Objective: To assess the effect of a 4-week herring diet compared to a reference diet on biomarkers for cardiovascular disease in obese subjects.
Design: Randomized crossover trial.
Setting: Department of Internal Medicine, Sahlgrenska University Hospital.
Subjects: Fifteen healthy obese men and women (age 24-70 years) included, 13 completed.
Intervention: Subjects were randomly assigned to four weeks of herring diet (150 g baked herring fillets/day 5, days/week) or reference diet (pork and chicken fillets) and switched diets after 2 weeks washout. P-total cholesterol, p-TAG, p-HDL, p-HDL(2), p-HDL(3), p-LDL, p-apolipoprotein A, p-apolipoprotein B, p-Lipoprotein (a), p-fibrinogen, p-C- reactive protein and p-antioxidative capacity were analysed at 0,2,4,6,8 and 10 weeks.
Results: P-HDL was significantly higher after the herring diet period compared to after the reference diet period; 1.22 vs 1.13 mmol/l (P=0.036). There was a small, but not statistically significant, decrease in TAG but no effect on other biomarkers. TEAC and FRAP, but not ORAC-values, indicated that plasma antioxidants may have been reduced. CRP tended to be lower after the herring diet compared to after the reference diet.
Conclusions: Consumption of oven-baked herring (150 g/day, 5 days/week) for 4 weeks, compared to consumption of pork and chicken fillets, significantly increased p-HDL. Patients with insulin resistance and obesity, who commonly have low HDL, may therefore benefit from addition of herring to the diet.