Reduction of plasma lipids, lipoproteins, and apoproteins by dietary fish oils in patients with hypertriglyceridemia.
Level 3 - non-randomized controlled study
Non-randomized controlled crossover dietary trial without explicit report of randomization in the abstract
PubMed 3990714 · doi:10.1056/NEJM198505093121902
What was done
Twenty hypertriglyceridemic patients (10 with Type IIb hyperlipidemia and 10 with Type V) were evaluated across three sequential dietary regimens of four weeks each: a control low-fat therapeutic diet (ratio of polyunsaturated to saturated fat, 1.4), a fish-oil diet rich in omega-3 fatty acids, and a vegetable-oil diet rich in linoleic acid (omega-6).
What was found
Compared to the control diet, the fish-oil diet reduced plasma cholesterol by 27% and triglycerides by 64% in the Type IIb group, with marked reductions in very-low-density lipoproteins (VLDLs). In the Type V group, the fish-oil diet led to a 45% decrease in total cholesterol, a 79% decrease in triglycerides, and dramatic reductions in VLDL and apoprotein E levels. In contrast, the vegetable-oil diet had minimal effect in Type IIb patients and caused a rapid and significant rise in plasma triglycerides in Type V patients.
Why it matters
This study established that dietary omega-3 fatty acids from fish oils exert potent triglyceride-lowering and lipoprotein-modifying actions in individuals with severe forms of hypertriglyceridemia.
Limits
The sample size was very small (n = 20 total, 10 per subtype), dietary duration was limited to four weeks per phase, long-term cardiovascular outcomes were not evaluated, and the abstract does not indicate whether diet allocation sequence was randomized.
Cited by
- supports In early research by Dr. Bill Harris, administering 30 grams of omega-3 per day to humans produced no negative effects over a short duration.