title: Food frequency questionnaire as an indicator of the serum composition of essential n-3 and n-6 polyunsaturated fatty acids in early pregnancy, according to body mass index.
abstract: BACKGROUND
  We investigated whether food frequency questionnaire (FFQ) may be indicative of the serum composition of essential n-3 and n-6 polyunsaturated fatty acids (PUFAs) in early pregnancy and if correlations are affected by body mass index (BMI).
  
  
  METHODS
  The present study comprised a prospective cohort conducted in Rio de Janeiro, Brazil. The sample was composed of 248 women, aged 20-40 years, between 6 and the 13 weeks of gestation. Dietary intake was assessed using a validated FFQ. Fatty acid serum compositions were determined in fasting serum samples, employing a high-throughput robotic direct methylation coupled with fast gas-liquid chromatography. Spearman's correlation (r(s)) was used to assess the relationship between fatty acid intake and corresponding serum composition. Women were classified according to BMI (kg m(-2) ) as underweight/normal weight (BMI < 25 kg m(-2) ; n = 139) or excessive weight (BMI ≥ 25 kg m(-2) ; n = 109).
  
  
  RESULTS
  In the total sample, dietary report was significantly correlated with the serum composition of total polyunsaturated fatty acid (PUFA; r(s) = 0.232, P < 0.001), linoleic acid (LA; 18:2n-6; r(s) = 0.271, P < 0.001), eicosapentaenoic acid (EPA; 20:5n-3; r(s) = 0.263, P < 0.001) and docosahexaenoic acid (DHA; 22:6n-3; r(s) = 0.209, P = 0.001). When analyses were stratified by BMI, significant correlations between FFQ and serum composition among underweight/normal weight women were observed for total PUFA (r(s) = 0.323, P < 0.001), LA (r(s) = 0.322, P < 0.001), EPA (r(s) = 0.352, P < 0.001) and DHA (r(s) = 0.176, P = 0.039). Among women of excessive weight, significant correlations were observed only for alpha linolenic acid (ALA; 18:3n-3; r(s) = 0.199, P = 0.040) and DHA (r(s) = 0.236, P = 0.014).
  
  
  CONCLUSIONS
  FFQ in early pregnancy may be used as a possible indicator of serum concentrations of fatty acids. Higher correlations were observed among underweight/normal weight women.
authors.affiliation: Nutritional Epidemiology Observatory, Josué de Castro Nutrition Institute, Rio de Janeiro Federal University, Rio de Janeiro, RJ, Brazil.
authors.forename: J
authors.initials: J
authors.lastname: Lepsch
authors.forename: J S
authors.initials: JS
authors.lastname: Vaz
authors.forename: J D
authors.initials: JD
authors.lastname: Moreira
authors.forename: T J P
authors.initials: TJ
authors.lastname: Pinto
authors.forename: M
authors.initials: M
authors.lastname: Soares-Mota
authors.forename: G
authors.initials: G
authors.lastname: Kac
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001938:Brazil; D004032:Diet; D004435:Eating; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D043371:Fatty Acids, Omega-6 / Q000097:blood*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6
keywords: body mass index; cohort study; epidemiology; fatty acids; food frequency questionnaire