Is coffee really bad for our heart? This is a question that coffee lovers keep asking their doctors hoping to get an answer that can allow them to drink as much coffee as possible. This is also an issue that is continuously debated over the years. Unfortunately, there is still no conclusive evidence on the connection between coffee (caffeine) and heart disease. From time to time, contradicting reports were released.

For example, a study, conducted by University of Athens and published in the American Journal of Clinical Nutrition in June 2005, found that coffee drinkers' major blood vessels were stiffer than those of non-coffee drinkers. As such, the researchers urged those people, who have high blood pressure or other risk factors for heart disease and drink more than three cups of coffee a day, to cut down on coffee consumption. On the other hand, a report, published in Circulation Journal in May 2006, showed that coffee drinkers did not have a higher risk of heart disease, even for those whose coffee intake exceeding six cups per day.

Yet another interesting research, published in the Journal of the American Medical Association in March 2006, reported that caffeine in coffee is unhealthy for some but beneficial to others, depending on a "gene" that determines how fast the chemical is metabolized. The study that was conducted by the University of Toronto on 4,024 study participants living in coffee-rich Costa Rica between 1994 and 2004. According to the research, slightly more than half of the participants had the slow version of the gene while the other half had the fast form. Individuals who had the slow-acting gene, as little as two cups of coffee a day is associated with an increased risk of heart disease: two or three cups of coffee a day increased the risk by 36% while four or more cups a day increased the risk by 64%. For those who had the fast version of the gene, there was no increased risk, even with four or more cups a day. More surprisingly, it is also found that individuals under 50 years of age who were fast metabolizers, consumption of as little as one to three cups a day was associated with a "lower risk of heart attack". Those with the fast-acting gene who drank two to three cups of coffee a day had a 22% reduced odds of having a heart attack, but consuming four or more cups a day did not further reduced the risk.

The study also revealed that the liver enzyme cytochrome P450 1A2 which is responsible for metabolizing caffeine, has slow 1F version and a fast 1A version. However, as tests to determine which form of gene one carries are not readily available, one cannot feel how fast one's body is getting rid of caffeine, it is advisable not to take more than 4 cups of coffee a day.

In general, the minor change in blood pressure due to their morning coffee is likely to be harmless for most people. However, researchers also warned that caffeine has a greater effect on blood pressure in people with a family history of hypertension or with borderline high blood pressure. If you are not sure which research is accurate or which gene you belong to, just stick to the lowest recommended one: drink 2 cups or less of coffee per day.