title: Changes in relative and absolute concentrations of plasma phospholipid fatty acids observed in a randomized trial of Omega-3 fatty acids supplementation in Uganda.
abstract: Expressing circulating phospholipid fatty acids (PLFAs) in relative concentrations has some limitations: the total of all fatty acids are summed to 100%; therefore, the values of individual fatty acid are not independent. In this study we examined if both relative and absolute metrics could effectively measure changes in circulating PLFA concentrations in an intervention trial. 66 HIV and HHV8 infected patients in Uganda were randomized to take 3g/d of either long-chain omega-3 fatty acids (1856mg EPA and 1232mg DHA) or high-oleic safflower oil in a 12-week double-blind trial. Plasma samples were collected at baseline and end of trial. Relative weight percentage and absolute concentrations of 41 plasma PLFAs were measured using gas chromatography. Total cholesterol was also measured. Intervention-effect changes in concentrations were calculated as differences between end of 12-week trial and baseline. Pearson correlations of relative and absolute concentration changes in individual PLFAs were high (>0.6) for 37 of the 41 PLFAs analyzed. In the intervention arm, 17 PLFAs changed significantly in relative concentration and 16 in absolute concentration, 15 of which were identical. Absolute concentration of total PLFAs decreased 95.1mg/L (95% CI: 26.0, 164.2; P=0.0085), but total cholesterol did not change significantly in the intervention arm. No significant change was observed in any of the measurements in the placebo arm. Both relative weight percentage and absolute concentrations could effectively measure changes in plasma PLFA concentrations. EPA and DHA supplementation changes the concentrations of multiple plasma PLFAs besides EPA and DHA.Both relative weight percentage and absolute concentrations could effectively measure changes in plasma phospholipid fatty acid (PLFA) concentrations.
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. Electronic address: xsong2@fredhutch.org.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Song
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Pho
authors.initials: P
authors.lastname: Diep
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Jeannette M
authors.initials: JM
authors.lastname: Schenk
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA; Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Corey
authors.initials: C
authors.lastname: Casper
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA; Uganda Cancer Institute, Kampala, Uganda.
authors.forename: Jackson
authors.initials: J
authors.lastname: Orem
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Zeina
authors.initials: Z
authors.lastname: Makhoul
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Johanna W
authors.initials: JW
authors.lastname: Lampe
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Marian L
authors.initials: ML
authors.lastname: Neuhouser
mesh_terms: D000328:Adult; D002784:Cholesterol / Q000097:blood; D002849:Chromatography, Gas; D019587:Dietary Supplements; D004311:Double-Blind Method; D005227:Fatty Acids / Q000097:blood*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005260:Female; D015658:HIV Infections / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood*; D012450:Safflower Oil / Q000008:administration & dosage*; D012514:Sarcoma, Kaposi / Q000097:blood*; D016896:Treatment Outcome; D014454:Uganda
chemical_list: D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D010743:Phospholipids; D012450:Safflower Oil; D002784:Cholesterol
keywords: Absolute concentration; DHA; EPA; Phospholipid fatty acid; Relative concentration; Weight percentage concentration