Vitamin K is a somewhat lesser known vitamin, but recent research has shown that it is crucial to bone health and to a number of other systems in the body and, possibly to the prevention of some disease. Vitamin K has two primary forms Vitamin K1, Phylloquinone, and the more bioavailable vitamin K2, the menaquinones.

The researchers noted that "anticarcinogenic activities of vitamin K have been observed in various cancer cell lines, including prostate cancer cells," but prior to this study no epidemiological studies had been done on the effects of the K vitamins on prostate cancer risk. The researchers used a food frequency questionnaire to assess the dietary intakes of the 11,319 men who participated in the "Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition" study. Based on the surveys, the researchers were able to determine the intakes of vitamin K1 and vitamin K2. The researchers found that an increased intake of vitamin K2 was associated with a 35% reduction of risk of developing prostate cancer, which the researchers state is a "non-significant" association. They further go on to state that a higher intake of vitamin K2 was associated with a 63% reduction in risk of advanced prostate cancer, which is significant. There was no reduction in prostate cancer risk from vitamin K1 found in this study.

Vitamin K1 one is available from dietary sources such as dark green leafy greens like spinach, as well as cruciferous vegetables. Vitamin K2 is found in much lower levels in dietary sources that include red meat, eggs and dairy products. Our HisHealth™ Complete Men's Multivitamin contains half of the USDA Daily Value for vitamin K in the form of vitamin K2. Learn more about HisHealth and all of our multivitamins here.

1. Nimptsch, K., S. Rohrmann, et al. (2008). "Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)." Am J Clin Nutr 87(4): 985-92.