Many who live in industrialized countries may not have heard of xanthan gum by name, but have likely consumed it.
Found in several processed foods such as soups, ice cream, and fruit juices, in personal care products such as toothpaste and shampoo, and in industrial products such as paints and adhesives, the complex polysaccharide is used for its properties as a stabilizer and thickening agent.
Until now, few studies have investigated the relationship between xanthan gum and the gut microbiome, which functions to break down polysaccharides. The food additive was thought to be a soluble fiber that absorbed water and turned into a gel-like substance, unable to be digested by the body and therefore not providing calories or nutrients.
The U.S. Food and Drug Administration (FDA) lists the product as a safe food additive, which is generally found at a concentration of 0.3 percent or lower in foods and beverages.
First approved by the FDA in 1969, xanthan gum has also been approved as a safe food additive by the World Health Organization and Food and Agriculture Organization (WHO/FAO), and is widely used in countries around the world such as Canada, Mexico, Brazil, China, Japan, and Korea.
Changing the gut microbiome
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In April 2022, a study published in the Nature Microbiology journal by dozens of scientists from the U.S., Norway, Canada, France, Saudi Arabia, and Denmark showed that “the ability to digest xanthan gum is common in human gut microbiomes from industrialized countries and appears contingent on a single uncultured bacterium in the family Ruminococcaceae.”
The authors found a microbe from the family Ruminococcaceae is able to break down carbohydrates from the xanthan gum, and a different gut microbe named Bacteroides intestinalis is able to then consume the smaller breakdown products. Short-chain fatty acids resulting from bacterial consumption can contribute to caloric intake.
Interestingly, the researchers found that the genetic signatures of these gut bacteria were less likely to be found in people who live in non-industrialized countries, which indicates regular consumption of xanthan gum may alter the gut microbiome of those who live in industrialized countries.
The researchers initially colonized germfree mice with a complex human microbiome containing the Ruminococcaceae microbe, but not Bacteroides intestinalis.
The data showed the amount of the Ruminococcaceae microbe “increased to substantial levels in a complex microbiome and that this was dependent on dietary XG [Xanthan gum].” Further studies introducing B. intestinalis into the mice supported the hypothesis that xanthan gum can promote the colonization and expansion of the Ruminococcaceae microbe and B. intestinalis, with B. intestinalis colonization “likely dependent” on the presence of the Ruminococcaceae microbe to release breakdown products for it to feed on.
Matthew Ostrowski, PhD from the University of Michigan Medical School Department of Microbiology and Immunology, stated, “While xanthan gum is generally considered safe, our results suggest that its widespread consumption may be enriching our microbiomes for bacteria that consume it. Our study is the first step in understanding how new food ingredients could be changing our microbiomes and whether these changes are good or bad.”
Dr. Ostrowski added, “This may be especially important for people who consume above-average amounts of xanthan gum, such as people with celiac disease and those following gluten-free diets.”
As stated by Dr. Ostrowski, further research is needed to investigate whether the changes to the gut microbiome with increased xanthan gum consumption are beneficial, detrimental, or both to our health.
Excessive amounts of xanthan gum are known to have laxative effects and other side effects such as gas and bloating. However, it is unknown whether the amount of calories released is enough to cause significant weight gain, and how the amount of released calories varies among individuals in each country.
