Investigation of the effects of a high fish diet on inflammatory cytokines, blood pressure, and lipids in healthy older Australians

Abstract

Background: Aging is a condition of chronic inflammation. In healthy Australians ≥64 years, the primary aim was to determine whether four servings/week of mixed fish (FISH) improves serum cytokines (i.e. C-reactive protein (CRP), IL-1, IL-6, TNF-a) compared to a diet low in fish (B1 serving/week, CONTROL); the secondary aims were to assess the effect of the diet on blood pressure and serum lipids (TC, HDL-C, TG, calculated LDL-C).

Methods: An 8-week randomized, parallel study, stratified by CRP (B3 mg/L vs. ≥3 mg/L) on entry to the study. Compliance was measured using 3-day weighed food records in weeks 1 and 7 of the study. A 12-h fasting blood sample was taken at baseline and 8-weeks for erythrocyte fatty acids as confirmation of compliance, and measurement of serum cytokines and lipids. Blood pressure was measured at both time points.

Results: Eighty participants completed the study (mean (SD) age: 69.6 (5.8) years). During week 1 of the study, mean ±SEM daily dietary intake of very long chain omega-3 polyunsaturated fatty acids (VLCN n-3 PUFA) in FISH vs. CONTROL was 1,676±129 mg vs. 27±5 mg (p <0.001). Mean (SD) gram intake of study fish and meat was 121 (45) g and 123 (78) g, for those allocated to FISH and CONTROL, respectively. Mean ±SEM percentage VLCN n-3 PUFA in erythrocytes at 8-weeks was higher in those allocated to FISH vs. CONTROL (10.2±0.2% vs. 8.2±0.3%, p <0.001). There was no between-group difference in CRP (n=80), IL-1B (n=33) or IL-6 (n=21) concentrations, blood pressure, or lipids, at 8-weeks.

Conclusions: Eight weeks consumption of four servings/week fish did not affect serum cytokine concentrations, blood pressure or lipids compared to a diet low in fish. In healthy older adults with low inflammatory burden, our results do not support that short-term consumption of mixed fish has a beneficial effect on selected cardiovascular biomarkers.

Keywords: older adults; fish; C-reactive protein; omega-3 long chain fatty acids; blood pressure; lipids

(Published: 15 January 2014)

Citation: Food & Nutrition Research 2014. 58: 20369 - http://dx.doi.org/10.3402/fnr.v58.20369

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