Does Canned Cod Liver Have Mercury? A Comprehensive Safety Guide

December 20, 2025 •

3 min read

According to the U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA), cod is categorized as a "Best Choice" fish, indicating its low mercury content. This favorable status extends to the processed product, answering the question, "Does canned cod liver have mercury?" with a reassuring perspective for most consumers.

Quick Summary

Canned cod liver contains minimal levels of mercury, often lower than larger predatory fish, and is considered safe for consumption. Rigorous testing and purification during processing further minimize heavy metal risks.

Key Points

Low Mercury Levels: Cod is a low-mercury fish, and studies confirm that the levels found in canned cod liver are also very low and safe for consumption.
Not a Predator: As a species lower on the food chain, cod does not bioaccumulate high levels of mercury like larger predatory fish, such as swordfish or shark.
Refined Processing: For products like cod liver oil derived from the liver, purification processes effectively remove heavy metals, making the risk negligible.
Nutrient-Dense Benefits: Canned cod liver provides significant nutritional benefits, including omega-3 fatty acids and vitamins A and D, with minimal heavy metal concerns.
Safe for Most Diets: Health authorities classify cod as a 'Best Choice' for consumption, and this includes canned versions for most people, though certain groups should monitor overall intake.
Consult Guidelines for Risk Groups: Individuals like pregnant women and young children should follow specific FDA/EPA guidelines for fish consumption to manage overall exposure conservatively.

Canned Cod Liver and Mercury: A Clear Picture

Many consumers are rightly concerned about mercury content in seafood due to its potential health effects, particularly in sensitive populations. Mercury naturally exists in the environment and accumulates in fish, with levels varying significantly based on the fish species, size, and position in the food chain. Cod, being lower on the food chain than large predators like swordfish or shark, accumulates far less mercury. When it comes to canned cod liver, this already low level is further mitigated by several factors, including the source and modern processing techniques.

The Science Behind Low Mercury in Cod

Research studies have specifically assessed contaminants in cod liver and supplements derived from it. A Polish study published in the journal Neuroendocrinology Letters analyzed canned cod liver and found very low total mercury concentrations, confirming its safety for human consumption. The methylmercury (the more toxic organic form) concentration was also found to be low in the samples. Another study on dietary supplements found cod liver oils had an average mercury concentration significantly lower than some vegetable oils, reinforcing its minimal heavy metal content.

Comparing Cod Liver to Other Fish

The mercury levels in canned cod liver are consistently low, especially when compared to fish higher on the food chain. This is due to the process of biomagnification, where contaminants increase in concentration as they move up the food chain. Larger, older predatory fish inevitably contain higher mercury levels than smaller fish that feed lower down.


Seafood Type	Typical Mercury Level (PPM)	FDA/EPA Category	Notes
Cod (Meat)	~0.111	Best Choice	Low mercury content, very safe for regular consumption.
Canned Cod Liver	Very Low (e.g., ~0.0002 mg/kg)	Safe Consumption	Processed product with minimal contaminants.
Canned Light Tuna	~0.126	Best Choice	Low mercury, but slightly higher than cod.
Canned Albacore Tuna	~0.350	Good Choice	Higher mercury than light tuna, limit intake.
Swordfish	~0.995	Avoid	High mercury content due to predatory nature.
Shark	~0.979	Avoid	Very high mercury content.

The Importance of Processing and Source

For products like canned cod liver, the manufacturing process plays a crucial role in ensuring safety. Reputable manufacturers use high-quality, wild-caught cod from carefully monitored fishing areas. The canning and cooking process itself, while not removing mercury, is performed under strict safety standards. For cod liver oil supplements, the oil is often purified through molecular distillation, a process that effectively removes mercury and other contaminants to levels that are often undetectable. For consumers, choosing products from trusted, transparent brands is the best way to ensure quality and minimize any potential risk.

Who Should Be Cautious?

While canned cod liver is safe for most, specific groups should always consider their overall seafood intake in consultation with a healthcare provider. The FDA and EPA provide special guidance for these sensitive populations.

Pregnant and breastfeeding women: They should consume 8–12 ounces of low-mercury fish per week and follow official dietary advice to manage overall mercury exposure. Cod falls into the Best Choice category for these individuals.
Children: Parents should provide smaller serving sizes adjusted for a child's age and weight, choosing from low-mercury options.
Individuals with high fish consumption: Those who eat fish multiple times per week should focus on a variety of low-mercury options and be mindful of their overall intake to stay within safe limits.

Conclusion

In short, canned cod liver has mercury, as virtually all seafood does, but the levels are extremely low and pose no significant health threat for the general population. Multiple scientific studies and regulatory agency guidelines confirm that cod is a safe, low-mercury choice. This nutrient-dense food offers excellent benefits from omega-3 fatty acids and vitamins A and D with minimal contaminant risk, especially from reputable producers. Consumers can enjoy it as part of a healthy diet without undue concern.

For more detailed information on mercury levels in commercial seafood and safety guidelines, consult the official FDA/EPA fish consumption advice.

Frequently Asked Questions

No, canned cod liver is not a high-mercury fish product. Cod is a relatively small fish low on the food chain, meaning it accumulates minimal amounts of mercury compared to larger predatory fish like tuna or swordfish.

Mercury levels in cod liver oil supplements are often lower or undetectable because the oil undergoes a purification process, such as molecular distillation, which removes heavy metals. Canned cod liver is also very low in mercury, but the purification in supplements is typically more thorough for removing contaminants.

The primary source of mercury in fish is methylmercury, a potent neurotoxin that accumulates in the fish's tissue through a process called biomagnification, where it builds up as larger fish consume smaller ones.

Yes, cod is listed as a 'Best Choice' fish by the FDA and EPA, indicating it is low in mercury and safe for pregnant and breastfeeding women to eat 2–3 servings a week. However, it is always best to consult a doctor about dietary choices during pregnancy.

Canning does not significantly affect the mercury content. The mercury level is determined by the fish itself. Modern canning practices, however, ensure overall product safety and quality.

Not necessarily. Canned fish products vary widely in mercury content based on the type of fish used. For example, canned light tuna (typically skipjack) is low in mercury, whereas canned albacore is higher.

Besides its low mercury level, canned cod liver is an excellent source of omega-3 fatty acids (EPA and DHA), and fat-soluble vitamins A and D, which support immune function, bone health, and brain health.