Abstract
BACKGROUND: It is important to assess vitamin K intake due to its involvement in multiple physiological processes. This study aims to validate a food frequency questionnaire for estimating vitamin K1, vitamin K2 and total vitamin K intake over 3 months in the adult Mexican population. METHODS: The food frequency questionnaire design included 49 food items and six frequency categories. The study included 42 young adults from Mexico classified as overweight or obese. Participants completed the food frequency questionnaire twice over a three-month period (at baseline and at the end of the study), and reproducibility was assessed using these measurements. Additionally, four 24-hour dietary recalls were collected throughout the same period to evaluate criterion validity. RESULTS: The final food frequency questionnaire showed good relative and absolute agreement in estimating vitamin K1 intake compared to the average of four 24-hour dietary recalls. In the estimation of vitamin K2 and total vitamin K intake, discrepancies in the agreement between the tools were observed. CONCLUSIONS: This study presents the first approach to developing a food frequency questionnaire for estimating vitamin K intake in the adult Mexican population. Its use is recommended for estimating vitamin K1 intake in both clinical practice and research. It is crucial to obtain more comprehensive and accurate information on food composition, both in Mexico and globally, to more precisely assess vitamin K2 intake in different populations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40795-025-01187-y.