cron-web.org

[MR]

A CRONie said:
> Recently it was mentioned that very high levels of Vitamin K could,
> since it is a fat soluble vitamin, lead to a build up in fatty tissue
> and potential toxicity.

Whoever said this was apparently extrapolating from other fat-soluble vitamins, notably vitamin A and to a very limited extent vitamin D. Wtih the exception of people taking warfarin/coumadin, which drug works exactly by inhibiting gamma-carboxylation of proteins via vitamin K2 (which is inhibited by even small increases in vitamin K intake, and appears to be almost unusable at normal doses when vit K supplementatioin >150 mcg), no one is in any meaningful danger from large dietary -- or even supplemental -- intake.

The Institute of Medicine of the National Academies of Sciences -- the folks who set the RDAs, etc, who are not exactly megadose supplement boosters -- say in their latest report on the subject,

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The AI [Adequate Intake] for men and women is 120 and 90 μg/day, respectively. No adverse effect has been reported for individuals consuming higher amounts of vitamin K, so a Tolerable Upper Intake Level (UL) was not established."

http://darwin.nap.edu/books/0309072794/html/162.html
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Vitamin K is an EXTREMELY safe nutrient. Most notably, we now have 2 reports (1,2), published after the above volume appeared, from a large, 3 year clnical trial in which women were administered 1 MILLIgram (1000 MICROgrams)/d of vitamin K1 (the form in plant foods), and "The only side-effect of the allocated intervention reported to the investigator were complaints of mild constipation in a few participants of the MD-group (n=4) and the MDK-group (n=3). No further adverse events occurred during the study". Shorter, smaller studdies at even higher doses (eg, (3-4), at 2000 mcg/d) reported none at all.

There are also now MANY (~20 last time I checked) long-term, controlled clinical trials using menatetrenone (MK-4 -- the mammalian form of vitamin K2 (not the same as bacterial "menaquinone," NB)), mostly against osteoporosis, but also against liver cancer, myelodysplastic syndromes, and post-MDS acute myeloid leukemia (I won't bother citing refs), and including patients with complicating factors like Parkinson's and Alzheimer's diseaes, almost all using the dose of *45* mg/d (45 000 mcg), with no or negligible side effects.

DISCLOSURE: I have formulated vitamin K-containing supplements for compensation in the past, and maintain a friendly relationship with the manufacturer of same, and may someday take up such work again; I specifically was responsible for the launching of the first (and AFAIK still only) menatetrenone supplements in North America, at megadose levels reflected in the clinical trials.

> 5x the RDA could be merely a "small megadose", providing additional
> benefits beyond just 100%.... or is 500% enough over time to cause a
> potentially damaging build-up?

You're fine .


> As most of us are practicing ON in our diets,
> I'd bet your nutrients look even better than mine:

> http://tenacity.net/storage/nutrients2006-03.jpg

Your nutrient intake is quite decent. Where does all that vitamin D come from? Is this report relative to the 200, 400, or 600 IU "RDA" for this vitamin?

-MR

1: Braam LA, Hoeks AP, Brouns F, Hamulyak K, Gerichhausen MJ, Vermeer C.
Beneficial effects of vitamins D and K on the elastic properties of the vessel
wall in postmenopausal women: a follow-up study.
Thromb Haemost. 2004 Feb;91(2):373-80.
PMID: 14961167 [PubMed - indexed for MEDLINE]

2: Braam LA, Knapen MH, Geusens P, Brouns F, Hamulyak K, Gerichhausen MJ,
Vermeer C.
Vitamin K1 supplementation retards bone loss in postmenopausal women between 50
and 60 years of age.
Calcif Tissue Int. 2003 Jul;73(1):21-6.
PMID: 14506950 [PubMed - indexed for MEDLINE]

3: Binkley NC, Krueger DC, Kawahara TN, Engelke JA, Chappell RJ, Suttie JW.
A high phylloquinone intake is required to achieve maximal osteocalcin
gamma-carboxylation.
Am J Clin Nutr. 2002 Nov;76(5):1055-60.
PMID: 12399278 [PubMed - indexed for MEDLINE]

4: Binkley NC, Krueger DC, Engelke JA, Foley AL, Suttie JW.
Vitamin K supplementation reduces serum concentrations of
under-gamma-carboxylated osteocalcin in healthy young and elderly adults.
Am J Clin Nutr. 2000 Dec;72(6):1523-8.
PMID: 11101481 [PubMed - indexed for MEDLINE]