Spinach, almonds and sweet potatoes usually land firmly in the “healthy food” category.

For most people, that’s reasonable advice.

But not everyone can deal with them…

Especially for someone with Crohn’s disease or ulcerative colitis, new research suggests there may be a complication hiding in some of these foods.

In fact, these compounds could affect people with more sensitive stomachs too.

Oxalates in these foods are the problem.

How Natural Compound Irritates The Gut

Oxalate is a naturally occurring compound found in plant foods.

It’s probably best known for its role in certain kidney stones…if your body can’t purge it, then it can create all kinds of issues

Now researchers at the University of North Carolina have found evidence that oxalate left behind in the digestive tract may also worsen intestinal inflammation in people with inflammatory bowel disease, or IBD.

That creates an awkward situation for healthy eaters.

Someone can follow a plant-rich diet, eat foods commonly promoted as nutritious, and still potentially expose an already inflamed gut to something that irritates it even more.

Normally, much of the oxalate people eat eventually leaves the body in stool.

Researchers found that people with Crohn’s disease and ulcerative colitis had lower levels of two proteins, SLC26A2 and SLC26A3, involved in handling oxalate in the intestine. Those levels dropped further as inflammation worsened.

With fewer of these transporter proteins working normally, more oxalate may remain inside the gut, where it could help fuel inflammation.

The researchers also found that people with Crohn’s disease had significantly more oxalate in their stool than people without IBD—even though both groups were eating similar amounts of plant-based foods.

High oxalate levels weren’t simply explained by Crohn’s patients loading up on spinach or nuts. Instead, it looked like their intestines were processing oxalate differently.

The same thing was even found when the researchers tested what happened when oxalate was added to the diets of mice with colitis.

And it was pretty telling…

Mice given extra oxalate along with a substance that triggers colitis were 60% less likely to survive than mice that didn’t receive the additional oxalate. In genetically susceptible mice, oxalate also caused inflammation to develop sooner and become more severe.

Lab experiments offered a possible explanation.

Oxalate increased inflammatory activity in macrophages and dendritic cells, immune cells that regulate the gut’s response to potential threats.

Researchers also found a possible connection between low levels of another transporter, SLC26A6, and stricturing Crohn’s disease. Nearly three-quarters of patients with low SLC26A6 levels had this more aggressive form of Crohn’s, in which inflammation and scar tissue can narrow parts of the intestine.

That finding is preliminary, but it raises the possibility that these transporters might someday help identify patients at greater risk.

So What Should People With IBD Eat?

Great question.

This study didn’t prove that oxalate in foods would be a major ongoing issue.

The research also didn’t show that a low-oxalate diet reduces Crohn’s or ulcerative colitis symptoms.

We would need some human clinical trials to answer that question.

Plus, eliminating plant foods broadly could create other problems. Fruits, vegetables, nuts, and other plant foods provide fiber, vitamins, minerals, and many other beneficial compounds.

A better long-term approach may be more personalized.

Some people with IBD may eventually benefit from reducing specific high-oxalate foods while keeping plenty of lower-oxalate plants in their diets.

Researchers are also interested in the gut microbiome. People with IBD often have lower levels of Oxalobacter formigenes, a bacterium that helps break down oxalate. Restoring oxalate-degrading bacteria could someday offer another option without requiring people to severely restrict what they eat.

For now, the study helps explain something patients often experience: two people can eat very similar diets and have very different reactions.