Can I buy you a drop? A perspective on communicating cancer risk from alcoholic beverages

Consumption of alcoholic beverages is common around the world, and its risks and benefits continue to be debated. In the last several years, meta-analyses of human epidemiological data have provided strong evidence for risk of alcohol-associated cancers at seven body sites. It is now well accepted that several cancers are associated with alcohol consumption, and that risk increases with dose. In publications of epidemiological studies, statements like, "…the safest level of drinking is none" (Lancet 2018; 392: 1015-1035) have been interpreted to mean that any level of alcoholic beverage consumption is harmful. An official of the World Health Organization-Europe declared that "It doesn't matter how much you drink - the risk to the drinker's health starts from the first drop of any alcoholic beverage." Recently, "one-drop" statements like this have been echoed by news outlets and in social media posts. If such pronouncements are unfounded, potential outcomes are that they raise unnecessary fear and hysteria among the alcohol-consuming public and sow distrust of respected sources. This commentary addresses the likelihood that very small amounts (e.g. one drop) of alcohol increase cancer risk. Examples of results from meta-analyses of human epidemiological studies that link alcohol consumption with human cancers are presented, with a focus on dose-response relationships. Next, what animal and in vitro studies suggest about alcohol-associated cancer thresholds is discussed. Thirdly, alcohol contents in common foods and production of alcohol from intestinal fermentation are explored, and how exposures from these compare to one drop of an alcoholic beverage is addressed. Finally, comments are offered on the consequences of issuing unsupported claims of cancer risk from consuming alcoholic beverages in moderation, and perspectives are shared on the responsibilities of researchers, public health agencies and the lay press to issue pronouncements that are evidence-based.