Scientific Studies
International Journal of Environmental Health, 2012 Jul-Sep;18(3):220-46.
Abstract
Background: Food dyes, synthesized originally from coal tar and now petroleum, have long been controversial because of safety concerns. Many dyes have been banned because of their adverse effects on laboratory animals or inadequate testing.
Conclusions: This review finds that all of the nine currently US-approved dyes raise health concerns of varying degrees. Red 3 causes cancer in animals, and there is evidence that several other dyes also are carcinogenic. Three dyes (Red 40, Yellow 5, and Yellow 6) have been found to be contaminated with benzidine or other carcinogens. At least four dyes (Blue 1, Red 40, Yellow 5, and Yellow 6) cause hypersensitivity reactions. Numerous microbiological and rodent studies of Yellow 5 were positive for genotoxicity. The inadequacy of much of the testing and the evidence for carcinogenicity, genotoxicity, and hypersensitivity, coupled with the fact that dyes do not improve the safety or nutritional quality of foods, indicates that all of the currently used dyes should be removed from the food supply and replaced, if at all, by safer colorings. It is recommended that regulatory authorities require better and independent toxicity testing, exercise greater caution regarding continued approval of these dyes, and in the future approve only well-tested, safe dyes.
Another study, published in the journal Antioxidants, used “human-relevant doses” — an amount comparable to what ordinary people might consume — of titanium dioxide and silicon dioxide in a lab test involving chicken eggs, which simulated a comparable response to that of a human.
Researchers injected the food dye nanoparticles into the eggs and, upon hatching, found cellular-level changes in the animals’ blood and intestines. Their findings suggest such dyes could have a similar impact on humans.
While the discovery is concerning, experts aren’t sounding alarm bells just yet – Tako admitted more research is needed before society swears off food coloring.
“We are consuming these nanoparticles on a daily basis,” said Tako. “We don’t really know how much we consume; we don’t really know the long-term effects of this consumption.”
Past data suggests that humans consume food coloring, specifically Red 40, in higher concentrations than the Food and Drug Administration advises — up to “two to three times the FDA’s accepted daily intake,” according to one doctor’s report.
FDA guidance states that synthetic food dye intake should not exceed more than 3.2 milligrams per pound of the consumer’s body weight; however, the amount of dye used in any given product can be difficult to ascertain without digging into the research.
A new study published in the journal Nature Communications has revealed that a common red dye in food can increase the risk of inflammatory bowel diseases, which affect some three million Americans, according to the Crohn’s and Colitis Foundation.
The additive, denoted as Red 40 or Allura Red on ingredients label, is the most prevalent dye used in many popular snacks and drinks, including Skittles, Doritos and Pepsi, as well as some cosmetics.
While the use of food coloring has increased over the years, studies on its effect in the gut are few thus far.
“What we have found is striking and alarming, as this common synthetic food dye is a possible dietary trigger for IBDs,” said McMaster University researcher Waliul Khan, the study’s senior author, in a statement. “This research is a significant advance in alerting the public on the potential harms of 'food dyes that we consume daily.”
The Ontario, Canada, team studied a group of mice fed high doses of Red 40 for 12 weeks — which researchers claimed was an appropriate model for humans in Western countries, where food coloring is typically a large part of people’s diets.
More specifically, they analyzed markers of common synthetic colorants in neuroendocrine intestinal cells, which play a roll in symptoms of gut inflammation, such as abdominal pain, bloating, diarrhea, dehydration and bloody stool.
They found that mice who consumed the largest amounts of Red 40 showed increased levels of serotonin — which helps regulate gut muscle movements and nutrient uptake — and interfered with healthy bacteria in the colon, leading to inflammation and ulcers of the digestive tract.
A human would need to consume a higher-than-recommended amount of the dye in order to produce the same results reported in the mice. However, even in achievable concentrations, researchers believe the biological imbalance caused by the introduction of Red 40 could make the body more susceptible to illness, in the gut and beyond.
“These findings have important implications in the prevention and management of gut inflammation,” said Khan.
“The literature suggests that the consumption of Allura Red also affects certain allergies, immune disorders and behavioral problems in children, such as attention deficit hyperactivity disorder (ADHD),” he added.