The study of Japanese men years found that moderate to light alcohol consumption, coupled with high levels of social support, were linked to lower rates of heart disease and stroke.

"But remember," Dr Hiroyasu Iso from Osaka University noted in a statement, "this beneficial effect of social support is confined to light-to-moderate drinking. Heavy drinking is risky irrespective of social support level."

In a report in the journal Alcoholism: Clinical and Experimental Research, the researchers note that light to moderate drinking has been shown to help protect against stroke and heart disease. Being surrounded by lots of family and friends is also known to be good for the heart and may even help people live longer.

The new study, Iso and colleagues say, shows that high levels of social support may enhance the heart-healthy effects of light to moderate alcohol consumption.

Iso's team examined drinking patterns, social support and cardiovascular health of 19,356 men in their 40s, 50s and 60s who were enrolled in the Japan Public Health Centre-based Prospective Study. Their alcohol consumption was classified into seven categories: never, past, occasional, 1 to 149, 150 to 299, 300 to 449, or 450 or more grams of alcohol per week.

During an average follow up of more than 9 years, 629 strokes and 207 coronary heart diseases were documented in the men.

Confirming past studies, heavier drinking (ie 300 grams per week or more) was associated with an increased risk of stroke. This may be explained at least partly by alcohol-induced high blood pressure, the researchers say.

In contrast to heavy drinking, light to moderate drinking – up to 299 grams of alcohol per week – was associated with reduced risks of stroke and heart disease, and the effect was more pronounced in men with high levels of social support, "probably due to avoidance of unhealthy behaviours and enhancement of stress buffering," Iso surmised.

Compared with light to moderate drinkers with high social support, those with low social support had unhealthier lifestyle behaviours; they were more apt to be sedentary and had fewer opportunities for medical checkups. They were also more likely to have high stress levels, no job, and no spouse.