Fish-oil esters of plant sterols differ from vegetable-oil sterol esters in triglycerides lowering, carotenoid bioavailability and impact on plasminogen activator inhibitor-1 (PAI-1) concentrations in hypercholesterolemic subjects

Abstract

Background: Consumption of plant sterol (PS) esters lower low-density lipoprotein (LDL)-cholesterol levels by suppressing intestinal absorption of cholesterol. Commercially available PS are mainly esterified to omega-6 fatty acid (FA), such as sunflower oil (SO) FA. Emerging trends include using other sources such as olive oil (OO) or omega-3 FA from fish oil (FO), known to exert potent hypotriglyceridemic effects. Our objective was to compare the actions of different FA esterified to PS on blood lipids, carotenoid bioavailability as well as inflammatory and coagulation markers.

Methods: Twenty-one moderately overweight, hypercholesterolemic subjects consumed experimental isoenergetic diets enriched with OO (70% of fat), each lasting 28-day and separated by 4-week washout periods, using a randomized crossover design. Diets were supplemented with three PS esters preparations, PS-FO, PS-SO, or PS-OO. All PS treatments contained an equivalent of 1.7 PS g/d, and the PS-FO provided a total of 5.4 g/d FO FA (eicosapentaenoic and docosahexaenoic acids).

Results: There were no differences between PS-containing diet effects on total cholesterol, LDL-cholesterol, or high-density lipoprotein (HDL)-cholesterol levels. However, PS-FO consumption resulted in markedly lower (P < 0.0001) fasting and postprandial triglyceride concentrations compared with PS-SO and PS-OO. These treatments affected plasma beta-carotene (P = 0.0169) and retinol (P = 0.0244), but not tocopherol (P = 0.2108) concentrations. Consumption of PS-FO resulted in higher beta-carotene (P = 0.0139) and retinol (P = 0.0425) levels than PS-SO and PS-OO, respectively. Plasma TNF-alpha, IL-6, C-reactive protein, prostate specific antigen, and fibrinogen concentrations were unaffected by the PS-interventions. In contrast, plasminogen activator inhibitor 1 (PAI-1) concentrations were lower (P = 0.0282) in the PS-FO-fed than the PS-SO, but not the PS-OO (P = 0.7487) groups.

Conclusion: Our findings suggest that, in hypercholesterolemic subjects consuming an OO-based diet, PS-FO results in lowered blood triglyceride and PAI-1 concentrations, and higher fat-soluble vitamin levels in comparison to the vegetable oil FA esters of PS (PS-SO and PS-OO). Thus, PS-FO may offer hyperlipidemic subjects a more comprehensive lipid lowering approach while reducing the potential risk of decreased plasma carotenoid concentrations.