Xanthan gum is an ingredient that most people have eaten without realizing it.
It is added to thousands of foods because it helps products stay smooth, thick, and stable. Ice cream, yogurt, salad dressings, sauces, gluten-free bread and pasta, protein drinks, and many packaged foods contain xanthan gum.
It is also commonly used to thicken drinks for people with dysphagia, a condition that makes swallowing difficult. For years, the additive has been considered safe, but a new study from the Federal University of São Paulo (UNIFESP) suggests scientists should take a closer look at its long-term effects.
The research, published in PLOS One, found that rats fed xanthan gum every day for 10 weeks developed inflammation in the colon, changes in their gut bacteria, and damage to the protective barrier lining the intestine.
The researchers stress that these findings should not cause panic or encourage people to avoid foods that contain small amounts of xanthan gum.
Instead, they believe the study highlights the need for carefully designed human research to determine whether long-term, frequent consumption could affect health.
Xanthan gum is produced through a fermentation process using the bacterium Xanthomonas campestris. After processing and purification, the final product is used as a food additive because it mixes easily with water and creates a smooth texture.
This is especially valuable for gluten-free foods, which often need extra ingredients to improve their consistency.
To investigate possible health effects, the researchers fed laboratory rats different amounts of xanthan gum over an extended period. They then examined the animals’ intestines, immune responses, and gut bacteria.
The team found clear evidence of inflammation. The intestinal wall contained more immune cells, particularly lymphocytes, suggesting the body’s immune system had become activated. Animals receiving medium and higher doses showed the strongest inflammatory changes.
The scientists also discovered that xanthan gum appeared to weaken the intestinal barrier. Normally, this barrier acts like a protective wall that prevents harmful substances from passing from the gut into the bloodstream.
The study found increased levels of a protein called Claudin-2, which is linked with greater intestinal permeability. When this barrier becomes “leaky,” inflammatory substances may pass through more easily, triggering immune reactions.
Blood tests and tissue analyses also showed higher levels of inflammatory molecules, including TNF-alpha and IL-1 beta. These substances are known to play important roles in inflammatory bowel diseases and other immune-related conditions.
Interestingly, the overall variety of gut bacteria did not change very much. However, the balance of different bacterial groups shifted. One group associated with inflammation became more common, suggesting that long-term xanthan gum consumption may disturb the normal gut ecosystem even without dramatically changing bacterial diversity.
The findings may also help explain earlier reports involving premature babies. More than a decade ago, thickened formula containing xanthan gum was linked to cases of necrotizing enterocolitis, a serious intestinal disease in premature infants. Although those reports could not prove that xanthan gum caused the illness, the new study provides biological evidence showing that the additive can directly trigger inflammation in an experimental model.
The researchers emphasize that these findings should be interpreted carefully. Rats are not humans, and the study does not prove that normal dietary intake causes the same effects in people.
Many individuals consume small amounts of xanthan gum without obvious health problems. Nevertheless, people who consume large amounts through multiple processed foods, supplements, or thickened beverages every day may deserve closer study.
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