Vitamin K2 for 35% lower prostate cancer risk

[Guest guest]

Increased consumption of vitamin K2 but not necessarily K1 were

associated with 35% lower prostate cancer risk:

link:

http://www.nutraingredients-usa.com/news/ng.asp?n=84537-vitamin-k-prostate-cance\

r-menaquinones

full text:

Vitamin K2 linked to lower prostate cancer risk

By ls

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.

Study details

Nimptsch, Rohrmann and Linseisen from the Division of Cancer

Epidemiology at the German Cancer Research Centre state that

epidemiologic studies of dietary vitamin K intakes have not been

conducted in relation to prostate cancer risk.

According to the European School of Oncology, over half a million news

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 per cent

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 associated with

a 35 per cent reduction in risk. However, the researchers stated that

this association was " non-significant " .

Furthermore, a strong association was documented when they considered

only advanced prostate cancer, with increased intake of menaquinones

linked to a 63 per cent reduction in risk.

While dietary sources of menaquinones include meat and fermented food

products like cheese, and natto, Nimptsch and co-workers report that

menaquinones from dairy had a stronger inverse association with

advanced prostate cancer than did menaquinones from meat.

" Our results suggest an inverse association between the intake of

menaquinones, but not that of phylloquinone, and prostate cancer, "

concluded the researchers. " Further studies of dietary vitamin K and

prostate cancer are warranted. "

Independent expert comment

Commenting on the research, Dr. Vermeer told this website that the

data, in addition to being consistent with other reports in the

literature, " the beneficial effect of the long-chain menaquinones has

previously been reported for cardiovascular disease; this specific

form of vitamin K2 is characterized by preferential transport (via

LDL) to extra-hepatic tissues (such as prostate and arterial vessel

wall), and by very long half-life times (three days versus 1.5 hours)

as compared to vitamin K1 and the short-chain menaquinone-4.

" I am highly pleased by this paper, which underpins the (widely

underestimated) importance of long chain menaquinones for disease

prevention, " Dr. Vermeer told this website.

" It also supports my opinion that intake of vitamin K2 supplements may

have a significant contribution to public health. "

K definitions

There are two main forms of vitamin K: phylloquinone, also known as

phytonadione, (vitamin K1) and menaquinones (vitamins K2). K1 is found

in green leafy vegetables such as lettuce, broccoli and spinach, and

makes up about 90 per cent of the vitamin K in a typical Western diet;

while K2, which makes up about 10 per cent of Western vitamin K

consumption and can be synthesised in the gut by microflora.

Menaquinones (MK-n: with the n determined by the number of prenyl side

chains) can also be found in the diet; MK-4 can be found in animal

meat, MK-7, MK-8, and MK-9 are found in fermented food products like

cheese, and natto is a rich source of MK-7.

MK-4 is distinct from other MKs because it is not a major constituent

of the spectrum of MKs produced by gut microflora, but can be derived

from K1 in vivo.

A synthetic form of vitamin K, known as K3, does exist but is not

recommended for human consumption.

The vitamin is less well known than vitamins A to E, but this

increasing body of research, as well as increased marketing and

advertising from supplement makers, is raising public awareness of

vitamin K.

Source: American Journal of Clinical Nutrition

April 2008, Volume 87, Number 4, Pages 985-992

" 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) "

Authors: K. Nimptsch, S. Rohrmann, J. Linseisen