A recently study published in the American Journal of Epidemiology (1) has found that men who drink large amounts of cola daily (around one litre) could be putting their reproductive health at risk. Men drinking large volumes of cola were found to have sperm counts that were almost 30% lower than in men who did not drink cola. It is important to note that most of the sperm counts in all men would still be considered normal by the World Health Organisation, however men with fewer sperm generally have a greater risk of being infertile.
The study(1) involved over 2,500 young Danish men who were going into military service in 2001-2005. Those who did not drink cola had better sperm concentration and total sperm counts and also tended to lead healthier lifestyles (diet and exercise). Men who drank a litre of more of cola daily had a significantly lower sperm count and also ate more fast foods and less vegetables and fruits. When looking at caffeine from other sources, such as coffee and tea, the decrease in sperm quality was much less pronounced indicating that caffeine was not to blame.
The reason for cola having a negative impact on sperm counts is not fully understood yet. It is unlikely to be due to the caffeine found in cola since coffee did not have the same effect on sperm counts even though the caffeine content of coffee is higher than cola. It is probable that the other ingredients in cola, such as sugar, could be involved. It could also be that the unhealthy lifestyles and diets in general in the high-cola drinkers could be to blame. It is still not clear if the cola or the unhealthy lifestyle, or both, is to blame. Further research would be needed to elucidate the results (1).
The results are worrying since many young men and boys drink a lot of cola and also have poor diets. It is not yet known how this may impact their reproductive health over their lifetime.
Last year I wrote about the links between diet and fertility in men and I would suggest reading that post for further information about how a healthy diet can impact reproductive health. In particular the antioxidants found in vegetables and fruits may well protect sperm from damage. In one of the studies mentioned in the post the authors stated (2) “In this study, we have found that people who consume more fruits and vegetables are ingesting more antioxidants, and this is the important point“, “We saw that, among the couples with fertility problems coming to the clinic, the men with good semen quality ate more vegetables and fruit (more vitamins, folic acid and fibre and less proteins and fats) than those men with low seminal quality“. “A healthy diet is not only a good way of avoiding illness, but could also have an impact on improving seminal quality. What we still do not understand is the difference between taking these vitamins naturally and in the form of supplements”.
A recent study (3) investigated the association between pre-conception dietary patterns and IVF outcomes in over 160 couples. Couples eating a healthy “Mediterranean style” diet rich in vegetables, fruits, fish, legumes (beans and pulses) and wholegrains and low in snacks and meat had a greater success of achieving pregnancy. The study was only an association study and does not prove that healthy eating can affect pregnancy outcome and fertility but the evidence is interesting and adds to the studies mentioned in the previous post on fertility. Healthy diet and lifestyle can impact all areas of health!
(1)Jensen TK et al. 2010. Caffeine Intake and Semen Quality in a Population of 2,554 Young Danish Men. Am J Epidemiol. 2010 Mar 25. [Epub ahead of print]
(2)Plataforma SINC (2009, June 3). Semen Quality May Depend Upon Antioxidants In Man’s Diet. ScienceDaily. Retrieved June 4, 2009, from http://www.sciencedaily.com/releases/2009/06/090602083727.htm
(3)Vujkovic M et al. 2010. The preconception Mediterranean dietary pattern in couples undergoing in vitro fertilization/intracytoplasmic sperm injection treatment increases the chance of pregnancy. Fertil Steril. 2010 Feb 18. [Epub ahead of print]
Written by Ani Kowal
Related posts:
