Currently nine artificial food colours are approved for use in the US, all of which are derived from petroleum (1). The Food and Agriculture Organization and the World Health Organization Expert Committee on Food Additives jointly assess the health risk associated with food additives and have set Acceptable Daily Intakes (ADI). The ADI is the amount that they believe it is safe to eat each day. Importantly, however, every country controls the dyes they allow in the food supply and it varies considerably (1).
Currently, food dyes are most commonly found in candy, beverages, desserts, cereals, and snack foods (2), i.e., foods targeting children. Why artificial rather than natural dyes? Because they are cheap! Despite growing concerns regarding the impact of synthetic food dyes on health, little has been done to reduce consumer exposure North America. We are NOT convinced that these dyes are necessary, NOR many of the foods proudly displaying their man-made glory, for that matter.
Would Kraft Dinner by any other colour taste as sweet? Petitioners against Yellow 5 and Yellow 6 certainly think so! Do artificial food colours *really* have a negative impact on behaviour in children and promote hyperactivity?
Artificial Food Colours and Hyperactivity
The idea that artificial flavours and colours can contribute to hyperactivity was popularized by Benjamin Feingold in the 1970s (1). Scientific testing of Feingold’s diet – a diet free of artificial food flavours and colours – suggested that there MAY be something to his hypothesis; however, only a small group of children showed improvements and the results were controversial (3). Research focused specifically on artificial food colours using “dye-challenge” studies, where children were given a variety of different dyes and doses, found that only a small subgroup of children had negative behavioural reactions to the dyes. As the dose increased, however, so did the number of children exhibiting behavioural problems such as: irritability, inability to sleep and pay attention, impulsivity, and hyperactivity (4).
A meta-analysis of 15 different studies led Schab and Trinh (5) to conclude that artificial food colours can promote hyperactivity in children with attention deficit hyperactivity disorder (ADHD). Another meta-analysis of 24 studies estimated that approximately 33% of children with ADHD would benefit from a restricted diet and 8% have negative reactions to artificial food colours (6). Artificial food colours may also increase hyperactivity in children not identified as having ADHD (7).
Perhaps it is this evidence that has prompted the European Union to require a warning “this food may have an adverse effect on activity and attention in children” for foods that contain any of six different food dyes (1). In addition to hyperactivity, it has also been suggested that individuals with asthma, eczema, and migraines may react to artificial food colours (1).
1. Toxic Chemical Compounds
Could the artificial food colours include chemical compounds that may be toxic in some way. Studies using high doses in rats suggest that weight gain could be suppressed (this is not in a good lose weight way but rather a may inhibit growth in children way). There was also evidence of liver stress, increased kidney function, and abnormal blood levels of red and white blood cells (8,9).
Studies looking at behavior found hyperactivity, increased anxiety, and depression-like bahaviours in rats (10). There are also reports of neurotoxicity demonstrated by a decrease in neurite growth a process that indicates the brain cells are healthy (11). Other dyes were found to reduce both physical activity and brain activity. High doses also decreased learning and memory in rats (12).
A second suggestion is that the effects of artificial food colours may be due to a hypersensitivity mechanism similar to an allergic reaction, although more research is needed (1).
3. Interactions with Essential Nutrients
It may be that artificial food colours interfere with the absorption of essential nutrients like iron and zinc. Zinc and iron have roles in the brain and deficiencies have been associated with hyperactivity, behavioural changes, and ADHD (1). One study found greater zinc losses in children given yellow dye but these results require confirmation (13). At this stage, however, the role of artificial food colours in nutrient absorption is largely speculation.
No Baloney’s advice. While artificial food colours have not been convicted of inducing hyperactivity in North America (yet), there is enough evidence to warrant pause and thinking twice before grabbing those brilliantly coloured treats!
Since artificial food colours provide absolutely no nutritional benefit we recommend avoiding them (and artificial flavours for that matter) as much as possible. You’ll get the added benefit of making overall healthier food choices – most good-for-you foods don’t contain artificial colour! While natural food colouring agents like beet, carrot, annatto, and paprika extracts are preferable to synthetic, carmine red colouring is *technically* natural but can still cause allergic reactions. When in doubt, go with plant-based colouring agents if you are at all concerned.
What to avoid on an ingredient list: Blue 1, Blue 2, Citrus Red 2, Green 3, Red 3, Red 40, Yellow 5, Yellow 6, “artificial color,” “artificial color added” or “colour added”.
- Stevens LJ et al. (2013) Mechanisms of behavioral, atopic, and other reactions to artificial food colors in children. Nutrition Reviews 71(5): 268-281.
- Marmion DM. (1991) Handbook of U.S. Colorants: Foods, Drugs, Cosmetics, and Medical Devices, 3rd Ed. New York: Wiley-Interscience 1991; 94.
- Williams JI et al. (1978) Diet in the management of hyperkinesis: a review of the tests of Feingold’s hypotheses. Can Psychiatr Association. 23(4):241-8.
- Rowe KS et al. (1994) Synthetic food coloring and behavior: a dose response effect in a double blind, placebo-controlled, repeated-measures study. J Pediatr 25: 691-8.
- Schab DW et al. (2004) Do artificial food colors promote hyperactivity in children with hyperactive syndromes? A meta-analysis of double-blind placebo-controlled trials. J Dev Behav Pediatr. 25(6): 423-34.
- Nigg JT et al. (2012) Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives. J Am Acad Child Adolesc Psychiatry 51:86-97.
- McCann D et al. (2007) Food additives and hyperactive behavior in 3-year-old and 8/9-year-old children in the community: a randomized, double-blinded, placebo-controlled trial. Lancet. 370:1560-1567.
- El-Wahab HM et al. (2013) Toxic effects of some synthetic food colorants and/or flavor additives on male rats. Toxicol Ind Health. 29(2):224-32.
- Amin KA et al. (2010) Effect of food azo dyes tartrazine and carmoisine on biochemical parameters related to renal, hepatic function and oxidative stress biomarkers in young male rats. Food Chem Toxicol. 48:2994-2999.
- Kamel MM et al. (2011) The potential health hazard of tartrazine and levels of hyperactivity, anxiety-like symptoms, depression and anti-social behaviour in rats. J Am Sci 7:1211-1218. http://www.jofamericanscience.org/journals/am-sci/am0706/183_6181am0706_1211_1218.pdf
- Lau K et al. (2006) Synergistic interactions between commonly used food additives in a developmental neurotoxicity test. Toxicol Sci. 90:178-87. http://toxsci.oxfordjournals.org/content/90/1/178.long
- Gao Y et al. (2011) Effect of food azo dye tartrazine on learning and memory functions in mice and rats, and the possible mechanisms involved. J Food Sci 76:T125-T129.
- Ward N et al. (1990) The influence of the chemical additive tartrazine on the zinc status of hyperactive children – a double-blind placebo-controlled study. J Nutr Med (1):51-57.