Behavioural and endocrine effects of chronic cola intake.

Consumption of cola beverages is very high worldwide. The health effects of cola intake are not clear, although epidemiological studies point toward associations with obesity, kidney diseases and osteoporosis. Experimental studies are surprisingly rare. In this study, we substituted drinking water of adult male Wistar rats with three different cola beverages for 3 months. Behavioural phenotyping, measurement of sex steroids in plasma and oxidative stress in testes were performed at the end of the study. A light-dark box showed increased locomotor activity and anxiety in all groups with cola intake. A subtle anti-depressive effect was seen in the forced swim test. Chronic cola intake increased both oestradiol and testosterone levels suggesting an additional mechanism of action beyond the known effects of caffeine on adenosine receptors.