Vitamin K and Testosterone

Hormonal interactions are difficult to quantify as there are so many variables at play. This makes it very difficult to determine the effects of nutrients on hormones, and giving advice on which nutrients may affect testosterone levels is therefore replete with caveats. Another problem with studies that investigate the effects of nutrients on hormones is that many of the studies are performed in animals. For example, in one study, researchers investigated the effects of vitamin K deficiency in testosterone production in rats. The results of the study showed that a vitamin K deficiency decreases testosterone synthesis through a downregulation of the Cyp11a enzyme, one of the key regulatory steps in the testosterone synthesis pathway. Further, the levels of Cyp11a mRNA correlated with the amount of vitamin K in the testis. Therefore in rats at least, vitamin K deficiency can cause sub-optimal synthesis of testosterone. However, in humans it is not clear if this effect is the same, or how it affects overall testosterone levels in the blood. 

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Shirakawa, H., Ohsaki, Y., Minegishi, Y., Takumi, N., Ohinata, K., Furukawa, Y., Mizutani, T. and Komai, M. 2006. Vitamin K deficiency reduces testosterone production in the testis through down-regulation of the Cyp11a a cholesterol side chain cleavage enzyme in rats. Biochimica et Biophysica Acta (BBA)-General Subjects. 1760(10): 1482-1488

About Robert Barrington

Robert Barrington is a writer, nutritionist, lecturer and philosopher.
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