Regular coffee consumption does not appear to affect men’s erections, but decaffeinated coffee intake might, suggests a recent study in the American Journal of Epidemiology.
The caffeine, antioxidants, and anti-inflammatory compounds in coffee are thought to have several health benefits, but their role in urological conditions has been unclear.
A previous study using data from 2001-2004 the National Health and Nutrition Examination Survey found that drinking two to three cups of coffee daily lowered a man’s risk for erectile dysfunction (ED). But this study’s cross-sectional design and small number of participants (3,742) prompted another team of researchers to explore the issue further.
They analyzed data from the Health Professionals Follow-up Study (HPFS) involving 21,403 men between the ages of 40 and 75 (median age 62) for a follow-up period of 10 years. Participants answered questions about their erectile function and their dietary habits. Other health and lifestyle characteristics, including obesity, diabetes, hypertension, smoking status, alcohol consumption, and marital status were assessed as well.
Thirty-four percent of the men self-reported ED. In 1998, 65% said they drank at least one cup of coffee – regular or decaffeinated – each day. Eleven percent reported drinking four or more cups. Coffee intake remained similar over time.
After adjusting for cardiovascular disease and lifestyle risk factors, the researchers found no statistically significant associations between coffee intake (total or regular) and ED.
When they compared the results of men who consumed the least and most amounts of decaffeinated coffee, they discovered a 37% increased risk of ED. This finding was especially strong for men who smoked.
The authors advised caution when interpreting the results for decaffeinated coffee drinkers, noting that only 0.9% of these men drank four or more cups a day. They added that there is “no strong biological plausibility between decaffeinated coffee intake and ED” (although there could be “deleterious chemical compounds” added during the decaffeination process).
Also, the heavier decaffeinated coffee drinkers in this study tended to have higher body mass indexes along with higher levels of hypertension, cholesterol, and alcohol consumption.
“Interestingly, we observed an association between decaffeinated coffee intake and ED only among current smokers, suggesting that residual confounding may have accounted for the association,” they wrote.
The authors also explained some of the study’s limitations. For example, it was not known how the coffee was brewed and whether the chemical composition changed during its preparation. Also, coffee intake was assessed every four years, so more recent changes would not be accounted for.
American Journal of Epidemiology via Medscape
Lopez, David S., et al.
“Coffee Intake and Incidence of Erectile Dysfunction”
(Full-text. May 2018)