What is safer to eat, tuna or salmon? A guide to mercury, nutrition, and contaminants

October 17, 2025 •

4 min read

According to the FDA and EPA, eating fish like salmon and canned light tuna up to three times a week is part of a healthy diet, but many wonder: What is safer to eat, tuna or salmon? This depends largely on mercury levels, which vary significantly by species.

Quick Summary

An in-depth comparison of tuna and salmon safety, analyzing contaminant levels like mercury and PCBs alongside key nutritional differences, including omega-3s and protein. Provides expert recommendations and guidelines for making informed choices.

Key Points

Mercury Levels Differ Drastically: Salmon is consistently low in mercury, whereas tuna mercury levels vary significantly by species, with larger tuna (like bigeye and albacore) containing more.
Wild Salmon is Generally Cleaner: Wild-caught salmon typically has lower levels of PCBs and other industrial contaminants compared to farmed salmon, though modern farming practices are improving safety.
Salmon is Richer in Omega-3s: Salmon provides a higher concentration of crucial omega-3 fatty acids (EPA and DHA) important for heart and brain health compared to tuna.
Moderate Tuna Consumption is Key: For most tuna varieties, especially albacore, limiting intake to one serving per week is recommended, while canned light tuna is a safer option for more frequent consumption.
Vulnerable Groups Need Extra Caution: Pregnant women, breastfeeding mothers, and young children should stick to low-mercury options like salmon and canned light tuna and limit or avoid higher-mercury fish.
The Best Approach is Variety: To maximize nutritional benefits and minimize contaminant exposure, experts recommend eating a variety of fish from the FDA's "Best Choices" list.

Both tuna and salmon are staples in healthy diets worldwide, lauded for their high-quality protein and beneficial fats. However, concerns about contaminants like mercury and polychlorinated biphenyls (PCBs) often lead people to question which option is the safer choice. The answer is not a simple one, as safety depends on the type of fish, its source, and your overall dietary habits. By examining the key factors of mercury content, other contaminants, and nutritional benefits, you can make the best decision for your health.

Mercury Levels: The Primary Safety Concern

Mercury is a naturally occurring element that, when released into the environment, can convert into a neurotoxin called methylmercury. Fish absorb this toxin, and it can accumulate in their tissues over time. Larger, predatory fish higher up the food chain tend to have the highest concentrations.

Tuna: A Mixed Bag of Mercury Content

Tuna species vary dramatically in their mercury content, with larger fish typically containing more.

Bigeye Tuna (often used for sushi): This large species has the highest mercury levels and should be avoided, especially by pregnant women and young children.
Albacore Tuna (also known as white tuna): This variety has significantly higher mercury than light tuna and is classified as a "Good Choice" by the FDA. Consumption should be limited to about one serving per week for most adults.
Canned Light/Skipjack Tuna: Made from smaller, younger tuna species, this is categorized as a "Best Choice." Its mercury levels are much lower, making it a safe option for 2–3 servings per week.

Salmon: Consistently Low in Mercury

In contrast, salmon is consistently one of the lowest-mercury fish available, earning its spot on the FDA's "Best Choices" list. Salmon feed lower on the food chain and don't live long enough to accumulate high levels of the metal. This makes it a safer option for frequent consumption, especially for sensitive populations like children and pregnant women.

PCBs and Other Contaminants

Beyond mercury, PCBs and other organic pollutants are also a consideration. These industrial chemicals accumulate in the fatty tissues of fish.

Farmed Salmon: Historically, farmed salmon has been shown to contain higher levels of PCBs and other pollutants compared to wild salmon. This is primarily due to contaminants found in their feed. However, modern regulations and improvements in feed quality are helping to lower these levels.
Wild Salmon: As wild salmon spend their lives in the open ocean, they typically have lower levels of industrial contaminants. Wild Alaskan salmon, in particular, is often cited for its clean contaminant profile.
Tuna: PCBs and dioxins are also found in tuna, though some studies suggest salmon may have higher concentrations of certain PCB types.

To minimize exposure to these contaminants, trimming fat and removing the skin from fish is an effective strategy, as these compounds are fat-soluble.

Nutritional Comparison: Omega-3s and Protein

Both fish are nutritional powerhouses, but their profiles differ. For heart and brain health, omega-3 fatty acids (EPA and DHA) are crucial.


Feature	Salmon	Tuna	Winner	Notes
Omega-3 Fatty Acids	Very high (1.5–2g+ per 3 oz)	Lower (0.1–1.0g per 3 oz, species-dependent)	Salmon	Salmon is a top food source for crucial EPA and DHA fats.
Mercury Content	Very low	Varies significantly (low in light tuna, high in bigeye)	Salmon	Salmon is consistently low-mercury across types, whereas tuna varies greatly.
Protein	High (approx. 22g per 3 oz)	High (approx. 25g per 3 oz)	Tuna	Tuna is a leaner, slightly higher protein option per calorie.
Vitamin D	Higher, especially wild-caught	Lower	Salmon	Salmon is one of the few natural food sources of vitamin D.
Selenium	High	Very high	Tuna	Tuna provides a higher dose of this important antioxidant.
Contaminants	Farmed can have higher PCBs; wild is cleaner	Higher mercury in larger species; PCBs are present	Wild Salmon	Less exposure to industrial contaminants compared to farmed salmon and larger tuna species.

Recommendations for Safe Consumption

To make the safest choice, consider a few simple rules based on expert advice from the FDA and EPA:

Vary Your Fish Intake: Rather than relying on a single type, rotate your seafood choices to balance nutritional benefits and minimize exposure to any single contaminant.
Choose Lower-Mercury Options: For frequent consumption, stick to low-mercury fish like salmon, sardines, and canned light/skipjack tuna. These are on the FDA's "Best Choices" list.
Mind Your Portions: Follow the FDA/EPA guidance of 2-3 servings (8-12 ounces) of low-mercury fish per week for adults.
For Vulnerable Populations: Pregnant women, breastfeeding mothers, and young children should be especially cautious with fish intake, strictly following the FDA's guidance and limiting consumption of higher-mercury species like albacore tuna.
Consider Wild vs. Farmed: While both have nutritional benefits, wild-caught salmon may be preferable if you are concerned about PCB levels. However, both wild and farmed salmon generally remain a low-mercury option.

Practical Tips for Enjoying Seafood Safely

Prioritize smaller fish species like sardines and canned light tuna, which accumulate fewer contaminants.
Purchase from reputable suppliers that adhere to sustainable and safe sourcing practices.
Follow official consumption guidelines, especially if you are in a vulnerable group. You can find more information on the official FDA-EPA website.
Consider the source and type of fish. Alaskan salmon, for example, is often cited for its low contaminant levels.
When preparing fish, particularly fatty types, use cooking methods that allow fat to drain away, such as baking or broiling on a rack.

Conclusion

When considering "What is safer to eat, tuna or salmon?", salmon is the clear winner for consistent, low-mercury seafood, making it a safer bet for frequent consumption. Canned light tuna also represents a safe, budget-friendly option, provided it's consumed within recommended limits. The key to safe seafood consumption lies in moderation and variety. By understanding the differences in mercury levels and potential contaminants between species, and following official health guidelines, you can confidently enjoy the significant nutritional benefits that both tuna and salmon offer without undue risk.

Frequently Asked Questions

Salmon consistently has lower mercury levels than most types of tuna. Larger tuna species like bigeye and albacore contain the highest mercury, while smaller skipjack tuna used for canned light tuna is a low-mercury option.

Yes, canned light tuna, typically made from smaller skipjack tuna, is a "Best Choice" according to the FDA due to its low mercury content. It is safe for most adults to consume 2-3 times per week as part of a balanced diet.

Salmon are lower on the aquatic food chain and have shorter lifespans than large, predatory tuna. This means they have less time to accumulate methylmercury from the water and other smaller fish they consume.

Wild-caught salmon generally has lower levels of industrial contaminants like PCBs compared to farmed salmon. However, both are considered safe and offer significant health benefits, though wild-caught can be more expensive.

Pregnant women should prioritize low-mercury fish. Salmon is an excellent choice, while canned light/skipjack tuna is also safe. Higher-mercury fish like albacore tuna should be limited to one serving per week.

Salmon is a far superior source of heart-healthy omega-3s (EPA and DHA) than tuna. One serving of wild-caught salmon provides significantly more omega-3s than most tuna varieties.

Varying your fish intake, choosing smaller species, and trimming the fat and skin can all help reduce your exposure to contaminants. Cooking methods that allow fat to drain, such as baking or broiling on a rack, are also beneficial.