Every year, the aisles of grocery stores and pharmacies across the country turn red and pink with countless Valentine’s Day-themed treats and candies. One of the stars of the show is a food dye called Red No. 3, which is used in everything from festive cookie icing to the iconic sugary conversation hearts. 

Much like titanium dioxide, which is used in popular Halloween candy like Skittles, Red No. 3 finds itself mired in controversy each candy-giving season, regardless of what scientists have concluded on its safety. 

What is Red dye No. 3?

Red dye No. 3 is an additive used in thousands of popular foods and drugs, including sprinkles, candy, frostings and icings, ice pops, and other sweet treats. It is also known as “erythrosine” and “FD&C Red No. 3.” Surprisingly, it’s also found in many foods that are not red. 

It has been criticized by advocacy groups for decades. After some (unpublished) studies linked extremely high doses of Red dye No. 3 to thyroid cancer in laboratory rats, the Food and Drug Administration (FDA) banned its use in cosmetics and externally applied drugs in 1990. 

When the ban was issued, regulators admitted the decision was more legal than scientific. “The actual risk posed by Red No. 3 is extremely small,” said Dr. Louis Sullivan, the then-Secretary of Health and Human Services. “However, federal law in this area is clear.” 

“In these circumstances, small as the risk is, we have no choice under the law but to end the provisional listing of this product.”

According to The Washington Post, there remains no evidence that consuming Red dye No. 3 as a food additive causes cancer in humans. FDA continues to permit the use of Red No. 3 in foods and requires it to be listed on the ingredient label of each product.

Research and Criticism of Red dye No. 3

FDA’s inconsistent policies on Red No. 3 make consumers uneasy, and understandably so. Only adding to the fear and confusion are advocacy groups, who petition hard for FDA to ban its use in candy and food. Consumers want clarity—is this red dye safe or not?

When FDA denied the petition for use on Red No. 3 in cosmetics and externally applied drugs, it specified the “FDA concluded that FD&C Red No. 3 is an animal carcinogen” based on a “chronic feeding study conducted in Charles River CD-1 rats.” 

However, as Sarah Codrea of the International Association of Color Manufacturers noted in The Washington Post, the “effects in experimental animals were observed at doses at least 60-fold higher than the levels of no effect observed in the human study.” 

The human study to which she was referring was a 14-day study that found no negative effects on the thyroid functions of 30 men taking varying doses of Red No. 3 (the groups were assigned 20, 60, and 200 milligrams daily). 

Both studies have significant limitations. Animal studies often use extremely high dosages, and the results of rat studies cannot be translated directly to people. The human study findings are also limited, since they only conducted the study for two weeks, which is nowhere near enough time to make conclusions about the human health effects of long-term exposure to Red No. 3. 

Some studies have claimed Red No. 3 is linked to “hyperactivity and other behavioral problems in children,” while other published studies and reviews show no behavioral effects or causal links with hyperactivity in children, especially those already diagnosed with ADHD. 

Research supported by the U.S. National Institutes of Health has determined that some studies have found connections with food colorings and behavioral problems in children, but more studies need to be conducted to fully understand the noted effects.

To eat, or not to eat? It depends on your philosophy

When it comes to risk analysis, there are two primary schools of thought. Those who follow the precautionary principle would argue that because there is some evidence Red No. 3 is linked to  cancer in animals, FDA should err on the side of caution and ban it. They are not willing to wait for research to decisively show danger before taking policy action on a specific exposure. 

Those who rely on risk-based decision-making (commonly used in the United States) would tell FDA to hold off on deciding until some degree of risk can be decisively proved. 

In the meantime, all sorts of goodies will continue to fill the grocery aisles on Valentine’s Day, including the billions of iconic, sugary “conversation hearts” sold each year. What note would you stamp on a candy heart and send to regulators at FDA: ban it, or prove it?