Health authorities in many countries have disseminated ‘low risk’ or ‘sensible drinking levels’, suggested maxima for personal consumption of alcohol usually expressed in ‘units’, or standard drinks, of alcohol, though there is wide variation between what constitutes a unit and how many of them may safely be consumed.
These limits are at best only a rough guide as individuals’ reactions to alcohol must always be taken into consideration when assessing recommended consumption levels. Sex, age, build, genetic make-up, state of health, drinking with or without food, and drug intake all affect the way alcohol is metabolized. For instance, glass for glass, women, regardless of their weight or size, absorb relatively more alcohol than men because of differences in levels of stomach enzymes, their lower body water content meaning that alcohol is more concentrated in their tissues and, if they are also taking the contraceptive pill, more slowly eliminated. This may explain why women who drink in excess of the recommended daily units experience significantly greater risks of poor health outcomes than men who do likewise. Additionally, women’s tissues are more susceptible to the damaging effects of alcohol. Conversely, it appears that the relationship between moderate consumption and better general health is stronger for women.