This systematic review suggests that supplementation with phytonadione and menaquinone-4 reduces bone loss .
In the case of the latter , there is a strong effect on incident fractures among Japanese patients
BACKGROUND Observational and some experimental data suggest that low intake of vitamin K may be associated with an increased risk of fracture .
OBJECTIVE To assess whether oral vitamin K ( phytonadione and menaquinone ) supplementation can reduce  bone loss  and prevent fractures .
Menatetrenone ameliorates osteopenia in disuse-affected limbs of vitamin D- and K-deficient stroke patients.
Significant reduction in bone mineral density ( BMD ) occurs in stroke patients on the hemiplegic and contralateral sides , correlating with the degree of paralysis and vitamin D and K deficiency due to malnutrition , and increasing the risk of hip fracture . We evaluated the efficacy of vitamin K2 ( menatetrenone : menaquinone-4 ; MK-4 ) in maintaining BMD by comparing serum biochemical indices of bone metabolism between treated and untreated patients . In a r and om and prospect i ve study , of 108 hemiplegic patients following stroke , 54 received 45 mg menatetrenone daily ( MK-4 group , n = 54 ) for 12 months , and the remaining 54 ( untreatment group ) did not . Nine patients excluded from the study . The BMD in the second metacarpals and serum indices of bone metabolism were determined . BMD on the hemiplegic side increased by 4.3 % in the MK-4 group and decreased by 4.7 % in the untreated group ( p < 0.0001 ) , while BMD on the intact side decreased by 0.9 % in the MK-4 group and by 2.7 % in the untreated group ( p < 0.0001 ) . At baseline , patients of both groups showed vitamin D and K1 deficiencies , high serum levels of ionized calcium , pyridinoline cross-linked carboxyterminal telopeptide of type I collagen ( ICTP ) , and low levels of parathyroid hormones ( PTH ) and bone Gla proteins ( BGP ) , indicating that immobilization-induced hypercalcemia inhibits renal synthesis of 1 , 25-dihydroxyvitamin D ( 1 , 25-[OH]2D ) and compensatory PTH secretion . Both vitamins K1 and K2 increased by 97.6 % and 666.9 % , respectively , in the MK-4 group . Correspondingly , a significant increase in BGP and decreases in both ICTP and calcium were observed in the MK-4 group , in association with a simultaneous increase in both PTH and 1 , 25-[OH]2D . One patient in the untreated group suffered from a hip fracture , compared with none in the MK-4 group . The treatment with MK-4 can increase the BMD of disused and vitamin D- and K-deficient hemiplegic bone by increasing the vitamin K concentration , and it also can decrease calcium levels through inhibition of bone resorption , result ing in an increase in 1 , 25-[OH]2D concentration
This systematic review suggests that supplementation with phytonadione and menaquinone-4 reduces bone loss .
In the case of the latter , there is a strong effect on incident fractures among Japanese patients
BACKGROUND Observational and some experimental data suggest that low intake of vitamin K may be associated with an increased risk of fracture .
OBJECTIVE To assess whether oral vitamin K ( phytonadione and menaquinone ) supplementation can reduce  bone loss  and prevent fractures .