
The consumption of caffeine found in coffee, tea, chocolate and cola-containing beverages is high in the industrialized world. There is some preliminary research to suggest that increased caffeine consumption is associated with a decrease in female fertility.
A 2010 Danish study examined the link between caffeine (including caffeine from cola drinks) and sperm quality in over 2500 men over the age of 18.
The study suggested that moderate caffeine intake is not associated with reduced semen quality, however there may be a link at high consumption levels. Caffeine consumption over 800 mg a day (about 7 cups of coffee) was associated with a slight reduction in semen quality.
The researchers then analysed the connection between sperm quality and different sources of caffeine, including coffee, tea, chocolate, and soft drinks. Only cola consumption was associated with a significant reduction in sperm quality, and men who drank cola had poorer semen quality than men who did not.
Because the caffeine content of cola is low (one cup of coffee contains about 117 mg compared with 35 mg in 1 cup of cola), it’s possible that the poor semen quality may be attributed to some unique ingredients in cola other than caffeine.
This may be related to the connection researchers found between high cola consumption and a number of additional unhealthy lifestyle practices. Men who drank more than a litre of cola a day were found to drink less milk, consume less fruit, vegetables, and fish, and consumed more burgers and alcohol compared with men who drank less than a litre of cola per day. They were also more likely to be either overweight or under weight (a high or low BMI), were more likely to have a disease of the reproductive organs, and were more likely to be a smoker. Men who consumed no caffeine had better semen quality, but also had a healthier lifestyle.
Lifestyle implications
Whether your goal is to improve fertility, or just to maintain good health, cutting back on cola drinks could be a good move. You can also attempt to modify the unhealthy lifestyle associated with a high consumption of soft drinks such as cola that may contribute to reduced sperm quality. Following are some lifestyle strategies that may be of benefit.
If you drink more than a litre of cola each day, reduce your intake
References available on request