Fish oil supplements provide beneficial Omega-3 fatty acids (EPA and DHA) and are widely used for heart, brain, and joint support. Despite these health advantages, a common side effect is the unpleasant phenomenon often called “fishy burps” or reflux. This repeating fish taste is a primary reason many people discontinue the supplement. However, this digestive discomfort is not an unavoidable trade-off, and understanding its cause is the first step toward stopping it.
Why Fish Oil Causes Reflux
Fish oil burps occur because the supplement releases its contents too early in the digestive tract. When a fish oil softgel is swallowed, the gelatin shell dissolves in the stomach’s acidic environment. Once the capsule breaks down, the liquid oil is released. Because oil is less dense than the stomach’s watery contents, it floats to the top.
This floating oil gathers near the lower esophageal sphincter, the muscular valve separating the stomach from the esophagus. When the sphincter relaxes to release gas (burping), it allows small amounts of the fish oil and its volatile organic compounds to travel back up. These compounds are responsible for the distinctive fish odor, creating the characteristic “fishy burp” or aftertaste.
The timing and location of the capsule breakdown are the most important factors. If the capsule dissolves rapidly in the stomach, the oil has more time to separate and float, increasing the chances of reflux. The goal of preventative strategies is to delay the capsule’s dissolution until it has passed into the small intestine, where the oil can be absorbed without rising back up. The digestive process in the small intestine is focused on fat absorption, which helps manage the oil.
Simple Methods to Stop Fishy Burps
The most effective way to address fish oil reflux is by adjusting how and when the supplement is taken. Taking fish oil with a full meal, especially one containing dietary fats, is recommended. The presence of fat stimulates the release of bile, which helps emulsify the fish oil. This accelerates its movement out of the stomach and into the small intestine for efficient absorption.
Splitting the daily intake into two smaller doses can also reduce the likelihood of burping. Taking one dose in the morning and one in the evening means the stomach has less oil to process at a single time, lowering the risk of reflux. Another technique is taking the supplement immediately before bed. However, some people find this increases burping, so testing what works best is important.
Chilling or freezing the softgel capsules temporarily hardens the gelatin shell. This physical change causes the capsule to break down more slowly in the warm stomach environment. This gives it a better chance of passing into the small intestine intact. Storing the bottle in the refrigerator can also help slow the dissolution rate if freezing is not desired.
How Supplement Quality Affects Burping
The quality and formulation of the fish oil significantly influence the likelihood of burping. A major contributor to an unpleasant aftertaste is oil that has gone rancid through oxidation. Fish oil is highly susceptible to oxidation when exposed to light, heat, or air. This process creates foul-smelling byproducts that taste worse when reflux occurs. A fresh, high-quality oil will have a much milder odor, and may not cause burping at all.
The chemical form of the oil also plays a role in digestive tolerance. Omega-3s come primarily in two forms: natural triglyceride (TG) and ethyl ester (EE). The TG form is the structure found naturally in fish and is better absorbed and more stable, leading to a lower risk of burps. The EE form is often used in concentrated supplements and may be associated with more frequent burping issues.
Many manufacturers offer capsules with an enteric coating, a special shell designed to resist stomach acid. This coating prevents the capsule from dissolving until it reaches the alkaline environment of the small intestine. Enteric coating is a formulation technique created to bypass the stomach. This eliminates the possibility of the oil floating to the top, which is an effective way to prevent fishy burps.