Red 40, a food dye found in snacks like Pepsi and Doritos can trigger inflammatory bowel disease

A food dye found in dozens of family favorite snacks may trigger severe bowel diseases, scientists warn. 

Red 40, also known as Allura red, is in several popular candies, sodas and chips – including Doritos, Skittles, and Pepsi – as well as baked goods and cake mix.

But researchers from McMaster University in Ontario, Canada, found the additive can hamper the gut’s ability to absorb nutrients, water and electrolytes, increasing a person’s risk of developing an inflammatory bowel disease. 

They say this wearing down of the body’s defenses could make people more susceptible to ulcerative colitis and Crohn’s disease. 

While the study was conducted in mice, the researchers say the findings translate to humans in Western countries, whose diets typically contain a lot of food coloring.  

Lead researcher Dr Waliul Khan said: ‘These findings have important implications in the prevention and management of gut inflammation.’

He added: ‘What we have found is striking and alarming, as this common synthetic food dye is a possible dietary trigger for IBDs.’ 

Inflammatory bowel diseases such as colitis and Crohn’s disease, a chronic condition that causes inflammation in your digestive tract, are estimated to affect about three million Americans.

The use of food coloring has increased over the last 100-plus years, but there has been little research into its effect on the gut.

The Food and Drug Administration (FDA) limits the amount of food coloring in food and cosmetics. Still, the chemicals in the dyes have been linked to myriad conditions.

As part of their study, the McMaster scientists gave mouse models Allura Red coloring in their meals for 12 weeks.

They found the additive increased the production of serotonin in the colon and disrupted gut bacteria, prompting cases of colitis, a chronic condition that causes ulcers and sores in the digestive tract.

Serotonin – sometimes dubbed the ‘happy hormone’ – is often talked about for its effects on the brain. Low levels of the hormone are usually a factor in people with depression.

But it is actually the gut that is responsible for producing 95 percent of the total serotonin in the body. 

In the gut, it’s responsible for the uptake of nutrients, electrolytes and water.

The researchers screened for several common synthetic colorants in a model of human enterochromaffin (EC) cells. 

It affects the colon and the rectum and can cause various issues related to inflammation including abdominal pain and bloating, diarrhea, dehydration, and blood stools.

Dr Khan said: ‘The literature suggests that the consumption of Allura Red also affects certain allergies, immune disorders and behavioural problems in children, such as attention deficit hyperactivity disorder.’

Studies have suggested an association between food coloring consumption to hyperactivity in kids. 

An April 2021 analysis of studies commissioned by the state of California reported that of 25 total studies on the subject, 16 identified some association between food coloring and neurobehavioral problems, ‘in particular exacerbation of attentional problems, such as in children with attention-deficit/hyperactivity disorder (ADHD), and other behavioral outcomes’.

Red 40, as well as Yellow 5, and Yellow 6 contain benzidene, a human and animal carcinogen permitted in low, presumably safe levels in dyes. The FDA calculated in 1985 that ingestion of free benzidine raises the cancer risk to just under the ‘concern’ threshold, or 1 cancer in 1 million people.

The findings were published in the journal Nature Communications.