Up to 20% of parents report that their children are ‘intolerant’ to food additives such as colourings and preservatives. However, research conducted using ‘blinded’ food challenges (where the child is given a food in which either an additive or a ‘placebo’ is hidden) has found that the rate of hypersensitivity to food additives is much less common – in fact, fewer than 1 in 100 children are thought to have adverse reactions to food additives.
Food additives are substances added to foods, usually to preserve or improve their quality. A number of food additives, both natural and artificial, are reported to cause symptoms in children. These symptoms have included skin rashes, asthma attacks, worsening of eczema, and even anaphylaxis. However, when colourings are given using ‘blinded food challenges’, these reactions are very rare.
Almost all reactions to food additives are non-allergic – that is, they do not involve the immune system (unlike conventional, IgE-mediated food allergy). Sometimes, these reactions may happen because of an inability of the gut to fully digest sugars in what we eat. For example, children who drink a lot of fruit juice often get diarrhoea, as their bodies cannot digest all the fructose sugar in fruit juice. Similarly, many children will develop lactose intolerance after an episode of gastroenteritis; the infection strips away the lining of the gut containing an enzyme called lactase, which is needed to help the body break down lactose, a sugar found in dairy foods. It can take a few weeks for the gut to fully heal, during which the child cannot fully absorb lactose and so develops diarrhoea.
Sometimes, children develop an itchy rash (called urticaria) which may suddenly start a few weeks after a viral infection and persist for many months. This condition is known as chronic urticaria. There is some limited data that about 1 in 3 of these children may experience rash after eating foods containing certain food additives, although this doesn’t happen all the time.
Many foods, such as dried fruits, fruit juice, wine and pickled foods, contain sulphites as a preservative. Some children with asthma can become wheezy after eating these foods, although the effect is almost certainly due to the acid in the stomach reacting with the sulphite, turning it into a gas which can irritate the airway.
In most children, there is very limited evidence for any role of food additives in causing non-allergic food reactions. Reactions may be more common in children with
chronic urticaria, but otherwise there is no reproducible and consistent evidence that additives can cause other symptoms, such as migraine, gut symptoms or aching joints.
Food Additives and Hyperactivity
Many parents are concerned about their child being hyperactive which can cause them to have difficulty concentrating and may result in impulsive behaviours. In fact, hyperactivity may affect between 2% and 5% of children in the UK. There are a number of factors which can affect hyperactive behaviours, including premature birth, genetics and how you bring your child up.
Attention deficit hyperactivity disorder (ADHD) is more than just hyperactive behaviour. It is associated with a specific pattern of behaviour, including reduced attention span and difficulties concentrating, to the extent that they affect the child’s ability to learn and function at home and at school. Children with ADHD often have learning difficulties and behavioural problems.
Since the 1970s, there have been a number of reports of children with ADHD responding to an additive-free diet. A number of studies have been carried out to investigate whether food additives can cause symptoms in children with ADHD, but unfortunately the results have not been consistent and it is difficult to draw firm conclusions.
In 2007, researchers in Southampton published a study which investigated whether children without ADHD developed hyperactive behaviours after eating certain food colourings and preservatives. They found a small increase in hyperactive behaviour with some additives, but results were not consistent.
Unfortunately, we simply do not have enough data to answer the question of whether food additives affect children’s behaviour. Many doctors have suggested that given the relative ease with which colourings and preservatives can be avoided, it may be helpful to trial an additive-free diet in children with hyperactive behaviour to see if there is any change in behaviour. So if your child shows signs of hyperactivity or ADHD, you may wish to avoid giving them the following artificial colours over 4 to 6 weeks to see if things improve:
- sunset yellow (E110)
- quinoline yellow (E104)
- carmoisine (E122)
- allura red (E129)
- tartrazine (E102)
- ponceau 4R (E124)
Since mid-2010, these colourings have been removed from many foods and drinks in the UK. They were previously found in many foods, including soft drinks, sweets, cakes and ice cream. When used in food, they must be listed in the ingredients, and the food label must now have a warning saying that the colour “may have an adverse effect on activity and attention in children”.
It is important to remember that simply taking these additives out of a child’s diet may not improve symptoms. If you think your child does react to additives, then you should speak to your GP or a dietician.
Last updated: March 2012