title: Omega-3 Fatty Acids and Vitamin D in Immobilisation: Part A- Modulation of Appendicular Mass Content, Composition and Structure.
abstract: Muscle size decreases in response to short-term limb immobilisation. This study set out to determine whether two potential protein-sparing modulators (eicosapentaenoic acid and vitamin D) would attenuate immobilisation-induced changes in muscle characteristics.
  
  
  
  The study used a randomised, double-blind, placebo-controlled design.
  
  
  
  The study took part in a laboratory setting.
  
  
  
  Twenty-four male and female healthy participants, aged 23.0±5.8 years.
  
  
  
  The non-dominant arm was immobilised in a sling for a period of nine waking hours a day over two continuous weeks. Participants were randomly assigned to one of three groups: placebo (n=8, Lecithin, 2400 mg daily), omega-3 (ω-3) fatty acids (n=8, eicosapentaenoic acid (EPA); 1770 mg, and docosahexaenoic acid (DHA); 390 mg, daily) or vitamin D (n=8, 1,000 IU daily).
  
  
  
  Muscle and sub-cutaneous adipose thickness (B-mode ultrasonography), body composition (DXA) and arm girth (anthropometry) were measured before immobilisation, immediately on removal of the sling and two weeks after re-mobilisation.
  
  
  
  Muscle thickness (-5.4±4.3%), upper and lower arm girth (-1.3±0.4 and -0.8±0.8%, respectively), lean mass (-3.6±3.7%) and bone mineral content (BMC) (-2.3±1.5%) decreased significantly with limb immobilisation in the placebo group (P<0.05). Despite no significant effect of group, ω-3 and vitamin D supplementation showed trends (p>0.05) towards attenuating the decreases in muscle thickness, upper/lower arm girths and BMC observed in the placebo group. The ω-3 supplementation group demonstrated a non-significant attenuation of the decrease in DXA quantified lean mass observed in the placebo group. Sub-cutaneous adipose thickness increased in the placebo group (P<0.05). ω-3 and vitamin D both blunted this response, with ω-3 having a greater effect (P<0.05). All parameters had returned to baseline values at the re-mobilisation phase of the study.
  
  
  
  Overall, at the current doses, ω-3 and vitamin D supplementation only attenuated one of the changes associated with non-injurious limb immobilisation. These findings would necessitate further research into either a) supplementation linked to injury-induced immobilisation, or b) larger doses of these supplements to confirm/refute the physiological reserve potential of the two supplements.
authors.affiliation: Gladys Onambele-Pearson, Health, Exercise and Active Living Research Centre, Department of Exercise and Sport Science, Manchester Metropolitan University, Crewe Green Road, Crewe, CW1 5DU, United Kingdom. Tel: +44 (0) 161 247 5594; Email: g.pearson@mmu.ac.uk.
authors.forename: E L
authors.initials: EL
authors.lastname: Bostock
authors.forename: C I
authors.initials: CI
authors.lastname: Morse
authors.forename: K
authors.initials: K
authors.lastname: Winwood
authors.forename: I M
authors.initials: IM
authors.lastname: McEwan
authors.forename: G L
authors.initials: GL
authors.lastname: Onambélé
mesh_terms: D050154:Adiposity / Q000187:drug effects; D000293:Adolescent; D000328:Adult; D001823:Body Composition; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage*; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007103:Immobilization; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D014807:Vitamin D / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014807:Vitamin D; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid