The effect of vitamin K1 supplementation on sensitivity and insulin resistance via osteocalcin in prediabetic women: a double-blind randomized controlled clinical trial.

2015-03-18
European journal of clinical nutrition 69(8)
- H Rasekhi
- M Karandish
- M T Jalali
- M Mohammad-Shahi
- M Zarei
- A Saki
- H Shahbazian

PubMed: 25782427
DOI: 10.1038/ejcn.2015.17

Study Design

Type: Randomized Controlled Trial (RCT)
Sample size: n = 43
Population: 82 prediabetic women
Methods: randomized to consume vitamin K1 supplement (n = 39) or placebo (n = 43) for 4 weeks
Duration: 4 weeks

Rigorous Journal

Background/objectives

A relationship between osteocalcin (OC) levels and factors associated with energy metabolism and insulin resistance has been reported recently. The aim of this study was to investigate whether modulation of ostecalcin isoforms via vitamin K1 supplementation would affect glucose metabolism or insulin sensitivity in prediabetic and premenopause women.

Subjects/methods

Eighty-two prediabetic women were randomized to consume vitamin K1 supplement (n = 39) or placebo (n = 43) for 4 weeks. Participants in the vitamin K1 supplement group received one pearl softgel capsule containing 1000 μm of phylloquinone, and the placebo group received one placebo capsule daily for 4 weeks. Blood samples were collected at baseline and after the 4-week intervention period to quantify carboxylated OC (cOC), undercarboxylated OC (ucOC) and relevant variables.

Results

Phylloquinone supplementation increased the serum levels of cOC and decreased ucOC, compared with placebo (12.53 ± 5.95 compared with 7.43 ± 4.85 ng/ml and 2.47 ± 1.91 compared with 4.79 ± 2.43 ng/ml, respectively; P < 0.001). Furthermore, intake of phylloquinone supplement led to significant decreases in %ucOC (17.97 ± 12.24 compared with 43.80 ± 19.86) and 2-h post-oral glucose tolerance test (OGTT) glucose (7.32 ± 1.50 compared with 8.62 ± 1.45 mmol/l), and 2-h post-OGTT insulin level (80.34 ± 42.24 compared with 112.43 ± 53.19 μIU/ml) and increased insulin sensitivity index (2.46 ± 0.71 compared with 1.75 ± 0.61) compared with placebo. Overall, a significant association was found between changes in %ucOC and changes in 2-h post-OGTT glucose (r = 0.308, P = 0.028).

Conclusions

The results of this study demonstrated that vitamin K1 supplementation for 4 weeks did not affect insulin resistance in premenopausal and prediabetic women but had beneficial effects on glycemic status and insulin sensitivity.

Research Insights

Vitamin K1→Improved Insulin Levels
intake of phylloquinone supplement led to significant decreases in ... 2-h post-OGTT insulin level (80.34 ± 42.24 compared with 112.43 ± 53.19 μIU/ml)... compared with placebo.
Effect
Beneficial
Effect size
Moderate
Dose
1000 μg/day
Vitamin K1→Improved Insulin Sensitivity
The results of this study demonstrated that vitamin K1 supplementation for 4 weeks did not affect insulin resistance in premenopausal and prediabetic women
Effect
Neutral
Effect size
Small
Dose
1000 μg/day
Vitamin K1→Increased Gamma-Carboxylated Osteocalcin Levels
Phylloquinone supplementation increased the serum levels of cOC and decreased ucOC, compared with placebo (12.53 ± 5.95 compared with 7.43 ± 4.85 ng/ml and 2.47 ± 1.91 compared with 4.79 ± 2.43 ng/ml, respectively; P < 0.001).
Effect
Beneficial
Effect size
Large
Dose
1000 μg/day
Vitamin K1→Reduced 2-Hour Post-OGTT Glucose Level
intake of phylloquinone supplement led to significant decreases in ... 2-h post-oral glucose tolerance test (OGTT) glucose (7.32 ± 1.50 compared with 8.62 ± 1.45 mmol/l)... compared with placebo.
Effect
Beneficial
Effect size
Large
Dose
1000 μg/day
Vitamin K1→Reduced Undercarboxylated Osteocalcin Level
intake of phylloquinone supplement led to significant decreases in %ucOC (17.97 ± 12.24 compared with 43.80 ± 19.86)... compared with placebo.
Effect
Beneficial
Effect size
Large
Dose
1000 μg/day