Is Red Dye No 40 OK?: A Look at the Health Controversy

October 17, 2025 •

4 min read

In recent years, public and legislative scrutiny around artificial food colors has increased, with states like California and West Virginia restricting their use in schools and foods. This renewed focus prompts a critical question for many consumers: is red dye no 40 ok? The answer is nuanced, depending on individual sensitivity and evolving scientific research.

Quick Summary

Red dye no. 40 is an FDA-approved synthetic colorant, yet concerns persist regarding potential links to hyperactivity, allergic reactions, and inflammation. Its regulatory status differs globally, and some U.S. states are restricting its use.

Key Points

Regulated but Controversial: The FDA considers Red Dye No. 40 safe, but significant concerns and ongoing research exist regarding its health impacts, especially in sensitive individuals.
Hyperactivity Link in Children: Studies suggest Red 40 can worsen behavioral issues like hyperactivity and inattentiveness in certain sensitive children, particularly those with ADHD.
Allergic Reactions: Though rare, Red 40 can trigger allergic reactions such as hives, swelling, and migraines in susceptible individuals; severe anaphylaxis is very uncommon.
Regulatory Differences: While approved in the U.S. (with a planned phase-out), the E.U. requires warning labels on products containing Red 40, and some U.S. states are banning it from school meals.
Identify on Labels: To avoid Red 40, check ingredient lists for 'FD&C Red No. 40', 'Allura Red AC', or 'E129'.
Choose Natural Alternatives: Beet juice, paprika, and fruit extracts are naturally sourced alternatives that can provide similar coloring with fewer associated risks.
Focus on Whole Foods: Since Red 40 is prevalent in highly processed foods, prioritizing a whole-foods diet is an effective way to minimize exposure.

What is Red Dye No. 40?

Red Dye No. 40, also known as Allura Red AC or FD&C Red No. 40, is a widely used synthetic food dye derived from petroleum byproducts. It is used to add a bright red color to numerous processed foods, beverages, cosmetics, and pharmaceuticals. It can also be used in combination with other dyes to create different colors or enhance visual consistency. In Europe, it is identified as E129. Due to its prevalence, checking ingredient lists is crucial for those who wish to avoid it.

The Regulatory Landscape of Red 40

The regulation of Red 40 varies internationally and within the United States.

United States

The U.S. FDA has considered Red 40 safe within set limits, requiring batch testing. However, this assessment is based on older data.
The FDA plans to phase out synthetic food dyes by late 2026, following a ban on Red Dye No. 3 due to cancer concerns.
States like California, Virginia, and West Virginia are implementing bans on Red 40 and other synthetic dyes in school meals, with some also enacting broader statewide restrictions by 2028.

European Union

The European Food and Safety Authority (EFSA) permits Red 40 but requires products containing it to carry a warning label stating it "may have an adverse effect on activity and attention in children". This requirement originated from the 2007 Southampton study.

Health Concerns Associated with Red Dye No. 40

Despite its widespread use, Red 40 has been linked to several health concerns, particularly in sensitive individuals.

Behavioral Effects in Children

Concerns regarding Red 40's potential link to hyperactivity in children, including those with ADHD, are prominent.

Studies, such as the Southampton Study, have indicated an association between consuming synthetic dye mixtures and increased hyperactivity.
A 2021 California review by OEHHA concluded that synthetic food dyes like Red 40 could contribute to neurobehavioral issues in some children.
Experts suggest Red 40 doesn't cause ADHD but can worsen symptoms in sensitive children; removing artificial dyes from their diet may improve behavior.

Allergic Reactions

While rare, allergic reactions to food dyes, including Red 40, can occur. Symptoms can range from mild to severe.

Mild reactions may include hives, rashes, itching, or facial swelling.
Severe, potentially life-threatening anaphylaxis is extremely rare.

Gut Health and Inflammation

Research is exploring the effects of Red 40 on the gut microbiome.

A 2023 mouse study showed that continuous Red 40 exposure negatively affected gut health, altered gut bacteria, and caused colon inflammation.
Further human research is needed to understand the implications of these animal study findings.

Contaminants and Potential Cancer Risk

During its production, Red 40 may contain trace amounts of contaminants like benzidine, a known carcinogen.

Older animal studies at high doses suggested a link between Red 40 and tumors, but human studies at typical consumption levels haven't shown this.
Current evidence is not sufficient to classify Red 40 as a carcinogen, but it remains under scrutiny.

Comparison: Red Dye No. 40 vs. Natural Alternatives


Feature	Red Dye No. 40 (Allura Red AC)	Natural Alternatives (e.g., Beet Juice, Paprika)
Source	Petroleum byproducts	Plant and insect-based sources
Color Intensity	Bright, highly vibrant, and consistent	Often more subtle and can vary slightly
Health Concerns	Linked to hyperactivity, allergies, and potential inflammation in studies; contains contaminants	Generally regarded as safer; some rare allergies possible
Regulatory Status	Approved in U.S. (pending phase-out); E.U. requires warning label	Exempt from batch certification; approved for general use
Cost	Less expensive for food manufacturers	Can be more expensive and less concentrated
Flavor Impact	Generally flavorless, making it versatile for many products	May impart a slight, natural flavor from the source material

How to Identify and Avoid Red Dye No. 40

To reduce or eliminate Red 40 intake, consider these strategies:

Read ingredient labels: Look for 'FD&C Red No. 40,' 'Allura Red AC,' 'CI Food Red 17,' or 'E129'.
Choose whole foods: Red 40 is common in processed items like candies, snacks, cereals, and soft drinks. A diet rich in fruits, vegetables, and unprocessed meats naturally avoids artificial dyes.
Seek natural colorings: Many brands now use natural alternatives from sources like beet juice or paprika.
Be aware of hidden sources: Red 40 can be in unexpected products, including some white foods, seasonings, medications, or vitamins.
Consult healthcare professionals: If you suspect sensitivity to Red 40, discuss it with a doctor or allergist.

Conclusion

While regulatory bodies have historically viewed red dye no 40 as safe for most people in small amounts, evolving scientific evidence linking it to hyperactivity in sensitive children and potential gut inflammation has led to increased scrutiny and regulatory changes. Ultimately, deciding if red dye no 40 is 'ok' involves personal health considerations, sensitivity, and weighing the available information. Opting for natural alternatives and a whole-foods-based diet is a proactive approach for those seeking to minimize potential risks.

Frequently Asked Questions

Red Dye No. 40, also known as Allura Red AC, is a synthetic colorant derived from petroleum byproducts.

No, Red Dye 40 does not cause ADHD, but some studies suggest it can exacerbate symptoms like hyperactivity and inattentiveness in sensitive children already diagnosed with ADHD.

Red Dye No. 40 is currently not banned at the federal level, though an FDA phase-out is planned for 2026. However, specific states like California and West Virginia are banning its use in school meals and other foods.

Yes, although allergic reactions to Red Dye 40 are rare, sensitive individuals may experience mild symptoms like hives or swelling.

Look for the names 'FD&C Red No. 40,' 'Allura Red AC,' or 'E129' in the ingredient list.

Common natural alternatives include beet juice or powder, paprika, and fruit or vegetable extracts.

Red Dye 40 is found in a wide variety of processed foods and drinks, including candies, cereals, snacks, beverages, and even some seasonings and medicines.