When it comes to your lungs, a couple of drinks a day may help keep the doctor away, researchers report.

Though considerable evidence has mounted that a daily dose of alcohol helps the heart, this study suggests the same may be true for lung function -- even for smokers.

"This is the biggest study that's ever looked at the possible protective effect of alcohol involving the lung," noted study author Dr. Stanton T. Siu, chief of pulmonary medicine at Kaiser Permanente Hospital in Oakland, Calif.

"We found that if you drank less than two glasses of alcohol per day of wine, beer, or hard liquor that you had much less likelihood of developing obstructive airways disease, which includes asthma and emphysema," he said.

"You do seem to get some benefit if you drink three to five drinks per day," added Siu. "But it wasn't as good if you drank just a little. And if you drank six or more, it actually had a bad effect. It made your lung function worse."

Siu was to present his findings October 24 at the American College of Chest Physicians annual meeting, in Chicago.

Previous studies have indicated that other dietary interventions -- such as consuming vitamin D supplements -- might offer some measure of protection against developing lung health problems.

For the current study, Siu and his colleagues analyzed the health records of almost 178,000 patients living in northern California. All had undergone exams between 1964 and 1973 as members of the same local health plan.

Exam questionnaires completed at the time recorded their smoking and drinking habits, as well as their lung function histories.

According to the surveys, 61 percent said they had already experienced some kind of cardio-respiratory illness.

An almost identical percentage said they drank less than two alcoholic drinks per day, while eight percent consumed three to five drinks daily. Just over two percent said they drank six or more glasses per day. A little more than 21 percent said they consumed no alcohol at all.

As part of their exams, all the patients also underwent a range of pulmonary function tests (PFT) designed to gauge how well a person inhales, exhales and transfers oxygen from the lungs into the bloodstream.

Stacking PFT results alongside drinking rates, Siu's team found that so-called "light to moderate drinkers" -- those who did not abstain altogether but consumed less than two glasses of alcohol per day -- were the least likely to have problems with lung function.

The relationship between moderate drinking and healthy lungs appeared to hold up regardless of smoking habits or a previous experience of lung and/or heart disease.

The survey records had not broken down alcohol consumption according to type of alcohol consumed, so it's not possible to tell from this study if any category of drink is healthier for the lungs than another.

Siu said light drinking's protective effect roughly translates to a 20 percent reduction in the risk for developing lung disease. The link between alcohol use and lung health held steady across all ethnic groups, all age groups, and for both men and women, he added.

"There was a little more of a positive impact for women," Siu said, "but not a huge difference. And, in fact, when we looked at three to five drinks per day, then the men did better than the women."

A second study, also presented at this week's meeting, found that vitamins might help keep lungs healthy, too.

In this instance, a team of researchers from Bangladesh, led by Kazi S. Bennoor from the National Institutes of Diseases of Chest and Hospital, followed a group of 200 healthy smokers between the ages of 30 and 50 for two months. They divided the participants into four groups: those told to consume 10,000 IUs daily of vitamin A; those taking 500 mg daily of vitamin C; those taking 200 mg daily of vitamin E; and those taking all three of the vitamins in combination.

All the patients had smoked cigarettes for at least 11 years.

Lung performance tests were conducted at the start of the study, at the two-month mark (when all vitamin supplementation was stopped), and six months following vitamin cessation. A fifth group of 50 healthy non-smokers who took no vitamin supplementation was also similarly examined for lung function.

Although none of the smokers achieved lung health comparable to that of the non-smoking group, Bennoor's team found that vitamin supplementation did significantly improve lung function in all four smoking groups.

No one vitamin appeared to positively impact lung health any more than another, but the group taking all three vitamins seemed to derive the biggest benefit.

However, six months after going off a vitamin regimen, the lung health of all the smokers reverted back to levels that were below those seen after two months of supplementation.

It's possible that antioxidant supplementation might help improve lung function, the team speculated, but such improvements are not retained when supplementation stops.

Dr. Neil Schachter, professor of pulmonary medicine and medical director of the Respiratory Care Department at Mount Sinai Medical Center, New York City, was a bit cautious on the results of both studies.

"These are interesting studies," he said. "But, first of all, there is simply not that much literature on alcohol and lung function. So, yes, there is this thought that one or two glasses of alcohol is good for your heart and too much is not good for your health in general. And I guess their findings go along with that general statement. But, nevertheless, I'd say the jury is still out."

"On the other hand, there's a lot of literature on vitamin supplementation as it relates to chronic lung disease," Schachter added. "There is a lot of evidence that diets loaded with what are considered healthy nutrients -- fruits, grains, those kind of things -- are associated with better lung health than those that are not. But attempts to supplement diets with vitamins in order to improve lung health have not been terribly successful. And this vitamin study was very, very small."

"So, while I understand that certainly people would much rather make themselves well with diet than they would with medication, it's important to recognize that this is very hard research to do," Schachter said. "So far, the attempts to sort of pluck out the ingredients that we think are the keys ones haven't been very successful. Much more work is needed," he added.

(Agencies via China Daily October 25, 2007)