Current research is working towards providing the direct link from artificial dyes to autism, sleep disturbances and other chronic problems in children. Previous studies show links to artificial dyes and cancer, hyperactivity, ADHD, allergies, and sterility.  http://melisann.hubpages.com/hub/Know-Which-of-Your-Vitamins-and-Medicines-Contain-Toxins

Each dye can be traced to its own set of possible side effects:

http://www.cspinet.org/reports/chemcuisine.htm

Blue Dye No. 1 can cause hyperactivity, skin rashes, bronchoconstriction – especially when combined with other artificial colors- and chromosomal damage. It may also cause issues with the gastrointestinal tract while inhibiting cell respiration and lead to ADHD, asthma, and other allergic reactions. (This dye is banned in Austria, Belgium, France, Germany, Norway Switzerland, and Sweden.) New studies show that Blue Dye is also absorbed through the skin. http://www.ncbi.nlm.nih.gov/pubmed/23127598

Blue Dye No. 2 is a synthetic coal tar dye commonly added to pharmaceutical drugs and is also used as a medical diagnostic aid.  The dye, which is banned in Norway, has been known to cause nausea, vomiting, high blood pressure, skin rashes, breathing problems, brain tumors and other allergic reactions.

Green Dye No. 3 is linked to tumors and gene mutations in test animals.

Red Dye No. 40 is a petroleum byproduct often used in medications and supplements that can cause allergy-like reactions, hyperactivity in children and potential cancer. Asthmatics and those intolerant to aspirin are at increased risk of a reaction to this dye, which is prohibited throughout Europe. http://www.npr.org/2011/03/30/134962888/fda-probes-link-between-food-dyes-kids-behavior

Red Dye No. 3 has been shown to cause cancer in lab animals.

Yellow Dye No. 5 is one of the most dangerous artificial colors.  Derived from Coal Tar, the dye is linked to cancer and provokes asthma attacks, skin reactions, and hyperactivity in children. It has been banned in Norway, Austria, and Finland.

Yellow Dye No. 6 is linked to hyperactivity, allergic reactions, nausea, and nasal congestion. It is often used in medications and supplements Yellow Dye #6 is banned in Finland, Norway, and the UK.

Unfortunately, these reactions and their connections to artificial food dyes have largely been dismissed by the FDA.  In 2004, an analysis of fifteen studies found evidence that artificial colors worsen the behavior of children with ADHD.  Even after studies found that artificial dyes affect the behavior of children without behavioral disorders, the FDA continues to deny any significant link between food dyes and behavioral problems.

By eliminating food dyes and food additives, studies have continuously shown increased improvements in children’s behavior.