Xanthan gum helps keep salad dressings smooth, gluten-free breads from crumbling and protein shakes from separating. For some people with swallowing difficulties, it also makes food and drinks safer to consume. A new animal study suggests sustained intake may affect the colon, but the findings are far from proof that xanthan gum causes gut inflammation in people.
In the study, published in PLOS One, researchers gave xanthan gum to male rats for 10 weeks and found signs of mild colon inflammation, changes in proteins involved in the intestinal barrier and a shift in one group of gut bacteria. Because the study included only 32 rats, it cannot establish whether typical exposure from food has similar effects in humans.
“This isn’t about demonizing xanthan gum. Rather, it’s about emphasizing the need to invest in translational studies involving humans,” said Alessandra Rischiteli, the nutritionist and speech-language pathologist who conducted the research. “It’s possible that occasional use in small amounts as an additive doesn’t harm health. The concern is with daily use as an ingredient and the cumulative effect of the thickener.”
Xanthan gum is produced through bacterial fermentation and is used to thicken, stabilize or improve the texture of products including sauces, yogurt, ice cream, baked goods, gluten-free pasta, supplements and protein shakes.
It also has an important medical use. People with dysphagia, or difficulty swallowing, may use xanthan gum-based thickeners to change the consistency of liquids and reduce the risk that food or drink will enter the airway.
The researchers divided the rats into four groups of eight. One group received no xanthan gum, while the others consumed low, medium or high amounts mixed into their diets. The doses were intended to represent a range of possible exposure, from xanthan gum in packaged and gluten-free foods to the larger quantities that may be used in medically thickened drinks.
After 10 weeks, rats receiving the medium and high amounts showed more immune cells in the colon wall, a sign of inflammation. Tissue analysis also found increased levels of inflammatory markers and changes in claudin-2, a protein involved in controlling movement between cells lining the intestine.
Higher claudin-2 expression can be associated with greater intestinal permeability. However, the researchers did not directly demonstrate that harmful substances crossed the rats’ intestinal barriers or that the animals developed a clinical intestinal disease. Describing the result as proof of a damaged or “leaky” gut would go beyond what the experiment established.
The inflammatory findings were also not uniform across every measurement. Some changes were stronger at the middle dose than at the highest dose, and different laboratory tests did not always produce the same result. The rats did not experience significant changes in body weight, food intake, blood glucose or blood lipids.
Researchers also examined the animals’ gut microbiota. Overall microbial diversity did not change significantly, although the highest-dose group had more bacteria from a relatively uncommon group called Elusimicrobiota. The researchers interpreted that shift as a possible sign of microbial imbalance, but one altered bacterial group is not enough to establish that the animals developed clinically meaningful dysbiosis.
The study builds on longstanding questions about the safety of xanthan gum-based thickeners for premature infants. Reports have previously linked a commercial thickening product with cases of necrotizing enterocolitis, a serious intestinal illness that primarily affects premature babies.
The rat findings may help researchers investigate possible biological mechanisms, but they do not prove that xanthan gum caused those infant cases. Premature infants have unusually vulnerable and underdeveloped digestive systems, so findings involving them cannot be applied broadly to older children or adults.
The results also should not prompt people with dysphagia to stop using a prescribed thickener. Liquids that are too thin can enter the airway and lead to choking, respiratory infections or aspiration pneumonia. Any change to food or drink consistency should be made with guidance from a physician or speech-language pathologist.
The researchers suggested that people who rely on thickeners might monitor their digestive health. However, their recommendation to consider probiotics was not tested in this experiment. The study provides no evidence that probiotics would prevent or reverse any effects associated with xanthan gum.
The research also cannot tell consumers whether the relatively small amount of xanthan gum in a serving of sauce, yogurt or gluten-free bread poses a concern. The doses were administered to rats, and translating animal exposure into realistic human intake is difficult. Human digestion, immune responses and gut microbial communities may respond differently.
The São Paulo Research Foundation, a public research funding agency in Brazil, supported the study.