When a controversy arises about a new drug or a new food additive, we often hear the phrase, "There' s no evidence that it causes any problems." Well, maybe there is no direct evidence these new drugs or food additives cause problems, but there is common sense evidence of significant risk.
Throughout evolution, humans have been consuming certain kinds of substances. Through natural selection, humans have grown accustomed to these substances. This process has tended to weed out any of the substances with negative effects.
Even substances that humans have been consuming for only a few generations - not enough time for evolution to have had a significant effect - have stood the test of time. A few generations is enough time to begin to assess the long-term health effects of the substances.
In contrast to "old" substances, evolution has not acclimated humans to new drugs and food additives. Nor has it been possible, in most cases, to assess the long-term impact of these substances. It is certainly conceivable that any particular new drug and food additive is not harmful, but there is definitely a significant risk.