Red wine has been touted as beneficial for cardiovascular health, but new research suggests while one glass may be healthy, two or more could actually do more harm than good over time.
Previous studies have suggested light or moderate drinking has a protective effect on the heart, and red wine was singled out as having specific benefits.
The studies found lower rates of heart disease among some European populations that regularly consume red wine.
A new study by Toronto's Peter Munk Cardiac Centre found that a single glass of red wine did have potentially helpful effects. But it also found that after two glasses, test subjects' heart rates rose and their hearts began pumping more blood than necessary.
Dr. John Floras said it may be that over time, increasing the heart rate and increasing the pumping action of the heart might be partly why heavy drinking has been shown to have adverse effects.
The study's findings are in this month's issue of the American Journal of Physiology.