The study found that high intake of the vitamin can slash the risk developing type 2 diabetes in half.
The scientists report that for every 100 micrograms per day increase in the intake of vitamin K1, the risk of developing diabetes decreased by 17%.
For the analysis, N. Ibarrola-Jurado, of Universitat Rovira i Virgili in Reus, Spain, and colleagues studied data from over 1900 elderly men and women in the Prevention with the Mediterranean Diet Trial at high cardiovascular disease risk, and a further 1069 people who were free of diabetes at baseline.
Participants who increased their dietary intake of vitamin K1 during the 5-year follow-up were found to be 51 per cent less likely to develop type 2 diabetes than those who lowered or did not change their intake.
Cross-sectional associations were tested in 1925 men and women in the Prevention with the Mediterranean Diet trial. A longitudinal analysis was conducted on 1069 individuals free of diabetes at baseline (median follow-up: 5.5 y). Biochemical and anthropometric variables were obtained yearly. Dietary intake was collected during each annual visit by using a food-frequency questionnaire, and phylloquinone intake was estimated by using the USDA database. The occurrence of type 2 diabetes during follow-up was assessed by using American Diabetes Association criteria.
Dietary phylloquinone at baseline was significantly lower in subjects who developed type 2 diabetes during the study. After adjustment for potential confounders, risk of incident diabetes was 17% lower for each additional intake of 100 μg phylloquinone/d. Moreover, subjects who increased their dietary intake of vitamin K during the follow-up had a 51% reduced risk of incident diabetes compared with subjects who decreased or did not change the amount of phylloquinone intake.
The researchers concluded that "dietary phylloquinone intake is associated with reduced risk of type 2 diabetes."
Vitamin K1 is one type of the naturally occurring Vitamin K, which is found high in green vegetables including raw spinach, raw leaf lettuce, raw kale, raw Swiss chard, raw watercress, raw parsley and cooked broccoli.
First published October 3, 2012, doi: 10.3945/ajcn.111.033498 Am J Clin Nutr November 2012 ajcn.033498