A Rainbow of Risks
Sarah Kobylewski, Ph.D. CandidateMolecular Toxicology Program University of California, Los Angeles
Michael F. Jacobson, Ph.D.
Center for Science in the Public Interest
Copyright © 2010 by Center for Science in the Public Interest First Printing June 2010
Printing: 5 4 3 2 1
Food dyes, synthesized originally from coal tar and now petroleum, have long been controversial. Many dyes have been banned because of their adverse effects on laboratory animals. This report finds that many of the nine currently approved dyes raise health concerns.
Blue 1 was not found to be toxic in key rat and mouse studies, but an unpublished study suggested the possibility that Blue 1 caused kidney tumors in mice, and a preliminary in vitro study raised questions about possible effects on nerve cells. Blue 1 may not cause cancer, but confirmatory studies should be conducted. The dye can cause hypersensitivity reactions.
Blue 2 cannot be considered safe given the statistically significant incidence of tumors, particularly brain gliomas, in male rats. It should not be used in foods.
Citrus Red 2, which is permitted only for coloring the skins of oranges not used for processing, is toxic to rodents at modest levels and caused tumors of the urinary bladder and possibly other organs. The dye poses minimal human risk, because it is only used at minuscule levels and only on orange peels, but it still has no place in the food supply.
Green 3 caused significant increases in bladder and testes tumors in male rats. Though the Food and Drug Administration (FDA) considers it safe, this little-used dye must remain suspect until further testing is conducted.
Orange B is approved for use only in sausage casings, but has not been used for many years. Limited industry testing did not reveal any problems.
Red 3 was recognized in 1990 by the FDA as a thyroid carcinogen in animals and is banned in cosmetics and externally applied drugs. All uses of Red 3 lakes (combinations of dyes and salts that are insoluble and used in low-moisture foods) are also banned. However, the FDA still permits Red 3 in ingested drugs and foods, with about 200,000 pounds of the dye being used annually. The FDA needs to revoke that approval.
Red 40, the most-widely used dye, may accelerate the appearance of immune-system tumors in mice. The dye causes hypersensitivity (allergy-like) reactions in a small number of consumers and might trigger hyperactivity in children. Considering the safety questions and its non-essentiality, Red 40 should be excluded from foods unless and until new tests clearly demonstrate its safety.
Yellow 5 was not carcinogenic in rats, but was not adequately tested in mice. It may be contaminated with several cancer-causing chemicals. In addition, Yellow 5 causes sometimes-severe hypersensitivity reactions in a small number of people and might trigger hyperactivity and other behavioral effects in children. Posing some risks, while serving no nutritional or safety purpose, Yellow 5 should not be allowed in foods.
Yellow 6 caused adrenal tumors in animals, though that is disputed by industry and the FDA. It may be contaminated with cancer-causing chemicals and occasionally causes severe hypersensitivity reactions. Yellow 6 adds an unnecessary risk to the food supply.
Almost all the toxicological studies on dyes were commissioned, conducted, and analyzed by the chemical industry and academic consultants. Ideally, dyes (and other regulated chemicals) would be tested by independent researchers. Furthermore, virtually all the studies tested individual dyes, whereas many foods and diets contain mixtures of dyes (and other ingredients) that might lead to additive or synergistic effects.
In addition to considerations of organ damage, cancer, birth defects, and allergic reactions, mixtures of dyes (and Yellow 5 tested alone) cause hyperactivity and other behavioral problems...