Is Swordfish Healthy? Nutrition Facts, Benefits, and Risks

Swordfish is a popular seafood choice known for its meaty texture and mild flavor. As a large predatory fish found in tropical and temperate ocean waters worldwide, it has become a staple in many restaurants and home kitchens. But is swordfish healthy?

This distinctive fish, easily recognized by its long, flat bill that resembles a sword, offers impressive nutritional value. However, concerns about mercury content have led many people to question whether they should include it in their diet.

This comprehensive guide explores the nutritional profile of swordfish, its potential health benefits, associated risks, and how to safely incorporate it into your diet.

Nutritional Profile of Swordfish

Swordfish delivers an impressive array of essential nutrients that your body needs to function optimally. Understanding its nutritional composition can help you make informed dietary decisions.

A typical 3-ounce (85-gram) serving of cooked swordfish contains:

• Calories: 146
• Protein: 20 grams
• Total Fat: 6.7 grams
• Saturated Fat: 1.8 grams
• Carbohydrates: 0 grams
• Selenium: 106% of the Daily Value (DV)
• Vitamin D: 71% of the DV
• Niacin (Vitamin B3): 52% of the DV
• Vitamin B12: 20% of the DV
• Potassium: 9% of the DV
• Magnesium: 7% of the DV

Rich Source of High-Quality Protein

Swordfish provides approximately 20 grams of complete protein per serving, containing all nine essential amino acids your body cannot produce on its own. This high-quality protein supports muscle growth, tissue repair, enzyme production, and immune function.

Abundant in Omega-3 Fatty Acids

One of the most valuable nutritional components of swordfish is its omega-3 fatty acid content. A single serving provides approximately 760-800 mg of combined EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), far exceeding the recommended daily intake of 250 mg suggested by dietary guidelines.

These essential fatty acids play crucial roles in brain function, heart health, and reducing inflammation throughout the body.

Exceptional Selenium Content

Swordfish stands out as one of the best dietary sources of selenium, providing more than 100% of your daily needs in a single serving. This trace mineral acts as a powerful antioxidant and supports thyroid function, immune health, and reproductive health.

Excellent Source of Vitamin D

With approximately 71% of the daily value for vitamin D per serving, swordfish is one of the few natural food sources of this essential nutrient. Many people struggle to get enough vitamin D, making swordfish a valuable dietary option for maintaining adequate levels.

Health Benefits of Eating Swordfish

The unique nutritional composition of swordfish translates into several potential health benefits when consumed as part of a balanced diet.

Supports Cardiovascular Health

The omega-3 fatty acids in swordfish offer significant benefits for heart health. Research indicates that EPA and DHA may help:

• Lower blood pressure by improving blood vessel elasticity and function
• Reduce triglyceride levels by 20-30%
• Decrease heart rate and improve overall cardiac function
• Prevent blood clot formation that can lead to heart attacks and strokes
• Reduce inflammation in blood vessels

The vitamin D content in swordfish also contributes to cardiovascular protection. Studies have linked adequate vitamin D levels to lower blood pressure and reduced risk of heart disease. People with vitamin D deficiency may face up to 60% higher risk of cardiovascular problems.

Promotes Brain Function and Mental Health

DHA, one of the primary omega-3 fatty acids in swordfish, is a major structural component of brain tissue. Adequate intake of omega-3s supports:

• Cognitive function and memory
• Mental clarity and focus
• Mood regulation
• Protection against age-related cognitive decline
• Healthy brain development in infants and children

Research suggests that regular consumption of omega-3-rich fish may help reduce the risk of depression and support overall mental well-being.

Strengthens Bone Health

Both vitamin D and selenium in swordfish play important roles in maintaining strong, healthy bones.

Vitamin D is essential for calcium absorption in the intestines. Without adequate vitamin D, your body cannot effectively use dietary calcium, regardless of how much you consume. This vitamin also directly influences bone cell activity and bone formation processes.

Selenium contributes to bone health by regulating bone metabolism. It helps maintain the balance between bone formation and bone breakdown, a process known as bone remodeling. Studies have found that low selenium levels are associated with decreased bone mineral density and increased risk of bone disease.

May Help Reduce Cancer Risk

The omega-3 fatty acids, vitamin D, and selenium in swordfish all possess properties that may help protect against certain types of cancer.

Omega-3 fatty acids have demonstrated anti-inflammatory effects that may help prevent cancer development. Laboratory and animal studies suggest these fatty acids may:

• Slow the growth of cancer cells
• Trigger cancer cell death (apoptosis)
• Prevent cancer from spreading to other tissues
• Reduce tumor size, particularly in colorectal cancer

Vitamin D may help prevent cancer cell reproduction and stop the formation of new blood vessels that feed tumors. Research has particularly linked adequate vitamin D intake to reduced risk of colorectal cancer.

Selenium acts as a powerful antioxidant that neutralizes harmful free radicals in the body. This protective effect may be particularly beneficial against liver, prostate, breast, and lung cancers.

However, it’s important to note that while these individual nutrients show promise in research, more studies are needed to confirm the cancer-protective effects of eating swordfish specifically.

Boosts Immune System Function

Multiple nutrients in swordfish support a healthy immune system. Selenium helps produce antioxidant enzymes that protect immune cells from damage. Vitamin D regulates immune responses and helps your body defend against pathogens. Omega-3 fatty acids reduce excessive inflammation that can impair immune function.

Supports Thyroid Health

Selenium is a critical component of enzymes that regulate thyroid hormone production and metabolism. Adequate selenium intake ensures proper thyroid function, which controls metabolism, energy levels, body temperature, and numerous other vital processes.

Potential Risks and Concerns

Despite its nutritional benefits, swordfish comes with important considerations that you should understand before making it a regular part of your diet.

High Mercury Content

The most significant concern with swordfish consumption is its high mercury content. As a large, long-lived predatory fish, swordfish accumulates substantial amounts of mercury through a process called bioaccumulation.

Mercury enters water bodies primarily through industrial pollution and coal burning. Small organisms absorb it, then larger fish consume these organisms, accumulating increasingly higher mercury concentrations as you move up the food chain. Swordfish, being apex predators with long lifespans, tend to contain some of the highest mercury levels among commonly consumed fish.

Mercury’s Health Effects

Mercury is a neurotoxin that can damage the nervous system, particularly the brain. The effects can be especially severe for:

• Developing fetuses: Mercury can cross the placental barrier and interfere with brain and nervous system development
• Infants and young children: Their developing nervous systems are particularly vulnerable to mercury’s toxic effects
• Pregnant and breastfeeding women: Mercury can pass through breast milk to nursing infants

In adults, excessive mercury exposure may cause neurological symptoms including memory problems, tremors, numbness, and coordination difficulties. Some research suggests that high mercury intake may even counteract some of the cardiovascular benefits of omega-3 fatty acids.

Who Should Avoid Swordfish

The U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) specifically recommend that certain groups avoid eating swordfish entirely:

• Pregnant women
• Women who are trying to become pregnant
• Breastfeeding mothers
• Young children

These recommendations aim to protect the developing nervous systems of fetuses and young children from mercury’s harmful effects.

Safe Consumption Guidelines

If you’re not in a high-risk group, you can still enjoy swordfish while minimizing mercury exposure by following these guidelines.

Recommended Serving Limits

For adults who are not pregnant or planning to become pregnant, the FDA recommends limiting swordfish consumption to:

• One serving (about 4 ounces cooked) per week, or
• Two servings per month

This frequency allows you to enjoy the nutritional benefits while keeping mercury exposure within safer limits.

Balance with Low-Mercury Fish

Rather than relying solely on swordfish, incorporate a variety of fish into your diet, emphasizing those with lower mercury content such as:

• Salmon
• Sardines
• Anchovies
• Trout
• Herring
• Atlantic mackerel
• Cod
• Tilapia

This approach provides omega-3 fatty acids and other nutrients while significantly reducing your overall mercury intake.

How to Select and Store Swordfish

Choosing high-quality swordfish and storing it properly ensures the best flavor, texture, and food safety.

Selecting Fresh Swordfish

When purchasing fresh swordfish, look for these quality indicators:

• Appearance: The flesh should be moist with a slight translucent quality. Avoid fillets with discoloration, dark spots, or dried edges
• Smell: Fresh swordfish should have a mild, ocean-like scent. Avoid any fish with a strong fishy, sour, or ammonia-like odor
• Texture: The flesh should be firm and spring back when gently pressed. Avoid mushy or soft areas
• Color: Look for flesh that is pinkish-white to beige. Very white or gray coloration may indicate poor quality or age

Frozen Swordfish

If buying frozen swordfish:

• Ensure packaging is intact without tears or frost buildup
• Avoid packages with visible ice crystals inside, which may indicate thawing and refreezing
• Check the “best by” date

Storage Guidelines

Proper storage is crucial for maintaining quality and preventing foodborne illness:

• Fresh swordfish: Store in the coldest part of your refrigerator and use within 1-2 days of purchase
• Frozen raw swordfish: Keep frozen at 0°F (-18°C) or below for up to 3-4 months
• Cooked swordfish: Refrigerate in an airtight container and consume within 3-4 days
• Frozen cooked swordfish: Store in freezer-safe containers for up to 6 months

How to Prepare and Cook Swordfish

Swordfish’s firm, meaty texture makes it versatile and easy to cook. Unlike more delicate fish, it won’t fall apart during cooking, making it ideal for various preparation methods.

Preparation Tips

Before cooking:

• Thaw frozen swordfish in the refrigerator overnight, never at room temperature
• Pat fillets dry with paper towels for better browning
• Remove any skin if desired, though keeping it on during cooking can help retain moisture
• Cut into steaks about 1 to 1.5 inches thick for even cooking

Marinating

Swordfish benefits from marinating, which adds flavor and helps keep it moist. Try these marinades:

• Mediterranean: olive oil, lemon juice, garlic, oregano, and thyme
• Asian-inspired: soy sauce, sesame oil, ginger, and lime
• Tropical: citrus juice, coconut milk, cilantro, and chili peppers

Marinate for 30 minutes to 2 hours in the refrigerator. Avoid marinating longer, as acidic ingredients can begin to “cook” the fish and affect its texture.

Cooking Methods

Grilling: This is perhaps the most popular method for swordfish. Preheat your grill to medium-high heat, brush the fish with oil to prevent sticking, and grill for 4-5 minutes per side until the internal temperature reaches 145°F (63°C).

Pan-searing: Heat oil in a skillet over medium-high heat. Sear the swordfish for 4-5 minutes on each side until golden brown and cooked through.

Baking: Preheat your oven to 425°F (218°C). Place swordfish in a baking dish, drizzle with olive oil and seasonings, and bake for 12-15 minutes.

Broiling: Position the oven rack about 4 inches from the heating element. Broil for 4-5 minutes per side, watching carefully to prevent burning.

Doneness Guidelines

Swordfish is best when cooked to medium, similar to a steak. Overcooking will result in dry, tough fish. The fish is done when:

• The internal temperature reaches 145°F (63°C) when measured with a food thermometer
• The flesh becomes opaque and flakes easily with a fork
• The center is still slightly pink for medium doneness

Serving Suggestions

Swordfish pairs well with:

• Fresh salads with citrus vinaigrette
• Grilled or roasted vegetables
• Rice pilaf or quinoa
• Pasta with light sauces
• Mango or pineapple salsa
• Roasted potatoes or sweet potatoes

Comparing Swordfish to Other Fish

Understanding how swordfish compares to other popular fish can help you make informed choices about which seafood to include in your diet.

Swordfish vs. Salmon

Both are excellent sources of omega-3 fatty acids and protein. Salmon generally contains more omega-3s than swordfish and has significantly lower mercury levels, making it safer for frequent consumption. However, swordfish contains more selenium.

Swordfish vs. Tuna

Like swordfish, tuna (particularly bigeye and albacore) is a large predatory fish with high mercury content. Both offer similar protein content and omega-3 benefits. Smaller tuna varieties like skipjack (used in most canned light tuna) contain much less mercury and are safer for regular consumption.

Swordfish vs. Mahi-Mahi

Mahi-mahi offers a similar firm texture but contains significantly less mercury than swordfish, making it a safer choice for more frequent consumption. However, swordfish provides higher amounts of omega-3s, selenium, and vitamin D.

Environmental and Sustainability Considerations

Beyond personal health, the environmental impact of seafood choices is increasingly important to many consumers.

Fishing Methods

Swordfish are caught primarily through longline fishing, which can result in bycatch of other marine species including sea turtles, sharks, and seabirds. Some fishing operations use circle hooks and other methods to reduce bycatch, which is more environmentally responsible.

Population Status

Many swordfish populations have recovered from previous overfishing due to management measures. However, sustainability varies by region. North Atlantic and U.S. Pacific swordfish populations are generally considered well-managed, while some other populations face concerns.

Making Sustainable Choices

When purchasing swordfish:

• Look for certifications from organizations like the Marine Stewardship Council (MSC)
• Choose U.S.-caught swordfish when possible, as U.S. fisheries generally follow stricter sustainability standards
• Ask your fishmonger about the origin and fishing methods used
• Consult sustainable seafood guides from organizations like Seafood Watch

Frequently Asked Questions

Is swordfish healthier than other types of fish?

Swordfish offers excellent nutritional value with high amounts of protein, omega-3 fatty acids, selenium, and vitamin D. However, its high mercury content makes it less healthy for frequent consumption compared to low-mercury fish like salmon, sardines, or trout.

Can I eat swordfish while trying to lose weight?

Yes, swordfish can be part of a weight loss diet. With approximately 146 calories per 3-ounce serving and 20 grams of protein, it’s relatively low in calories while being highly satisfying. The protein and healthy fats help promote feelings of fullness.

How can I tell if swordfish has gone bad?

Signs of spoiled swordfish include a strong fishy or ammonia smell, slimy texture, discoloration, or any sour odor. Fresh swordfish should smell mildly of the ocean and have firm, moist flesh.

Is wild-caught or farm-raised swordfish better?

Swordfish is not currently farm-raised commercially, so all swordfish available for purchase is wild-caught. This actually simplifies the decision-making process compared to species like salmon or tilapia.

Does cooking method affect mercury content?

No, cooking does not reduce the mercury content in swordfish. Mercury binds tightly to the fish’s proteins and remains present regardless of the cooking method used.

The Bottom Line: Is Swordfish Healthy?

So, is swordfish healthy? The answer depends on who you are and how often you eat it.

Swordfish undeniably offers impressive nutritional benefits. It’s an excellent source of high-quality protein, omega-3 fatty acids, selenium, and vitamin D—nutrients that support heart health, brain function, bone strength, and immune system performance. For healthy adults, occasional consumption of swordfish can be part of a nutritious, balanced diet.

However, the high mercury content presents a significant concern that cannot be ignored. Pregnant women, those planning pregnancy, breastfeeding mothers, and young children should avoid swordfish entirely due to mercury’s harmful effects on developing nervous systems.

For other adults, moderation is key. Limiting swordfish to one serving per week or less, while incorporating a variety of lower-mercury fish into your diet, allows you to enjoy its benefits while minimizing potential risks.

When you do choose swordfish, select high-quality, sustainably caught fish, store it properly, and prepare it using healthy cooking methods like grilling, baking, or pan-searing rather than deep-frying.

Ultimately, swordfish can be a healthy addition to your diet when consumed mindfully and as part of a diverse seafood rotation that emphasizes lower-mercury options.

Sources:

• FoodData Central – U.S. Department of Agriculture
• FDA – Advice About Eating Fish
• EPA – Fish and Shellfish Advisories
• PubMed Central – National Institutes of Health
• Dietary Guidelines for Americans – USDA
• Monterey Bay Aquarium Seafood Watch