Dietary vitamin K intake is associated with decreased neurofilament light chain among middle-aged and older adults from the NHANES

Purpose Neurofilament-light chain (NfL) is associated with neurodegenerative diseases, which are increasingly prevalent with aging. Vitamin K has been shown a neuroprotective effect. Therefore, we aimed to explore the potential relationship between dietary vitamin K intake and serum NfL.Methods This study was conducted on the 2013-2014 cycles of the National Health and Nutrition Examination Survey, a multi-site population-based study of the US general population. Serum NfL level was measured using a highly sensitive immunoassay. Dietary vitamin K intake was estimated from two-day dietary recall interviews, and its relationship with NfL was determined using linear regression models.Results The study included a total of 1,533 participants with a median age of 46 years, comprising 801 women (52.2%) and 732 men (47.8%). The median dietary intake of vitamin K was 81.6 mu g/d, and the median serum NfL was 12 pg./mL. After adjusting for potential confounding factors in the full model, individuals with higher dietary vitamin K intake had lower serum NfL levels (Q4 vs. Q1, beta = -4.92, 95%CI: -7.66, -2.19, p = 0.002). A non-linear negative dose-response association is found between dietary vitamin K intake and serum NfL levels (P for non-linearity = 0.008); this association reaches a plateau when the dietary vitamin K intake is higher than 200 mu g/d. According to the results of stratified analysis, the relationship between dietary vitamin K intake and serum NfL levels was stronger in the population of middle-aged and older adults.Conclusion The present study suggested a negative association between dietary vitamin K intake and serum NfL levels in the general US population, especially in middle-aged and older adults. This study might offer a novel nutritional idea for the primary prevention and mechanism exploration of neurodegenerative diseases.