Who Should Avoid Mackerel Fish?

November 24, 2025 •

3 min read

According to the FDA, specific groups, including pregnant women and young children, should limit or avoid high-mercury fish species like king mackerel due to potential neurodevelopmental risks. Understanding who should avoid mackerel fish is crucial for maximizing its health benefits while minimizing associated dangers.

Quick Summary

A guide detailing who should avoid certain mackerel types, focusing on pregnant women, children, and individuals with allergies or histamine intolerance. It outlines the risks of mercury and scombroid poisoning, emphasizing safety through informed choices and proper food handling.

Key Points

Pregnant and Breastfeeding Women: Should strictly avoid high-mercury king mackerel and limit other varieties.
Young Children: Are more vulnerable to the effects of mercury and should avoid high-mercury species.
Individuals with Histamine Intolerance: Should be cautious with mackerel, as it is naturally high in histidine and prone to developing high histamine levels if improperly handled.
People with Fish Allergies: Must avoid mackerel completely due to potential for severe allergic reactions.
Those Managing High Blood Pressure: Should limit or avoid high-sodium canned and smoked mackerel varieties.
Anyone eating fresh mackerel: Must ensure it is handled and refrigerated properly to prevent scombroid (histamine) poisoning.
Individuals on Blood Thinners: Should consult a doctor about their mackerel and omega-3 intake to manage bleeding risk.

Mercury Levels: A Critical Concern for Some

While mackerel is a rich source of omega-3 fatty acids, its mercury content varies significantly between species. The primary concern is methylmercury, a potent neurotoxin that can accumulate in larger, longer-living predatory fish. High exposure can pose risks, particularly to a developing fetus or young child.

King Mackerel vs. Atlantic Mackerel

Not all mackerel species are created equal regarding mercury levels. The distinction is critical for sensitive populations like pregnant and breastfeeding women, and young children.


Feature	King Mackerel	Atlantic Mackerel
Trophic Level	Higher (Predatory)	Lower (Forage Fish)
Typical Size	Large	Small to Medium
Mercury Content	High	Low
FDA/EPA Advisory	AVOID for pregnant women, breastfeeding women, and young children.	SAFE to eat two to three servings per week.

For most adults, occasional consumption of king mackerel is not a significant risk, but safer alternatives are always available. Atlantic mackerel is widely recommended as a low-mercury option.

Histamine Poisoning (Scombroid Toxicity)

Anyone can develop scombrotoxin poisoning, a type of foodborne illness caused by eating fish that has not been properly refrigerated. The bacteria in the fish convert the naturally occurring amino acid histidine into high levels of histamine, which is not destroyed by cooking.

Symptoms of Scombroid Poisoning

Tingling or burning sensation in the mouth
Facial flushing and sweating
Nausea, vomiting, or diarrhea
Headaches and dizziness
Hives and rash

Risk Factors: The risk is highest when fish is left unrefrigerated or not handled hygienically after being caught, allowing bacteria to multiply. To prevent this, always purchase fish from reputable sources and keep it chilled or frozen until cooked.

Fish Allergies and Intolerances

Some people have a genuine fish allergy, and mackerel is no exception. A fish allergy can cause a wide range of symptoms, from mild skin rashes and digestive issues to severe, life-threatening anaphylaxis. A true allergy is a reaction to a fish's protein, usually parvalbumin, which is heat-stable and present across different species. For those with a confirmed fish allergy, avoiding all fish is the safest course of action.

Histamine intolerance is a different issue, where the body lacks sufficient enzymes (like diamine oxidase or DAO) to break down histamine efficiently. In such cases, consuming high-histamine foods like mackerel can trigger allergy-like symptoms.

High Sodium in Canned and Smoked Varieties

For individuals with hypertension or those on a sodium-restricted diet, commercially canned or smoked mackerel can be a concern. These products often use salt as a preservative, significantly increasing their sodium content. Always check the nutrition label for sodium levels, or opt for fresh mackerel to control the salt content in your diet. Rinsing canned fish can help, but does not remove all excess sodium.

Other Considerations and Medication Interactions

Compromised Immune Systems

Individuals with weakened immune systems should be cautious when consuming fish, especially if raw or undercooked, due to the risk of foodborne illnesses from bacteria, parasites, or viruses. Always ensure mackerel is cooked thoroughly to an internal temperature of 145°F (63°C).

Medication Interactions

Certain medications, particularly blood thinners like warfarin, may interact with high intake of omega-3 fatty acids found in fish. This interaction can increase the risk of bleeding. Patients on these medications should consult a doctor and monitor their intake carefully.

Conclusion: Informed Choices for Safe Consumption

While mackerel offers substantial nutritional benefits, including heart-healthy omega-3s, it's not a suitable choice for everyone. Pregnant women, young children, and breastfeeding mothers must be diligent in avoiding high-mercury species like king mackerel. Individuals with fish allergies or histamine intolerance should also proceed with extreme caution, while those managing hypertension should be mindful of sodium in processed mackerel products. By making informed choices, checking for freshness, and opting for low-mercury varieties like Atlantic mackerel, you can enjoy this nutritious food safely while considering alternatives if necessary. For those seeking omega-3 benefits without fish, plant-based supplements from algae oil are a viable option for discussion with a healthcare provider.

Alternative Omega-3 Sources

For those who cannot consume mackerel, here are some alternatives:

Other Fish: Salmon, sardines, and herring are excellent low-mercury options.
Plant-Based Options: Chia seeds, flaxseed, and walnuts provide alpha-linolenic acid (ALA), a precursor to omega-3s.
Supplements: Algae-based supplements are a vegan source of EPA and DHA, the most beneficial forms of omega-3s.

Frequently Asked Questions

No, mercury content varies significantly by species. Large, long-lived species like king mackerel have high mercury levels and should be avoided by pregnant women and children. Smaller, short-lived species like Atlantic mackerel are low in mercury and considered safe.

Yes, if the fish was not properly refrigerated before cooking, it could cause scombroid poisoning. This is because the bacteria in spoiled fish produce heat-stable histamines that are not destroyed by cooking.

Symptoms can include a tingling or burning sensation in the mouth, facial flushing, hives, headache, nausea, and dizziness. They can appear within minutes to a few hours of eating contaminated fish.

The best prevention is to ensure the fish is kept properly chilled (on ice or refrigerated) from the time of capture until it is cooked. Always buy from a reputable source.

Omega-3 supplements, particularly algae-based ones, are a good alternative for those who cannot eat fish due to allergies or other health concerns. However, eating fish provides a wider range of nutrients beyond just omega-3s.

Canned mackerel can be a convenient option, but be aware that it can be high in sodium due to preservatives. Individuals with high blood pressure should choose low-sodium versions and rinse the fish thoroughly.

A fish allergy is an immune system response to a fish protein. Histamine intolerance is a metabolic disorder where the body cannot properly break down histamine, which can be present in high amounts in certain foods like mackerel, causing allergy-like symptoms.