title: Fish consumption, sleep, daily functioning, and heart rate variability.
abstract: OBJECTIVE
  This study investigated the effects of fatty fish on sleep, daily functioning and biomarkers such as heart rate variability (HRV), vitamin D status (serum 25-hydroxyvitamin D (25OHD), and eicosapentaenoic acid (EPA, 20:5n-3) + docosahexaenoic acid (DHA, 22:6n-3) in red blood cells. Moreover the relationship among sleep, daily functioning, HRV, vitamin D status, and levels of EPA+DHA was investigated.
  
  
  METHODS
  Ninety-five male forensic patients from a secure forensic inpatient facility in the USA were randomly assigned into a Fish or a Control group. The Fish group received Atlantic salmon three times per week from September to February, and the Control group was provided an alternative meal (e.g., chicken, pork, beef), but with the same nutritional value as their habitual diet, three times per week during the same period. Sleep (sleep latency, sleep efficiency, actual sleep time, and actual wake time), self-perceived sleep quality and daily functioning, as well as vitamin D status, EPA+DHA, and HRV, were assessed pre- and post-intervention period.
  
  
  RESULTS
  There was a significant increase in sleep latency from pre- to post-test in the Control group. The Fish group reported better daily functioning than the Control group during post-test. Fish consumption throughout the wintertime had also an effect on resting HRV and EPA+DHA, but not on vitamin D status. However, at post-test, the vitamin D status in the Fish group was still closer to the level regarded as optimal compared to the Control group. Vitamin D status correlated negatively with actual wake time and positively with sleep efficiency during pre-test, as well as positively with daily functioning and sleep quality during post-test. Finally, HRV correlated negatively with sleep latency and positively with daily functioning.
  
  
  CONCLUSIONS
  Fish consumption seemed to have a positive impact on sleep in general and also on daily functioning, which may be related to vitamin D status and HRV.
authors.affiliation: University of Bergen, Bergen, Norway ; Centre for Research and Education in Forensic Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors.forename: Anita L
authors.initials: AL
authors.lastname: Hansen
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), Bergen, Norway.
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Dahl
authors.affiliation: Sand Ridge Secure Treatment Center (SRSTC) Mauston, WI.
authors.forename: Gina
authors.initials: G
authors.lastname: Olson
authors.affiliation: Sand Ridge Secure Treatment Center (SRSTC) Mauston, WI.
authors.forename: David
authors.initials: D
authors.lastname: Thornton
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), Bergen, Norway.
authors.forename: Ingvild E
authors.initials: IE
authors.lastname: Graff
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), Bergen, Norway.
authors.forename: Livar
authors.initials: L
authors.lastname: Frøyland
authors.affiliation: Ohio State University, Department of Psychology, Columbus, OH ; Mannheim Institute of Public Health, Social and Preventive Medicine, Mannheim Medical Faculty, Heidelberg University, Mannheim, Germany.
authors.forename: Julian F
authors.initials: JF
authors.lastname: Thayer
authors.affiliation: University of Bergen, Bergen, Norway ; Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Bergen, Norway.
authors.forename: Staale
authors.initials: S
authors.lastname: Pallesen
mesh_terms: D056044:Actigraphy; D000203:Activities of Daily Living; D000328:Adult; D000818:Animals; D004032:Diet; D004281:Docosahexaenoic Acids / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000097:blood; D005399:Fishes; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D014807:Vitamin D / Q000097:blood; D055815:Young Adult
chemical_list: D014807:Vitamin D; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid
keywords: DHA; EPA; HRV; daily functioning; fatty fish consumption; sleep; vitamin D