According to a new study published in the open-access journal PLoS Medicine, postmenopausal women with osteopenia did not prevent age-related bone mineral density (BMD) decline after taking a daily high dose supplement of vitamin K1. However, Angela Cheung (University of Toronto) and colleagues also found that vitamin K1 may offer protection against fracture and cancer in these women. These findings come from a randomized controlled study called the “Evaluate the Clinical use of vitamin K Supplementation in Postmenopausal Women with Osteopenia” (ECKO) trial.

Ten million people in the US have the bone disease osteoporosis, and 18 million have osteopenia – a milder precursor to osteoporosis. Osteoporosis is most common in women after menopause, but it can also inflict men.

The evaluation consisted of 440 postmenopausal women with osteopenia who were randomly assigned to receive either 5 mg of vitamin K1 or a placebo every day for two years. The researchers were also able to measure the long-term effects of vitamin K supplements from 261 of theses women who continued their treatment for two additional years.

Cheung and colleagues found no significant difference in measurements of lower back and hip BMD decline, after two years and after four years, between the vitamin K and placebo groups.

However, compared to placebo group women, women who took vitamin K over the four-year period had fewer fractures (9 vs. 20 women) and fewer cancer incidences (3 vs. 12 women). The researchers note that women tolerated the Vitamin K supplements quite well during the four-year period and there were no significant difference in adverse health effects between the treatment and placebo groups. Since the study was not designed to measure the effect on fractures or cancer (and the numbers were small), the authors insist that these results be examined cautiously.

“Vitamin K1 supplementation at a daily dose of 5 mg does not protect against age-related decreases in BMD, but may reduce the incidence of fractures and cancers in postmenopausal women with osteopenia. Additional studies need to be conducted to understand the potential mechanisms behind these observations. Before high-dose vitamin K1 supplementation can be recommended for general use, further randomized controlled trials have to be done to confirm these findings,” conclude the authors.

Vitamin K supplementation in postmenopausal women with osteopenia (ECKO Trial): A randomized controlled trial
Cheung AM, Tile L, Lee Y, Tomlinson G, Hawker G, et al.
PLoS Medicine (2008). 5(10): e196.
doi:10.1371/journal.pmed.0050196
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About PLoS Medicine

PLoS Medicine is an open access, freely available international medical journal. It publishes original research that enhances our understanding of human health and disease, together with commentary and analysis of important global health issues. For more information, visit http://www.plosmedicine.org

About the Public Library of Science

The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world’s scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org

Written by: Peter M Crosta