Effect of vitamin K1 supplementation on vitamin K status in cystic fibrosis patients.
BACKGROUND
Patients with cystic fibrosis are at risk for impaired vitamin K status due to fat malabsorption from pancreatic insufficiency. This study was designed to assess vitamin K status and measure the effect of vitamin K1 supplementation in cystic fibrosis patients.


METHODS
Eighteen outpatients participated in a crossover study to determine the effect of vitamin K1 (phylloquinone) supplementation. After obtaining initial data, each subject was randomly assigned to either a 4-week study treatment of 5 mg oral vitamin K1 supplementation per week, or no supplementation and then crossed over to the other treatment for a second 4 week period. Plasma, serum and urine samples were collected and analyzed pre-study and at the end of each study period.


RESULTS
The mean concentration of plasma vitamin K1 for the supplemented group was significantly higher than the unsupplemented group, [0.34 nmol/L and 0.21 nmol/L, respectively (p < 0.05)]. The percent of undercarboxylated osteocalcin increased on supplementation from 17% to 31%, (p < 0.005). Prothrombin induced in vitamin K absence (PIVKA-II) increased on supplementation from 5 ng/mL to 22 ng/mL, (p < 0.005). The ratio of urinary gamma-carboxyglutamic acid/creatinine was similar for both study periods.


CONCLUSIONS
In contrast to other studies in cystic fibrosis, this study demonstrated a need for vitamin K1 supplementation. The carboxylation state of osteocalcin and PIVKA-II were the most sensitive indices of changes in vitamin K1 status. Although the 5 mg vitamin K1/week dose improved these vitamin K parameters, normal levels were not achieved.
Beker
L T
LT
Children's National Medical Center, Department of Pulmonary Medicine, Washington DC 20010, USA.
Ahrens
R A
RA
Fink
R J
RJ
O'Brien
M E
ME
Davidson
K W
KW
Sokoll
L J
LJ
Sadowski
J A
JA
D015055:1-Carboxyglutamic Acid / Q000187:drug effects / Q000652:urine; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D003404:Creatinine / Q000652:urine; D018592:Cross-Over Studies; D003550:Cystic Fibrosis / Q000097:blood* / Q000178:diet therapy* / Q000652:urine; D015930:Diet Records; D005260:Female; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood / Q000187:drug effects; D011446:Prospective Studies; D011498:Protein Precursors / Q000032:analysis / Q000187:drug effects; D011516:Prothrombin / Q000032:analysis / Q000187:drug effects; D010837:Vitamin K 1 / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood*
D015415:Biomarkers; D011498:Protein Precursors; D015675:Osteocalcin; C016186:vitamin K1 oxide; C008208:acarboxyprothrombin; D015055:1-Carboxyglutamic Acid; D010837:Vitamin K 1; D011516:Prothrombin; D003404:Creatinine