4/9/2008- An increased intake of vitamin K2 may reduce the risk of prostate cancer by 35 per cent, suggest results from the European Prospective Investigation into Cancer and Nutrition (EPIC).
The potential benefits of 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 Centre in Heidelberg.
The findings, based on data from the 11,319 men taking part in the EPIC Heidelberg cohort, are published in this month's issue of the American Journal of Clinical Nutrition.
The study, by Katharina Nimptsch, Sabine Rohrmann and Jakob Linseisen, adds to a small but ever-growing body of science supporting the potential health benefits of vitamin K, 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 University of Maastricht, who told NutraIngredients.com that the study was "high quality."
"The anti-tumor effect of K2 vitamins 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 K," he added.
Much of the developing research on vit K2 is coming from the laboratories of Drs. Vermeer, Geleijnse, and Schurgers at the University of Maastricht in the Netherlands, along with several laboratories in Japan, the champions of K2.
MK-7 and MK-8,9,10 come from bacterial fermentation, whether in natto, cheese, or in your intestinal tract; MK-4 is naturally synthesized by animals from vitamin K1. While natto is the richest source of the MK-7 form, egg yolks and fermented cheeses are the richest sources of the MK-4 form.
Chicken contains about 8 mcg MK-4 per 3 1/2 oz serving; beef contains about 1 mcg. Egg yolks contain 31 mcg MK-4 per 3 1/2 oz serving (app. 6 raw yolks). Hard cheeses contain about 5 mcg MK-4 per 3 1/2 oz serving, about 70 mcg of MK-8,9; soft cheeses contain about 30% less. Natto contains about 1000 mcg of MK-7, 84 mcg MK-8, and no MK-4 per 3 1/2 oz serving.
Thanks to the research efforts of the Dutch and Japanese groups, several phenomena surrounding vitamin K2 are clear, even well-established fact:
--Vitamin K2 supplementation (via frequent natto consumption or pharmaceutical doses of K2) substantially improves bone health. While K2 by itself exerts significant bone density/strength increasing properties in dozens of studies, when combined with other bone health-promoting agents (e.g., vitamin D3, prescription drugs like Fosamax and calcitonin), an exaggerated synergy of bone health-promoting effects develop.
--The MK-4 form of vitamin K2 is short-lived, lasting only 3-4 hours in the body. The MK-7 form, in contrast, the form in natto, lasts several days. MK-7 and MK-8-10 are extremely well absorbed, virtually complete.
--Bone health benefits have been shown for both the MK-7 and MK-4 forms.
This is a new study following the original study quoted, carried out by the same researchers.
NEW STUDY SUPPORTS PROSTATE BENEFIT FROM VITAMIN K2
An improved vitamin K2 status may reduce the risk of prostate cancer, suggest results from German scientists that build the science linking the vitamin to improved prostate health.
Scientists from the German Cancer Research Center report that an improved status of the vitamin was linked to a lower risk of both advanced-stage prostate cancer and high-grade prostate cancer. The authors, led by Katharina Nimptsch, published their findings in the journal Cancer Epidemiology, Biomarkers & Prevention.
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.
The study adds to a small but ever-growing body of science supporting the potential health benefits of vitamin K, most notable for bone and blood health, but also recently linked to improved skin health.
Last year, the same researchers reported that increased intakes of vitamin K2, but not K1, were associated with a 35% reduction in prostate cancer risk. The potential benefits of K2 were more pronounced for advanced prostate cancer.
The findings were based on data from the 11,319 men taking part in the European Prospective Investigation into Cancer and Nutrition (EPIC) Heidelberg cohort, and were published in the April 2008 issue of the American Journal of Clinical Nutrition (Vol. 87, pp. 985-992).
Commenting on the new study, Nimptsch and her co-workers said: "In this nested case-control study including 250 prostate cancer cases and 494 matched controls, we aimed to confirm this cancer-protective effect using serum undercarboxylated osteocalcin (ucOC), a biomarker of vitamin K status inversely associated with vitamin K intake."
A higher ratio of ucOC to intact total osteocalcin (iOC) is indicative of poorer vitamin K status.
Nimptsch and her co-workers recruited 250 people with prostate cancer and 494 healthy controls. Levels of ucOC and iOC were analyzed from serum samples and every 0.1 increment in the ratio was associated with a 38% increase in advanced-stage prostate cancer, and a 21% increase in high-grade prostate cancer. No relationship between ucOC/iOC and total prostate cancer was observed, they said.
"The increased risks of advanced-stage and high-grade prostate cancer with higher serum ucOC/iOC ratio strengthen the findings for dietary menaquinone intake," concluded Nimptsch and her co-workers.
Cancer Epidemiology, Biomarkers & Prevention 18(1):49-56, 2009