Methods for health risk assessment of chemicals: are they relevant for alcohol?

A description is given of the principles used for toxicological risk assessment of food additives and environmental contaminants. The terminology is not generally accepted. Hazard identification is to identify whether a substance may cause toxic effects in man. Dose-response assessment is to understand the relationship between exposure and various toxic effects. The shape of dose-response curves is discussed. For most effects (including nongenotoxic carcinogens), a threshold is assumed, under which there is no risk. For genotoxic compounds, no such threshold is assumed. For substances with a threshold, an uncertainty factor is applied to the no-observed-adverse-effect level or the lowest-observed-adverse-effect level, to arrive at an acceptable or tolerable daily intake. In the case of ethanol, some of these principles of toxicological risk assessment may be used and based on epidemiological dose-response data. The critical effects are liver effects, fetal damage, and cancer. All of these effects may be assumed to have thresholds. Possible uncertainty factors are discussed. However, because of the decreased risk of cardiovascular effects at low/moderate intakes and the fact that alcohol intake is a lifestyle factor, it is doubtful whether the application of a no-observed-adverse-effect level/uncertainty factor approach--as used for food additives and environmental pollutants, to which there is unavoidable exposure--is really applicable or meaningful for ethanol.