A daily glass of red wine is good for your heart

What actually happened

The protective J-curve came from observational studies comparing moderate drinkers to non-drinkers. The flaw is who ends up in the non-drinking group: it quietly includes former heavy drinkers and people who quit because they were already sick, the 'sick-quitter' effect. Moderate drinkers, meanwhile, tend to be wealthier, more active, and in better health to begin with. Studies that correct for these biases, including large 2022–2023 analyses, see the supposed benefit shrink toward nothing.

Against that faded upside sits a hard downside. The International Agency for Research on Cancer classifies alcohol as a Group 1 carcinogen, the same category as tobacco and asbestos, and it is causally linked to at least seven cancers, including breast and bowel. Risk for these rises from the very first drink, with no threshold below which it is absent.

So the WHO's 2023 position is not a stricter version of the old advice; it inverts it. The claim that a daily glass actively improves your health does not survive careful study, which is why national guidance in several countries has been cut sharply. 'A little is good for you' has become 'less is better, and none is safest.'