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Fasting, Plasma Vitamin K1

Indications: The relationship between vitamin K and osteoporosis is well-established. New research indicates vitamin K testing is indicated for patients with a personal or family history of atherosclerosis and type 2 diabetes.As vitamin K1 is 98-99% of vegetable origin, this test is also a good indicator of both diet quality and digestive efficiency. Physicians concerned with “anti-aging” may be interested in new data concerning vitamin K and neuronal aging.

CLINICAL SIGNIFICANCE:

The Vitamins K are fat soluble, antioxidant (1) vitamins found in many green vegetables and someo ils, mostly phylloquinone, or Vitamin K1. (The Vitamin K2 form is synthesized by intestinal bacteria.) The K Vitamins have an important role in calcium homeostasis, supporting bone mineralization and discouraging soft tissue (including arterial) calcification. Women with calcified aortae (2) were found to have marginal Vitamin K levels (inferred by measurement of osteocalcin (3)) andVitamin K2 suppressed aortic calcification in rats fed an atherogenic diet (4).

Overt “Vitamin K” deficiency presents with a bleeding diathesis, which is rarely encountered. However, according to a recent review article, subclinical deficiency of K vitamins is common, and has negative consequences: “Because the Vitamin K requirement of bone and vessel wall is higher than that of the liver (where the clotting factors are produced), recommended daily allowance values for K vitamins must be redefined. According to the new definition, a substantial part of the population is mildly deficient in Vitamin K, and at later ages this deficiency may contribute to increased bone fracture risk, arterial calcification, and cardiovascular disease” (5).

The Vitamin K assay is useful in the settings of impaired digestion and/or suboptimal diet. Specific indications include: the elderly, patients who have had significant antibiotic exposure, alcoholics and patients with liver disease or chronic GI problems (cysticfibrosis, celiac disease, ulcerative colitis, Crohn’s disease or post-surgical short gut). Women (and men!) on low fat diets should have their K vitamin status monitored, especially if there is a family history of osteoporosis.

Both rat (6) and human (7) studies have indicated that low Vitamin K1 intake is associated with abnormal insulin and glucose responses to a glucose load. Clearly, any patient with a family history of osteoporosis, atherosclerosis or Type II diabetes should consider this assay. Because calcification of soft tissue is a general marker of aging, Vitamin K will likely gain status as an anti-aging nutrient as its impact on calcium homeostasis becomes more widely recognized. Recent work has also indicated that Vitamin K-dependent proteins play a role in the development and aging of the nervous system (8,9). To date, Vitamin K has not received the attention it deserves. Clinicians who want to stay on the cutting edge of preventive and nutritional medicine will consider Meridian Valley Laboratory’s Vitamin K1 assay.

  1. Vervoort L, Ronden J, Thijssen H. The potent antioxidant activity of the Vitamin K cycle in microsomal lipid peroxidation. Biochem Pharmacol1997;54:871-876.
  2. Jie K, Bots M, Vermeer C, Witteman J et al. Vitamin K intake and osteocalcin levels in women with and without aortic atherosclerosis: a population-based study. Atherosclerosis 1995;116:117-123.
  3. Knapen M, Hamulyak K, Vermeer C. The effect of Vitamin K supplementation on circulating osteocalcin (bone Gla protein) and urinary calciumexcretion. Ann Int Med 1989;111:1001-1005.
  4. Seyama Y, Hayashi M, Takegami H,Usami E. Comparative effects of Vitamin K2 and Vitamin E on experimental arteriosclerosis. Int J Vit Nutr Res1999;69:23-26.
  5. Vermeer C, Schurgers L. A comprehensive review of Vitamin K and Vitamin K antagonists. Hematol Oncol Clin North Am 2000 Apr;14:339-353.
  6. Sakamoto N, Wakabayashi I, Sakamoto K. Low Vitamin K intake effects on glucose tolerance in rats. Int J Vit Nutr Res 1999;69:27-31.
  7. Sakamoto N, Nishiike T, Iguchi H, Sakamoto K. Relationship between acute insulin response and Vitmain K intake in healthy young male volunteers.Diabetes Nutr Metab 1999 Feb;12:37-41.
  8. Tsaioun K. Vitamin K-dependent proteins in the developing and aging nervous system. Nutr Rev 1999 Aug;57:231-240.
  9. Nakajima M, Furukawa S, Hayashi K, Yamada A et al. Age-dependent survival-promoting activity of Vitamin K on cultured CNS neurons. Brain ResDev Brain Res 1993 May;73:17-23.