Prevalence of inadequate intake of folate in the post-fortification era: data from the Brazilian National Dietary Surveys 2008–2009 and 2017–2018

The objectives were to compare the evolution of dietary folate intake, to estimate the prevalence of folate inadequacy (POFI) and the contribution of food groups to folate intake (dietary folate plus folic acid from fortified foods) in two post-fortification periods in the Brazilian population, according to life stages, geographic regions and per capita income. Population-based study including representative data from the National Dietary Survey – Brazilian Household Budget Surveys (NDS-HBS) 2008–2009 and 2017–2018, with a total of 32 749 (2008–2009) and 44 744 (2017–2018) individuals aged ≥ 10 years old, excluding pregnant and lactating women. The National Cancer Institute method was used to estimate the distributions of usual dietary folate intake. POFI was estimated according to estimated average requirement cut-off point method. After 10 years of the first NDS-HBS, POFI has increased in all sex-age groups, except for 10–13 years. POFI among women of reproductive age was around 30 and 40 % in 2008–2009 and 2017–2018. Higher POFI was observed in the North region. The top five food groups contributors to folate intake in Brazil were beans, breads, pasta and pizza, cakes and cookies and non-alcoholic beverages groups in both periods, differing in the rank order of the last two groups. Although being a country that has adopted mandatory folic acid flour fortification for almost two decades, increased POFI was observed in 2017–2018. This study brings significant scientific information, which can help understand folate dietary data in different contexts and consequently guide the approach for public health fortification strategies.