Understanding Erythrosine (Red Dye 3)
Erythrosine (INS 127, FD&C Red No. 3) is a synthetic cherry-pink or red color additive derived from petroleum. It has been used for decades to color various foods, including candied fruits, maraschino cherries, icings, and sweets. The dye contains a significant amount of iodine as part of its chemical structure, a key factor in many of the health concerns associated with it. Its use in food has been the subject of ongoing safety reviews and regulatory changes by authorities worldwide, leading to bans or severe restrictions in many countries.
Potential health risks and side effects
Scientific studies, primarily involving animal models but also considering human exposure, have raised several concerns regarding the consumption of erythrosine. The severity of these effects is often dose-dependent and can be influenced by individual factors.
Thyroid hormone disruption
One of the most significant and well-documented side effects of erythrosine is its potential to interfere with thyroid function. The high iodine content of erythrosine is the primary cause. In animal studies, and observed to a lesser degree in humans, erythrosine can inhibit the conversion of thyroxine (T4) to the more active hormone tri-iodothyronine (T3) in the liver.
This disruption leads to a compensatory increase in thyroid-stimulating hormone (TSH) from the pituitary gland. While this mechanism is more pronounced in rodents, which have different thyroid physiologies, human studies have also shown elevated TSH levels at higher doses. For individuals with pre-existing thyroid conditions, or those consuming large quantities of erythrosine, this disruption could pose a significant risk.
Carcinogenic potential
Erythrosine’s impact on thyroid function has led to concerns about its carcinogenic potential, particularly related to the thyroid gland. Long-term, high-dose feeding studies in male rats have shown that erythrosine can lead to the formation of benign thyroid tumors (adenomas). This effect is considered secondary to the chronic overstimulation of the thyroid gland by excess TSH, not a direct genotoxic effect.
Although toxicologists have noted that the tumor development mechanism in rats is likely not relevant to humans at typical consumption levels, the U.S. FDA’s Delaney Clause requires a ban on any food additive found to cause cancer in animals. It was this clause, and a 2022 petition from advocacy groups, that ultimately triggered the January 2025 FDA ban on Red 3 in food and ingested drugs.
Behavioral effects in children
Some research has linked erythrosine, along with other synthetic food dyes, to behavioral issues such as hyperactivity and attention deficit disorders in children. The evidence remains mixed and inconclusive, with some studies showing an effect while others do not. Factors like dosage and individual sensitivity likely play a role. The European Food Safety Authority (EFSA) noted the potential for behavioral issues in sensitive individuals, which factored into their decision to limit erythrosine use.
Other potential organ toxicity and side effects
Beyond the thyroid, animal studies have indicated potential toxic effects on other organs at high doses. A 2025 study on rats demonstrated dose-dependent hepatorenal (liver and kidney) damage, increased oxidative stress, and DNA damage. While these effects were seen at levels exceeding standard human exposure, they highlight potential concerns with high or prolonged intake. Other reported effects include hypersensitivity reactions, like skin rashes, and increased photosensitivity.
Distinction from Erythromycin
It is crucial to differentiate erythrosine (the food dye) from erythromycin (the antibiotic). The names are similar, but they are entirely different substances with distinct uses and side effects. Erythromycin is a macrolide antibiotic used to treat bacterial infections. Its side effects include nausea, stomach cramps, liver dysfunction, and, in rare cases, heart rhythm disturbances. Do not confuse these health concerns with those associated with the food coloring agent.
Global regulation vs. U.S. ban: A comparison
| Feature | U.S. Regulation (as of Jan 2025) | E.U. Regulation (current) | Other Markets (e.g., Australia/NZ) |
|---|---|---|---|
| Regulatory Status | FDA ban on use in food and ingested drugs effective Jan 2027/2028. | Severely restricted. Authorized only for specific products like candied cherries. | Permitted in certain uses, such as candied cherries, icings, and frostings. |
| Key Justification | Legal requirement (Delaney Clause) following animal cancer evidence, despite human risk being low. | Restrictive use based on safety evaluations and potential behavioral issues. | Use permitted within acceptable daily intake (ADI) limits set by regulatory bodies. |
| Timeline | Ban finalized in Jan 2025, following a long history of use and scrutiny. | Restrictions in place since at least the mid-1990s. | Ongoing reviews, with use typically based on ADI guidelines. |
| Consumer Impact | Manufacturers must reformulate products to remove the dye by 2027/2028. | Long-term consumer exposure to the dye in food is minimal. | Consumers must check labels as the dye may still be present. |
Foods and products containing erythrosine
While the U.S. ban will eliminate erythrosine from food and ingested drugs, it has historically been found in a variety of items. Consumers outside the U.S. or before the ban's effective date should check product labels for FD&C Red No. 3, erythrosine, or E127. Common products have included:
- Maraschino cherries
- Candies and lollipops
- Cake-decorating gels, frostings, and icings
- Certain breakfast cereals
- Some sweets and chewing gums
- Cosmetics, like lipsticks and blushes (already banned in the U.S.)
- Some ingested medications (soon to be banned in the U.S.)
- Dental disclosing tablets and solutions
What does this mean for consumers?
The recent bans and long-standing restrictions on erythrosine highlight a broader trend towards minimizing or eliminating synthetic dyes from the food supply. For consumers, the best course of action is to be aware of what is in your food. Opting for products with natural coloring agents or simply minimizing consumption of highly processed foods and sweets can reduce exposure to erythrosine and other synthetic dyes. Always read the ingredients list on packaged foods to make an informed choice.
Conclusion In summary, the side effects of erythrosine are tied to concerns about thyroid function disruption, potential links to cancer in animals, and possible behavioral issues in sensitive children. While international regulatory stances have varied, the recent FDA ban on erythrosine in food and ingested drugs signals a significant shift based on precautionary principles and mounting evidence. As the food industry adapts, consumers can protect their health by remaining vigilant, reading labels, and opting for more natural alternatives.
Read more about the FDA's decision to ban Red Dye No. 3(https://www.aljazeera.com/news/2025/1/16/what-is-red-dye-3-and-why-has-the-us-fda-banned-it-in-food-and-drinks).
