title: Effects of the flavonol quercetin and α-linolenic acid on n-3 PUFA status in metabolically healthy men and women: a randomised, double-blinded, placebo-controlled, crossover trial.
abstract: Increased dietary intake and tissue status of the long-chain n-3 PUFA, EPA and DHA, is associated with cardiovascular benefits. Epidemiological and animal studies suggest that concomitant nutritive intake of flavonoids may increase the conversion of α-linolenic acid (ALA) to longer-chain n-3 fatty acids EPA and DHA. We investigated the effects of increased ALA intake on fatty acid composition of serum phospholipids and erythrocytes in metabolically healthy men and women and whether fatty acid profiles and ALA conversion were affected by regular quercetin intake or sex. Subjects (n 74) were randomised to receive at least 3·3 g/d ALA with either 190 mg/d quercetin (ALA+quercetin) or placebo (ALA+placebo) in a double-blinded, placebo-controlled, crossover trial with 8-week intervention periods separated by an 8-week washout period. A total of seven subjects dropped out for personal reasons. Data from the remaining sixty-seven subjects (thirty-four males and thirty-three females) were included in the analysis. Both interventions significantly increased serum phospholipid ALA (ALA+placebo: +69·3 %; ALA+quercetin: +55·8 %) and EPA (ALA+placebo: +37·3 %; ALA+quercetin: +25·5 %). ALA + quercetin slightly decreased DHA concentration by 9·3 %. Erythrocyte ALA and EPA significantly increased with both interventions, whereas DHA decreased. Fatty acid composition did not differ between sexes. We found no effect of quercetin. Intake of 3·6 g/d ALA over an 8-week period resulted in increased ALA and EPA, but not DHA, in serum phospholipids and erythrocytes. Neither quercetin supplementation nor sex affected the increment of ALA and relative proportions of n-3 PUFA in serum phospholipids and erythrocytes.
authors.affiliation: 1Department of Nutrition and Food Sciences,Nutritional Physiology,University of Bonn,53115 Bonn,Germany.
authors.forename: Constanze
authors.initials: C
authors.lastname: Burak
authors.affiliation: 2Institute of Animal Nutrition and Physiology,Christian-Albrechts-University Kiel,24118 Kiel,Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wolffram
authors.affiliation: 3Institute of Clinical Chemistry and Clinical Pharmacology,University Hospital Bonn,53127 Bonn,Germany.
authors.forename: Berndt
authors.initials: B
authors.lastname: Zur
authors.affiliation: 4Department of Biopharmaceutics and Pharmaceutical Technology,Institute of Pharmacy and Biochemistry,Johannes Gutenberg University,55122 Mainz,Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Langguth
authors.affiliation: 5Institute of Medical Biometry, Informatics and Epidemiology,University of Bonn,53105 Bonn,Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Fimmers
authors.affiliation: 1Department of Nutrition and Food Sciences,Nutritional Physiology,University of Bonn,53115 Bonn,Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Alteheld
authors.affiliation: 1Department of Nutrition and Food Sciences,Nutritional Physiology,University of Bonn,53115 Bonn,Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Stehle
authors.affiliation: 1Department of Nutrition and Food Sciences,Nutritional Physiology,University of Bonn,53115 Bonn,Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Egert
mesh_terms: D000328:Adult; D001823:Body Composition; D018592:Cross-Over Studies; D004032:Diet; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000097:blood; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000097:blood; D004912:Erythrocytes / Q000737:chemistry; D005227:Fatty Acids / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D010743:Phospholipids / Q000097:blood; D010919:Placebos; D011794:Quercetin / Q000008:administration & dosage*; D017962:alpha-Linolenic Acid / Q000008:administration & dosage*
chemical_list: D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D010743:Phospholipids; D010919:Placebos; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D011794:Quercetin; D015118:Eicosapentaenoic Acid
keywords: 
                 n-3 Long-chain PUFA; 
                 α-Linolenic acid;  ALA 
                    α-linolenic acid;  DPA docosapentaenoic acid; Quercetin; Sex differences