Titanium dioxide has also been classified as a possible human carcinogen by the International Agency for Research on Cancer, which has caused concern about its use in food products. This classification, however, is currently based on limited evidence from animal studies that involved the inhalation of titanium dioxide particles that increased the risk of lung cancer.

Because beauty should never come at the price of your health.

People eating lots of candy should be more worried about the sugar and how it can cause high blood pressure and obesity, says Westerhoff.

So, what does it all mean for you, the consumer? Should you stop eating Skittles or begin checking foods for the presence of titanium dioxide? Here's a closer look.

Australian researchers examined how titanium dioxide as a food additive affected gut microbiota in mice by orally administering it in drinking water. The study, published in the journal Frontiers in Nutrition in 2019, found the treatment could “alter the release of bacterial metabolites in vivo and affect the spatial distribution of commensal bacteria in vitro by promoting biofilm formation. We also found reduced expression of the colonic mucin 2 gene, a key component of the intestinal mucus layer, and increased expression of the beta defensin gene, indicating that titanium dioxide significantly impacts gut homeostasis.” The changes were then linked to colonic inflammation, along with a higher expression of inflammatory cytokines, which are signal proteins that help with regulation. The researchers concluded that titanium dioxide “impairs gut homeostasis which may in turn prime the host for disease development.”