Study Finds that Nanoparticle Commonly Added in Food has Adverse Effects on Gut Microbiota

Anahita Kodali, Medical Sciences, News, Summer 2020

Figure 1: Wrigley’s, a popular brand of gum, contains E171. Other brands containing the additive include Trident, Pur, and EPIC.

Image Credit: Wikimedia Commons


Food directly impacts people’s weight and health.  One indisputable factor that contributes to weight gain is the number of calories consumed – if people consume high amounts of calories and do not burn off enough with exercise or physical activity, the surplus calories will be stored as fat. Additionally, poor diets can also cause health issues. Eating processed food and drinking large amounts of alcohol and soft drinks is a diet high in fats and sugars, which also contributes to weight gain1.

Beyond weight, diet also impacts the gut microbiota negatively. Gut microbiota are the myriad of microorganisms in the guts that play critical roles in boosting immunity, nutrient metabolism, and maintaining good health2. Imbalanced gut microbiota have been associated with obesity, cardiovascular disease, and inflammatory bowel disease3. As America faces an ever-growing obesity epidemic, it is more important now than ever to better understand the complex interaction between food and health.

Researchers from the University of Massachusetts Amherst recently have found that a very common food additive has significant effects on gut microbiota. The team studied the effect of exposure to titanium dioxide nanoparticles (TiO2 NPs) in food on health, which was recently banned in France but is still available in the US via the additive E171, a product added to common food items like gum, candy, drinks, and desserts in order to make the products look whiter and more opaque3. In this study, the researchers studied two groups of mice. One population was fed a high-fat diet (similar to that of many Americans) and the other was fed a low-fat diet. Both groups were given either E171 or TiO2 as part of their daily feedings4.

They had three critical findings. For one, all of the mice fed high-fat diets became overweight or obese. These findings corroborate previously done research on the effect of high-fat diets on weight. Secondly, all of the mice had disruptions in their gut microbiota; the mice had lower levels of fatty acids critical to colon health and they had inflammation of the colon (inflamed colons can cause symptoms like abdominal pain and diarrhea). To test that these changes were due to the addition of TiO2 NPs, the team performed a fecal transplant study. They gave a new population of mice antibiotics to clear out their microbiota and then transplanted fecal matter from the original mice (which had diets with TiO2 NPs) into the new population; this confirmed that the disruptions in gut microbiota were directly related to TiO2 NPs. Lastly, obese mice were most impacted by TiO2 NPs, which means that these nanoparticles caused the most damage in mice that were also consuming high fat diets4.

Lead author Professor Hang Xiao said that he believes the study has significant implications for the future of the American food industry regulations3. As TiO2 NPs have been shown to have adverse health effects, which are further compounded by obesity, it will be important to evaluate if any TiO2 NPs and E171 should be allowed in common American foods in the future.



[1] Causes: Obesity. (2019, May 16). Retrieved June 29, 2020, from

[2] Jandhyala, S. M. (2015). Role of the normal gut microbiota. World Journal of Gastroenterology, 21(29), 8787. doi:10.3748/wjg.v21.i29.8787

[3] University of Massachusetts Amherst. (2020, June 25). Common food additive causes adverse health effects in mice: Researchers find TiO2 nanoparticles produce inflammation in colon. ScienceDaily. Retrieved June 28, 2020 from

[4] Cao, X. et. al. (2020) Foodborne Titanium Dioxide Nanoparticles Induce Stronger Adverse Effects in Obese Mice than Non‐Obese Mice: Gut Microbiota Dysbiosis, Colonic Inflammation, and Proteome Alterations. Small, 2001858 DOI: 10.1002/smll.202001858

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