What are the side effects of FCF food coloring?

December 28, 2025 •

3 min read

Studies have suggested that consumption of FCF food coloring and other synthetic dyes may be associated with various health issues. This article explores what are the side effects of FCF food coloring, specifically focusing on the common examples found in many processed foods and beverages.

Quick Summary

This guide details the potential adverse reactions linked to FCF dyes, including behavioral issues in children, allergic responses, and possible links to other health concerns.

Key Points

Behavioral Changes: Synthetic FCF food coloring, notably Sunset Yellow FCF, has been linked to increased hyperactivity and attention deficits, especially in children.
Allergic Reactions: Certain individuals may experience hypersensitivity to FCF dyes, manifesting as hives, rashes, and asthma symptoms.
Contaminants: Some artificial food dyes may contain traces of carcinogenic contaminants, though regulatory bodies consider these to be at safe levels.
Digestive Issues: Problems like gastrointestinal discomfort and potential inflammation have been reported, possibly due to the interaction of azo dyes with gut bacteria.
Regulatory Guidance: Both the FDA and EFSA have established acceptable daily intake limits for FCF dyes, but ongoing research continues to evaluate potential long-term effects.
Awareness is Key: To avoid potential side effects, consumers, especially parents, should check product labels for FCF dye names and consider natural food colorant alternatives.

What are FCF food colorings?

FCF stands for "For Coloring Food" and was historically used to distinguish food-grade dyes. Today, it often refers to synthetic food colors like Brilliant Blue FCF (E133 or FD&C Blue #1) and Sunset Yellow FCF (E110 or FD&C Yellow #6). These petroleum-derived artificial colors enhance the visual appeal of food products.

Documented side effects of FCF food coloring

While regulatory bodies like the FDA and EFSA consider these dyes safe within established acceptable daily intake (ADI) levels, research and reported sensitivities highlight potential side effects.

Hyperactivity and behavioral issues in children

Synthetic food dyes have been linked to hyperactivity in children. The 2007 "Southampton study" associated certain dyes, including Sunset Yellow FCF, with increased hyperactive behavior. The California Environmental Protection Agency also connected synthetic dyes to adverse neurobehavioral outcomes in children. This led the EU to require a warning label for certain azo dyes like Sunset Yellow FCF: "May have an adverse effect on activity and attention in children".

Allergic reactions and hypersensitivity

Sensitive individuals may experience allergic reactions or hypersensitivity to FCF food colorings, with symptoms varying in severity.

Skin reactions: Hives, rashes, or itchy skin.
Respiratory problems: Asthma symptoms and wheezing.
Other symptoms: Rare, severe reactions like facial swelling.

Potential carcinogenic contaminants

Concerns exist regarding potential carcinogenic contaminants in some synthetic dyes, although regulatory bodies find no conclusive evidence that FCF dyes themselves cause cancer at approved levels. Some azo dyes may contain trace amounts of carcinogens like benzidine, which, while deemed safe by regulators, concern consumer groups due to potential cumulative exposure.

Digestive system impacts

Azo dyes, including some FCF colorings, can be metabolized by gut bacteria, potentially causing negative effects. A 2021 study suggested Sunset Yellow S (Sunset Yellow FCF) could damage the small intestine's mucous membrane in a test-tube environment. Other reported issues include nausea, abdominal pain, and diarrhea.

Table: Comparison of Common FCF Dyes


Feature	Brilliant Blue FCF (FD&C Blue #1)	Sunset Yellow FCF (FD&C Yellow #6)
Type	Synthetic, triarylmethane dye	Synthetic, azo dye
E-Number	E133	E110
Color Profile	Bright blue, water-soluble	Orange-red powder, water-soluble
Common Uses	Candies, beverages, baked goods, dairy products, toothpaste, cosmetics	Beverages, jams, sweets, canned fruit, sauces, cereals
Behavioral Effects	Associated with hyperactivity in sensitive children, often in combination with other additives.	Explicitly linked to hyperactivity in children; requires EU warning label.
Allergic Reactions	Documented cases of allergic reactions in sensitive individuals.	More frequently linked to allergic and intolerance reactions, including hives and wheezing.
Other Health Concerns	Potential for genotoxicity and impact on fetal development at high doses, based on animal studies.	Potential genotoxic and carcinogenic effects, though inconclusive in human terms.

How to avoid FCF food coloring

To minimize exposure to artificial FCF colorings:

Check ingredient labels: Look for "Brilliant Blue FCF," "Sunset Yellow FCF," "FD&C Blue #1," "FD&C Yellow #6," or E-numbers (E133, E110).
Eat whole foods: Processed foods are major sources of dyes. A diet of fruits, vegetables, and lean proteins reduces artificial coloring intake.
Choose natural options: Many products use natural colorants from plants and minerals like beet extract or turmeric.
Be aware of hidden sources: Dyes can be in condiments, medications, and pet food.

Conclusion

While FCF food colorings are regulated and have established safety guidelines, studies and consumer reports suggest potential health concerns, especially for sensitive individuals and children. Key side effects include hyperactivity in children and allergic reactions. By checking labels and choosing natural alternatives, consumers can make more informed dietary choices. Many manufacturers are adopting natural colorants due to increasing demand for transparency. Reducing processed food intake is a primary strategy for minimizing exposure.

Food Dyes: A Rainbow of Risks - Center for Science in the Public Interest

Frequently Asked Questions

Brilliant Blue FCF (E133) is a triarylmethane dye that creates a blue color, while Sunset Yellow FCF (E110) is an azo dye that creates an orange-yellow color. Both are synthetic food colorings with distinct chemical compositions and are linked to different potential side effects in sensitive individuals.

While the specific FCF dyes like Brilliant Blue FCF and Sunset Yellow FCF are approved in many regions, regulations differ. For example, the EU requires a warning label on foods containing Sunset Yellow FCF regarding its potential effect on children's activity and attention, a regulation not universally enforced in the U.S..

There is no conclusive evidence from regulatory bodies that FCF food coloring directly causes cancer in humans at approved levels. However, some studies have noted the potential for carcinogenic contaminants within the dyes and have raised concerns about high-dose, long-term exposure in animal studies.

Growing evidence suggests that synthetic food dyes, including FCF colorings, can exacerbate hyperactivity and behavioral issues in sensitive children, including those with ADHD. Many parents choose to minimize or eliminate these additives from their children's diets based on this evidence.

For those who wish to avoid synthetic dyes, natural colorants derived from plants and minerals are available. Common examples include beet extract, turmeric, annatto, and grape skin extract, which provide a range of colors.

Check the ingredients list on the product label. Look for specific names like "Brilliant Blue FCF," "Sunset Yellow FCF," or their codes, such as E133 or E110. In the U.S., they are listed as "FD&C Blue No. 1" or "FD&C Yellow No. 6".

Acceptable daily intake levels are set by regulatory agencies, though they may differ. For example, EFSA established an ADI of 6 mg/kg of body weight for Brilliant Blue FCF and 4 mg/kg for Sunset Yellow FCF. These levels are designed to be well below amounts associated with negative health effects.