From CommonDreams.org

The overwhelming majority of our additive intake today has been part of the diet of humans for generations: yeast, salt, sugar, baking powder. But thousands of other additives, derived from both natural and synthetic sources, have recently become commonplace in western eating. What are these substances doing to our bodies and our minds? We are just beginning to find out.

A study published today by Southampton University, into the impact of additives on groups of three-year-olds and eight-year-olds, produced some alarming results. The Food Standards Agency-commissioned report found a link between hyperactivity among children and certain food colourings, as well as a preservative used in sweets, drinks and processed foods in the UK.

We are only just beginning to learn the impact of synthetic additions to what we eat. The industrialisation of the food supply has turned consumers into the unwitting subjects of a vast, ongoing scientific experiment.

Spices and preservatives have been added to foods for millennia in order to make them last longer and taste better. And there is a long history of using additives to mislead consumers, with various chemicals employed to supply taste, enhance colour and disguise the aroma of spoiled meats. Before the advent of federal food safety laws in the United States, dangerous heavy metals were routinely used as colouring agents in children's sweets.

It would be hard to find a processed food on a supermarket shelf (or on a fast food menu) that does not contain a vast array of chemical additives. Indeed, the packaged food industry and the fast food industry are dependent on the use of such additives to prevent spoilage, to allow the transport of products long distances, and to maintain uniformity. Any finding that such additives pose a threat to human health will threaten the financial health of these industries. And that is why so few large-scale studies have been conducted. The absence of adequate information greatly benefits the producers of industrial food.

In the United States there is an extremely cosy relationship between the food industry and the government agencies that are ostensibly regulating it. Until a few years ago, the head of the food and drug administration - our version of the Food Standards Agency, responsible for the safety of most of the food that Americans eat - was a former executive vice president of the national food processors association. Similarly close ties between industry and government can be found in the European Union. As a result, hundreds of food additives are never tested for harmful effects. And the risks posed by consuming a variety of additives in combination are rarely explored.

I don't think that people should feel panicky about food additives or succumb to the latest food scare. The best advice is probably caveat emptor. We simply don't know what effect these things are having on us. And government food safety agencies don't seem eager to find out. "Food additives play a vital role in today's bountiful and nutritious food supply," the US food and drug administration claimed in a brochure some years ago. "They make possible an array of convenience foods without the inconvenience of daily shopping."

Perhaps a little less convenience, and a lot more unprocessed food, would be the wise course.

Eric Schlosser is the author of Fast Food Nation: What the All-American Meal Is Doing to the World, and Chew on This: Everything You Don't Want to Know About Fast Food comment@guardian.co.uk