Dietary intake and biomarker status of folate in Swedish adults

Abstract

PurposeNational data on folate status are missing in Sweden, and regional data indicate folate insufficiency in up to more than 25% of the study populations. The objectives were to determine folate intake and status in the adult Swedish population as well as identifying dietary patterns associated with beneficial folate status.MethodsFolate intake was estimated using a web-based 4-d food record in adults aged 18–80 years (n = 1797). Folate status was measured as erythrocyte (n = 282) and plasma folate concentrations (n = 294). Factor analysis was used to derive a dietary pattern associated with a higher folate status.ResultsMedian folate intake was 246 µg/day (Q 1 = 196, Q 3 = 304, n = 1797) and for women of reproductive age 227 µg/day (Q 1 = 181, Q 3 = 282, n = 450). As dietary folate equivalents (DFE), median intake was 257 µg/day (Q 1 = 201, Q 3 = 323) and for women of reproductive age 239 µg/day (Q 1 = 185, Q 3 = 300). Low blood folate concentrations were found in 2% (erythrocyte concentrations <317 nmol/L) and 4% (plasma concentrations <6.8 nmol/L) of the participants, respectively. None of the women of reproductive age had erythrocyte folate concentrations associated with the lowest risk of neural tube defects. Dietary patterns associated with higher folate status were rich in vegetables, pulses and roots as well as cheese and alcoholic beverages, and low in meat.ConclusionsPrevalence of low erythrocyte folate concentrations was low in this population, and estimated dietary intakes are well above average requirement. However, to obtain a folate status optimal for prevention of neural tube defects major dietary changes are required and folic acid supplements recommended prior to conception.

Systematic Review of Observational Studies with Dose-Response Meta-Analysis between Folate Intake and Status Biomarkers in Adults and the Elderly

“…We found statistically significant higher estimates for folate intake-status serum/plasma relationship when microbiological assay was used rather than non-microbiological assay, whereas the estimates for RBC folate did not statistically differ between the 2. Our finding that the type of analytical method had a considerable influence on the response, confirms the expert opinion that comparison of studies that used different assays requires caution, as different analytical methods are known to cause up to 30% difference in folate status results [38]. Indeed, future research should benefit from methodologically comparable data on folate intake and status.…”

Global folate status in women of reproductive age: a systematic review with emphasis on methodological issues

“…In most cases, appropriate procedures were followed to ensure specimen integrity (Supplementary Table S1, online only). In a few cases, storage or handling of samples under suboptimal conditions may have led to folate losses (Côte d'Ivoire 2007, Sierra Leone 2013, the United Kingdom 2000–2001, and 2008–2012, and Uzbekistan 2008); in other cases, incomplete information was provided (Afghanistan 2013, Australia 2011–2012, Cambodia 2014, Ecuador 2012, Jordan 2010, Lebanon 2003, Mongolia 2004, and Sweden 2010–2011). No information was reported in one survey (Newfoundland, Canada).…”

“…Of the remaining five surveys reporting RBC folate concentrations, four (Australia, Canada 2007–2009, Sweden, and the United Kingdom 2000–2001) used a PBA method and reported the prevalence of folate insufficiency in WRA. The prevalence of folate insufficiency (RBC folate <906 nmol/L) in WRA was <1% in the Australian Health Survey 2011–2012, 22% in the Canadian Health Measures Survey 2007–2009, and 100% in Sweden's Riksmaten Adults 2010–2011 survey . Because of the high calculated prevalence factors in the Australian (2.33) and Canadian (1.34) surveys, the prevalence of folate insufficiency is likely underestimated in these surveys (data not shown).…”

“…The prevalence factor for the NDNS RP years 1–4 2008–2012 survey was 0.70, indicating that the reported prevalence of folate deficiency of 17% is likely an overestimate (Table ). The remaining five surveys (Austrian Nutrition Report 2010–2012, Bahrain 2002, Newfoundland, Canada, Irish National Adult Nutrition Survey 2008–2010, and Sweden's Riksmaten Adults 2010–2011 survey) did not report a prevalence of folate deficiency based on serum folate.…”

“…Countries with high-income economies. There were 14 surveys conducted within 12 countries with high-income economies (Argentina, 69 Australia, 38 Austria, 70 Bahrain, 71 Canada, 46,72 France, 73 Ireland, 74 New Zealand, 75 Spain, 76 Sweden, 45 the United Kingdom, 34,35 and the United States 77 ). Two surveys each were conducted in Canada 46,72 and the United Kingdom.…”