Hypersensitivity to food additives
Food additives are a large and varied group of substances added to food to, for example, prevent growth of microorganisms, give colour or flavour, improve texture or prevent browning. In the European Union food additives have number codes called E-numbers. There are few scientific investigations concerning food additives and hypersensitivity. There are many different food additives and relatively few people who react to any individual substance, which means that the few published descriptions of food additive hypersensitivity are based on a small number of patients.
One exception is sulphites. Various types of sulphites are used as preservatives and anti-browning agents in food manufacturing. They may be present in many different foods such as wine, beer, dried fruit and vegetables, white vegetables (e.g. horseradish sauces and relishes, and sauerkraut), biscuits, crustaceans and mussels. Hypersensitivity to sulphites is relatively well described, especially in people with asthma, and they may also trigger skin reactions such as hives (urticaria). When used at levels of or above 10mg per kg, sulphites have to be labelled on pre-packed foods within the EC.
Food additives made from allergenic foods
Food additives made from allergenic foods may contain residual allergens. One example is lecithin (E322) which is used as an emulsifier. Lecithin is most often extracted from soy or rapeseed, but can also be produced from egg or sunflower seeds. Lecithin may contain remnants of protein from the food it is extracted from. This means that allergic people who are highly sensitive to soy, rape, egg or sunflower seeds might react to lecithin. The origin of lecithins derived from the most common allergenic foods (as defined in local legislation) must be declared on food labels.
Food colours and hyperactive children
In 2007 a group of British scientists published a study showing that children who drank a mixture of 4 synthetic food colours and a food preservative became more hyperactive than when they did not drink the mixture. The level of food colours and food preservative in the experimental drink was comparable to the level that children may drink or eat in real life if they consume brightly coloured sweets or soft drinks. In 2008 the European Food Safety Authority (EFSA) assessed this study. They concluded that the findings may be relevant for specific individuals showing sensitivity to food additives. Since mixtures and not individual additives were tested in the study, it is not possible to ascribe the increased hyperactivity to any of the individual food additives. It is also unclear what the findings mean in practice since it is unknown whether the small alterations in attention and activity would interfere with schoolwork and other intellectual functioning.
The colours and preservative used in the experimental drinks were:
- Tartrazine (E102)
- Quinoline Yellow (E104)
- Sunset Yellow FCF (E110)
- Ponceau 4R (E124)
- Allura Red AC (E129)
- Carmosine (E122)
- Sodium benzoate (E211) - preservative
The EFSA assessment of the study on food colours and hyperactive children:
- Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC) on a request from the Commission on the results of the study by McCann et al. (2007) on the effect of some colours and sodium benzoate on children’s behaviour. The EFSA Journal (2008) 660, 1-54.
The British study on food colours:
- McCann, D., Barrett, A., Cooper, C., Crumpler, D., Dalen, L., Grimshaw, K., Kitchin, E., Lok,K., Porteous, L., Prince, E., Sonuga-Barke, E., O’Warner, J., Stevenson, J. (2007). Food
additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community a randomized, double-blinded, placebo-controlled trial. The Lancet,370 (9598), 1560-1567.