The unpleasant fishy taste and smell often experienced with omega-3 supplements are widely, and wrongly, assumed to be a normal side effect. In reality, a potent, high-quality omega-3 supplement should taste and smell clean, much like the fresh sea. The culprit behind the pungent aroma and repeating "fish burps" is a process called oxidation, which causes the oil to go rancid.
The science of a fishy omega-3
Why oxidation is the root cause
Omega-3 fatty acids, especially EPA and DHA found in fish oil, are highly polyunsaturated. This chemical structure makes them extremely vulnerable to oxidation, a reaction with oxygen that breaks down the fatty acid molecules. When exposed to air, light, or heat, this degradation process accelerates, producing volatile compounds like aldehydes and ketones that cause the distinct and unpleasant fishy odor.
- Exposure to oxygen: This is the primary driver of rancidity. Once a fish oil bottle is opened, the oil is exposed to air, starting the oxidation clock. Even capsules offer imperfect protection.
- Heat and light: Both accelerate the chemical reactions that lead to spoilage. Storing supplements in a warm, bright place like a kitchen counter or cabinet can quickly degrade the oil.
- Processing quality: Inadequate or rushed processing during manufacturing can lead to oil that is already partially oxidized before it even reaches the consumer. Higher quality products undergo more careful processing to minimize oxygen exposure.
- Additives and casings: Some additives in softgel casings can cause digestive issues, triggering burps and releasing trapped, rancid oil. Flavors like lemon are often used to mask the taste of poor-quality, oxidized oil.
How to spot and avoid rancid omega-3
Knowing how to identify a fresh supplement is crucial to ensure you are receiving the intended health benefits and not a compromised, potentially harmful product.
Practical tips for testing your omega-3
- The sniff test: If you have capsules, break one open and give it a sniff. A strong, overpowering fishy smell is a clear red flag. Fresh fish oil should have a mild, oceanic scent or no smell at all.
- The taste test: A truly fresh fish oil should not cause a fishy aftertaste or make you gag. If you experience repeating "fish burps," it's a strong indicator of rancidity.
- Check for transparency: Reputable manufacturers provide third-party testing results, often using the TOTOX (total oxidation) value to demonstrate the oil's freshness. Avoid brands with overly long shelf-life claims.
- Consider alternative sources: If you're consistently bothered by a fishy taste, consider supplements derived from algae. Algae is the original source of EPA and DHA and provides the benefits without the fish.
Comparison table: Fish oil vs. algae oil
| Feature | Fish Oil | Algae Oil |
|---|---|---|
| Omega-3s | Primarily EPA and DHA | Primarily DHA, often with EPA |
| Freshness/Rancidity | High risk of oxidation; easily turns rancid. | Low risk of oxidation if processed well; often more stable. |
| Taste/Aftertaste | Often associated with fishy taste and burps. | Generally has a clean, non-fishy taste and is odor-free. |
| Source | Derived from oily fish like sardines, mackerel, and anchovies. | Sourced from cultivated marine algae, a sustainable plant-based source. |
| Suitability | Ideal for those who consume fish or don't mind a subtle taste. | Excellent for vegans, vegetarians, and those seeking a guaranteed fish-free taste. |
| Bioavailability | Good absorption, especially in triglyceride form. | High bioavailability, with some studies suggesting improved absorption. |
How to prevent the fishy problem
Once you've purchased a fresh omega-3 supplement, proper storage and consumption methods are key to keeping it that way.
Essential tips for managing your supplement
- Store properly: Always store your fish oil in a cool, dark place, and refrigerate liquid oils after opening to slow down oxidation.
- Take with food: Taking your omega-3 supplement with a meal containing other fats can improve absorption and reduce the likelihood of fishy burps by helping your body digest the oil more efficiently.
- Freeze capsules: For softgels, some people find that freezing them slows down the digestive breakdown in the stomach, minimizing aftertaste.
- Use enteric-coated options: These capsules are designed to bypass the stomach and dissolve in the small intestine, preventing the oil from causing reflux.
- Divide your dose: If a single large dose is causing issues, try splitting it and taking smaller doses with different meals throughout the day.
Conclusion
While a fishy taste in an omega-3 supplement can seem normal, it is a sign that the oil is oxidized and has gone rancid. This not only makes for an unpleasant experience but also reduces the supplement's health benefits. By learning to identify the signs of rancidity and taking steps to ensure freshness, you can choose a high-quality product and enjoy the benefits of omega-3 without the notorious fishy taste or burps. Making smart choices about the brand and form of your supplement, as well as practicing proper storage, will help you avoid the unpleasant side effects and get the most out of your nutritional investment.
Further resources
For more information on the testing and quality standards for omega-3 supplements, refer to the Global Organization for EPA and DHA Omega-3 (GOED) website.
