Canadian Study warns against Wine Overdose

A Canadian study done on limited subjects in Toronto General Hospital suggests that a glass of red wine or any alcohol is beneficial for heart but more than two can be stressful for the body.

The study is entitled "Dose-related effects of red wine and alcohol on hemodynamics, sympathetic nerve activity, and arterial diameter" and has been published in the February edition of the American Journal of Physiology, Heart and Circulatory Physiology.

It was conducted on 13 volunteers to determine whether red wine with high polyphenol content differs from alcohol in its effects on specific markers associated with a greater risk of high blood pressure, coronary artery disease and heart failure.

Several earlier studies on larger subjects have suggested that moderate drinking has a protective effect on the heart; especially red wine, containing antioxidant polyphenols.

In the Toronto study conducting at the Peter Munk Cardiac Center of the Toronto General Hospital, Dr. John Floras, Director of Cardiology Research , heading the study said that tests on volunteers showed that drinking a single glass of red wine (6-glasses to a bottle) or an amount of ethanol equal to that found in a beer or a serving of spirits, had potentially helpful effects on the heart and blood vessels.

"One standard drink of both the red wine and the alcohol causes the blood vessels to dilate, which could make it easier for blood to flow through the vessels and reduce the work of the heart," he said.

"But more than two drinks turn on the nervous system. And when that happens, it results in an increase in the impulses going to the blood vessels, which act as a brake on further blood vessel dilation."

Floras said after two drinks, subjects' heart rates rose and their hearts began pumping more blood than necessary.'

Dr. Floras cautioned this study measured the effects of these drinks on one occasion only. The effects of daily wine or alcohol intake may be quite different.

Reacting to the results of the study Dr. George Fodor, head of research for the University of Ottawa Heart Institute's Minto Prevention and Rehabilitation Centre, said the findings challenge the "the nonsensical statement that the French have low levels of heart disease because they drink red wine."

The bottom line is if there is any benefit in alcohol, the range is very narrow," Dr. Fodor said on Tuesday. 'This study, I think, is a warning against trying to justify the drinking of alcohol for alleged health benefits,' he opined.

Healthy, non-smoking adults who were not heavy drinkers or total alcohol abstainers were studied. Participants attended three separate morning sessions during which "standard" drinks of red wine, ethanol or water were administered at random, single-blind, two weeks apart. A 4-oz glass of wine (120 ml- 6 glasses a bottle), and a 1.5-oz (45 ml) shot of liquor is considered to be a standard drink. All blood alcohol levels alcoholic were below .08, the normal legal limit for drivers in the US and Canada.

While agreeing the study is small, Floras said it is unique because it compares three different drinks - water, ethanol and red wine, in the same individuals.
Flora also showed concern that 'if the amount of safe drinking is repeated on a daily basis in individuals who have high alcohol consumption, they ultimately may be at higher risk of a heart attack or stroke or high blood pressure.'

This study was supported by the Heart and Stroke Foundation of Ontario, the Canadian Institutes of Health Research, and the Canada Research Chairs Program.

The study has a few drawbacks, least of which is the subject size which is too small and the period is too short. However, it is a step in the right direction and the study is not sponsored by a wine related group which vouches for its neutrality. It also does not seem to have taken the alcohol content of the wine for effects - editor




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