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Food Dyes-The Science

Food dyes have always been one of the most controversial classes of food additives because they serve only a cosmetic purpose. They do not contribute anything nutritionally and in fact may make foods of poor nutritional quality more appealing.

I’m sure Lisa Leake is a well-meaning young lady and a fine mother. But I think she could use a lesson in chemistry. Lisa and fellow food blogger Vani Hari are the movers and shakers behind a petition to “remove all dangerous artificial food dyes” from Kraft’s classic Macaroni and Cheese and replace them with the natural dyes used in the United Kingdom. The argument is that Yellow #5, also known as tartrazine, and Yellow #6, known as Sunset Yellow, may be linked to health problems whereas the natural colours, namely beta-carotene and paprika have no such dark clouds hanging over their heads.

Food dyes have always been one of the most controversial classes of food additives because they serve only a cosmetic purpose. They do not contribute anything nutritionally and in fact may make foods of poor nutritional quality more appealing. Before getting back to Lisa and Vani’s petition and allegations of “danger,” a little history seems to be in order.

As early as 400 BC, Pliny the Elder noted that wine was sometimes artificially coloured, possibly with squid ink. Saffron, paprika, turmeric, beet extract and various flower petals have long been used to colour foods. A peasant in the middle ages may well have eaten bread that was adulterated with lime to mimic refined flour, preferred by the rich but unavailable to the poor. King Edward I (1272 to 1307) took such adulteration very seriously and issued an edict that a baker guilty of such an offence should be “dragged down the great street where the most people are assembled with the faulty loaf hanging around his neck.” Should he repeat the offence, he would be “pilloried for an hour and if he still didn’t learn his lesson, his oven would be pulled down and the baker made to foreswear the trade in the city forever.”

In the 14th century the colouring of butter was made illegal in France, and a law passed in 1574 forbade the colouring of pastries to simulate the presence of eggs. Copper compounds were commonly used to “green up” vegetables. In 1820 English chemist Friedrich Accum recounted the misadventures of a “young lady who amused herself by eating pickles impregnated with copper.” The episode did not have a happy outcome. “She soon complained of pain in the stomach. In nine days after eating the pickle, death relieved her of her suffering.” Accum also documented the use of red and white lead, vermilion (a mercury compound) and copper arsenite in candies designed to appeal to children. He actually published the names of the guilty manufacturers, making some powerful enemies in the process, yet adulteration continued unabated.

The situation was certainly no better in America. Pickles were bathed in copper sulphate and milk was tinged yellow with lead chromate. Indeed this was such a common process that when white milk was available, people refused to drink it thinking it had been adulterated. But even back then there were consumer advocates. At the 1904 St. Louis Exposition they displayed silks coloured with dyes used by food manufacturers, implying that chemicals that could be used to dye fabrics were not suitable for consumption. This is what I would refer to as a “fallacy by association.” Palm oil, for example, is used to make napalm, but that has nothing to do with its safety as a food. Similarly, food dyes cannot be declared dangerous just because they are made from petroleum, a substance no one would ever want to consume.

While I have no problem urging a reduction in the use of food dyes, I have a problem with unscientific arguments used towards this end. Such as Lisa Leake’s claim that “food companies are feeding us petroleum disguised as brightly coloured food dyes.” To dig herself an even deeper hole, she goes on to list seven reasons why she “hates” food dyes, with number one being that “they are made in a lab with chemicals derived from petroleum, a crude oil product, which also happens to be used in gasoline, diesel fuel, asphalt, and tar.” This is senseless fear-mongering from a young mom boiling over with emotional energy but lacking any scientific background.

The allegation that we are being fed petroleum disguised as food dye is blatantly absurd. Food dyes, while synthesized from compounds found in petroleum, are dramatically different in molecular structure from any petroleum component. Furthermore, the safety of a chemical does not depend on its ancestry, but on its molecular structure. And the way to evaluate safety is through proper laboratory and animal studies with continued monitoring of human epidemiology.

Over the years, as testing methods became more and more sophisticated, and regulations more stringent, many of the dyes used historically by the food industry were removed from the market. The ones that remained, such as tartrazine and Sunset Yellow, passed the scrutiny of regulatory agencies and are allowed in a wide variety of foods.

The legal use of a food dye, however, cannot guarantee that no adverse effect will be noted. There is always the possibility that a small subset of the population will experience some adverse reaction. Allergic reactions as well as behavioural problems in children have been noted with some food dyes, although there is a divergence of opinion about the seriousness of the problem. It is such uncertainty that has prompted the petition against Kraft. While the goal is reasonable, the suggestion that food dyes are a problem because they are man-made chemicals derived from petroleum is not.

While it is true the dyes used by Kraft in North America have all passed through the regulatory hoops and hurdles, there have been enough questions raised about them to give us reason to evoke the precautionary principle, which states that even if there is no proof of harm, a chemical with some potential for harm should be replaced if a safer alternative is available. Paprika and beta-carotene are indeed better choices. Of course that still begs the question of why macaroni and cheese should be coloured in the first place. Anyway, all this has put me in a mood for some mac and cheese. Made from scratch. No colour needed. Yumm!

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