Reduce your heart failure risk with coffee
A new study should provide good news to coffee drinkers. Moderate coffee consumption may reduce the risk of heart failure. Researchers affiliated with the Harvard School of Public Health and the University of Alabama published their findings online on June 26 in the journal Circulation: Heart Failure.
The researchers noted that the medical literature contains conflicting information regarding whether coffee consumption can reduce the risk of heart failure. Therefore, they conducted a systematic review and a dose-response meta-analysis of prospective (forward-looking) studies that assessed the relationship between habitual coffee consumption and the risk of heart failure. They searched electronic databases (MEDLINE, EMBASE, and Cinahl) from January 1966 through December 2011. Eligible studies were prospective cohort studies that examined the association of coffee consumption with heart failure. (A prospective cohort study is a study that follows over time a group of similar individuals (cohorts) who differ with respect to certain factors under study (i.e., coffee consumption), to determine how these factors affect rates of a certain outcome (i.e., heart failure. A meta-analysis is a compilation of several similar studies to increase the validity of the findings.)
The researchers identified five independent prospective studies of coffee consumption and heart failure risk, which included 6,522 heart failure events and 140,220 participants. They found a statistically significant J-shaped relationship between coffee consumption and heart failure. Compared to no consumption, the strongest inverse association (lowered risk) was seen with four servings per day; furthermore, a potentially higher risk was found at higher levels of consumption. There was no evidence that the relationship between coffee and heart failure risk varied by sex or by baseline history of myocardial infarction or diabetes. The cup size used in the study was a Scandinavian cup, which is about half the size of an American cup; thus, the greatest benefit from coffee consumption was found with two American cups per day.
The authors concluded that moderate coffee consumption is inversely associated with risk of heart failure, with the largest inverse association observed for consumption of four servings per day.
Take home message:
This study supports the cardio-protective effect of moderate coffee intake. It also reinforces the fact that in many lifestyle choices, moderation is the key. Individuals who drink considerably more than two American cups a day have an increased risk of heart failure compared to individuals who drink no coffee. The beneficial effect is undoubtedly due to caffeine and other sources of caffeine such as tea are alternative beverages. Decaffeinated coffee does contain some caffeine—about 50% that of regular coffee. Thus; four cups of decaf equal two cups of regular coffee.
Diabetics have an increased risk of cardiovascular disease. Coffee has been reported to lower the risk of type 2 diabetes; thus, this may play a role in coffee’s beneficial effect. Last year, UCLA researchers released the results of a study that may explain why coffee reduces the risk of Type 2 diabetes. The researchers discovered a possible molecular mechanism behind coffee’s protective effect: a protein called sex hormone-binding globulin (SHBG). SHBG regulates the biological activity of the body’s sex hormones, testosterone and estrogen, which have long been thought to play a role in the development of Type 2 diabetes. Coffee consumption increases plasma levels of SHBG, and the researchers found that women who drink at least four cups of coffee a day are less than half as likely to develop diabetes as non-coffee drinkers.
Another possible benefit of coffee consumption is of particular interest to women. According to another UCLA study published last year, drinking at least four cups of coffee per day is associated with a lower risk for endometrial cancer (cancer of the lining of the uterus). Drinking four or more cups of coffee per day was associated with a 25% relative risk reduction compared with consuming less than one cup daily.
Reference: Circulation: Heart Failure