Effect of Green Tea Supplementation on Blood Cadmium and Male Sex Hormone Levels in Automobile Workers in Emene, Enugu State, Nigeria

Background: Cadmium is a toxic metal and a known endocrine disruptor capable of altering sex hormone levels especially in the occupationally exposed persons. Some phytochemicals including green tea (Camellia sinensis) may prove to be beneficial in reducing blood cadmium levels and the associated adverse health effects.

Aim: This study assessed the levels of blood cadmium and male sex hormones in automobile workers as well as the effect of subsequent green tea supplementation.

Methods: The study was carried out in two parts; the cross-sectional and intervention study. 124 subjects comprising of 62 automobile workers and 62 age-matched occupationally unexposed control subjects in Emene, Enugu State, Nigeria were recruited for the cross-sectional study. Subsequently, 28 out of the 62 automobile workers received green tea supplement daily (2 green tea bags soaked in 150 ml of freshly boiled water for 5 minutes) for two months. 5mls of venous blood samples were collected from all subjects before the intervention (baseline) as well as after one and two months of green tea supplementation for the determination of blood cadmium, serum testosterone, follicle stimulating hormone (FSH) and luteinizing (LH) levels.

Results: The mean blood cadmium and serum FSH and LH levels were significantly higher in the automobile workers (2.41 ± 0.26 µg/dl, 11.64 ± 4.31 iu/l and 7.67 ± 2.82 iu/l respectively) when compared to the control (0.14 ± 0.02 µg/dl, 9.09 ± 2.90 iu/l and 5.54 ± 1.54 iu/l respectively) (p<.05) while the mean serum testosterone level was significantly lower in the automobile workers (6.96 ± 2.07 ng/ml) when compared to the control (8.99 ± 2.95 ng/ml) (p<.05). Following supplementation with green tea, blood cadmium and serum LH levels reduced significantly (2.19 ± 0.38 µg/dl and 7.67 ± 2.82 iu/l respectively), serum testosterone increased significantly (7.75 ± 2.18 ng/ml) whereas serum FSH level did not differ significantly when compared with the baseline values (p>.05).

Conclusion: This study indicates that blood cadmium level is elevated and sex hormone levels are altered in automobile workers, and two months supplementation with green tea reduced the blood cadmium and regulated serum testosterone and LH levels with no significant effect on serum FSH level.