Fish Oil and C-Reactive Protein

Abstracts of Published Studies Showing Fish Oil and its Potential Efficacy to Lower C-Reactive Protein

Dietary fish oil decreases C-reactive protein, interleukin-6, and triacylglycerol to HDL-cholesterol ratio in postmenopausal women on HRT.

Ciubotaru I, Lee YS, Wander RC.

Department of Nutrition, The University of North Carolina at Greensboro, Greensboro, NC 27402, USA.

BACKGROUND: Atherogenesis is a complex process involving both a low-grade inflammation and a disturbed lipid profile. Although dietary fish and fish oil improve the latter of these two risk factors, their impact on the former is less clear. OBJECTIVE: This study addressed the effect of supplementation with fish oil in doses achievable with diet on serum C-reactive protein (CRP), interleukin-6 (IL-6), and the lipid profile. METHODS AND RESULTS: Thirty healthy subjects taking HRT were randomly divided into three groups and supplemented for five weeks with 14 g/day safflower oil (SO), 7 g/day of both safflower oil and fish oil (LFO), or 14 g/day fish oil (HFO). Measurements included serum high-sensitivity CRP, IL-6 in plasma and in cell culture supernatant collected from 24-hr lipopolysaccharide (LPS)-stimulated whole blood, and lipid profile markers. CRP and IL-6 were adjusted for body mass index (BMI). Fish oil supplementation significantly decreased CRP and IL-6 compared to SO, with a greater effect in the LFO than HFO groups. Plasma triacylglycerol (TG) and the TG/HDL-C ratio were significantly lower in the HFO compared to the SO group. CONCLUSIONS: These results suggest that dietary fish oil may decrease the risk for cardiovascular disease through the modulation of both plasma lipids and inflammatory markers in healthy postmenopausal women. J Nutr Biochem. 2003 Sep;14(9):513-21.

Consumption of (n-3) fatty acids is related to plasma biomarkers of inflammation and endothelial activation in women.

Lopez-Garcia E, Schulze MB, Manson JE, Meigs JB, Albert CM, Rifai N, Willett WC, Hu FB. Department of Nutrition, Harvard School of Public Health, Harvard Medical School, USA. elopezga@hsph.harvard.edu

We evaluated the hypothesis that intake of (n-3) fatty acids is inversely associated with biomarkers of inflammation and endothelial activation. We conducted a cross-sectional study of 727 women from the Nurses' Health Study I cohort, aged 43-69 y, apparently healthy at time of a blood draw in 1990. Dietary intake was assessed by a validated FFQ in 1986 and 1990. C-reactive protein (CRP) levels were 29% lower among those in the highest quintile of total (n-3) fatty acids, compared with the lowest quintile; interleukin-6 (IL-6) levels were 23% lower, E-selectin levels 10% lower, soluble intracellular adhesion molecule (sICAM-1) levels 7% lower, and soluble vascular adhesion molecule (sVCAM-1) levels 8% lower. The intake of alpha-linolenic acid was inversely related to plasma concentrations of CRP (beta = -0.55, P = 0.02), Il-6 (beta = -0.36, P = 0.01), and E-selectin (beta = -0.24, P = 0.008) after controlling for age, BMI, physical activity, smoking status, alcohol consumption, and intake of linoleic acid (n-6) and saturated fat. Long-chain (n-3) fatty acids (eicosapentaenoic and docosahexaenoic) were inversely related to sICAM-1 (beta = -0.11, P = 0.03) and sVCAM-1 (beta = -0.17, P = 0.003). Total (n-3) fatty acids had an inverse relation with CRP (beta = -0.44, P = 0.007), IL-6 (beta = -0.26, P = 0.009), E-selectin (beta = -0.17, P = 0.004), sICAM-1 (beta = -0.07, P = 0.02), and sVCAM-1 (beta = -0.10, P = 0.004). These associations were not modified by intake of vitamin E, dietary fiber, trans fatty acids, or by the use of postmenopausal hormone therapy. In conclusion, this study suggests that dietary (n-3) fatty acids are associated with levels of these biomarkers reflecting lower levels of inflammation and endothelial activation, which might explain in part the effect of these fatty acids in preventing cardiovascular disease. J Nutr. 2004 Jul;134(7):1806-11.

A dietary supplement attenuates IL-6 and CRP after eccentric exercise in untrained males.

Phillips T, Childs AC, Dreon DM, Phinney S, Leeuwenburgh C.

University of Florida, Biochemistry of Aging Laboratory, College of Health and Human Performance, Center for Exercise Science, College of Medicine, Gainesville 32611, USA.

PURPOSE: This study investigated the effects of a dietary supplement on exercise-induced markers of cell damage and the inflammatory mediators C-reactive protein (CRP) and interleukin-6 (IL-6). METHODS: The supplement contained mixed tocopherols, flavonoids, and docosahexaenoate. Forty healthy, nonsmoking, untrained males (aged 18-35 yr) were randomly assigned to receive either the supplement (N = 20) or placebo (N = 20) during the 14-d experimental protocol. Blood samples were collected on day 0 (baseline), day 7 (eccentric exercise-induced injury), day 10, and day 14. OBJECTIVE: Markers of cell damage (creatine kinase (CK) and lactate dehydrogenase (LDH)) and inflammation IL-6 and CRP were assessed at these time points in conjunction with subjective range of motion (ROM) and perceived pain measurements. Statistical analyses were conducted using nonparametric methods (P < 0.05). RESULTS: Eccentric arm curl exercise was used to induce an acute phase injury response as evidenced by significant (P < 0.0001) increases in CK, LDH, and pain, as well as a decreased range of motion 3 d after the exercise. There were no significant differences between groups in CK and LDH responses. In contrast, there were significant group differences for IL-6 (P = 0.008) and CRP (P = 0.003). At day 10, by Mann-Whitney U test of changes, the placebo group had significantly greater increases in IL-6 and CRP than the treatment group (P = 0.05 and P < 0.01), respectively. CONCLUSION: This study suggested that exercise-induced inflammation, evaluated by changes in IL-6 and CRP, was significantly reduced by the dietary supplement. Med Sci Sports Exerc. 2003 Dec;35(12):2032-7.

C-reactive protein, dietary n-3 fatty acids, and the extent of coronary artery disease.

Madsen T, Skou HA, Hansen VE, Fog L, Christensen JH, Toft E, Schmidt EB.

Department of Cardiology, Aalborg Hospital, Aalborg, Denmark. austrine@hotmail.com

The acute-phase reactant C-reactive protein (CRP) has emerged as an independent risk factor for coronary artery disease. Experimental and clinical studies provide evidence of anti-inflammatory effects of n-3 polyunsaturated fatty acids (PUFA) derived from fish. We have studied the effect of marine n-3 PUFA on CRP levels in 269 patients referred for coronary angiography because of clinical suspicion of coronary artery disease. All patients filled out a food questionnaire regarding fish intake. The n-3 PUFA content of granulocyte membranes was determined and the concentration of CRP in serum was measured using a highly sensitive assay. The results were related to angiographic findings. CRP was significantly higher in patients with significant coronary stenoses than in those with no significant angiographic changes (p <0.001), but the CRP levels were not associated with the number of diseased vessels. Subjects with CRP levels in the lower quartile had a significantly higher content of docosahexaenoic acid (DHA) in granulocytes than subjects with CRP levels in the upper quartile (p = 0.02), and in a multivariate linear regression analysis, DHA was independently correlated to CRP (R(2) = 0.179; p = 0.003). The inverse correlation between CRP and DHA may reflect an anti-inflammatory effect of DHA in patients with stable coronary artery disease and suggest a novel mechanism by which fish consumption may decrease the risk of coronary artery disease. Am J Cardiol. 2001 Nov 15;88(10):1139-42.