Hi there
well firstly I would present this:
Educational advice is often given to patients starting treatment with vitamin K Antagonists (VKAs). A great emphasis is made on nutritional information. Common belief is that dietary vitamin K intake could counteract the anticoagulant effect by VKAs and ...
www.ncbi.nlm.nih.gov
the whole thing is worth a read, but the conclusion is IMO sufficient
In conclusion, the available evidence does not support current advice to modify dietary habits when starting therapy with VKAs. Restriction of dietary vitamin K intake does not seem to be a valid strategy to improve anticoagulation quality with VKAs. It would be, perhaps, more relevant to maintain stable dietary habit, thus avoiding wide changes in the intake of vitamin K. Based on this, until controlled prospective studies provide firm evidence that dietary vitamin K intake interferes with anticoagulation by VKAs, the putative interaction between food and VKAs should be eliminated from international guidelines.
next we need to understand that to make a (clinically) significant variation on INR we need a lot of vitamin K ...
for example this paper:
Warfarin is the most commonly used oral anticoagulant in the UK. It is associated with few side effects apart from haemorrhage. The most appropriate way to reverse the anticoagulant effect of warfarin depends on the clinical circumstances. In serious ...
www.ncbi.nlm.nih.gov
suggests for reversal of INR
>5 but <9 | high risk of bleeding |
Vitamin K (1–2.5 mg orally; 2–4 mg orally if more urgent reduction needed) |
So, lets look at amounts present in high vitamin K foods, from this source:
Spinach, Vitamin K and Warfarin
www.ptinr.com
One cup of raw spinach has about 144.9 mcg of vitamin K while a cup of cooked spinach has 888.5 mcg of vitamin K.
there are of course others which provide not significantly different results.
so lets remember that there are one thousand milligrams (mg) in a microgram (mcg) and so lets take 1mg as the lower end and say that 1000mcg are needed or about 7 cups of raw spinach.
Serve that out and look at it and ask "am I going to eat that"
So my point is not just an opinion, its backed by a variety of sources of evidence AND my own measurements of myself over the last 10 years ...
Please, eat well. Manage your dose based on weekly INR measurements and
keep a steady hand on the dosage tiller.
Best Wishes