There were a few previous discussion threads about Vitamin K2 and natto; the most recent thread is here Vit K or K2 Dilemma
A new research study is "Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7". The abstract is at PubMed, PMID: 17158229. Some media reports have additional details from the study, and (of particular interest to us osteo-challenged):
Blood levels of the K1 group and K2 (MK-7) group both peaked after four hours. However, the levels of vitamin K1 were 86 per cent lower after only eight hours, while K2 (MK-7) levels were only 50 per cent lower after 68 hours, indicating slower excretion from the body. (This would seem to indicate that my present consumption of 100g of natto every other day should be keeping my K2 levels fairly high. )
Bone turnover was also measured (as a ratio of circulating carboxylated and uncarboxylated osteocalcin), and the researchers reported that both forms of vitamin K showed activity after three days. However, vitamin K1's effect did not increase further while MK-7's effect increased over the six-week study period.
But people who take blood thinning medication (and are told to avoid Vitamin K), need to particularly avoid K2.
Anyway, I wouldn't be surprised if within a decade K2 is routinely recommended (just like calcium and D) for patients with osteoporosis.
I think I read that there were studies done-where vitamin k2 was given in large doses, such as 40mg daily-and there were increases in BMD. I would never take that large a dose, but I have found it a little difficult to obtain vitamin k or k2. I was taking "life extentions vit k1 with k2'. Took it for three months-ran out and was unable to get new supply. The health food stores in NY do not carry vit k. I do not want to eat natto-the idea of it, just turns me off. So I have sort of given up on vit K. Wish I could find some-adequately priced also.
I found some interesting information on vitamin K and osteoporotic fracture rates at Linus Pauling Institute website. The Institute is at Oregon State University . When you go to the website go to micronutrients information section. Information is available on the latest scholarly studies of various vitamins and minerals.
More reported news: A recent study in Japan followed nearly 1,000 women for three years to determine the effects of natto and other soy products on bone mineral density. Natto had the strongest protective effect: It reduced bone loss at the top of the thighbone by more than 80%; this benefit increased as the women got older.
PikaB-I went to the site PubMed, a site set up by NIH and the Nat'l Library of Medicine to do a search on magnesium and bone. Oddly enough, that search turned up a treasure trove of information on K2. Most of the research looked extremely positive to me. One of the studies noted that while bmd was not increased by the k2, fracture rates were much lower. Thus, the researchers noted that k2 appeared to enhace the quality of the bone. If you have not checked out this research I think you would find it very interesting. Let me know what you think. If you go to pubmed you can do the search by putting in menatetrenone.
I don't think I would like to eat natto, but I am interested in finding out about
k2 supplementation. Have you found it yet?
Also as I said I started my research on magnesium and bone. I have been taking a bone formula that included magnesium and I really liked the composition of the formula. It included calcium citrate, K phytonadione, mag,zinc, copper, manganese ,d2 and boron. The principal problem I have is that the d is d2 and I have read that it is D3 that has the significantly better
bioavailability. (If interested the d2/3 discussion I read was at the site of the
Oregon Osteoporosis Center by Dr. McClung , who as far as I can discern is a major researcher in the field.) Now I am looking for another bone formula which would include the D3 instead. As I am looking over formulas , I am finding one that I am leaning toward but it has inadequate magnesium. Well, what was odd about the pubmed search on magnesium and bone, was that the K2 researchers used rats that had been magnesium deprived in their study. I don't want to summarize why they did that because I have to go back to the article and look at it more carefully first. But, I think that magnesium is quite important. Anyway , have you or others out there been interested in getting magnesium as well? When I went to the endo , the only supplement instructions I was given was to take calcium and vitamin D. I know mag is a component of some of the drug store brand calcium formulas. From what I gather it seems important.
PikaB and others- In my previous post I indicated researchers were testing K2
effect on rats that had been placed on low magnesium diet. At that time, I wasn't clear on why the researchers did that-the low mag diet. I went back to the pubmed studies and read this sentence-the low magnesium diet reduced bone strength without decreasing mineral content,so the low magnesium model is considered a good model for examining bone quality.
Again while the focus of the research was K2 , it seems an important comment on magnesium.
I just found this site which is great. What is "natto" and how does one acquire it? Is it sold or purchased online or thru ? What is the difference between this and a supplement pill? How is one sure of the right amount in the supplement? Great information, glad I found this site. Thank you.
Natto is a form of fermented soybeans, popular in Japan. Most of its bone-healthy stuff is supposedly in Vitamin K-2, which is available in some health food stores. I prefer to eat the natto as a whole food, which I find in the frozen food section of an Asian supermarket.