Vitamin K2 Lowers Prostate Cancer by 35 Percent

An increased intake of vitamin K2 may reduce the risk of prostate cancer by 35 percent, suggest results from the European Prospective Investigation into Cancer and Nutrition (EPIC). The potential benefits of vitamin K2 were more pronounced for advanced prostate cancer, while vitamin K1 intake did not offer any prostate benefits, report the researchers from the German Cancer Research Center in Hiedelberg. The findings, based on data from the 11,319 men taking part in the EPIC Hiedelberg cohort, are published in the April, 2011, issue of the American Journal of Clinical Nutrition.

The study, by Katharina Nimptsch, Sabine Rohrmann and Jakob Linselsen, adds to an ever growing body of science supporting the potential health benefits of vitamin K2, most notable for bone and blood health, but also recently linked to improved skin health. The study has been welcomed by leading vitamin K researcher Cees Vermeer, PhD, from the VitaK and Cardiovascular Research Institute CARIM at the Unviersity of Maastricht, who said that the study was "high quality". "The anti-tumor effect of vitamin K2 has been suggested in several other (mainly Japanese) papers; in most cases these papers were based on smaller numbers, however. Also, in Japan it is usual to provide very high doses of the short-chain menaquinone-4 (45 mg/day or higher)," said Dr Vermeer. "The elegance of the Nimptsch paper is that the effect is found at nutritional doses of Vitamin K2," he added.

According to the European School of Oncology, over half a million new cases of prostate cancer are diagnosed every year world wide, and the cancer is the direct cause of over 200,000 deaths. More worryingly, the incidence of the disease is increasing with a rise of 1.7 percent over 15 years. A food frequency questionnaire was used to assess habitual dietary intakes at the start of the study, with vitamin K intakes divided into phylloquinone (Vitamin K1) and menaquinones (vitamin K2) and total and advanced prostate cancer in the Heidelberg cohort of the European Prospective investigation into Cancer and Nutrition.

The researchers documented 268 incident cases of prostate cancer during the 8.6 years of follow-up. Of these 113 cases were classified as advanced prostate cancer. While no reduction in the risk of prostate cancer was observed for vitamin K1 (phylloquinone), an increased intake of all menaquinones (vitamin K2) was associaed with a 35 percent reduction in risk. Furthermore, a strong association was documented when they considered only advanced prostate cancer, with increased intake of vitamin K2 linked to a 63 percent reduction in risk.

While dietary sources of vitamin K2 include meat and femented food products like cheese and natto, Nimptsch and co-workers report that vitamin K2 from dairy had a stronger inverse association with advanced prostate cancer than did vitamin K2 from meat.