Even avid supporters of moderate drinking temper their recommendations with warnings about the dangers of alcohol, which has been tied to breast cancer, accidents, liver disease, cancers, heart damage and strokes.

“It is very difficult to form a single-bullet message because one size doesn’t fit all,” said Dr Arthur L Klatsky, a cardiologist in Oakland, California, who wrote a landmark study in the early 1970s finding that members of the Kaiser Permanente healthcare plan who drank in moderation were less likely to be hospitalised for heart attacks than abstainers.

“People who would not be able to stop at one to two drinks a day shouldn’t drink and people with liver disease shouldn’t drink,” Klatsky said. On the other hand, “the man in his 50s or 60s who has a heart attack and gives up his glass of wine at night — that person is better off being a moderate drinker.”

Health organisations have phrased their recommendations gingerly.

The American Heart Association says people should not start drinking to protect themselves from heart disease. The 2005 US dietary guidelines say “alcohol may have beneficial effects when consumed in moderation.”

The association was first made in the early 20th Century. In 1924, a Johns Hopkins biologist, Raymond Pearl, published a graph with a U-shaped curve, its tall strands on either side representing the higher death rates of heavy drinkers and nondrinkers; in the middle were moderate drinkers, with the lowest rates. Dozens of other observational studies have replicated the findings, particularly with respect to heart disease.

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