Following a request from the European Commission to the European Food Safety Authority (EFSA), the Panel on Food Additives and Nutrient Sources added to Food (ANS) was asked to deliver a scientific opinion re-evaluating the safety of Tartrazine (E 102) when used as a food colouring substance.
Tartrazine (E 102) is an azo dye authorised as a food additive in the EU and previously evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1966 and the Scientific Committee for Food (SCF) in 1975 and 1984. Both committees established an Acceptable Daily Intake (ADI) of 7.5 mg/kg bw/day. In 2002, TemaNord in its assessment recommended that the evaluation should be updated with inclusion of newly published data including results from studies on genotoxicity, chronic toxicity/carcinogenicity and reproductive and developmental toxicity.
Specifications for Tartrazine have been defined in the EU Commission Directive 2008/128/EC and in the Codex Alimentarius. Tartrazine consists essentially of 3-carboxy-5-hydroxy-1-(4'-sulphophenyl)-4-(4'-sulphophenylazo) pyrazole trisodium salt and subsidiary colouring matters together with sodium chloride and/or sodium sulphate as the principal uncoloured components. Tartrazine is described as the sodium salt. The calcium and the potassium salts are also permitted (Directive 2008/128/EC).
The purity is specified as not less than 85 % total colouring matters, calculated as the sodium salt. The remaining 15 % may be accounted for by sodium chloride or sodium sulphate (but this is never mentioned explicitly), water insoluble matter not more than 0.2 %, subsidiary colouring matters not more than 1.0 % and organic compounds other than colouring matters with a total not more than 0.5 % (4-hydrazinobenzene sulphonic acid, 4-aminobenzene-1-sulphonic acid, 5-oxo-1-(4-sulphophenyl)-2-pyrazoline-3-carboxylic acid, 4,4′-diazoaminodi(benzene sulphonic acid), tetrahydroxysuccinic acid).
The absorption, distribution, metabolism and excretion of Tartrazine have been extensively studied in animals and humans. Whilst the majority of studies are 40-50 years old the techniques and methods used for the identification of the parent compound and its metabolites were those used to elucidate and identify the metabolic pathways of most xenobiotics. Following oral administration at a range of doses absorption of intact Tartrazine is negligible to low (< 5 %) and this intact Tartrazine is predominantly excreted unchanged in urine. After oral administration there is extensive metabolism of Tartrazine by the gastrointestinal microflora to sulphanilic acid and aminopyrazalone (which may then be subsequently cleaved to sulphanilic acid and α-amino-β-ketobutyric acid fragments with the latter breaking down further via intermediary metabolism with release of carbon dioxide). Both sulphanilic acid and aminopyrazalone can be absorbed to a greater extent than Tartrazine.
The studies included in the JECFA evaluation have been described in very little detail and appear to be inadequate for a proper evaluation of the subchronic toxicity of Tartrazine. The study by Aboel-Zahab and co-workers gives some more detail on the subchronic toxic effects of mixtures containing Tartrazine. This study cannot however be used for a re-assessment of the ADI of Tartrazine, as animals were exposed to a mixture of food colours rather than Tartrazine alone, the dose level of each colour has not been specified and it is not clear what were the amounts/percentage of the colours used in the diet to achieve the cited level of 0.8 g/kg bw/day. Furthermore, only one dose was tested.
In the previous evaluations there were no indications of Tartrazine-related adverse effects on reproduction or development. In the more recent study by Tanaka, adverse effects on reproductive parameters were also not demonstrated up to and including dose levels of 773 and 1225 mg/kg bw/day for males and females, respectively, the highest dose levels tested. The results from behaviour tests conducted during the lactation period present some indications of differences in the performance of treated animals compared to the controls, most often in a direction of accelerated achievement of coordination (better performance compared to controls). However, these findings are not consistent, no convincing dose-response relationship could be observed and some findings in the high-dose groups are indicative of faster neurological development. While a statistically significant reduction in locomotor activity at weaning appeared to be a consistent finding, the test method did not take into account the possibility of habituation nor the biphasic (inverted V-shaped) pattern of activity from 15 to 30 days of post-natal life.
The Panel concludes that the studies by Tanaka did not demonstrate any adverse effects of Tartrazine on neurobehavioral development.
The Panel concludes that revision of the ADI based on these data is therefore not warranted.
Studies on micronucleus induction in vitro and in vivo Sister Chromatid Exchange (SCE), micronucleus and chromosome aberration tests were negative. Data from an unscheduled DNA synthesis (UDS) assay conducted in vitro and ex vivo on mammalian cells were also negative. Tartrazine induced chromosomal aberrations in Chinese hamster fibroblast cell line and showed a significant increase in SCE and chromosomal aberrations in mouse and rat bone marrow cells, following acute and chronic exposure to high doses of Tartrazine via the diet. Using the Comet assay, Sasaki et al. showed that Tartrazine induced DNA damage in the colon of mice at doses close to the ADI. In contrast, in a more recent study by Poul et al. Tartrazine did not reveal genotoxic effect in the micronucleus gut assay in mice at doses up to 2000 mg/kg bw. The authors comment on the results of the in vivo Comet assay by Sasaki et al. that the transient DNA damage observed in the colon of mice are unable to be fixed in stable genotoxic lesions and might be partly explained by local cytotoxicity of the dye.
The available carcinogenicity studies include the six carcinogenicity studies reviewed by JECFA, as well as the three more recent ones described by TemaNord, namely the publications of Maekawa et al. from 1987, and Borzelleca and Hallagan from 1988, plus the most recent study by Moutinho et al. from 2007. These studies have demonstrated that Tartrazine does not have a potential to induce benign or malignant neoplasias.
The Panel considered, in light of the negative carcinogenicity studies and negative results in standard in vivo genotoxicity studies, that the biological significance of the positive genotoxicity results in other studies is uncertain. Therefore the Panel concluded that the effects reported in these studies are not expected to result in carcinogenicity.
A study by McCann et al. has concluded that exposure to two mixtures of 4 synthetic colours plus a sodium benzoate preservative in the diet, one of them, Mix A, containing Tartrazine, resulted in increased hyperactivity in 8- to 9-year old and 3-year old children in the general population. In an earlier study by the same research team there was some evidence for adverse behavioural effects of a mixture of 4 synthetic colours (including Tartrazine) and sodium benzoate in 3-year old children on the Isle of Wight (Bateman et al,. 2004).
Recently, the EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) published an opinion on this McCann et al. study. In this opinion the AFC Panel also presented an overview of earlier studies that reported effects of food colours in general on child behaviour, the majority of these studies being conducted on children described as hyperactive or with a clinical diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD).
In its opinion the AFC Panel concluded that the McCann et al. study provides limited evidence that the two different mixtures of synthetic colours and sodium benzoate tested had a small and statistically significant effect on activity and attention in some children selected from the general population, although the effects were not observed for all children in all age groups and were not consistent for the two mixtures. The AFC Panel also concluded that the findings may thus be relevant for specific individuals within the population, showing sensitivity to food additives in general or to food colours in particular.
However, the AFC Panel, assisted by experts in human behavioural studies in the ad hoc Working group preparing the opinion, also concluded that the clinical significance of the observed effects remains unclear, since it is not known whether the small alterations in attention and activity would interfere with schoolwork and other intellectual functioning.
The AFC Panel also concluded that:
- since mixtures and not individual additives were tested in the study by McCann et al., it is not possible to ascribe the observed effects to any of the individual compounds, and
- in the context of the overall weight of evidence and in view of the considerable uncertainties, such as the lack of consistency and relative weakness of the effect and the absence of information on the clinical significance of the behavioural changes observed, the findings of the study cannot be used as a basis for altering the ADI of the respective food colours or sodium benzoate.
The ANS Panel concurs with these conclusions.
The Panel concludes that the present database does not give reason to revise the ADI of 7.5 mg/kg bw/day established by the SCF.
In humans, adverse reactions such as urticaria and vasculitis after Tartrazine intake have been reported in a number of studies. Data from animal and human studies have not convincingly demonstrated that
Tartrazine is able to induce an immune mediated (hypersensitivity) response, and the adverse reactions reported in humans following exposure to Tartrazine appear to be intolerance reactions. The reports of these adverse effects are often characterised by poorly controlled challenge procedures; sometimes Tartrazine is given with a mixture of other colours. In comparison, recent studies performed under properly controlled conditions imply that sensitivity to food additives in patients with chronic urticaria/angioedema or asthma is uncommon. However, given the available information, the Panel concludes that Tartrazine may induce intolerance reactions in a small fraction of the population. The Panel also notes that sensitive individuals may react at dose levels within the ADI.
The dietary exposure to Tartrazine from the Maximum Permitted Levels (MPLs) of use was estimated by the Panel using the Budget method (Tier 1) with the assumptions described in the report of the SCOOP Task 4.2. The Panel calculated a theoretical maximum daily exposure of 8.1 mg/kg bw/day for adults, and 13.1 mg/kg bw/day for a typical 3 year-old child.
Refined exposure estimates have been performed both for children and the adult population according to the Tier 2 and the Tier 3 approaches described in the SCOOP Task 4.2, which combines, respectively, detailed individual food consumption information from the population with the MPLs of use as specified in the Directive 94/36/EC on food colours (Tier 2), and with the maximum reported use levels of Tartrazine, as identified by the Panel from the data by the UK Food Standards Agency, the Food Safety Authority of Ireland, the Agence Française de Sécurité Sanitaire des Aliments, the Union of European Beverage Associations, the European Spirits Organisation, the Federation of European Food Additives, Food Enzymes and Food Culture Industries and the Confederation of the Food and Drink Industries of the EU (Tier 3). For children (aged 1-10 years), estimates have been calculated for 9 European countries (Belgium, France, UK, the Netherlands, Spain, Czech Republic, Italy, Finland and Germany). For the adult population, the Panel has selected the UK population as representative of the EU consumers for Tartrazine intake estimates.
When considering MPLs (Tier 2), the mean dietary exposure of European children (aged 1-10 years) ranged from 0.8 mg/kg bw/day to 3.4 mg/kg bw/day and from 0.8 mg/kg bw/day to 9.4 mg/kg bw/day at the 95th percentile. Estimates reported for the UK adult population give a mean dietary exposure of 0.9 mg/kg bw/day and of 2.1 mg/kg bw/day for high level (97.5th percentile) consumers of soft drinks. The main contributors to the total anticipated exposure (>10 %) were soft drinks (50 % at average level and 80 % for high level consumers).
When considering maximum reported use levels (Tier 3), the mean dietary exposure to Tartrazine for European children (aged 1-10 years), ranged from 0.2 mg/kg bw/day to 1.9 mg/kg bw/day and from 0.4 mg/kg bw/day to 7.3 mg/kg bw/day at the 95th percentile. Estimates reported for the UK adult population give a mean dietary exposure of 0.3 mg/kg bw/day and of 0.5 mg/kg bw/day for high level (97.5th percentile) consumers of soft drinks.
The Panel concludes that at the maximum reported levels of use of Tartrazine, refined (Tier 3) intake estimates are below the ADI of 7.5 mg/kg bw/day.
The Panel further notes that the specifications of Tartrazine need to be updated with respect to the percentage of material not accounted for that may represent sodium chloride and/or sodium sulphate as the principal uncoloured components.
The Panel notes that the JECFA specification for lead is ≤ 2 mg/kg whereas the EC specification is ≤ 10 mg/kg.
The Panel notes that the aluminium lake of the colour could add to the daily intake of aluminium for which a Tolerable Weekly Intake of 1 mg aluminium/kg bw/week has been established and that therefore specifications for the maximum level of aluminium in the lakes may be required.