Gastrointestinal Symptoms as Side Effects of Omega-3 Supplements
Yes, gastrointestinal symptoms are common side effects of omega-3 supplements, particularly with non-prescription fish oil products which frequently cause burping, fishy taste in the mouth, and dyspepsia. 1
Common Gastrointestinal Side Effects
Non-prescription fish oil supplements commonly cause gastrointestinal side effects including:
Prescription omega-3 products also have gastrointestinal side effects, though they are generally better tolerated than non-prescription supplements 1
Differences Between Supplement Types
Non-prescription fish oil supplements have more variable content and quality compared to prescription products, which may contribute to their higher rate of gastrointestinal side effects 1
EPA/DHA combination products are associated with more treatment-related gastrointestinal adverse events including eructation (belching) and nausea compared to EPA-only formulations 2
Prescription omega-3 fatty acid preparations may cause eructation, dyspepsia, and taste perversion, particularly with ethyl ester preparations 1
Severity and Clinical Significance
Most gastrointestinal side effects from omega-3 supplements are mild and transient 1, 4
In a systematic review of randomized controlled trials, omega-3 fatty acids were found to be generally safe and well-tolerated but not free of adverse effects 2
In studies of perinatal women, omega-3 supplements were well tolerated with only transient side effects reported 4
A Cochrane review found significantly higher rates of diarrhea (RR 1.36,95% CI 1.01 to 1.84) and upper gastrointestinal tract symptoms (RR 1.65,95% CI 1.25 to 2.18) in patients taking omega-3 supplements compared to placebo 3
Risk Factors for Increased Side Effects
Higher doses of omega-3 supplements may increase the likelihood of gastrointestinal side effects 5, 2
Taking large quantities of supplement capsules (common with non-prescription products) may contribute to increased gastrointestinal symptoms 1
Combined EPA/DHA formulations appear to have more gastrointestinal side effects than EPA-only formulations 2
Recommendations to Minimize Side Effects
Consider prescription omega-3 products which are generally better tolerated than non-prescription supplements 1
Start with lower doses and gradually increase to minimize gastrointestinal symptoms 1
Take supplements with meals to reduce gastrointestinal irritation 5
If using supplements for cardiovascular benefits, consider that a combined EPA+DHA intake of approximately ≥900 mg/day is associated with cardiovascular protection 5
For patients with severe gastrointestinal symptoms, consider switching to a different formulation or a prescription product 1