Consuming 170-375 mg of caffeine each day is associated with lower rates of erectile dysfunction (ED), according to a team of American and Greek researchers.
This amount of caffeine is typically found in two to three cups of coffee.
About 85% of adults consume caffeine, the authors noted. Coffee is thought to have health benefits because of its antioxidants and anti-inflammatory properties. However, the relationship between caffeine and erectile function has not been widely studied.
The researchers examined data from the National Health and Nutrition Examination Survey (NHANES), a long-term research project focusing on the health and nutrition of United States residents. NHANES participants answered health questions using a computer-based interview system. Data on erectile function was collected during the 2001-2002 and 2003-2004 NHANES study segments.
Participants also gave information on their food and beverage intake from the previous 24 hours.
Overall, 3,724 men provided valid data on erectile function. Their mean age was 49 years and 54% of them were white. Approximately 41% were considered overweight and 31% were obese. Fifty-one percent had hypertension and about 12% had diabetes.
The researchers included coffee, tea, soda, and energy drinks as caffeine sources.
Based on caffeine intake, the men were divided into quintiles:
• 1st quintile – 0 – 7 mg of caffeine each day
• 2nd quintile – 8 – 84 mg each day
• 3rd quintile – 85 – 170 mg each day
• 4th quintile – 171 – 303 mg each day
• 5th quintile – 304 – 700 mg each day
Overall, the researchers found that men who consumed between 170 and 375 mg of caffeine daily were less likely to report ED on the NHANES self-interview. Men in the 3rd and 4th quintiles were less likely to have ED compared to those in the 1st quintile after several variables, including age, physical activity level, and body mass index were accounted for.
Odds ratios for ED in each quintile were:
• 1st quintile – 1.00
• 2nd quintile – 0.67
• 3rd quintile – 0.58
• 4th quintile – 0.61
• 5th quintile – 0.69
Total caffeine intake was also associated with lower rates of ED in overweight/obese, hypertensive, and non-diabetic men.
The authors suggested that caffeine may improve blood flow to the penis by relaxing penile arteries and smooth muscle tissue.
The association was not found with diabetic men, however. “Diabetes is one of the strongest risk factors for ED and it remains one of the most difficult medical conditions to treat,” the authors wrote. “Thus, it’s possible this is one of the reasons we couldn’t find lower prevalence of ED among men with higher intake of caffeine.”
They acknowledged that other risk factors for ED, such as cardiovascular disease, were not accounted for in this study. Therefore, further prospective studies are needed to verify these results.
The study was published online in April in PLOS One.
Lopez, David S., et al.
“Role of Caffeine Intake on Erectile Dysfunction in US Men: Results from NHANES 2001-2004”
(Full-text. Published online: April 28, 2015)