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The Eclectic Physician
Vitamin and Mineral Information
Vitamin K
The information on this page compiled by
Beth Burch N.D.
Index
(click on the keywords)
Function
Vitamin K is necessary for the formation of prothrombin
and clotting factors VII, IX, and X. It is also required for the binding
of calcium to the bone protein osteocalcin by converting osteocalcin from
its inactive to its active form. Vitamin K is produced by intestinal bacteria
as well as being available in foods. Vitamin K deficiency is characterized
by uncontrolled bleeding due to lack of clotting factors. Deficiency is
usually found in people taking oral anticoagulants or long term antibiotic
therapy, but is also found in newborns (who lack the intestinal bacteria
to produce vitamin K) and in some cases of malabsorption like cystic fibrosis
(1).
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Forms
-
Vitamin K-1 (Phylloquinone)- from plant sources
-
Vitamin K-2 (Menaquinone)- produced by intestinal bacteria
-
Vitamin K-3 (Menadione)- synthetic form
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Food Sources
-
Excellent sources of vitamin K include dark green leafy vegetables, green
tea, broccoli, lettuce and cabbage. Good sources include asparagus, oats
and whole wheat.
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Dosage
-
Recommended Daily Allowance (RDA)
-
Infants- 5-10 mcg
-
Children (ages 1-10)- 15-30 mcg
-
Adults- 45-80 mcg
-
Pregnancy- 65 mcg
-
Lactation- 65 mcg
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Optimal Supplementation
Treatment
of Health Conditions
-
1-10 mg daily orally or by injection
Conditions used
for
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Prevention of hemorrhagic disease of the newborn (2)
-
Osteoporosis (3, 4, 5)
-
Excessive menstrual bleeding (6)
-
Vitamin K deficiency
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Side effects
-
Large doses may cause headache, nausea, vomiting, sweating, flushing, liver
dysfunction.
-
In infants, excessive doses can cause hemolytic anemia, jaundice, kinicterus
and death.
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Contraindications
-
Allergic reactions to vitamin K supplements
-
Use of oral anticoagulant medications
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Interactions
with other nutrients
-
High doses of vitamin E (> 600 IU) may interfere with vitamin K action
-
Vitamin K facilitates the incorporation of calcium into bones
-
Vitamin K & vitamin D may have a synergistic effect in preventing bone
loss (7)
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Interactions
with medications and herbs
-
Broad spectrum antibiotics can interfere with vitamin K action
-
Mineral oil prevents absorption of vitamin K
-
Vitamin K counteracts the effects of oral anticoagulants like warfarin
-
Aspirin and phenytoin may interfere with vitamin K action
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References
1. Rashid M et al, Prevalence of vitamin K deficiency in cystic
fibrosis, Am J Clin Nutr 1999;70(3):378-82
2. Prevention of haemorrhagic disease of the newborn. Routine vitamin
K1
administration is justified, Prescrire Int 1998;7(36):125-7
3. Feskanich D et al, Vitamin K intake and hip fractures in women:
a prospective study, Am J Clin Nutr 1999;69(1):74-9
4. Iwamoto I, A longitudinal study of the effect of vitamin K2 on bone
mineral density in postmenopausal women a comparative study with vitamin
D3 and estrogen-progestin therapy, Maturitas 1999;31(2):161-4
5. Weber P et al, Management of osteoporosis: is there a role for vitamin
K?, Int J Vitam Nutr Res 1997;67(5):350-6
6. Lusher JM, Systemic causes of excessive uterine bleeding, Semin
Hematol 1999;36(3 Suppl 4):10-20
7. Matsunaga S et al, The effect of vitamin K and D supplementation
on ovariectomy-induced bone loss, Calcif Tissue Int 1999;65(4):285-9
.
* The information presented in this web site is intended to inform and educate.
It is not intended replace a qualified medical practitioner to diagnose or treat medical conditions.
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