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A recent study found that patients with early-stage Alzheimer's disease consumed less vitamin K than did cognitively intact control subjects. (J Am Diet Assoc. 2008 Dec;108(12):2095-9). (Link: vitamin K and Alzheimers; Source: Alzheimers newsletter:
Daily Value: none (80 mcg RDA males; 65 mcg females)
Hazardous level: safe at more than 10xRDA
Average intake in US diet: 70-100 mcg
Function: name for a group of compounds which are essential for the formation of prothrombin and at least five other proteins involved in blood clotting. SINCE 2009, it has been learned that vitamin K at levels above the Daily Value has many other important functions, activating and carboxylating a variety of proteins involved in calcium regulation. In particular, it activates calcitonin, an enzyme that decalifies arteries, lowering blood pressure, relieving much hazard from plaque, and able to reduce heart disease risk in the US by 30 to 50%. See Linus Pauling meeting notes of 2009.
DOSAGE RATIONALE: Vit K comes from green leafy veggies. US intake is 70-100 mcg daily, daily value is 120 mcg, have just discovered the true requirement for health is 360 to 500 mcg daily. (cooked spinach has 888 mcg, but peas have only 48, chicken has 2.)
KEY NOTES AND REFERENCES:
1. Jeffrey B Blumberg et al, Effect of vitamin E supplementation on vitamin K status in adults with normal coagulation status
Notes from (3): Elevated doses of vitamin E have an anticoagulant effect when vitamin K intake is low. Average vitamin K intake among US adults is low. Since vitamin E is the most frequently purchased single nutrient supplement in the US, this might be a concern. However, high vitamin E intakes did not alter coagulation times in healthy adults. The results of the study left unlcear whether high dose vitamin E is beneficial or harmful in its interactdion with vitamin K and coagulation.