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
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
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,'
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
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