Fish oil is a popular dietary supplement, consumed for its concentration of beneficial omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Since the human body cannot produce these polyunsaturated fats efficiently, dietary intake or supplementation is necessary. The finished golden capsule represents the end of an intricate, multi-stage industrial process designed to maximize the oil’s potency and purity, transforming crude fish oil into a refined product prepared for consumption.
Sourcing the Raw Oil and Initial Extraction
The manufacturing process begins with the selection of raw material, typically small, oily fish species like anchovies, sardines, and mackerel. These fish are preferred because their short lifespan means they accumulate fewer environmental toxins, such as heavy metals, compared to larger predatory fish. The fresh catch is quickly transported to processing facilities to prevent oxidation and maintain the oil’s initial quality.
The crude oil is extracted from the fish tissue using wet rendering. This process involves cooking the whole fish at temperatures between 90°C and 100°C, which coagulates the proteins and separates the tissue, water, and oil. The cooked mass is then mechanically pressed, and high-speed centrifuges separate the crude oil from the water and solid residue.
Refining the Oil for Purity and Safety
The crude oil contains various impurities that must be removed before it is safe and palatable. The first purification step is degumming, which uses water or mild acids (such as phosphoric or citric acid) to remove phospholipids and other non-fat components called gums.
Next, neutralization removes free fatty acids (FFAs), which contribute to rancidity. This is achieved by treating the oil with a caustic soda solution, which reacts with the FFAs to form soap stock that is then separated.
Bleaching is performed to remove colored pigments and trace metals that can accelerate oxidation. The oil is mixed with natural adsorbent materials, such as activated clay, which bind to these impurities. The clay and contaminants are filtered out, leaving a lighter-colored oil.
Deodorization, often using vacuum steam distillation, achieves the removal of volatile compounds and final contaminants. The oil is briefly exposed to high temperatures and steam under a deep vacuum, which strips away substances like aldehydes and ketones that cause the fishy smell and taste. This process also significantly reduces the levels of persistent organic pollutants (such as dioxins and PCBs), creating a neutral-tasting product that meets international safety standards.
Advanced Concentration Techniques
To create high-potency supplements, manufacturers employ advanced techniques to increase the concentration of EPA and DHA beyond their naturally occurring levels, which are typically around 30% in crude oil. The primary method for this is molecular distillation, a process that separates compounds based on their molecular weight and boiling point.
Because omega-3 fatty acids are susceptible to heat, this separation occurs under an extremely high vacuum, allowing it to happen at relatively low temperatures (150°C to 200°C). This low-temperature, high-vacuum environment concentrates the oil and serves as the final, most effective step for stripping away remaining heavy metals, like mercury.
To enable this concentration, the purified oil is first chemically converted from its natural triglyceride (TG) form into an ethyl ester (EE) form by reacting it with ethanol. The EE form allows for precise separation during distillation. After the targeted EPA and DHA levels are achieved, the oil is either bottled as the semi-synthetic EE concentrate or undergoes re-esterification, which uses enzymes to convert the EE form back into a re-esterified triglyceride (rTG) form that mirrors the oil’s natural structure and is associated with higher bioavailability.
Encapsulation and Quality Assurance
The final, concentrated fish oil is vulnerable to oxidation, so stabilizers are added before encapsulation. Antioxidants, like tocopherols (Vitamin E) and rosemary extract, are mixed into the oil to protect the omega-3 bonds from oxygen and light exposure.
The oil is then encapsulated into soft gels. The shell is typically made of gelatin (derived from bovine or porcine sources) or from vegetable alternatives. The soft gel casing is created, immediately filled with the stabilized oil, and hermetically sealed to create an oxygen barrier. The pills are then dried to achieve the proper consistency.
The last stage involves rigorous quality assurance, frequently conducted by independent third-party organizations like the International Fish Oil Standards (IFOS) and the Global Organization for EPA and DHA Omega-3s (GOED). These bodies test the finished product to verify potency, ensuring EPA and DHA levels match the label claim. They also check for purity by confirming contaminants like heavy metals and PCBs are below stringent limits, and measure freshness using oxidation markers.