AMHERST, Mass., Dec. 27 (UPI) -- A new study of U.S. National Cancer Institute data suggests that the traditional way to evaluate drug tests and toxin evaluations is wrong for very low doses.
The data review was led by Edward J. Calabrese of the University of Massachusetts at Amherst. Calabrese and colleagues examined information from more than 56,000 tests of 2,200 drugs on 13 strains of yeast and concluded that the results strongly supported the theory of hormesis, which says that low doses have the opposite effect of high doses. For example, the team found that high doses of anti-cancer drugs frequently inhibited yeast growth but enhanced it at low doses. Since most drug and toxin tests use very high doses and humans are normally exposed to low doses in the environment, Calabrese thought the data could have profound public policy and health implications.
"I believe that hormesis ... is the fundamental dose-response (model) and government testing and risk assessment procedures should reflect that," Calabrese said. He cited environmental regulations, where it has been assumed that most carcinogens possess real or theoretical risks at low levels and must be completely removed from the environment, and the pharmaceutical industry, where lifesaving drugs have been missed under traditional testing procedures and medication dosing may be distorted.
Calabrese said other scientists want more evidence about additional factors that can influence the effects of chemicals at low doses, such as toxic buildup, before they embrace hormesis and stand behind the kind of radical change that will result if it is accepted and says he welcomes the interest and the debate.
For more information, see the December issue of the journal Toxicological Sciences.