In 2004 a University in South Hampton found that there is a direct link between food colourings and preservatives and increased hyperactive behaviour in children. Some of the most common colourings found in foods include the following: 1. Tartrazine* 2. Quinoline Yellow E104 3. Brilliant Blue E133 4. Sunset Yellow E110 5. Carmoisine E122 6. Ponceau 4R E124 7. Indigo Carmine E132 * Tartrazine is a synthetic yellow dye found in products including squash, cordial, fizzy drinks, cake mixes, custard powder, soups, sauces, ice cream, ice lollies, sweets, chewing gum, marzipan, jam, jelly, marmalade, mustard, yoghurt. Also look out for it popping up in medicinal capsules. The Hyperactive Children's Support Group (hacsg.org.uk) believes this additive can cause hyperactivity in children. These children are at risk of continuing behavioural difficulties, such as poor social adaptation and educational problems. (source: Organix)

Another criticism--and you can decide for yourself how valid it is--is that food colorants "train" kids to choose brightly-colored foods over more "natural" versions.  Anyone who has ever made fresh juice at home knows that store-bought orange juice is brighter, store-bought grape juice is more "purple", etc.

There's already considerable evidence that kids and young adults are eating fewer fresh fruits and vegetables than any other generation in recorded history.  (USDA 2009).  Much of that is being blamed squarely on fast food and convenience foods like cold cereals, pre-packaged lunch kits and sports drinks.

Every thing that is away from nature and is artificial has its short comings. They can cause harm to health.