Phenolic antioxidants: Health Protection Branch studies on butylated hydroxyanisole.

Synthetic phenolic antioxidants have been added to foods for decades to retard the autooxidation of lipid that leads to rancidity. The major antioxidants, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), are used in foods world wide. Recent studies suggest that BHA, and perhaps BHT, are carcinogenic to rodents. International efforts, including those at the HPB in Ottawa Canada, have helped place the results of the chronic rodent studies into perspective. It seems likely that the neoplastic effects observed at very high dietary levels of BHA and BHT occur only after effective biological defense mechanisms are overloaded. The renewed interest in the toxicity of phenols is beneficial to an understanding of the complex biological effects of naturally occurring phenolics, including reduction of the levels of reactive oxygen species that are associated with various disease states in an aging human population.