The lowest rate of heart failure was found in people who drink up to seven drinks a week, with men showing a 20% lower risk.
Researchers from Harvard Medical School say that, while there is already evidence for the benefit of moderate alcohol intake on the risk of developing certain heart conditions, research into a link with heart failure has been lacking.
They maintain a high intake of alcohol can be damaging: with heavy drinkers at most risk of death by any cause.
23m people affected by heart failure
Heart failure – where the heart ceases to pump blood around the body as efficiently – is a ‘major public health problem,’ with 23m people affected worldwide.
Usually heart failure occurs because the heart muscle has been damaged (for example, from a heart attack), or through disease, infections, or drugs.
The study looked at nearly 15,000 men and women in early to middle age. Participants were divided into six categories, including abstainers, former drinks, light drinkers, and heavy drinkers.
In the follow-up period, 1,271 men and 1,237 women developed heart failure. The lowest rate of heart failure was seen in the group of people who drunk up to seven drinks a week. The highest rate was seen among former drinkers.
“We observed that participants who consumed up to seven drinks a week of alcohol had a lower risk of incident heart failure compared with abstainers, with a less pronounced association in women than in men,” said Alexandra Gonçalves, one of the researchers.
One small glass of wine
A ‘drink’ was defined as containing 14g of alcohol: approximately equivalent to one small (125ml) glass of wine, half a pint of beer, or less than a shot of liquor.
After taking other factors into account (age, blood pressure, BMI, cholesterol levels, smoking habits, etc), men who consumed up to seven drinks a week showed a 20% reduced risk of developing heart failure, when compared to abstainers. For women, the reduced risk was 16%.
Former drinkers showed the highest risk of heart failure – at 19% and 17% increased risk for men and women respectively.
The researchers also looked at death from any cause. They found heavy drinkers (those consuming 21 or more drinks a week) had an increased risk of death of 47% (men) and 89% (women).
“In this community-based sample, mild alcohol consumption was associated with lower risk of incident heart failure, with a similar but less definite association in women than in men,” said Gonçalves.
“Higher amounts of alcohol intake were not associated with the risk of heart failure, but heavy alcohol intake increased the risk of all-cause mortality among men and women from this cohort. These findings suggest that, despite the dangers of heavy drinking, mild alcohol consumption in early-middle age may be associated with lowering the risk of heart failure.”
The researchers admit there was a limit to the number of very heavy drinkers in the study, while the effects of binge drinking were not considered.
Risks and benefits
“The association between moderate alcohol intake and the risk of heart failure is still controversial, as some studies do not find an association and the cardiovascular mechanisms of potential benefit of alcohol consumption in heart failure are uncertain,” said Gonçalves
“Myocardial damage [damage to heart muscle] may occur as a consequence of direct toxic effects of alcohol or its metabolites by ethanol-induced apoptosis [cell death]; associated hypertension [high blood pressure], coexisting nutritional deficiencies, or, rarely, toxic addition to alcoholic beverages.
“Conversely, the cardiovascular mechanisms of alcohol benefit in heart failure may involve the risk reduction for coronary artery disease (CAD), neurohormonal changes or blood pressure lowering.
“Importantly, the balance of risks and benefits is likely to differ in different populations and by gender and across race and age groups.”