National Diet and Nutrition Survey data reveal a decline in folate status in the UK population between 2008 and 2019.
The American Journal of Clinical Nutrition 2023
PubMed ID : 37839706
Folate is essential for healthy growth and development. Fortification of foods with folic acid can improve folate status and reduce the risk of neural tube defects (NTD). Following concern around folate status in the UK, the UK government announced in 2021 the intention to introduce mandatory folic acid fortification.
The objective was to describe folate status in the UK population prior to the implementation of mandatory folic acid fortification of non-wholemeal wheat flour and to assess trends in folate status, including in females of reproductive age (FRA).
Data were from the UK National Diet and Nutrition Survey Rolling Programme (2008-2019), a cross-sectional, nationally-representative survey of children and adults aged 1.5+ years (n 5,792 with folate result). Serum folate concentration was measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) and red blood cell (RBC) folate concentration by microbiological assay. Concentration data were compared against method-specific cut-offs and thresholds, and relationships explored against demographic and lifestyle characteristics.
RBC and serum folate concentration significantly decreased by ∼3 percentage points per year between 2008 and 2019 in all age/sex groups. Prevalence of deficiency (RBC folate <305 nmol/L) was highest in children aged 11-18 years (17% in 2016-19). The proportion of FRA below the cut-off for increased risk of NTD (RBC folate <748 nmol/L), increased from 69% to 89% between 2008 and 2019. Ethnicity, smoking status and income were significant determinants of RBC and serum folate concentrations.
These data reveal a decline in population folate status in the UK between 2008 and 2019 and, a high prevalence of folate deficiency. A high proportion of FRA had RBC folate concentrations below the cut-off for increased risk of NTD. These data provide information on folate status in a population not currently exposed to mandatory folic acid fortification, and are essential to model and assess its impact.
In this paper, we examined folate levels in the UK population. Folate (vitamin B9) is a water soluble vitamin found in foods such as leafy vegetables, legumes, egg yolks, liver and some citrus fruits. It is required for many essential functions in the body, including DNA synthesis and repair. Folate deficiency can lead to megaloblastic anaemia, where red blood cells are abnormally large and underdeveloped. In pregnancy low folate intakes are associated with a risk of neural tube defects. Therefore, it is particularly important that women of child bearing age have sufficient folate intake.
We used data from the UK National Diet and Nutrition Survey Rolling Programme (NDNS RP), a UK government-funded survey of children and adults aged 1.5 years and over, designed to assess nutrient intake and nutritional status of the general UK population. The NDNS RP is performed by the MRC Epidemiology Unit, University of Cambridge together with the National Centre for Social Research (NatCen). Using the data from the NDNS RP, we assessed trends in population folate levels between 2008 and 2019.
We showed that folate levels decreased by about 3% per year. Children aged 11-17 years had the lowest folate levels, and almost one in five of this age group were classified as deficient. We also showed that in 2019, nine out of ten women of child bearing age had blood folate levels that are associated with a high risk of neural tube defects.
Following concerns regarding folate status in the UK, the Government announced in 2021 the intention to introduce mandatory folic acid fortification of non-wholemeal wheat flour. Our data will be vital to assess the impact of mandatory fortification on the change in folate levels of the UK population over the coming years.