(CNN) If you are living with heart disease, having a small amount of alcohol each day is linked to a lower risk of having another heart attack, stroke, angina (heart pain because of constricted arteries) or an early death, according to a new large study.
"This is not the general population -- the study applies to people who have already had something happen that relates to cardiovascular health," said alcohol researcher Emmanuela Gakidou, who is senior director of organizational development and training at the Institute for Health Metrics and Evaluation at the University of Washington.
"And what they find is that if you continue to drink after you've had a cardiac event, it's not that bad for you, as long as you keep consumption low," said Gakidou, who was not involved with the study.
When compared with people who do not drink at all, the study found drinking up to 105 grams of alcohol each week -- the equivalent of just over a bottle of wine or a six-pack of medium strength beer -- appeared to protect people who had already suffered a heart problem from having another occurrence or an early death.
That's much less than the recommended upper drinking limit set by the World Health Organization for men and women (166 grams per week) or the limit for men currently recommended in the United Statues (196 grams per week).
However, the most benefit came from drinking less than half that amount, according to the study published Monday in the journal BMC Medicine.
"Our findings suggest that people with CVD (cardiovascular disease) may not need to stop drinking in order to prevent additional heart attacks, strokes or angina, but that they may wish to consider lowering their weekly alcohol intake," said study author Chengyi Ding, a postdoctoral student at University College London, in a statement.
But this finding would not apply to everyone, as drinking alcohol raises the risk for certain diseases such as cirrhosis, tuberculosis and cancer and for alcohol-related accidents and injuries, Gakidou said.
"If your main health condition risk is cancer, then the safest level of drinking is probably zero," Gakidou said. "And if you're younger than 40-years-old or so, the safest level of alcohol is still zero because younger adults die from injuries related to alcohol around the world."
In what researchers are calling the largest study to date to examine the risk of alcohol use in people with existing cardiovascular disease, data was collected from over 14,000 people who had already had a heart attack, stroke or angina and who were followed for up to 20 years. Results from an additional 12 studies was added to the analysis to make a combined sample of over 48,000 people.
The new study found the lowest risk occurred when people with existing heart conditions drank from 6 to 8 grams of alcohol per day (42 to 56 grams a week). People who drank 8 grams of alcohol a day had a 27% lower risk of a second cardiovascular event compared with people with heart disease that did not drink.
But when people drank a bit less -- only 6 grams of alcohol a day -- the benefit almost doubled. They had a 50% lower risk of having another heart attack, stroke or episode of angina than those who did not drink.
That's not a lot of booze at one sitting. In the United States, that would be about a half a glass of regular beer or wine or 0.75 ounces of distilled spirits.
In the UK, where a standard unit of alcohol is 10 milliliters or 8 grams, it's a bit more complicated. For example, "a pint of strong lager contains 3 units of alcohol," according to the UK's National Health Services. So 6 grams of alcohol would only be a third of a pint of strong lager a day.
For decades, a "drink a day" was considered fine by public health standards because many similar studies over the years found a positive association between moderate drinking and a reduced risk of heart disease, the world's leading killer. In fact, most health organizations still allow one to two drinks a day for men and one or fewer drinks a day for women as part of their dietary guidelines.
Other studies also found a connection between moderate drinking and a reduced risk of Type 2 diabetes, a growing epidemic globally.
But all along, there were practical problems. After all, many people pour heavy and end up adding much more than a "standard" or "unit" of alcohol to their mixed drink. The arrival of "gravity" beers and wines with much higher than normal levels of alcohol also compounded the issue. Just how much alcohol were people really drinking in that "one to two" drinks?
Another issue: Just how truthful are people when they tell study researchers how much they drink?
"A 60-year-old male in Greece and 75-year-old woman in Germany -- who knows what they have in mind when they're answering that question," the IHME's Gakidou said. "The probability that someone is going to answer truthfully and factually is likely zero."
Research began to show a connection between drinking and the development of dementia, liver disease, high blood pressure, osteoporosis, digestive disorders and cancer, another leading killer.
Add to that the global toll drinking has on the loss of life from accidents and injuries, and the message for the masses was that no amount of alcohol was beneficial for health.
'While some studies have found improved health outcomes among moderate drinkers, it's impossible to conclude whether these improved outcomes are due to moderate alcohol consumption or other differences in behaviors or genetics between people who drink moderately and people who don't," according to the US Centers of Disease Control and Prevention.
Gakidou, who authored a 2016 study that concluded no amount of alcohol was safe, told CNN that research since she published her study is beginning to hone in on more specifics about how alcohol contributes to illness. Soon, she says, we may even know how alcohol raises -- or lowers -- the risk of individual diseases by age, gender and country or region that people live in.
"We may be able to say 'If you are a 30-year-old male living in Sub-Saharan Africa or in Europe or Southeast Asia, here is your safest level of drinking.' And then if you're a 60-year-old female living in these regions, what is your safest level of drinking," Gakidou said.
Until science discovers exactly how alcohol interacts with all the various diseases and conditions that affect us, there's one thing public health organizations agree on: If you don't drink, don't start -- even if you have a heart condition.
The CDC states current guidelines "do not recommend that individuals who do not drink alcohol start drinking for any reason." The agency says those who should avoid alcohol completely include:
And if adults of "legal drinking age choose to drink alcoholic beverages, drinking less is better for health than drinking more," the CDC states.