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Colour additives, both natural and artificial, are used in the food industry for a variety of reasons, including: to offset colour loss due to exposure to light, air, temperature extremes, moisture and storage conditions; to correct natural variations in colour; to enhance colours that occur naturally; to provide colour to colourless items, and for “fun” foods.  Processed foods such as cookies, cakes, sports drinks, margarine, cheeses etc. tend to contain the highest amount of colour additives. 

In Canada, colour additives are considered food additives and are governed under the same regulations as food additives in Division 16 of the Canadian Food and Drug Act and Regulations.  In order to be approved, toxicological and safety information must be submitted to Health Canada.  Following a review of this information, only the colour additives considered safe may be used in consumer products. 

The use of colour additives has been linked in some scientific studies to hyperactivity in children.  Attention Deficit/Hyperactivity Disorder (ADHD) is a condition that becomes apparent in some children around the age of preschool or early school years. Children affected by this disorder have difficulty to pay attention and/or control their behaviour.  Throughout the 1970’s several scientific papers claimed that between 30 and 50% of children with hyperactivity disorder improved when placed on a diet free of artificial colours and salicylates. Attempts to replicate these findings throughout the 1980’s presented varied results; some studies ascertain a clear link, while others did not.  Most recently, a study in a British scientific paper, The Lancet (September 2007), reported a link between consumption of fruit juices containing colour additives and an increase in signs of hyperactivity in children of age 3, and of age 8-9. 

It is difficult to interpret what potential effect artificial colours and dyes have on children with ADHD; overall findings from the research remain inconclusive.  There is a wide variability in response from the children in these scientific studies, suggesting some persons may be more sensitive than others.  In addition to affecting ADHD, a very small subset of the population (approximately 0.1%) has other side effects when exposed to colour additives.  These side effects can include rash, flushing, asthma, dizziness and fainting.  Individuals with known sensitivities may avoid artificial colours as any addition of colour to a food product must be listed in the ingredients on the food package; however, the word ‘colour’ is often listed and used to encompass all colour additives in the product, rather than listing them individually. 

Food colour additives approved for use in Canada include Allura Red, Amaranth, Erythrosine, Indigotine, Sunset Yellow FCF, Tartrazine, Fast Green FCF, Brilliant Blue FCF, Ponceau SX, and Citrus Red No. 2 (Table 1). 

Table 1: Colour additives approved for use in Canada and their alternate names.

Types

Tartrazine, Sunset Yellow, Ponceau SX, Allura Red

Health Canada has approved all of the above additives for use as colour additives in Canada. Little information is available on each additive, however all approved colour additives can be found on the Health Canada website, using the food additive dictionary. 

Tartrazine
 

Tartrazine, also known as Yellow 5 and E102, is an azo-based yellow dye that is used in many foods and medications.  An azo dye is a dye that has two nitrogens connected by a double bond in its chemical structure (See Figure 1).  A small portion of the population, ranging from 1 to 10 out of every ten thousand people (0.01% to 0.1% of the population), has a sensitivity to tartrazine.  Adverse reactions include urticaria (skin rash), rhinitis (runny nose), asthma, purpura (purple skin bruising) and systemic anaphylaxis (shock).  This intolerance seems to be more common in people with asthma or sensitivity to aspirin. 

Figure 1: Chemical structure of Tartrazine showing the azo (N=N) group. Source: Wageningen University.

Sunset Yellow

Sunset Yellow, also known as E110, Orange Yellow S and Yellow 6, is a synthetic coal tar and azo dye and is used in fermented foods that must be heat treated.  It can be found in foods such as packet soups, breadcrumbs, ice cream, canned fish, lemon curd, hot chocolate mix, some jams and jellies and many medications.

For some individuals, consumption of this colour additive has resulted in urticaria (hives), rhinitis (runny nose), nasal congestion, allergies, hyperactivity, abdominal pain, nausea, and distaste in food.  In some scientific studies it has been linked to an increased incidence of tumours in animals and chromosomal damage; however the levels ingested in these studies were much higher than would be consumed by a human.  The World Health Organization’s review of Sunset Yellow found no evidence of increased tumour incidence in both short term and long term studies conducted on rats, guinea pigs, hamsters and dogs.  The acceptable daily intake (ADI) was set at 2.5 milligrams/kilogram bodyweight per day.

In several scientific studies, Sunset Yellow has been shown to cause allergic or intolerance reactions in certain people, particularly those with a pre-existing sensitivity to aspirin.

Figure 2: Chemical structure of the artificial colour, Sunset Yellow. Source: Wageningen University.

Ponceau SX:

Ponceau SX, also known as FD&C Red No. 4, is permitted in Canada in or on fruit peel, glazed fruits and maraschino cherries at a maximum level of 150 parts per million. 

Allura Red:

A study has demonstrated that hypersensitivity reactions occurred in 15% of the population challenged with allura red.  In this test, all 52 participants who had been suffering from hives and, or rash for four weeks or more were placed on an elimination diet in which all potential sources of allura red and any food known to cause rash or hives, were removed from their diet, with the exception of necessary medications.  Following three weeks of no symptoms, participants were ‘challenged’ orally with allura red and symptoms were monitored.  Of those tested, 15% showed a positive reaction such as reoccurrence of rash or hives. 

Figure 3: Chemical structure of the artificial colour, Allura Red. Source: Wageningen University.

Information Sources:

Department of Justice Canada. (2008). Food and Drugs Act. Retrieved from, http://laws.justice.gc.ca/en/showtdm/cr/C.R.C.-c.870

European Union Food Information Council. (2007). Hyperactivity and artificial food colours. Retrieved from, http://www.eufic.org/article/en/artid/hyperactivity-artificial-food-colours/

Health Canada. (2007). Food Additive Dictionary. Retrieved from http://www.hc-sc.gc.ca/fn-an/securit/addit/diction/index_e.html

McCann. D., Barrett, A., Cooper, A., Crumpler, D., Dalen. L., Grimshaw,K., Kitchin, E., Lok, K., Porteous, L., Prince, E., Sonuga-Barke, E.,  Warner, J.O. & Stevenson, J. (2007).  Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial.  The Lancet, 370 (9598): 1560 – 1567. doi:10.1016/S0140-6736(07)61306-3, Retrieved from, http://www.thelancet.com/journals/lancet/article/PIIS0140673607613063/abstract?isEOP=true

South African Association for Food Science and Technology. (2002). Tartrazine.  Retrieved from http://www.saafost.org.za/Library/Position%20Statements/TARTRAZINE.pdf

United Kingdom. Food Guide. (N.D.). E110: Sunset Yellow. Retrieved from http://www.ukfoodguide.net/e110.htm

Wageningen University. (2007). Food-Info.net: Azo dyes. Retrieved from http://www.food-info.net/uk/colour/azo.htm.

World Health Organization. (1998). Sunset Yellow FCF (WHO Food Additives Series 17).  Retrieved from http://www.inchem.org/documents/jecfa/jecmono/v17je29.htm.