Dark Truths About Permitted Colours

Several recent research studies show that synthetic additives that are used to colour food yellow, red, green or blue and approved under the Prevention of Food Adulteration (PFA) Act may be carcinogenic or provoke allergic reactions of varying intensity if they are consumed in quantities beyond their recommended doses.

Studies conducted by the National Institute of Nutrition in Hyderabad had shown that Ponceau 4R, the approved red colouring agent, caused an allergic condition called glossities of the tongue in children who consumed flavoured aniseed (saunf).

Tartrazine, the yellow colouring agent, has been found to cause dermatitis (the cracking and flaking of skin) and can exacerbate asthmatic conditions. And people who consume food containing excess brilliant blue FCF can be prone to thyroid tumours.

 

Scientists Ramesh Bhat and Pulkit Mathur have observed that the safety of permitted colours is a function of their total intake. And the point is that there is a fairly high chance of the average consumer exceeding permissible levels.

In a day, a person may be exposed to synthetic food colours in the form of biscuits, confectionery items, soft drinks, sweetmeats and desserts. The maximum permitted intake could be easily exceeded in any given day due to the widespread use of artificial colouring agents in various foodstuffs.

The World Health Organisation Expert Committee on Food Additives (WHOECFA) has set an acceptable daily intake (ADI) based on toxicological studies on animals and data from human clinical studies. The ADI has been defined as the amount that can be consumed every day, throughout the lifetime of an individual without any harmful effects.

The ADI for permitted colours varies from 0.1 mg per kg of body weight for erythrosine (red additive) to 25 mg per kg body weight for fast green. The more toxic the food colour, the lower the ADI (see table).

However, conventional WHOECFA wisdom may need to be rewritten with the increasing use of colouring agents and the growing popularity of fast foods and soft drinks. A 20-kg child (between five to seven years old) who consumes 100 ml of a pink ice cream with erythrosine added in the concentration of 200 parts per million as is permitted in India, will be consuming 10 times the ADI for erythrosine.

This is a situation when only a single source of erythrosine has been considered in his daily diet. The child can be exposed to erythrosine from a number of other foods like pastries, cakes, cola drinks and others. Erythrosine is added to medicine as well, adding to the total exposure.

The growing evidence of the thyroid toxicity of erythrosine has caused the WHOECFA to lower the ADI from time to time. For example, the ADI in 1978 was 2.5 mg per kg body weight. This was reduced to 1.25 mg per kg body weight and then to 0.6 mg per kg body weight in 1986. The 1990 evaluation reduced the ADI to 0.1 mg per kg body weight.

Bhat and Mathur have argued that it has become important to monitor the total daily intake of all food colours so that the ADI of none of the colours should be exceeded. This is easier said than done as Indian health officials do not have the mechanism needed for closely monitoring food additive consumption.

The Indian governments central committee for food standards has recommended restricting the quantity of synthetic food colour that may be added depending on technological necessity from the existing uniform limit of 200 ppm. Synthetic colours were to be prohibited in all dairy products except ice cream, in sweets, savouries and wafers, in soup powder, flavouring agents, sweetened ice, milk-based beverages or food supplements, bottled/ canned strawberries, cherries, tomato juice and processed or preserved papaya. A move to make this a law has been kept in abeyance due to pressure from the food processing industry.

The industry has been pointing out the difficulties they would face in the form of loss of business if the use of colour were banned. Colourless processed foods, they contend, would look unappetising and therefore be unacceptable to the consumer. Also, the concerns of toxicity or otherwise were not backed up by solid proven clinical data findings.

After extensive deliberation, the committee amended the list of foods in which addition of synthetic colours is permitted and revised the maximum permissible level of colour for each food category. An official notification is due soon showing the new permitted levels of synthetic colour additives and the kind of foodstuffs it can be added to.

The two scientists have argued that the amended rules should be considered a temporary measure for the next 10 years which should culminate in a total ban on the use of synthetic food colours. This measure may not be as unrealistic as the food industry suggests. Norway and Sweden do not allow the use of synthetic food colours. If the industry in these countries where the variety of processed foods is much greater can survive without synthetic food colours, why cant the Indian industry?

The other compelling reason for change is that western countries could soon ban processed foods containing artificial colouring agents. This would mean that the considerable exports from India may face rejection. Different members of the European Union (EU) have different rules, but the trend towards lowering the permitted levels and cutting down on the number of approved dyes is clearly emerging. So a total ban on artificial colouring agents may be good both from the point of view of domestic public health and from exports.

There are precedents to show that solutions can be found. When the EU recently banned azo dyes in leather textiles, Indian exporters had little time for change. It was thanks to Indian scientists who came out with substitutes in three months that our leather exports were saved.

In India, the solutions are easier. Indian processed food manufacturers need to shift to natural colours for example, saffron could be used to replace the more extensively used synthetic sunset yellow FCF. The possibility of using alternative natural colour additives, which can be as inexpensively produced as synthetic colours, needs to be explored more fully.

Historically, the traditional use of food ingredients involved an integrated approach where one item served a variety of purposes. Saffron, for instance, was not just a colouring agent but was known for its stimulant and stomachic properties while turmeric is a stomachic with antioxidant properties. It has been shown to lower lipid peroxidation (cholesterol-reducing properties) by enhancing the activities of antioxidant enzymes. Chilli, a red colouring agent, was also used in several ailments like varicose veins, anorexia, liver congestion and as a prophylactic and therapeutic drug.

In India, it is not just excess intake of permitted colours that is a cause for concern, but widespread use of unauthorised dyes sold as food colours. Auramine, a popular blue colouring agent, was found to inhibit growth and cause dysfunction of the liver and kidneys. Metanil yellow consumption could lead to degenerative changes in the stomach, ileum, rectum, liver, kidney and ovary. Rodamine B (red) was shown to cause growth retardation, haemolysis of red blood cells and degenerative changes in liver and kidney.

While the PFA has become aware of the need to reduce the intake of permitted colours, it has been found that unpermitted dyes are sold in larger quantities than the former. It is a common sight to see colouring agents in powder form prominently displayed in village fairs. There is no control over their production or consumption. These dyes are mostly used by the textile industry and find their way into the unorganised foodstuff sector.

Public health is substantially at risk due to the unchecked sale of unpermitted chemical dyes and some initiative is needed from the government to curb this practice. Scientists argue that a sustained public campaign to educate consumers about the ill-effects of synthetic colouring agents could help. But the fast-growing processed foods industry needs to curb its voracious appetite for profit as well.