title: Blood docosahexaenoic acid and eicosapentaenoic acid in vegans: Associations with age and gender and effects of an algal-derived omega-3 fatty acid supplement.
abstract: OBJECTIVE
  Several studies have demonstrated that vegetarians and vegans have much lower plasma concentrations of omega-3 fatty acids (i.e., docosahexaenoic and eicosapentaenoic acids) when compared to those who eat fish. The purposes of this study were 1) to define the age and/or sex-specific docosahexaenoic plus eicosapentaenoic acids levels in red blood cell membranes (expressed as a percent of total fatty acids; hereafter the omega-3 index) in long-term vegans, and 2) to determine the effects of a vegetarian omega-3 supplement (254 mg docosahexaenoic plus eicosapentaenoic acids/day for 4 months) on the omega-3 index.
  
  
  METHODS
  A sample (n = 165) of vegans was recruited, and their omega-3 index was determined using a dried blood spot methodology. A subset of 46 subjects with a baseline omega-3 index of <4% was given a vegetarian omega-3 supplement for 4 months and then retested.
  
  
  RESULTS
  The mean ± SD omega-3 index was 3.7 ± 1.0% which was similar to that of a cohort of omnivores (deployed US soldiers) from a recently-reported study. Among the vegan cohort, the index was significantly higher in females than males (3.9 ± 1.0% vs. 3.5 ± 1.0%; p = 0.026) and was directly related to age (p for trend = 0.009). The omega-3 index increased from 3.1 ± 0.6% to 4.8 ± 0.8% (p = 0.009) in the supplementation study.
  
  
  CONCLUSIONS
  We conclude that vegans have low baseline omega-3 levels, but not lower than omnivores who also consume very little docosahexaenoic and eicosapentaenoic acids. The vegans responded robustly to a relatively low dose of a vegetarian omega-3 supplement.
authors.affiliation: Hahn School of Nursing and Health Sciences, University of San Diego, CA, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Sarter
authors.affiliation: Department of Biostatistics, Gillings School of Global Public Health and School of Nursing, University of North Carolina at Chapel Hill, NC, USA.
authors.forename: Kristine S
authors.initials: KS
authors.lastname: Kelsey
authors.affiliation: Department of Biostatistics, Gillings School of Global Public Health and School of Nursing, University of North Carolina at Chapel Hill, NC, USA.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Schwartz
authors.affiliation: Sanford School of Medicine, University of South Dakota and OmegaQuant Analytics, LLC, Sioux Falls, SD, USA. Electronic address: bill@omegaquant.com.
authors.forename: William S
authors.initials: WS
authors.lastname: Harris
mesh_terms: D000328:Adult; D000367:Age Factors; D014676:Diet, Vegetarian / Q000009:adverse effects*; D004041:Dietary Fats / Q000008:administration & dosage; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000097:blood*; D015118:Eicosapentaenoic Acid / Q000097:blood*; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D005227:Fatty Acids / Q000097:blood*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D012737:Sex Factors; D016896:Treatment Outcome
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid
keywords: Ageing; Biomarkers; Omega-3 fatty acids; Omega-3 index; Vegan; Vegetarian