title: Supplementation of arachidonic acid-enriched oil increases arachidonic acid contents in plasma phospholipids, but does not increase their metabolites and clinical parameters in Japanese healthy elderly individuals: a randomized controlled study.
abstract: BACKGROUND
  The importance of arachidonic acid (ARA) among the elderly has recently gained increased attention. The effects of ARA supplementation in the elderly are not fully understood, although ARA is considered to be associated with various diseases. We investigate whether ARA supplementation to Japanese elderly subjects affects clinical parameters involved in cardiovascular, inflammatory, and allergic diseases. We also examine the levels of ARA metabolites such as prostanoids during intervention.
  
  
  METHODS
  We conducted a randomized, double-blind and placebo-controlled parallel group intervention trial. ARA-enriched oil (240 or 720 mg ARA per day) or placebo was administered to Japanese healthy men and women aged 55-70 years for 4 weeks followed by a 4-week washout period. The fatty acid contents of plasma phospholipids, clinical parameters, and ARA metabolites were determined at baseline, 2, 4, and 8 weeks.
  
  
  RESULTS
  The ARA content in plasma phospholipids in the ARA-administrated groups increased dose-dependently and was almost the same at 2 weeks and at 4 weeks. The elevated ARA content decreased to nearly baseline during a 4-week washout period. During the supplementation and washout periods, no changes were observed in eicosapentaenoic acid and docosahexaenoic acid contents. There were no changes in clinical blood parameters related to cardiovascular, inflammatory and allergic diseases. ARA supplementation did not alter the level of ARA metabolites such as urinary 11-dehydro thromboxane B2, 2,3-dinor-6-keto prostaglandin (PG) F1α and 9,15-dioxo-11α-hydroxy-13,14-dihydro-2,3,4,5-tetranor-prostan-1,20-dioic acid (tetranor-PGEM), and plasma PGE2 and lipoxin A4. ARA in plasma phospholipids was not correlated with ARA metabolite levels in the blood or urine.
  
  
  CONCLUSIONS
  These results indicate that ARA supplementation, even at a relatively high dose, does not increase ARA metabolites, and suggest that it does not induce cardiovascular, inflammatory or allergic diseases in Japanese elderly individuals.
authors.affiliation: Institute for Health Care Science, Suntory Wellness Ltd, Osaka, Japan. saki_kakutani@suntory.co.jp
authors.forename: Saki
authors.initials: S
authors.lastname: Kakutani
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ishikura
authors.forename: Norifumi
authors.initials: N
authors.lastname: Tateishi
authors.forename: Chika
authors.initials: C
authors.lastname: Horikawa
authors.forename: Hisanori
authors.initials: H
authors.lastname: Tokuda
authors.forename: Masanori
authors.initials: M
authors.lastname: Kontani
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawashima
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kiso
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shibata
authors.forename: Ikuo
authors.initials: I
authors.lastname: Morita
mesh_terms: D000368:Aged; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D016718:Arachidonic Acid / Q000008:administration & dosage* / Q000493:pharmacokinetics; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000188:drug therapy; D019587:Dietary Supplements; D004311:Double-Blind Method; D004435:Eating; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage* / Q000493:pharmacokinetics; D007249:Inflammation / Q000097:blood / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood*
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D007155:Immunologic Factors; D010743:Phospholipids; D016718:Arachidonic Acid