The universal appeal of colour in food is undeniable. In the world of sweets in particular, colour plays a crucial role; vibrant and bright hues make products visually appealing and often irresistible, especially to children. This aesthetic quality is a major factor in the commercial appeal of sweets. Behind these attractive colours, however, often lurk synthetic additives, of which azo dyes are a prominent group.
candymixmatch.com chooses to deliver candy without these azo (synthetic dyes)
Click here for an azo (synthetic) dye free candy assortment
Azo (synthetic) dyes have long been a topic of debate, both within the scientific community and among consumers, due to potential health effects.
For consumers who want to make informed choices, a thorough understanding of these substances is essential.
This blog aims to provide a detailed overview of azo (synthetic) dyes, their applications, reasons for their use, associated health concerns and regulations. After reading this blog, you will better understand why candymixmatch.com has made the choice to sell only candy without these azo (synthetic) dyes.
What exactly are azo (synthetic) dyes?
Azo dyes are a class of synthetic dyes that do not occur naturally. Their chemical basis is nitrogen, and they are characterized by the presence of one or more 'azo groups' (-N=N-), a chemical compound that is synthesized artificially in a laboratory. The specific molecular structure of these compounds, in particular the π-th localization, is responsible for their characteristic vivid colors, which mainly range from red, orange and yellow. An important property is their good solubility in water.
These dyes are solids and often occur as salts. The colored component is usually an anion, often due to the presence of 1-3 sulfonic acid groups which significantly improve the water solubility. Azo dyes can be classified in different ways, for example based on the number of azo groups or in broader categories such as disperse dyes, metal complex dyes, reactive dyes and substantive (direct) dyes.
In addition to their use as colorants in various materials, some azo dyes are also used as acid-base indicators, such as methyl orange, or even in the recording layers of DVD-R/+R discs.
Most azo dyes are produced by a process called 'azo coupling', an electrophilic substitution reaction. Chemically related compounds are 'azo pigments', which unlike azo dyes are insoluble in water and other solvents.
These pigments are of great importance in the production of plastics, rubbers and paints, including artists' paints, and are known for their excellent colour properties and good lightfastness.
In the European Union, permitted azo dyes are provided with an E-number. It is a general characteristic that most E-numbers starting with E1 contain an azo group. The assignment of an E-number follows extensive safety tests by the European Food Safety Authority (EFSA).
This creates an interesting dynamic: while the term “synthetic” sometimes has negative connotations for consumers, the E number indicates an official assessment of safety and approval.
This tension between the perception of “natural” as inherently better and the scientific/regulatory assessment of “safe” is a central theme in the debate surrounding food additives.
The following table lists common azo dyes used in food, including their E numbers. Quinoline yellow (E104) is also included here, as although not an azo dye it is often mentioned in the context of the 'Southampton Six' and the discussion of hyperactivity in children.
Name Colorant | E-number
- Tartrazine | E102
- Quinoline Yellow | E104
- Sun Yellow FCF | E110
- Azorubine (Carmoisine) | E122
- Amaranth | E123
- Ponceau 4R | E124
- Allura Red AC | E129
- Brown HT | E155
- Litholrubine BK | E180
Why are azo (synthetic) dyes used in sweets and food?
The use of azo colorants in the food industry, and specifically in sweets, is driven by a combination of economic, functional, aesthetic and commercial considerations.
One of the main drivers is cost effectiveness and ease of production. Azo dyes are relatively simple and very cheap to synthesize in a laboratory. This makes them an attractive option for manufacturers looking for efficient and affordable ways to color their products.
In addition to low production costs, azo dyes also offer excellent functional properties. They are exceptionally stable, resistant to high temperatures and insensitive to acid and light.
This stability is crucial for the shelf life and preservation of the appearance of food throughout the entire production process, during storage and transportation.
Without this stability, colors would quickly fade or change, reducing the product's attractiveness.
However, the primary purpose of adding color to food is aesthetic and commercial. Colorants are used to enhance natural colors, to compensate for color loss that may occur during processing or storage, or to add color to products that would otherwise be colorless.
In the context of sweets, the brightly coloured azo dyes provide a cheerful, vibrant and inviting appearance, which is essential for commercial appeal, especially among the target group of children.
The question arises whether these colourings have a "real necessity", or whether a sweet must necessarily be coloured bright blue. Although the European Food Safety Authority (EFSA) assesses the "necessity" of an additive when assigning E numbers, in the case of colourings this necessity is often commercial or aesthetic rather than nutritional or safety related.
This creates a paradox: the substances are approved, but their primary function is to improve marketability.
This tension between industrial practice and consumer health concerns is a recurring point of discussion. The “why” behind the use of azo dyes therefore does not always lie in the essential properties of the food itself, but rather in market dynamics and the desire to make products as attractive as possible to the consumer.
The disadvantages and health concerns surrounding azo (synthetic) dyes
Although azo dyes are widely used and subject to regulation, there are legitimate concerns and debates about their potential adverse effects. These concerns primarily focus on hyperactivity in children and the potential formation of carcinogens.
Hyperactivity in children: The 'Southampton Six' debate
The most prominent discussion about azo dyes in food arose after the so-called Southampton investigation in 2007.
Scientists from the University of Southampton, commissioned by the UK Food Standards Agency (FSA), concluded that a mixture of five azo dyes (E102, E110, E122, E124, E129) and one other dye (E104) can cause hyperactivity in children.
This particular group of dyes has since become known as the 'Southampton Six'.
The study involved tests on both three-year-old toddlers and eight- and nine-year-olds who had not previously been diagnosed as hyperactive, with concentrations used corresponding to daily dietary intake.
As a result of this research, the UK government advised parents and manufacturers to avoid the dyes in question. However, an expert panel from the European Food Safety Authority (EFSA) did not consider an outright ban necessary, as they did not consider the evidence from the UK study to be sufficient to establish a definitive causal link. Despite this position of EFSA, the Council of Ministers of Europe decided as a compromise that manufacturers will be required to place a specific warning on products containing these dyes from 2010.
The obligatory warning reads: "May have an adverse effect on activity and attention in children".
The expectation was that this disclaimer would encourage manufacturers to replace the controversial dyes with natural alternatives.
Although some manufacturers did indeed switch, many products, including soft drinks and sweets, still contain the 'Southampton Six'.
Some supermarket chains, such as Lidl, have long since removed these dyes from their range, while others, such as Albert Heijn and Jumbo, continued to offer products containing these dyes, albeit with a promise from Albert Heijn to remove them by the end of 2016.
The difference between the EFSA scientific conclusions (no proven link to behavioural problems, generally safe at current levels) and the EU regulatory decision (mandatory warning labels) illustrates the precautionary principle.
This principle states that where a plausible risk exists, even without full scientific consensus, measures should be taken to prevent potential harm.
This is a crucial concept in food safety policy, especially with vulnerable populations such as children in mind. It shows that public policy is not based solely on definitive evidence, but also on risk management and societal concerns. Foodwatch even calls for a ban on E102 (Tartrazine) because of its link to hyperactivity and asthma attacks.
The following table provides an overview of the 'Southampton Six' and the mandatory warning that must appear on products containing these colourings:
E-number | Name of dye | Mandatory warning text
- E102 | Tartrazine | May have an adverse effect on activity and attention in children
- E104 | Quinoline Yellow | May have an adverse effect on activity and attention in children
- E110 | Sunset yellow | May have an adverse effect on activity and attention in children
- E122 | Azorubine | May have an adverse effect on activity and attention in children
- E124 | Ponceau 4R | May have an adverse effect on activity and attention in children.
- E129 | Allura Red AC | May have an adverse effect on activity and attention in children
Potential carcinogens and allergic reactions
In addition to the discussion about hyperactivity, there are concerns about the potential carcinogenic properties of some azo dyes and the possibility of allergic or pseudo-allergic reactions.
Although azo dyes are generally considered to have little toxicity in food and do not cause acute poisoning at normal doses – for that extremely high doses would be required – a major concern is that some azo dyes can be broken down in the body to aromatic amines. These aromatic amines can be carcinogenic. In particular, azo dyes derived from benzidine have been classified as carcinogens, and their production was halted in many Western countries in the 1980s. The European Union has banned the manufacture or sale of consumer products containing these amines since September 2003.
A study in mice showed that high doses of the azo dye Carmoisine (E122) caused kidney failure and liver toxicity and was suspected of causing liver oncogenesis (carcinogenicity). This highlights a “hidden” risk: the dye itself may not be directly carcinogenic, but its metabolites formed in the body may be. This requires strict regulation, not only for the dyes themselves, but also for the migration of their breakdown products into food contact materials. For example, the EU Food Contact Material Framework (EU 10/2011) requires that plastic food contact products do not release primary aromatic amines (PAA) above 0.01 mg/kg food. There are strict rules on which azo dyes may and may not be used and what their maximum concentration may be, especially in textiles and food contact materials.
In terms of allergic reactions, although azo food dyes are generally not considered allergenic and do not cause direct allergic reactions via the immune system, they can trigger pseudo-allergic reactions in sensitive individuals. These reactions are not typical immune system reactions, but can lead to the release of histamine, which causes symptoms that closely resemble allergies. Symptoms can range from itchy mouth, skin inflammation (such as itching, redness, hives and eczema), gastrointestinal problems (such as diarrhoea, flatulence and nausea), headaches/migraines, and in rare cases serious reactions such as anaphylaxis (although the latter is very rare for dyes). Tartrazine (E102) is specifically mentioned as a dye that may exacerbate existing allergic reactions to other substances. The distinction between a “true” allergy and a “pseudo-allergic” reaction is important for consumers as it clarifies the nature of the body’s reaction and helps in managing symptoms.
In general, azo dyes are considered to be of low toxicity; very high doses (a few grams) would be needed to cause symptoms of poisoning. Furthermore, because they are highly soluble in water and hardly soluble in fat, they do not accumulate in the body but are largely excreted in the urine. These properties contribute to their general safety profile at low intakes. However, this low acute toxicity and rapid excretion must be weighed against the chronic risks, such as the formation of carcinogenic degradation products and the individual sensitivity that can lead to hyperactivity or pseudo-allergic reactions. The concept of "safe" is therefore often dose-dependent and does not exclude all risks for all individuals.
Regulation and Consumer Protection in the EU
The European Union has a strict framework for the regulation of food additives, including colourings, to ensure consumer safety. This framework includes EU-wide regulations, national provisions and the ongoing safety assessments by the European Food Safety Authority (EFSA).
All food additives, including colourings, must be authorised in the EU before they can be used in food. The awarding of an E number means that an additive has passed safety tests and is approved for use. In addition, the presence of food colourings must be indicated on the label, with both their name and their E number, to ensure transparency for the consumer.
The REACH Regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals) specifically restricts the use of certain azo dyes that can degrade to aromatic amines. Appendix 9 of REACH lists additional azo dyes that are restricted in textiles or leather at concentrations above 0.1% by weight. For plastic food contact materials, Regulation (EU) No 10/2011 applies, which requires that primary aromatic amines (PAA) do not migrate above 0.01 mg/kg food. In cosmetic products (Regulation (EC) 1223/2009), the use of o-Dianisidine- and Benzidine-based azo dyes is prohibited.
In addition to EU-wide regulations, some European countries have imposed additional national restrictions. For example, Germany bans certain azo dyes in consumer goods and sets lower migration limits for PAA in food contact materials. The Czech Republic and Switzerland also have specific rules for children’s products and textiles. The EU Ecolabel, an environmental label, has criteria for the content of azo dyes in products such as mattresses and textiles, reflecting the broader societal desire to reduce these substances.
EFSA plays a central role in the safety assessment of food colours and other additives. They have re-evaluated all previously authorised food colours (41 in total, completed in 2016) and are conducting ongoing follow-up assessments. For example, in 2009, EFSA recommended lowering the Acceptable Daily Intake (ADI) for Quinoline Yellow (E104), Sunset Yellow (E110) and Ponceau 4R (E124). This ongoing process of re-evaluation and adjustment of ADI values demonstrates that the concept of ‘safety’ is not static, but evolves with new scientific evidence and growing public understanding. This implies that even substances that are currently authorised may be subject to stricter regulation or even bans in the future, as recently happened with Titanium Dioxide (E171). This dynamic nature of safety assessments is an important consideration for both consumers and businesses, and emphasises the need to remain informed and adaptable.
Natural alternatives and conscious choices
The growing concern about synthetic dyes and mandatory warning labels have led to an increasing demand and supply of natural alternatives in the food industry. There are now many natural dyes available that can serve as a substitute for azo dyes.
Examples of these natural alternatives include beetroot juice for red and pink hues, turmeric for yellow, paprika extract for orange, egg yolk for warm yellow, spinach cooking liquid for green, red cabbage cooking liquid for blue-purple, blueberry or blackberry juice for purple, and cocoa or coffee for brown hues. These alternatives are considered "100% safe" by many consumers.
The industry shift to natural colourings has been partly driven by consumer pressure and mandatory warning labels. Manufacturers are increasingly opting for these options. For example, companies such as Candy Mix & Match have made a conscious decision not to sell sweets with azo colourings, even if this limits their product range. They do this out of an explicit consideration for the health of their customers. This illustrates a growing trend where 'azo-free' and 'naturally coloured' sweets can offer a competitive advantage.
However, switching to natural dyes also presents challenges for manufacturers. Each natural alternative has its own color intensity, stability, and cost. Natural dyes can be less stable, less vibrant, or more expensive to use than their synthetic counterparts. This means that switching is not always a simple one-to-one replacement and can lead to trade-offs in product appearance, shelf life, and price.
For consumers who want to make conscious choices, there are practical tips
Always check the label of products for E numbers, especially those starting with E1, as these often contain an azo group.
- Make a conscious choice for products that contain natural dyes.
- The most important advice remains to moderate the consumption of snacks, soft drinks and sweets containing azo dyes, regardless of the discussion about safety, as these products often also contain a lot of sugar and/or saturated fat, which in themselves are reasons for moderation.
- In case of symptoms of hypersensitivity or hyperactivity in children, avoiding these dyes may be worth a try. In case of health questions, a doctor or dietician should always be consulted.
Conclusion: Color with knowledge
Azo (synthetic) dyes are effective, stable and economically attractive synthetic colorants that are widely used to add visual appeal to food, especially sweets.
Although the European Food Safety Authority (EFSA) generally considers these substances to be safe for normal intake, there are legitimate concerns. These include the debate over hyperactivity in children, known as the ‘Southampton Six’, and the potential formation of carcinogens through the breakdown of some azo dyes in the body. These concerns have led to mandatory warning labels and strict regulation in the EU and at national level.
The dynamics surrounding azo dyes reflect a shift in the understanding of “acceptable risk”. Where previously the focus was on strict approval and safety assessments, public concern, scientific debate and the precautionary principle are now also taken into account.
This has led to regulatory action (such as warning labels) even without a fully scientifically proven causal link, and the industry gradually moving to “cleaner” alternatives. Consumer demand for products with natural dyes has become a powerful driver, going beyond mere regulatory compliance and turning the absence of controversial additives into a competitive advantage.
It is critical that consumers remain informed and make informed choices when purchasing sweets and other foods. This includes carefully reading labels and considering products that align with personal health beliefs and the latest scientific insights.
This approach makes it possible to continue enjoying colorful sweets in a responsible way, while at the same time encouraging the market to offer healthier and more transparent options.
Now you know why candymixmatch.com chooses to sell only candy without azo (synthetic) dyes.
Disclaimer
candymixmatch.com is not an authority on chemical and synthetic dyes and has compiled this blog based on various online sources. 
