Common Digestive and Sensory Side Effects
One of the most frequently cited reasons people discontinue taking fish oil supplements is the unpleasant digestive and sensory side effects. These issues are usually mild and tend to subside as your body adjusts to the supplement, but they can be a nuisance for some users.
- Fishy Burps and Aftertaste: This is perhaps the most common complaint. A distinct, unpleasant fishy taste can linger in the mouth or come up as a burp hours after taking the supplement. It can be caused by the oil being released and digested in the stomach.
- Nausea, Heartburn, and Indigestion: Fish oil's high fat content can sometimes trigger digestive discomfort. Heartburn is a common symptom of acid reflux, and nausea or a general feeling of stomach upset may occur, especially on an empty stomach.
- Diarrhea and Loose Stools: High doses of fish oil can have a laxative effect and cause diarrhea or loose stools. For some individuals, this is a sign that their intake may be too high and could be adjusted.
Risks Associated with High Dosages
While generally safe in recommended amounts, exceeding the suggested intake of omega-3 can lead to more serious side effects. It is suggested not to exceed certain intake levels from supplements.
- Increased Bleeding Risk: High intake of fish oil is known to have blood-thinning properties, which can increase the risk of bruising and bleeding. This is particularly concerning for individuals taking anticoagulant medications or those with existing bleeding disorders. It is also recommended to stop taking fish oil before surgery to prevent excess bleeding.
- Low Blood Pressure (Hypotension): Omega-3s can lower blood pressure, which is beneficial for many. However, when combined with blood pressure-lowering medication or for those already with low blood pressure, high intake of fish oil could cause blood pressure to drop too low, leading to dizziness or lightheadedness.
- Reduced Immune Function: At very high intake, omega-3s' powerful anti-inflammatory effects may suppress the immune system's response to infection. This could be a concern for individuals with compromised immune systems or the elderly.
- Vitamin A Toxicity: Certain omega-3 supplements, specifically cod liver oil, contain high amounts of vitamin A. Chronic intake of excessive vitamin A can lead to toxicity, causing symptoms like dizziness, joint pain, nausea, and in severe cases, liver damage.
- Potential Link to Atrial Fibrillation: Some studies have observed a correlation between high intake omega-3 supplementation and an increased risk of developing atrial fibrillation (AFib), an irregular heart rhythm. This effect appears to be intake-dependent, and the findings are mixed, but it warrants caution, especially for individuals at risk of heart problems.
Potential Drug Interactions
Fish oil supplements can interact with certain medications, making it essential to consult a healthcare provider before starting supplementation, particularly if you are on other treatments.
- Anticoagulant and Antiplatelet Drugs: The blood-thinning effect of fish oil can be compounded by medications like warfarin (Coumadin) or antiplatelet drugs such as aspirin, increasing the risk of bleeding.
- Blood Pressure Medications: As mentioned, fish oil can lower blood pressure. Taking it with blood pressure-lowering drugs could result in a dangerous drop in blood pressure.
- Birth Control Pills: Some oral contraceptives may reduce the triglyceride-lowering effects of fish oil.
- Orlistat (Weight-Loss Drug): This medication can interfere with the absorption of fatty acids, potentially reducing the benefits of fish oil. It is recommended to take them at least two hours apart.
Comparison of Common Omega-3 Sources
To help manage potential side effects, understanding the different sources of omega-3 is beneficial. Not all supplements are created equal.
| Feature | Fish Oil | Krill Oil | Algae Oil (Vegan) |
|---|---|---|---|
| Source | Oily fish like salmon, mackerel, and anchovies. | Krill (small crustaceans). | Algae (microalgae). |
| EPA & DHA Form | Usually in triglyceride or ethyl ester form. | Mostly phospholipid form, which may be better absorbed. | Primarily triglyceride form. |
| Purity Concerns | Can contain contaminants, but high-quality supplements are purified. | Less risk of contamination due to lower position on food chain. | Very low risk of contaminants and heavy metals. |
| Common Side Effects | Fishy burps, heartburn, nausea. | Generally fewer side effects, less fishy aftertaste. | No fishy taste, eliminates concerns for those with fish allergies. |
| Cost | Generally more affordable. | Often more expensive. | Higher cost, but ideal for vegans or those with allergies. |
How to Minimize Side Effects
For most people, the side effects of fish oil are manageable with a few simple strategies.
- Take with Meals: Taking fish oil with food, especially a meal containing other fats, significantly improves absorption and reduces gastrointestinal issues like reflux and indigestion.
- Start with a Lower Intake: If you are new to fish oil, begin with a small amount and gradually increase it over a few weeks to allow your body to adjust.
- Choose Enteric-Coated Capsules: These capsules are designed to pass through the stomach and dissolve in the intestines, preventing the fishy burps and aftertaste.
- Try Different Forms or Sources: If standard fish oil is causing issues, consider trying liquid fish oil, gummies, or switching to krill or algae oil supplements.
- Freeze Your Capsules: For some, freezing the softgels can reduce the likelihood of fishy burps, as it delays the oil's release until it is further along the digestive tract.
Conclusion
While omega-3 fish oil offers numerous health benefits, understanding what are the side effects of taking omega-3 fish oil is important for safe and comfortable supplementation. Mild digestive issues and a fishy aftertaste are common but can be managed with simple adjustments like taking the supplement with food or choosing an enteric-coated variety. High intake poses more significant risks, including increased bleeding tendency and potentially affecting blood pressure or immune function. Always inform your doctor about your fish oil usage, especially if you are on blood-thinning medication or have underlying health conditions. For those concerned about allergens or purity, high-quality, third-party tested supplements or plant-based alternatives like algae oil are excellent options to consider.
For more information on dietary supplements and their effects, you can visit the NIH Office of Dietary Supplements.
