In the past, research has not shown any link between Attention Deficit Hyperactivity Disorder and food dyes. Newer studies show that synthetic preservatives and artificial coloring agents can make the symptoms of ADD and ADHD worse. The older studies were inclonclusive on this point, perhaps because the clinical methods of measuring this behavior were inappropriate. Parents' reports of food additives proved to be better indicators whether additives were present than clinical tests. Several major studies show academic performance increased and disciplinary problems decreased in large non-ADD student populations when artificial ingredients and artificial coloring were eliminated from school food programs.

This criticism originated during the 1950s. As a result, many foods that used dye (such as red velvet cake) became less popular.

Researchers at King Feisal University state that the use of synthetic color in various foods has adverse effects on some of biochemical analysis, specifically at high concentration and when administered for long periods of time. Changes in liver and kidney histopathological structure and increases in white blood cell count indicated that inflammation is specific to certain colorants.

See also: https://en.wikipedia.org/wiki/Food_coloring

Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License and Creative Commons Attribution-ShareAlike License.)