lower levels in intestinal tissue from patients with both ulcerative colitis and Crohn's disease. This reduction appeared across affected tissues regardless of whether active inflammation was present, and the more inflamed the tissue became, the lower the expression of these transporters tended to be. When these transport systems are impaired, less dietary oxalate is absorbed, leaving more oxalate behind in the intestinal environment where it may amplify the inflammation already associated with IBD.

Dietary Intake Comparison

People with Crohn's disease had significantly higher levels of oxalate in their stool than people without IBD, even though the two groups regularly consumed similar amounts of plant-based foods. Researchers reached that conclusion using a validated dietary questionnaire, the Diet History Questionnaire III, and DNA metabarcoding, a molecular method that detects plant species represented in stool samples. According to the researchers, this is the first time DNA metabarcoding has been used to evaluate diet in a population with IBD. Postdoctoral scholar Anna Salvador, PhD, RD, LDN, led the study in the lab of Shehzad Z. Sheikh, MD, PhD, Professor of Medicine and Genetics at UNC School of Medicine.