Caffeine

(Reuters Health) - Women with heart disease who down a few cups of coffee each day tend to live as long as those who avoid the beverage, a large study finds.

The results was reported in the American Journal of Clinical Nutrition. In theory, coffee could be problematic because it has caffeine and other compounds that can raise blood pressure or have other negative effects on the cardiovascular system. But some studies have found that coffee drinkers have no increased risk of a second heart attack or premature death. A few others have even hinted at protective effects from coffee.In this study, which followed nearly 12,000 U.S. nurses with a history of heart disease or stroke, those who regularly drank caffeinated coffee were no more likely to die than non-coffee-drinkers during the study period - which for some was more than 20 years.

Researchers found no link between a woman's coffee intake and her risk of death from heart attack, stroke or any other cause. And that was true even of women who downed four or more cups per day."What this study shows is that, in a general population, there's no obvious harm, or benefit, to consuming coffee after a heart attack," said Ahmed El-Sohemy, an associate professor at the University of Toronto who has studied coffee intake and heart health. The problem is that certain individuals may benefit from some caffeine, while others may be harmed, according to El-Sohemy, who was not involved in the new study.Some research, for example, has linked coffee drinking to increased risks of high blood pressure in people who are naturally "slow metabolizes" of caffeine. But the reverse pattern has been seen in people who quickly process caffeine: more coffee, lower heart risks.

The findings, Lopez-Garcia said, "support the idea" that people with heart disease who already drink coffee do not have to give it up. But she also advised checking with your doctor, particularly if you have uncontrolled high blood pressure or other conditions that could be aggravated by caffeine -- like sleep problems or anxiety.

El-Sohemy was even more cautious. It is hard to make individual recommendations on safe coffee intake, according to the researcher, because of genetic variations in people's caffeine metabolism. "I don't see how any results can be interpreted from studies that don't take this genetic difference into account," El-Sohemy said. Tests for genetic variations in the enzyme that processes caffeine are not routinely available, he noted.

SOURCE: http://bit.ly/kUXi5R American Journal of Clinical Nutrition, online May 11, 2011.