title: Non-enzymatic antioxidant capacity (NEAC) estimated by two different dietary assessment methods and its relationship with NEAC plasma levels.
abstract: OBJECTIVE
  We aimed to quantify and compare dietary non-enzymatic antioxidant capacity (NEAC), estimated using two dietary assessment methods, and to explore its relationship with plasma NEAC.
  
  
  METHODS
  Fifty healthy subjects volunteer to participate in this study. Two dietary assessment methods [a food frequency questionnaire (FFQ) and a 24-hour recall (24-HR)] were used to collect dietary information. Dietary NEAC, including oxygen radical absorbance capacity (ORAC), total polyphenols, ferric-reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity, was estimated using several data sources of NEAC content in food. NEAC status was measured in fasting blood samples using the same assays. We performed nonparametric Spearman's correlation analysis between pairs of dietary NEAC (FFQ and 24-HR) and diet-plasma NEAC, with and without the contribution of coffee's NEAC. Partial correlation analysis was used to estimate correlations regardless of variables potentially influencing these relationships.
  
  
  RESULTS
  FFQ-based NEAC and 24-HR-based NEAC were moderately correlated, with correlation coefficients ranging from 0.54 to 0.71, after controlling for energy intake, age and sex. Statistically significant positive correlations were found for dietary FRAP, either derived from the FFQ or the 24-HR, with plasma FRAP (r ~ 0.30). This weak, albeit statistically significant, correlation for FRAP was mostly present in the fruits and vegetables food groups. Plasma ORAC without proteins and 24-HR-based total ORAC were also positively correlated (r = 0.35).
  
  
  CONCLUSIONS
  The relationship between dietary NEAC and plasma FRAP and ORAC suggests the dietary NEAC may reflect antioxidant status despite its weak in vivo potential, supporting further its use in oxidative stress-related disease epidemiology.
authors.affiliation: Departamento de Nutrición y Bromatología, Facultad de Farmacia, University of Granada, Campus Universitario de Cartuja S/N, 18071, Granada, Spain.|Nutrition and Food Science Doctorate Program (RD 99/2011), University of Granada, Granada, Spain.
authors.forename: Cayetano Javier
authors.initials: CJ
authors.lastname: Carrión-García
authors.affiliation: Departamento de Nutrición y Bromatología, Facultad de Farmacia, University of Granada, Campus Universitario de Cartuja S/N, 18071, Granada, Spain. ejguerra@ugr.es.
authors.forename: Eduardo J
authors.identifier: http://orcid.org/0000-0002-2841-7743
authors.initials: EJ
authors.lastname: Guerra-Hernández
authors.affiliation: Departamento de Nutrición y Bromatología, Facultad de Farmacia, University of Granada, Campus Universitario de Cartuja S/N, 18071, Granada, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: García-Villanova
authors.affiliation: Escuela Andaluza de Salud Pública, Instituto de Investigación Biosanitaria ibs.GRANADA, Hospital Universitario de Granada/University of Granada, Granada, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.|Genetic and Molecular Epidemiology Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Molina-Montes
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage* / Q000378:metabolism*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood; D015992:Body Mass Index; D003069:Coffee / Q000737:chemistry; D003430:Cross-Sectional Studies; D004032:Diet; D004043:Dietary Fiber / Q000008:administration & dosage; D004734:Energy Metabolism; D005260:Female; D005504:Food Analysis; D005638:Fruit; D006801:Humans; D008297:Male; D011939:Mental Recall; D018977:Micronutrients / Q000008:administration & dosage / Q000097:blood; D015596:Nutrition Assessment; D059808:Polyphenols / Q000008:administration & dosage* / Q000097:blood*; D011795:Surveys and Questionnaires; D014675:Vegetables; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood; D055815:Young Adult
chemical_list: D000975:Antioxidants; D003069:Coffee; D004043:Dietary Fiber; D018977:Micronutrients; D059808:Polyphenols; D014810:Vitamin E; D001205:Ascorbic Acid
keywords: Dietary antioxidants; Dietary assessment; Non-enzymatic antioxidant capacity; Oxidative stress