Effect of Fish Oil on Plasma Triglycerides in Adults

The purpose of this small, short pilot study is to determine the feasibility (e.g., recruitment, dose acceptance, retention) of a future longer trial comparing the effects of two types of omega-3 fats from fish oil on plasma triglycerides. The two types of fish oil are composed of (1) omega-3 fatty acids in triglyceride form; and (2) as esterified free fatty acids (i.e. ethyl esters). Although these two types of fish oil supplements are available to the public, it remains unclear whether they are equally effective in lowering plasma triglycerides.

This study is a double-blinded, parallel design, placebo controlled trial with three active treatment arms to compare the triglyceride (TG) lowering effects of the same dose of EPA and DHA provided in three formulations of supplements that differ in the proportion of omega-3 FA present as ethyl esters vs. triglycerides. The active therapy for each of the three fish oil supplementation arms is 4 g/day of combined EPA and DHA provided as: a) 90% TG formulation, b) 60% TG formulation, or c) ethyl esters (esterified fatty acids)(i.e., 0% TG). The placebo was a soy oil supplement with an identical total fat content. The primary outcome is the 12-week change in TG concentrations in the active groups vs. placebo. Secondary outcomes include LDL particle distribution, defined as either subclasses LDL1, LDL2, LDL3 and LDL4, and LDL subclass phenotype patterns A, B, or A/B.