Artificial colours, preservatives, hyperactivity and child behaviour

Artificial colours, preservatives, hyperactivity and child behaviour

Artificial food colours, preservatives and child behaviour: what parents need to know

As a paediatrician, one of the most common concerns I hear from families is this:

“Could food be affecting my child’s behaviour?”

While behaviour is always multifactorial there is growing scientific evidence that certain artificial additives can contribute to behavioural changes in some children.

Two groups of additives stand out in the research:

  • Synthetic food dyes

  • Sodium benzoate

Synthetic food dyes and behaviour

Synthetic food dyes are commonly added to processed foods to enhance colour and appeal, particularly in products marketed to children.

The dyes most frequently linked to behavioural changes include:

  • Tartrazine (Yellow No. 5)

  • Sunset Yellow (Yellow No. 6)

  • Allura Red (Red No. 40)

  • Carmoisine (Red No. 3)

  • Quinoline Yellow

What does the research show?

  1. Tartrazine (Yellow No. 5): This dye has been associated with behavioural changes such as irritability, restlessness, and sleep disturbances. A dose-response effect has been observed, with higher doses leading to more prolonged behavioural effects. 

  2. Sunset Yellow (Yellow No. 6) and Allura Red (Red No. 40): These dyes have been implicated in increasing hyperactivity in children. A study published in The Lancet demonstrated that a mix of artificial food colours, including sunset yellow and allura red, significantly increased hyperactivity in both 3-year-old and 8/9-year-old children. 

  3. Carmoisine (Red No. 3) and Quinoline Yellow: These dyes have also been linked to increased hyperactivity. The same study in The Lancet found that carmoisine and quinoline yellow, when included in a mix of artificial food colours, contributed to behavioural changes in children. 

Clinical trials have demonstrated associations between synthetic food dyes and:

  • Increased hyperactivity

  • Irritability

  • Restlessness

  • Sleep disturbances

Importantly, a dose-response effect has been observed in some studies meaning higher exposure may lead to more prolonged or noticeable behavioural effects.

A review conducted by the California Office of Environmental Health Hazard Assessment (OEHHA) examined 27 clinical trials and found that 64% of challenge studies reported a positive association between synthetic food dyes and adverse behavioural outcomes in children.

This does not mean every child will be affected however, it does suggest that a subset of children are sensitive particularly those with underlying neurodevelopmental vulnerabilities.

Sodium Benzoate: the preservative often overlooked

Sodium benzoate is a widely used preservative found in:

  • Soft drinks

  • Fruit juices

  • Cordials

  • Confectionery

  • Packaged snack foods

A landmark study published in The Lancet demonstrated that a combination of artificial food colours and sodium benzoate significantly increased hyperactivity in both:

  • 3 year-old children

  • 8-9 year-old children

Follow-up studies confirmed that behavioural changes were noticeable to parents when children consumed these additive combinations.

While sodium benzoate alone is less frequently studied in isolation, the combination with synthetic dyes appears particularly problematic.

How might food additives impact childhood behaviour?

The exact mechanisms are still being explored, but several biological pathways are being considered:

1. Neurotransmitter effects

Some dyes may interact with neurotransmitter systems involved in attention, impulse control and mood regulation.

2. Neurotoxic potential

There is emerging discussion about possible neurotoxic properties at certain exposure levels.

3. Gut–Brain axis

Additives may alter the gut microbiome, leading to production of metabolites that influence brain function and behaviour.l.

Which children are most vulnerable?

Not every child reacts to food additives. However, sensitivity appears more likely in:

  • Children with ADHD

  • Children with sensory processing differences

  • Children with emotional regulation challenges

  • Children with sleep disturbance

  • Children with existing gut issues

For these children, dietary triggers may amplify underlying vulnerabilities.

What should parents do?

If your child is experiencing behavioural challenges, consider:

1. Observing patterns

Does behaviour worsen after brightly coloured processed foods? After parties? After soft drinks?

2. Reading labels

Look for:

  • Tartrazine (102)

  • Sunset Yellow (110)

  • Allura Red (129)

  • Carmoisine (122)

  • Quinoline Yellow (104)

  • Sodium benzoate (211)

3. Trialling a reduction

A short, structured additive-reduction trial (2-4 weeks) can sometimes provide clarity. This should be practical and sustainable not restrictive or anxiety provoking.

A balanced perspective

Food additives are unlikely to be the sole cause of behavioural differences however, in susceptible children, they may be one contributing factor. 

Given the potential adverse effects of food dyes and additives, it is important to consider dietary modifications in children exhibiting behavioural issues, particularly those with ADHD or if you have big worries about your child's level of activity, irritability and/or sleep.

 

Dr Claire Gibbons

Paediatrician and Founder, Base Kids

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