Sunset yellow FCF: a permitted food dye

Sunset Yellow FCF (SY), used frequently in ready-made foods, cosmetics, and the pharmaceutical industry, may cause many health problems. This study is intended to evaluate the morphological and cellular effects of SY on the embryonic chicken immune system throughout incubation.

Effects of Sunset Yellow FCF on Immune System

As food dyes increase the attractiveness of food, they are an important group among food additives. These food additives are said not to have significant side effects unless the specified limits are exceeded. A study conducted on synthetic food dyes reported that the permissible rates were exceeded in the majority of the samples and that one of the most widely used food azo dyes was Sunset Yellow FCF (E110). This dye (Sunset Yellow FCF) is a synthetic chemical containing azo groups and is used in many manufacturing processes such as those in the food, drug, cosmetic, textile, and leather industries. In 2011, the acceptable daily intake (ADI) was set at 0–2 mg/kg b.w. by the FAO/WHO Joint Expert Committee on Food Additives (JECFA). The European Food Safety Authority (EFSA) also reported that the ADI of Sunset Yellow FCF should be between 1 and 2.5 mg/kg b.w./day. Over-exposure to azo dyes may cause serious health problems such as hyperactivity in children, chromosomal aberrations, and allergic reactions. [1]

There is not enough information about the passage and passage rates through the placental barrier of Sunset Yellow FCF in mammals. Chicken eggs without the placental barrier are accepted as the most suitable and preferred material in embryonic and teratogenic studies. A standard method for such studies known as the chicken embryotoxicity screening test (CHEST) was developed by Jelinek et al. The obtained results from this test can also be adapted to mammals. CHEST was used in this study, which aims to evaluate the developmental and morpho-histological effects of Sunset Yellow FCF on the thymus, bursa of Fabricius, and spleen. In addition, since the present study is an embryo study, it may provide information about the effects of Sunset Yellow FCF throughout pregnancy. Synthetic colours are man-made compounds that are not found in nature. These compounds, containing one or more azo groups, lead to many health problems. One of the synthetic dyes is Sunset Yellow FCF, which has cytotoxic and genotoxic effects. Although Sunset Yellow FCF has undesirable effects, it is widely used in many industries. Many studies have shown that Sunset Yellow FCF has mutagenic and carcinogenic effects. Moreover, this food dye is found in 15% of drugs such as anti-inflammatories, antihistamines, vitamin medications, bronchodilators, and others. It is stated that preparations containing these compounds may have undesirable effects attributable to the azo compounds in them. In 2008, the European Parliament and the Council of the European Union decided that foods and beverages containing some artificial colourings must be labelled with the text “may have unwanted effects on attention and activity in children”. Also, according to an EFSA Scientific Opinion, newly submitted data provides a basis to revise the established temporary ADI.

According to the results obtained from the present study, it was concluded that Sunset Yellow FCF used as colouring in many industries has unfavourable effects on the embryonic development of the thymus, bursa of Fabricius, spleen, and blood tissue proportional to the given dose. The ADI of Sunset Yellow FCF was established as 2 mg/kg by JECFA in 2011. However, we believe that the reliability of this daily consumption limit should be reassessed in the light of this study. The dose given to the eggs in the Sunset Yellow FCF1,000 group was 2 mg/kg. In addition to spurring debate about the ADI for Sunset Yellow FCF, this study offers a model in chick embryos to see the embryological effects in humans. It may be concluded that the use of products containing Sunset Yellow FCF during pregnancy carries great risks for the health of both mother and foetus.

Alters functional responses of splenocytes at non-cytotoxic dose

Sunset Yellow FCF (SY) (Disodium 6-hydroxy-5-[(4-sulfophenyl)azo]-2-napthalenesulfononate) is an azo dye permitted for food usage in several countries including India. It is extensively used in food preparations such as confectionary products, ice candy, sweets, savory samples, frozen desserts and beverages, cosmetics, medicines, and dietary supplements, etc. The maximum permissible level of SY in food commodities is 100–200 ppm, however, various studies have reported that this limit is frequently exceeded manifolds. Also, SY has been observed to be present in those food commodities like tomato sauce where its use as a colorant is prohibited under regulatory guidelines.[2]

Earlier acute, chronic and long-term studies in mice did not suggest any significant adverse effect of SY. No mutagenic or carcinogenic potential of SY has been observed either in vitro or in vivo studies. However, reports suggest that dietary exposure of SY alters the reproductive and neurobehavioral parameters in mice. In a recent study it has been reported that although SY did not affect the body weight and spleen weight but significantly decreased the thymus weight along with alteration in monocyte counts and suppressed delayed type hypersensitivity response. However, immunomodulatory effects of SY at cellular level have not been explored yet. Further, US FDA (2000) has also expressed concerns regarding the need for immunotoxicity risk assessment of chemicals added to food articles. The immune response is largely governed by the type of foreign assault, portal of antigen encounter with immune components and the levels of different cytokines at the site of action. Effectors of immune system (activated lymphocytes and phagocytes) play a major role in immune reactions by talking to each other through proinflammatory cytokines, such as IL-2, IL-4, IL-6, IFN-γ, TNF-α and IL-17. 

The Multifaceted Nature of Sunset Yellow FCF

Sunset Yellow FCF is a crystalline substance at room temperature, with crystallites between 5 and 20 μm. Thermal analysis and calorimetry study performed in air indicate the evaporation of adsorbed water up to 188 °C, after which the material is thermally stable up to 330 °C. Oxidative decomposition takes place in four exothermic stages, of which the main one is between 510 and 643 °C with heat release of 4519.6 J g−1. At 913 °C, the residue of 31.77% is obtained. Sunset Yellow FCF, used for colouring processed foods, can be safely used at temperatures below 330 °C (it is recommended that foods containing this azo dye be thermally processed in an oxygen-poor atmosphere—preferably in closed containers.[3]

Sunset Yellow FCF bioactivity was highlighted by its interaction with proteins (collagen and bovine serum albumin—BSA), by its antioxidant activity and its phytotoxicity on wheat. The results indicated that as the concentration of Sunset Yellow FCF in the solution increases, BSA can bind the food dye azo forming a complex with the dye. This can disrupt the normal biological function of BSA. Sunset Yellow FCF has an undesirable effect on collagen and poses a potential risk to the skin. The antioxidant activity of Sunset Yellow FCF increases with increasing its concentration, the highest value of GAE equivalent gallic acid (458.1 mg L−1), being recorded for the concentration of 0.25%, most likely due to the presence of hydroxyl group. Treating wheat with aqueous Sunset Yellow FCF solutions, at concentrations of 0.01–0.05%, could increase its resistance to drought conditions. At low concentrations, Sunset Yellow FCF does not harm wheat, but at concentrations above 0.25%, there are negative changes in wheat growth.

References

[1] ?olako?lu F, Sel?uk ML. Effects of Sunset Yellow FCF on Immune System Organs During Different Chicken Embryonic Periods. J Vet Res. 2020 Oct 15;64(4):597-607.

[2] Yadav A, Kumar A, Tripathi A, Das M. Sunset yellow FCF, a permitted food dye, alters functional responses of splenocytes at non-cytotoxic dose. Toxicol Lett. 2013 Mar 13;217(3):197-204.

[3] Leulescu, M., P?l?rie, I., Rotaru, A. et al. Sunset Yellow: physical, thermal and bioactive properties of the widely employed food, pharmaceutical and cosmetic orange azo-dye material. J Therm Anal Calorim 148, 1265–1287 (2023).

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