Weight reduction, but not a moderate intake of fish oil, lowers concentrations of inflammatory markers and PAI-1 antigen in obese men during the fasting and postprandial state.
BACKGROUND
In obese subjects, chronic low-grade inflammation contributes to an increased risk of metabolic abnormalities, which are reversed by weight loss. Sustained weight loss, however, is difficult to achieve and more insight into dietary approaches on anti-inflammatory responses in obese subjects is needed. In this respect, fish oil deserves attention.


METHODS
Eleven obese men (BMI: 30-35 kg m(-2)) received daily fish oil (1.35 g n-3 fatty acids) or placebo capsules in random order for 6 weeks. Eight subjects continued with a weight reduction study that lasted 8 weeks. Mean weight loss was 9.4 kg. At the end of each experimental period a postprandial study was performed.


RESULTS
Relative to fasting concentrations, interleukin-6 (IL-6) levels increased by 75% 2 h and by 118% 4 h after the meal (P < 0.001), when subjects consumed the control capsules. In contrast, C-reactive protein (C-RP) concentrations decreased slightly by 0.7% and 6.6% (P = 0.046), and those of plasminogen activator inhibitor-1 (PAI-1) antigen by, respectively, 26% and 53% (P < 0.001). Tumour necrosis factor-alpha (TNF-alpha; P = 0.330) and soluble TNF-receptor concentrations (sTNF-R55 and sTNF-R75; P = 0.451 and P = 0.108, respectively) did not change. Changes relative to fasting concentrations were not significantly affected by either fish oil or weight reduction. Absolute IL-6, C-RP, sTNF-R55, sTNF-R75, and PAI-1 antigen concentrations, however, were consistently lower after weight reduction, but not after fish oil consumption.


CONCLUSIONS
For slightly obese subjects a moderate intake of fish oil does not have the same favourable effects on markers for a low-grade inflammatory state as weight reduction.
Jellema
A
A
Department of Human Biology, Maastricht University, Maastricht, the Netherlands.
Plat
J
J
Mensink
R P
RP
D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002214:Capsules; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000097:blood; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000097:blood; D005215:Fasting; D005395:Fish Oils / Q000008:administration & dosage*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood / Q000276:immunology*; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood*; D019518:Postprandial Period; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D015431:Weight Loss / Q000276:immunology*
D015415:Biomarkers; D002214:Capsules; D005395:Fish Oils; D015850:Interleukin-6; D017395:Plasminogen Activator Inhibitor 1; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D004281:Docosahexaenoic Acids; D002097:C-Reactive Protein; D015118:Eicosapentaenoic Acid