[Dietary vitamin K intake of healthy individuals aged 50 and above in China in 2015-2017].

Objective: To assess the status of vitamin K(VK) dietary intake in healthy Chinese middle-aged and elderly population.

Methods: The population sample was extracted from the Chinese Adult Chronic Disease and Nutrition Surveillance(CACDNS) 2015-2017. A total of 1409 subjects were enrolled after screening. Food frequency questionnaire was used to investigate dietary intake data, and the VK food composition database(including VK_1, MK-4, MK-7 and MK-9) established by the "China Food Composition Database" team was updated for the analysis of VK dietary intake. We calculated the dietary intake of various VK subtypes and added them up to obtain the total VK intake.

Results: The median intake of VK_1, MK-4, MK-7 and VK_2 were 77.49, 7.53, 1.39 and 9.01 μg/d, respectively. The median dietary intake of total VK was 91.87 μg/d. In differential analysis, there were statistically significant differences in dietary intake of total vitamin K among different age groups, residence categories, and southern and northern populations(P<0.05). The VK dietary intake in 75 years old and above group was lower than that in 50-64 years old and 65-74 years old groups, the intake in urban group was higher than that in rural group, and the intake in southern group was higher than that in northern group. The main food source of VK_1 was vegetables(82.26%), while the main food sources of VK_2 were eggs(71.32%) and meat(22.42%).

Conclusion: The total dietary intake of vitamin K of the middle-aged and elderly population in China is higher than the current adequate intake(AI) in dietary reference intakes(DRIs). We suggest that the AI values of total VK, VK_1 and VK_2 in the diet of healthy middle-aged and elderly people in China be 90, 80 and 10 μg/d, respectively.