Fish oil is a widely used supplement in the United States. According to the Centers for Disease Control and Prevention, over one in five adults aged 60 and above, and one in six adults aged 40 to 59, take fish oil. The supplement’s popularity stems from the numerous health claims on its labels. A 2023 article in JAMA Cardiology highlighted that while most fish oil supplements advertise heart health benefits, fewer than 20% utilize a health claim approved by the Food and Drug Administration (FDA). Currently, the FDA has sanctioned only qualified health claims about fish oil’s influence on blood pressure and coronary heart disease.
Do you rely on fish oil to lower your cholesterol? Approximately 5% of fish oil supplements claim to “support” healthy cholesterol or lipid metabolism, which might be somewhat misleading. A 2009 meta-analysis in the International Journal of Cardiology reviewed 47 studies and found that fish oil supplementation does not significantly affect total cholesterol, LDL cholesterol, or HDL cholesterol. However, fish oil supplements could lower triglyceride levels, depending on the dosage, indicating a complex relationship between fish oil and cholesterol.
How fish oil may affect your blood lipids
Fish oil supplements vary. Check your supplement label for two crucial omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA may enhance mood and reduce inflammation, while DHA is vital for brain function and development. The EPA and DHA content can differ among fish oil products, which may affect how the supplement influences your blood lipids.
A 2012 review in the Journal of Clinical Lipidology found that DHA might have a more substantial impact on cholesterol and triglyceride levels. While DHA can lower triglycerides, it might also increase LDL (“bad”) and non-HDL cholesterol. However, DHA tends to increase HDL (“good”) cholesterol more than EPA. Due to varying EPA and DHA ratios in clinical trials, drawing broad conclusions about fish oil supplements’ effects on cholesterol is challenging.
A 2023 review in the Journal of the American Heart Association noted that different EPA to DHA ratios could lead to varying effects on cholesterol and triglycerides. Generally, 2 grams of fish oil daily can reduce triglycerides by approximately 43 points, while 3 grams may lower them by around 69 points. Individuals with obesity or heart disease observed more pronounced triglyceride-lowering effects. Fish oil supplements have inconsistent effects on LDL cholesterol but may slightly increase HDL cholesterol.
Other possible benefits of fish oil
The Dietary Guidelines for Americans suggest consuming fatty fish twice a week for its protein, vitamins, minerals, and essential omega-3 and omega-6 fatty acids. While fish oil supplements contain omega-3s, the FDA indicates they may not provide the same health benefits as whole fish consumption. (Here are other foods to consider for more omega-3 intake.)
A 2017 study in Nutrition and Diabetes compared fish oil supplements to eating fish. One group took 2 grams of fish oil daily, while the other consumed trout twice a week. A cooked trout fillet contains about 1.4 grams of omega-3s. After 8 weeks, the trout group experienced greater reductions in total cholesterol, LDL cholesterol, and triglycerides, along with a more significant increase in HDL cholesterol. Conversely, the fish oil group saw a slight increase in LDL cholesterol.
So, should you stop taking fish oil? Not necessarily. Fish oil supplements may still benefit individuals who don’t eat much fish. A 2019 study in the New England Journal of Medicine monitored over 25,000 adults aged 50 and above to assess vitamin D3 and fish oil’s effects on heart disease and cancer. While fish oil didn’t prevent either condition overall, the supplement was associated with a 28% lower risk of heart attack. Among individuals who rarely consumed fish, the supplement reduced the risk of a major cardiovascular event by 19% and a 40% lower risk of heart attack. People with two or more heart disease risk factors had a 44% lower risk of heart attack when taking a fish oil supplement.
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