Methodology for estimating dietary data from the semi-quantitative food frequency questionnaire of the Mexican National Health and Nutrition Survey 2012.

Objective: To describe the methodology used to clean up and estimate dietary intake (DI) data from the Semi-Quantitative Food Frequency Questionnaire (SFFQ) of the Mexican National Health and Nutrition Survey 2012. Materials and methods: DI was collected through a shortterm SFFQ regarding 140 foods (from October 2011 to May 2012). Energy and nutrient intake was calculated according to a nutrient database constructed specifically for the SFFQ. Results: A total of 133 nutrients including energy and fiber were generated from SFFQ data. Between 4.8 and 9.6% of the survey sample was excluded as a result of the cleaning process.Valid DI data were obtained regarding energy and nutrients consumed by 1 212 pre-school children, 1 323 school children, 1 961 adolescents, 2 027 adults and 526 older adults. Conclusions: We documented the methodology used to clean up and estimate DI from the SFFQ used in national dietary assessments in Mexico.