In the U.S., there are seven FDA-approved, mostly petroleum-derived food dyes currently in use: Blue 1, Blue 2, Green 3, Red 40, Red 3, Yellow 5 and Yellow 6.
The three most widely-used colors – Red 40, Yellow 5 and Yellow 6 – contain known carcinogens, and the FDA has admitted that Red 3 is a carcinogen as well.
According to the Center for Science in the Public Interest, studies have found that Blue 2, which is made of coal tar, causes brain cancer in male rats, while Red 3 gave lab rats thyroid tumors.
Yellow 5 can not only cause allergy-like hypersensitivity reactions, but can also be contaminated with cancer-causing substances. Yellow 6 has been implicated in tumors of the adrenal gland and kidney.
