From the Guidelines
Fish oil supplements, particularly prescription-grade products, can effectively reduce triglyceride levels by 20-50% in individuals with elevated levels, with high doses of 2-4 grams per day of combined EPA and DHA recommended. For this purpose, the American Heart Association suggests that 2 to 4 g of eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) per day can decrease serum triglyceride concentrations by 25% to 30% 1. A dose-response relationship exists between marine-derived omega-3 PUFA and triglyceride lowering, with an approximate 5% to 10% reduction in triglycerides for every 1 g of EPA/DHA consumed 1.
Key Considerations
- Fish oil has modest effects on other lipid parameters, potentially increasing HDL cholesterol slightly (by 1-3%) and sometimes raising LDL cholesterol (by 5-10%), particularly in those with very high triglycerides 1.
- Prescription-grade fish oil products (like Lovaza, Vascepa, or Epanova) may be more reliable in potency than over-the-counter supplements, as they are FDA-approved for treating elevated triglyceride levels and have verified efficacy and consistent content 1.
- Fish oil works by decreasing the liver's production of VLDL (very low-density lipoprotein) and accelerating triglyceride clearance from the bloodstream 1.
- While fish oil supplements are generally safe, they may increase bleeding risk, so it is essential to inform your healthcare provider if you're taking blood thinners or planning surgery.
Administration and Safety
- For optimal results, take fish oil supplements with meals to improve absorption and reduce gastrointestinal side effects like fishy taste or burping.
- The most frequent adverse effects of prescription omega-3 fatty acid preparations include eructation, dyspepsia, taste perversion, and musculoskeletal pain 1.
- Multiple randomized controlled trials have demonstrated an increase in the risk of atrial fibrillation (AF) with therapy, particularly with higher doses (1.8 to 4 g daily) of prescription ethyl ester and carboxylic acid preparations of DHA and EPA mixtures and pure EPA 1.
Alternative Sources of Omega-3 Fatty Acids
- For general heart health, consuming fatty fish like salmon or mackerel twice weekly can provide beneficial omega-3 fatty acids without requiring supplements.
- Table 10 from the American Heart Association's scientific statement provides a list of selected foods with their omega-3 PUFA content per 3.5-oz serving, which can be a useful guide for individuals seeking alternative sources of omega-3 fatty acids 1.
From the Research
Effects of Fish Oil on Lipid Levels
- Fish oil supplements have been shown to reduce fasting blood triglyceride levels in individuals with hyperlipidemia, with a clinically significant reduction of -0.34 mmol/L [ 2 ].
- However, the use of fish oil supplements as a substitute for FDA-approved prescription ω-3 fatty acids for the treatment of elevated triglycerides or prevention of cardiovascular events is not recommended due to limited regulatory oversight and evidence of quality concerns [ 3 ].
- Fish oil supplementation has also been shown to have a dose-dependent reduction of fasting blood triglycerides, but not total, HDL, or LDL cholesterol in hyperlipidemic subjects [ 2 ].
Comparison with Other Lipid-Lowering Therapies
- Fish oil has been shown to improve triglycerides in combination with other lipid-lowering therapy such as a statin or fibrate [ 4 ].
- Omega-3 fatty acid formulations containing EPA and DHA have been shown to increase LDL-C levels, while icosapent ethyl (IPE) has been shown to lower triglyceride levels without raising LDL-C levels, alone or in combination with statin therapy [ 5 ].
- Long-chain omega-3 fatty acids may be a well-tolerated and effective alternative to fibrates and niacin for reducing triglyceride levels in patients with hypertriglyceridemia [ 6 ].
Cardiovascular Benefits
- Fish oil has been shown to have antiplatelet activity, improve heart failure, and improve vascular function in diabetes [ 4 ].
- Fish oil has also been shown to slightly decrease morbidity and mortality in patients with class II-IV heart failure compared to placebo [ 4 ].
- The cardiovascular benefits of fish consumption are attributed to the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) [ 5 ].