Fish oil supplementation does not lower C-reactive protein or interleukin-6 levels in healthy adults.
BACKGROUND
The n-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may prevent a range of chronic conditions through anti-inflammatory actions. However, as clinical trials using these fatty acids for primary prevention are yet unavailable, their putative role in disease prevention rests, in part, on evidence of anti-inflammatory actions in healthy individuals.


OBJECTIVE
To investigate in a double-blind, placebo-controlled clinical trial whether supplementation with a moderate dose of EPA+DHA reduces common biomarkers of chronic, systemic inflammation in healthy individuals.


METHODS
A total of 261 healthy individuals aged 30-54 years who were free of inflammatory conditions and consumed ≤ 300 mg per day EPA+DHA were included in the study. Participants were randomly assigned to 18 weeks of either fish oil supplementation providing 1400 mg per day EPA+DHA or matching placebo. Outcome measures were serum levels of C-reactive protein (CRP) and interleukin (IL)-6. In a substudy, ex vivo cytokine production was measured. Missing data for CRP and IL-6 were estimated using regression imputation. Data analyses conformed to intention-to-treat principles.


RESULTS
Participant blinding was verified. Red blood cell EPA+DHA increased by 64% in the active treatment group, but serum CRP and IL-6 were not affected by supplementation (P ≥ 0.20). Findings were consistent with and without imputed values and across subgroups. Similarly, EPA+DHA supplementation did not alter ex vivo production of four pro-inflammatory cytokines (P ≥ 0.20).


CONCLUSIONS
Supplementation with 1400 mg EPA+DHA did not reduce common markers of systemic inflammation in healthy adults. Whether this or a higher dose affects other measures of inflammation, oxidative stress or immune function warrants examination.
Heart and Vascular Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
M F
MF
Muldoon
Department of Medicine, Jackson Memorial Hospital, Miami, FL, USA.
B
B
Laderian
Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA.
D C H
DC
Kuan
School of Nursing, University of Pittsburgh, Pittsburgh, PA, USA.
S M
SM
Sereika
Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA.
A L
AL
Marsland
Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA.
S B
SB
Manuck
D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis*; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000097:blood; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged
D005395:Fish Oils; C508600:IL6 protein, human; D015850:Interleukin-6; D004281:Docosahexaenoic Acids; D002097:C-Reactive Protein; D015118:Eicosapentaenoic Acid
cytokines; docosahexaenoic acid; eicosapentaenoic acid; fish oils; inflammation