Food dyes add a splash of color to many of the items we eat, but chronic exposure to a particular colorant may actually have impacts on our gut health, a new study has found.

For their study, published Tuesday in Nature Communications, researchers looked at the potential impacts of exposure to Allura Red synthetic colorant on gut health.

Inflammatory bowel diseases (IBDs), Crohn's Disease and ulcerative colitis are long-term disorders that affect the tissues of the digestive tract. There is growing evidence that people's diet may be influencing the development of IBDs, with some studies showing how "high levels" of additives may alter the gut microbiome and promote colitis, the researchers said.

Despite a significant increase in the use of synthetic colorants in the past 50 years, it is still "poorly understood" how they affect intestinal inflammation.

"Allura Red AC (AR) is a highly common synthetic colorant; however, little is known about its impact on colitis," the researchers wrote. "Among many azo dyes, Allura Red AC (FD&C Red 40 or E129) (AR) is the most widely used colorant in many countries and can be found in commonly consumed dietary products aimed at children (e.g., breakfast cereals, beverages, and confectioneries)."

To find out how it may be impacting gut health, the researchers used animal models to see the impact of chronic or intermittent exposure to AR. They found the mice that were chronically exposed to AR for 12 weeks — at levels relative to people's usual exposure — actually developed mild colitis.

"The current data suggest that AR enhances the susceptibility to colitis," the researchers wrote.

"This study demonstrates significant harmful effects of Allura Red on gut health and identifies gut serotonin as a critical factor mediating these effects," study senior author Waliul Khan, of McMaster University, said in a news release. "These findings have important implications in the prevention and management of gut inflammation."

They also found that exposure to AR in early life may lead to "heightened susceptibility to colitis." This is important since many food manufacturers use such synthetic colorants in their products to make them more appealing to children. Hence, children may be at higher risk of exposure than adults.

The researchers did not find increased susceptibility with intermittent exposure to AR. Further, the increased susceptibility was not observed in mice that were not engineered to develop the condition, reported New Atlas. This could mean the trigger occurs in those who are already susceptible to it, whether due to their lifestyle or genetics.

Still, the results were "striking and alarming," said Khan, noting the possibility of the dye being a trigger for IBS.

"This research is a significant advance in alerting the public on the potential harms of food dyes that we consume daily," he said.

"Collectively, we show that chronic, but not the intermittent exposure to AR enhances colitis susceptibility..." the researchers wrote. "(F)uture studies are necessary to identify similar effects in humans."

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