What is red dye 40, and is food colouring bad for you?
As new legislation is passed in the US to ban six common chemicals, our nutrition expert reveals the truth about food dyes
The debate around synthetic food dyes and their potential harm has been going on for decades. The governor of California has just passed a bill to ban the use of several popular dyes in school food. Concerns have been growing regarding their effect on children’s behaviour, with red dye 40, yellow dyes 5 and 6, blue dyes 1 and 2, and green dye 3 under the spotlight and included in the ban that's due to come into force at the end of 2027.
What are food dyes?
Food dyes or colourings are added to food and beverages to enhance or change their colour and taste. They can be natural or synthetic.
- Natural food dyes are typically derived from plants or minerals. For example, beetroot for red and turmeric for yellow.
- Synthetic food dyes are man-made. These are more commonly used in processed foods because they provide more vibrant colours. All the food dyes affected by the new legislation are synthetic.
How common are they?
Incredibly so! From ice cream to peanuts, meat to medicines, synthetic food dyes are everywhere. Their bright colours make food appealing, replace colour lost in processing and provide consistency in the appearance of products. Artificial food dyes are commonly used in ultra processed foods, which make up a significant portion of the average diet. In the UK and US, ultra-processed foods account for about two-thirds of adolescents’ energy intake, which means these food dyes are finding their way into the diet in abundance.
What will change when the ban takes effect?
The US is one of the few industrialised countries without strict regulations. The Food and Drug Administration (FDA) maintains that approved food dyes are safe for consumption within established limits.
Conversely, in the UK food dyes are regulated by the European Foods Safety Authority (EFSA) and the Food Standards Agency (FSA). In 2010, the EU introduced a requirement for a warning label on products containing certain artificial colourings which were linked to hyperactivity in children. Some artificial dyes, such as red 40 and yellow 5, are commonly used in the USA but restricted or banned in the UK.
However, that does look like it is set to change with the California bill forbidding food and drinks containing this group of food dyes to be offered in schools within the state. These changes are driven by concerns that these dyes harm children’s ability to learn. According to a 2021 study, they are linked to behavioural difficulties and decreased attention among children.
Which popular foods are at risk?
Some of the common snacks and drinks that use the controversial dyes, and may need to be reformulated, include:
- Sweets (candy) such as Skittles, M&Ms and Starburst, which contain red 40 and yellow 5 and 6
- Breakfast cereals such as Fruit Loops and Lucky Charms, which are often coloured with dyes like blue 1, red 40 and yellow 5
- Snack foods such as Doritos, Cheetos and nacho cheese-flavoured crisps, which use yellow 6 and red 40 to enhance appearance
- Fizzy drinks and sports beverages such as Mountain Dew and Gatorade, which contain yellow 5, blue 1 or red 40 to add bright colour
- Packaged desserts such as jelly, icing and ice pops
- Baked goods such as pre-made cake mixes and cookie dough.
What does the rest of the world say?
The FDA has approved the use of several synthetic dyes and maintains they are safe for consumption within the specified limits. It does require food manufacturers to list food colourings on ingredient labels but, unlike in the UK, it does not mandate warning labels for potential health risks.
In the UK, the FSA ensures that the warning “May have an adverse effect on activity and attention in children” is included on products containing certain dyes. This disparity has increased criticism of US regulatory practices, as European brands sold in the US often contain artificial dyes that aren’t used in their European versions.
In Australia, the response to the use of food dyes is also the subject of debate. Food Standards Australia New Zealand (FSANZ) allows the use of some synthetic dyes that are banned or restricted in the EU. Food manufacturers are required to list food colourings by name or international code but are not mandated to include a warning label. Their regulatory system is more aligned with the US than the UK.
Consumer pressure is high worldwide, as parents and health-conscious consumers drive a change towards clearer labelling and a preference for products without synthetic additives. In response, many food manufacturers and fast-food chains have reformulated their products to remove or reduce synthetic dyes.
What is the evidence against food dyes?
Foods containing specific dyes have been linked to hyperactivity and behavioural problems in children. In particular, red dye 40 and yellow dye 5 have been found to pose significant risks to children when their brains are in a critical stage of development. Research has found that these dyes don’t affect all children in the same way; some are more sensitive to the effects than others.
Studies have shown that foods often contain a mixture of the most widely consumed dyes (red 40, yellow 5 and yellow 6), and exposure to just 1mg of yellow 5 (tartrazine) can affect more sensitive children. For context, certain brightly coloured cereals can contain more than 30mg in one serving. The cumulative impact of so much dyed food – from breakfast, lunch, dinner and snacks – is being attributed to the rise in behavioural problems such as ADHD. This has prompted scientists and lawmakers across the globe to look closely at the research on food dyes and behavioural problems in children. The report states that dyes are associated with inattentiveness, hyperactivity and restlessness in sensitive children, disturbing sleep and the ability to concentrate. However, it is important to note that most of the acceptable daily intake levels are based on studies that are 35 – 70 years old.
Where are we now?
There are several safe and natural alternatives to synthetic food dyes derived from plants, minerals, and other natural sources. For example, turmeric root adds bright yellow colour and has potent anti-inflammatory properties. Beetroot provides a vibrant red or pink with no reported health risks. Spirulina creates a blue colour as well as making green when combined with yellow. Carrots, saffron and paprika have also been used for reds, yellow and purple shades.
Many parents and carers will want to try and limit their children’s consumption of food dye by avoiding ultra processed foods, especially those that are artificially coloured. Check food labels, or choose fresh, whole foods (preferably organic) to help swerve potentially harmful additives.
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