What is the safest fish to eat? A Guide to Low-Mercury and Healthy Seafood

The FDA recommends that adults eat 2-3 servings of low-mercury fish per week to reap its health benefits. With concerns about contaminants, understanding what is the safest fish to eat is crucial for making informed dietary decisions and protecting your health.

Quick Summary

This guide outlines factors affecting fish safety, including mercury and other contaminants. It details low-mercury, high omega-3 seafood choices and provides a comparison to help you select safe and healthy fish.

Key Points

• Prioritize Low-Mercury Fish: Smaller, shorter-lived species like sardines, salmon, and trout are the safest due to minimal mercury accumulation.

• Consult FDA Guidelines: Use the FDA and EPA's 'Best Choices' list for guidance on which fish to eat regularly.

• Limit High-Mercury Species: Avoid or severely limit large, predatory fish such as king mackerel, shark, swordfish, and bigeye tuna.

• Choose Sustainably Sourced Fish: Look for certifications like MSC or ASC to ensure your fish is responsibly harvested, benefiting both your health and the environment.

• Consider Vulnerable Groups: Pregnant women, breastfeeding mothers, and young children should be extra cautious, sticking to 'Best Choice' fish and avoiding all high-mercury species.

• Cook Seafood Thoroughly: Always cook fish and shellfish to the proper internal temperature to kill harmful bacteria and parasites.

• Vary Your Fish Intake: Diversify your seafood choices to reduce overall exposure to any single contaminant.

Fish is a cornerstone of a healthy diet, rich in high-quality protein, essential vitamins, and heart-healthy omega-3 fatty acids. However, concerns over environmental pollutants like mercury and PCBs can make choosing the right fish confusing. The key to safely enjoying seafood is to understand the risks and prioritize low-mercury options.

Understanding Mercury in Seafood

Mercury is a naturally occurring element that is also released into the environment through industrial pollution. In water, it is converted into methylmercury, a potent neurotoxin that accumulates in the food chain.

How Methylmercury Accumulates

Methylmercury's accumulation is a process known as biomagnification. Small fish and shellfish consume microorganisms containing small amounts of mercury. When larger fish prey on these smaller ones, the mercury is concentrated in their bodies. This means older, larger predatory fish, such as shark and swordfish, have the highest mercury levels and are generally considered the least safe for frequent consumption.

Which Fish are Low in Mercury?

Fish that are smaller and have shorter lifespans tend to have the lowest mercury levels. The FDA and EPA provide guidance on which fish are considered "Best Choices" for their low mercury content. These include popular and nutritious options that can be enjoyed regularly.

The Safest Fish to Eat: Best Choices for Your Diet

For regular consumption, focus on fish that are low on the food chain. Many of these are also packed with beneficial omega-3s, vitamin D, and other vital nutrients.

Nutrient-Rich, Low-Mercury Fish

• Sardines and Anchovies: These small, oily fish are loaded with omega-3 fatty acids, calcium, and vitamin D. Because they feed on plankton, their mercury content is exceptionally low. They are also a highly sustainable choice.
• Salmon: Both wild and sustainably farmed salmon are considered safe and healthy, with low mercury and high omega-3 content. Look for certifications like the Marine Stewardship Council (MSC) for wild-caught or Aquaculture Stewardship Council (ASC) for farmed fish to ensure responsible sourcing.
• Trout: Freshwater trout, particularly farmed rainbow trout, is a nutritious and low-contaminant option. It provides a significant dose of vitamin D and omega-3s.
• Catfish and Tilapia: US-farmed catfish and tilapia are typically low in mercury and other contaminants, offering a mild, lean protein source. It is important to know the source, as farming regulations vary by country.
• Shellfish: Most shellfish, including shrimp, scallops, and oysters, are very low in mercury and provide excellent protein and minerals like zinc. However, cooking them thoroughly is crucial to avoid bacteria and viruses.
• Atlantic Mackerel: A great source of omega-3s, Atlantic mackerel is a low-mercury, sustainable option, unlike its high-mercury cousin, the King mackerel.

Wild-Caught vs. Farmed Fish: Making a Sustainable Choice

The debate over wild vs. farmed fish is complex, with both having potential health and environmental trade-offs.

• Wild-caught fish: Benefits include a more natural diet and often higher omega-3 levels in oily fish. The main drawback is the potential for environmental contaminants like mercury, which is higher in older, predatory species. Sustainability is also a concern for wild populations.
• Farmed fish: Modern aquaculture practices can control fish feed, sometimes leading to higher omega-3 content and lower mercury levels than some wild fish. However, poorly managed farms can have issues with antibiotics and pollution. It is best to choose sustainably farmed fish with ASC certification.

Ultimately, safety depends on the species and the source, not just whether it's wild or farmed. For example, responsibly sourced farmed salmon is often safer than wild-caught swordfish.

Safest Fish to Eat: A Comparison Table

Fish Species	Mercury Level (Best Choice, Good Choice, Avoid)	Omega-3 Content	Sustainability Notes
Salmon (Wild Alaska)	Best Choice	High	Excellent management in Alaska
Sardines	Best Choice	High (more than salmon)	Very low carbon footprint, sustainable
Shrimp	Best Choice	Low	Varies; check certification
Trout (Freshwater)	Best Choice	Medium-High	Farmed options are sustainable
Cod	Best Choice	Low	Pacific cod is well-managed
Canned Light Tuna	Best Choice	Medium	Skipjack has lowest mercury
Albacore Tuna	Good Choice	Medium	Higher mercury than skipjack, limit intake
Halibut	Good Choice	Medium-Low	Higher mercury than best choices, limit intake
Swordfish	Avoid	Medium	High mercury content
King Mackerel	Avoid	High	Highest mercury content

Special Considerations for Vulnerable Groups

For pregnant or breastfeeding women and young children, avoiding high-mercury fish is especially important due to the potential for mercury to harm the developing nervous system. The FDA and EPA recommend these groups choose from the "Best Choices" list and limit their intake of certain "Good Choices" fish, such as canned albacore tuna. Eating cooked seafood is also recommended to reduce the risk of food poisoning from bacteria.

Conclusion: Making Informed Choices for a Healthy Diet

To make the safest seafood choices, prioritize variety from the FDA's "Best Choices" list, with a special focus on oily fish like salmon, sardines, and trout for their potent omega-3 benefits. By choosing sustainably sourced, low-mercury fish and cooking it properly, you can maximize the nutritional advantages of seafood while minimizing potential health risks. Informed decisions are the key to a healthy and safe fish-eating experience. For comprehensive, up-to-date guidance, consult the official FDA guidelines.

For more detailed information on specific fish and seafood recommendations, check out the FDA's comprehensive guide on eating fish. FDA Advice on Eating Fish

References

• 10 healthy fish to eat - BBC Good Food
• Advice about Eating Fish - FDA
• Which Fish Have the Highest and Lowest Mercury Levels? - MedicineNet
• Best and Worst Seafood Dishes for Your Health - WebMD
• What’s the most sustainable kind of seafood? - The Green Stars Project
• Top 10 Sustainable Fish to Eat | Alaskan Salmon Co.
• Avoiding Mercury In Fish - NewYork-Presbyterian
• Farmed Seafood or Wild? How do you choose? - Aquaculture Stewardship Council
• Wild? Farmed? Which Should You Eat? - Bastyr University
• Wild Fish Vs. Farmed Fish: Pros & Cons Explained! - Seafood Direct UK
• 5 Healthiest Fish to Eat—And Which to Avoid - Verywell Health
• Fish on Your Plate: Which Are the Healthiest and Which Should You ... - GymBeam
• Finding omega-3 fats in fish: Farmed versus wild - Harvard Health
• What Types of Fish Contain Omega-3? - OmegaQuant
• Eating Fish During Pregnancy: What Varieties Are Safe? - What to Expect

Frequently Asked Questions

Which fish has the least amount of mercury?

Small fish and shellfish generally have the least amount of mercury. According to the FDA, options like sardines, anchovies, salmon, trout, pollock, and shrimp are considered 'Best Choices' for their low mercury content.

Is canned tuna safe to eat?

Yes, but it depends on the type. Canned 'light' tuna, which typically comes from smaller skipjack fish, has significantly lower mercury levels than canned albacore ('white') tuna. The FDA classifies canned light tuna as a 'Best Choice,' while canned albacore is a 'Good Choice' with a recommendation to limit intake.

Are there any fish I should completely avoid due to mercury?

Yes, large, predatory fish that live longer tend to accumulate the most mercury and should be avoided, especially by vulnerable populations. The FDA's 'Choices to Avoid' list includes species such as king mackerel, shark, swordfish, marlin, and tilefish from the Gulf of Mexico.

Is wild-caught fish always better than farmed fish?

Not necessarily. While wild-caught fish offers a natural diet and potentially higher omega-3s, it can contain environmental contaminants. Sustainably farmed fish, with proper certifications like ASC, can offer consistent nutritional value with controlled contaminant levels. The safest choice depends on the species and source.

How often can I eat fish safely?

For most healthy adults, the FDA recommends eating 2 to 3 servings of 'Best Choice' (low-mercury) fish per week. Vulnerable groups like pregnant women and young children should follow specific guidelines and avoid high-mercury options.

How can I tell if a fish is sustainably sourced?

Look for certifications from reputable organizations. For wild-caught fish, the Marine Stewardship Council (MSC) is a good indicator. For farmed fish, the Aquaculture Stewardship Council (ASC) provides assurance of responsible practices.

What is the primary health benefit of eating low-mercury, oily fish?

The primary benefit is the high concentration of heart-healthy omega-3 fatty acids, EPA and DHA, which are crucial for brain function, cardiovascular health, and reducing inflammation.