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| Proper name |
Phylloquinone |
| Category |
Water-soluble vitamin |
| Functions |
Blood clotting - Vitamin K is needed to produce prothrombin and other blood
clotting factors (factors IV, IX and X). Bone strength - Required to form
osteocalcin, a bone protein that attracts calcium to the bone and modulates
the deposition of calcium into the bone matrix. Vitamin K is also associated
with matrix GLA protein. Vitamin K is thought to be important in maintaining
bone density and preventing osteoporotic fractures. Cancer prevention
- Laboratory experiments indicate vitamin K inhibits the growth of breast,
ovary, colon, stomach, kidney, liver and lung cancer. |
| RDA |
65 mcg for women, 80 mcg for men. |
| Therapeutic
dose |
30 to 100 mcg. |
| Deficiency symptoms |
Deficiency may occur in infants due to the lack of intestinal flora and
to a lesser extent in persons undergoing antibiotic therapy. Deficiencies
also occur in persons with defective fat absorption such as persons with
gallstones or lacking a gallbladder. |
| Toxicity |
Can cause a fatal form of jaundice in infants. Large doses can be toxic.
Best forms Dietary forms and intestinal bacteria provide sufficient amounts
of this nutrient. |
| Best
forms
|
Food sources |
| Food
sources |
Dark green vegetables and liver are the highest food sources. |
| Lab
tests |
Prothrombin time |
| Drug
interactions |
Anti-clotting drugs such as Warfarin or Dicumerol specifically inhibit the
action of vitamin K. Antibiotics may reduce the production of vitamin K2
in the intestines. Other drugs that may deplete vitamin K include: Aminoglycosides,
Barbiturates, Cephalosporins, Chlortetracycline, Cholestyramine Resin, Colestipol,
Demeclocycline, Doxycycline, Ethosuximide, Fluoroquinolones, Fosphenytoin,
Macrolides, Methsuximide, Mineral Oil, Minocycline, Oxytetracycline, Penicillins,
Phenytoin, Primidone, Sulfonamides, Tetracyclines and Trimethoprim. |
| Nutrient interactions |
Production of vitamin K may be assisted by taking probiotics such as lactobacillus
acidophillus or bifido bacteria. |
| Metabolism |
Phylloquinone (K1)
is found in the diet. Menaquinone (K2) is synthesized by intestinal bacteria
and constitutes half our daily supply. Menadione (K3) is a synthetic water-soluble
form that is converted in the liver into the biologically active forms,
K1 or K2. K1 and K2 require bile salts and pancratic lipase for absorption
with chylomicrons in the upper intestine into the lymph system, and from
there through the portal circulation to the liver. Small amounts are
stored in the liver. Excess amounts are excreted rapidly.
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