Vitamin K Decreases Insulin Resistance in Men

Vitamin K has been suggested to be a helpful nutrient for decreasing the risk of heart disease (see "Calcium Increases Risk of Heart Attacks").

In this study, 500 µg/day of phylloquinone (vitamin K1) was given daily as part of an osteoporosis study. This was an ancillary study of a 36-month, randomized, double-blind, controlled trial evaluating the effect on bone loss of supplementation with 500 µg/day of phylloquinone (vitamin K1).

• The study sample consisted of 355 nondiabetic men and women, aged 60 to 80 years (60% were women).
• The main endpoint of this ancillary study was insulin resistance at 36 months, measured by homeostasis model assessment of insulin resistance (HOMA-IR).
• Secondary outcome measures were fasting plasma insulin and glucose concentrations.
• In both men and women, there was evidence of decreased bone breakdown.
• At the 36-month visit (but not at 6 months), HOMA-IR and plasma insulin was significantly lower for men in the supplement group vs. those in the control group (P =.01), after adjustment for baseline HOMA-IR, BMI, and weight change. There was not a significant decrease in women though, and it was suspected that this occurred because the vitamin K (being fat soluble) was being stored in fatty tissue more in women.

The study authors conclude: "Vitamin K supplementation for 36 months at doses attainable in the diet may reduce progression of insulin resistance in older men — but not in older women."

This suggests that vitamin K (which can be found in a good multivitamin powder) may decrease the risk of developing diabetes and heart disease, as well as osteoporosis.

References

Diabetes Care. November 2008;31:2092-2096.

For more information, see the article at Medscape online (free registration required).