Two food dyes – tartrazine and erythrosine, better known as Yellow 5 and Red 3 – were found to cause kidney damage in test animals.

A coalition of seven scientists from universities and medical centers in Nigeria published their results in the journal Toxicology Mechanisms and Methods in January.  Like most synthetic dyes, Yellow 5 and Red 3 are created from petroleum and are legally permitted to contain the toxic contaminants lead, mercury, and arsenic.  Of the seven dyes still permitted to be added to food in the United States, yellow and red are used in the greatest amount.

These additives have been found to cause damage to the body and in many ways, but it wasn’t until the 1970s that they received a great deal of attention and would become the subject of many studies.  The widely used Yellow 5 was found to trigger a wide range of health problems, from asthma and hives to anaphylactic shock.  Red 3 was found to cause thyroid tumors in mice, and despite the fact that this required the government to ban its use, the dye continues to be added to foods and non-food products.

But the reaction that has attracted the most attention is the effect these chemicals have on behavior – particularly the behavior of children.

By the 1970s pediatricians were seeing a growing number of children who were overactive – generally referred to as “hyperactive.”  Brain damage was ruled out as a cause and doctors were perplexed.  It was the chief of allergy at the Kaiser-Permanente Medical Center in San Francisco who discovered the most likely reason so many children were having problems was that food manufacturers were adding an increasingly large amount of synthetic additives to foods, especially those products designed to appeal to children.  With a distinguished career in both pediatrics and allergy, Ben Feingold, M.D., recognized that a person could be sensitive to virtually anything in our food, water or air.  But of all the potential offenders, synthetic chemicals were a likely culprit since the increase in hyperactivity coincided with the increase in the use of additives like food dyes.  He designed a simple test where the synthetic dyes and several other additives would be excluded for a few weeks and parents would look for changes in the child’s symptoms.

The media named the regimen the “Feingold Diet’ and wrote extensively about the rapid improvement many parents were seeing.  Grateful families in the United States and abroad formed nonprofit support groups to help other families wishing to use the program.  See for information.  Although food dyes and other unwanted additives continue to be used in many products, manufacturers have seen that there is a growing market for families who want their food to contain just food – not unpronounceable chemical additives.