Alcohol is especially good for the heart because it causes minor stresses in the cells—and this is a harmless way to 'teach' the heart how to respond should it ever come under life-threatening stress, such as from a heart attack.
Drinking activates a mitochondrial enzyme known as ALDH2 (aldehyde dehydrogenase-2), which helps rid the heart of toxic by-products from the alcohol and triggers a molecule in heart cells that helps protect them from major damage, as can happen when there's a heart attack.
The ethanol in alcohol starts this protective process, and "when the cells are submitted to a higher level of stress, they know how to deal with it," said researcher Julio Ferreira from the University of Sao Paulo.
The effect could halve the number of deaths from heart attack, the researchers estimate after testing laboratory mice with a drug that stimulates ALDH2 in the same way that ethanol does. The rate of deaths from a heart attack was 70 per cent but fell to 35 per cent in the mice with higher levels of the enzyme.