Standardization of methodology and analysis of unmetabolized folic acid after mandatory fortification with folic acid: population-based study in São Paulo City

Abstract

Introduction: Many countries, including Brazil, fortification of foods with folic acid was adopted as a public strategy to prevent and folate deficiency. In the United States, post-fortification period, there was a positive evolution of nutritional parameters of folate, prevalence of inadequate intake falled, increased concentrations of vitamin and decreased homocysteine concentration. However, some individuals exceeded the limit maximum tolerable (UL), and had unmetabolized folic acid (UMFA) in the blood. The presence of UMFA is due the synthetic form intake. There are few studies about metabolism and biological effects of UMFA. However, the UMFA can be an important factor in safety issues associated with high intake of folic acid. Objective: To standardize an analytical methodology for detecting UMFA, analyze the UMFA concentrations in the population, and the relations with dietary intake, vitamins and homocysteine concentrations, and interaction with the genetic variants involved in folate metabolism. Methodology: This study was conducted in 750 individuals of the representative sample in São Paulo. Diet, anthropometric data and blood samples were collected. Biochemical analysis(folate, B6, B12 and homocysteine) DNA extraction and genotyping were performed. The UMFA will be determined by Kalmbach and Selhub"s methodology proposed. Multiple models will be done considering the results of dietary intake, blood concentrations and interaction with the genetic variants involved in folate metabolism. (AU)