Dr. Louis W. Sullivan, the Secretary of Health and Human Services in 1990, told The New York Times that “[t]he actual risk posed by Red No. 3 is extremely small.” When it comes to how small that risk was considered to be, the FDA explained that the “risk of getting cancer from Red No. 3 is no larger than 1 in 100,000 over a lifetime of consumption.” For context, the danger posed by natural disasters is 70 in 100,000, while railroad accidents and air disasters are 6 in 100,000.
So what should we make of that rat study? Could this food dye pose a risk of cancer to humans?
“Because erythrosine has been found to cause cancer in rats, some people may worry that it may be dangerous for humans also,” explains Dr. Kelly Johnson-Arbor, medical toxicologist and co-medical director of the National Capital Poison Center. “It’s important to remember that rats are very different than human beings, and some chemicals that are toxic to rats and other laboratory animals are not harmful to humans due to differences between the species.” Additionally, she points out that “toxicity studies in laboratory animals often involve the use of very high doses of chemicals, much larger than would be expected after human exposure. Since rats are much smaller than humans, these high doses correspond to exposures that would never be encountered by most humans.”
Another fact that might put your mind at ease is that erythrosine has very poor absorption into the human body after consumption, and only about 1% of all erythrosine is actually absorbed into the bloodstream after ingestion, according to Johnson-Arbor. “The body does not metabolize erythrosine, and it exits the body unchanged in the feces. Because of all of these characteristics, human exposure to erythrosine in foods is likely minimal. It is likely safe for most humans to consume erythrosine, or red dye number 3, on an occasional basis.”
https://www.eatthis.com/news-red-no-3-in-your-food/
OK, how do they make yellow peeps from red dye?