Fish, swordfish, raw

Swordfish (scientific name Xiphias gladius) is a large, migratory marine fish found throughout temperate and tropical oceans worldwide. It’s known for its elongated, flat bill that resembles a sword — hence the name — and its robust, dense flesh that holds up well to grilling, searing, and roasting. Though not botanically classified like plants, swordfish is categorized within the Xiphiidae family, and its defining characteristics include a streamlined body adapted to high‑speed swimming and a diet consisting of smaller fish and cephalopods. Culturally and historically, swordfish has been harvested by coastal communities for centuries, prized both for its size and meat quality. In ancient Mediterranean cultures, it appeared in mosaic art and literature as a symbol of maritime prowess. Today, swordfish remains a culinary staple in many regions, from Italian grilled pesce spada to Japanese preparations and Caribbean fish stews. Swordfish is most commonly sold as thick steaks or loins rather than fillets because of the firm texture and uniform thickness of the meat. These steaks can range in color from creamy white to slightly pink or orange — a variation driven by the fish’s diet. For example, swordfish feeding on shrimp with carotenoid pigments may display a more orange hue, often marketed as "pumpkin swordfish." The species is wild‑caught rather than farmed, with major harvests coming from U.S. Atlantic waters and Mediterranean fleets. Swordfish populations are managed under fishery quotas and monitoring programs in many regions to support sustainability. However, fishing methods vary: harpoon and longline gear are common, with varying bycatch implications. Making sustainable choices at the seafood counter — such as choosing harpoon‑caught over longline — can help reduce environmental impact. From a nutritional perspective, raw swordfish is a powerhouse of essential nutrients, particularly high‑quality protein and long‑chain omega‑3 fatty acids (including EPA and DHA), which contribute to cardiovascular and cognitive health. It also delivers minerals like selenium and phosphorus at levels that support antioxidant defenses and bone structure. Because swordfish is a top predator with a long lifespan, it tends to bioaccumulate environmental contaminants such as methylmercury, which is why certain populations — especially pregnant and breastfeeding individuals and young children — are advised to limit or avoid consumption. Mercury accumulation is driven by trophic biomagnification: small organisms absorb mercury from water and sediment, larger fish eat them, and so on up the food chain, with concentrations increasing at each step. Variations in swordfish nutritional composition can occur depending on geographic region, diet, and season, but raw swordfish consistently ranks as a nutrient‑dense seafood. It’s often compared to salmon or tuna in terms of protein density and omega‑3 content, although mercury risks differ. Finally, swordfish’s firm flesh and mild flavor make it a versatile culinary ingredient, but its safety profile and sustainability considerations influence how often and for whom it should be consumed.

Swordfish’s nutrient profile illustrates why it’s both revered and approached with caution. On a raw 100 g basis, swordfish delivers around 144 kcal, 19.66 g of complete protein, and 6.65 g of total fat with zero carbohydrates or dietary fiber. This makes it an efficient choice for low‑carbohydrate or ketogenic patterns because almost all energy comes from protein and beneficial fats. Beyond macronutrients, swordfish contributes remarkable micronutrients. Selenium appears at 57.4 µg per 100 g — over 100% of the daily requirement for many adults — where this mineral functions as a cofactor for glutathione peroxidases and other antioxidant enzymes that mitigate oxidative stress. Phosphorus (255 mg) supports skeletal integrity and energy metabolism as a component of ATP. Potassium (418 mg) helps regulate fluid balance and blood pressure, while vitamin B12 (1.7 µg) and B6 (0.543 mg) are crucial for neurological function and amino acid metabolism. Vitamin D is a standout nutrient in swordfish: 13.9 µg per 100 g raw. Few whole foods provide meaningful vitamin D, making swordfish and other oily fish valuable, especially for individuals with limited sun exposure. Vitamin D plays roles in calcium homeostasis, immune modulation, and muscle function. Another group of nutrients warranting attention are the long‑chain omega‑3 PUFAs — EPA and DHA — which in swordfish are present in combined amounts exceeding 0.75 g per 100 g. EPA and DHA integrate into cell membranes and influence lipid profiles, inflammatory mediators, and vascular function more profoundly than shorter‑chain omega‑3s like ALA. Omega‑3s are also recognized for their roles in brain health, particularly during early development and aging. When comparing raw swordfish to other seafood, its amino acid profile stands out: essential amino acids such as lysine and leucine support muscle protein synthesis, making swordfish a protein‑rich choice for athletes and older adults. Compared with salmon, swordfish has slightly less total fat but still offers substantial omega‑3 content, while its vitamin D content often exceeds that found in many farmed fish. When matched against tuna, swordfish delivers higher selenium and vitamin D but shares similar omega‑3 profiles. However, mercury levels in swordfish can be considerably higher than in smaller fish like sardines or trout, which is a crucial consideration when crafting balanced dietary recommendations. Finally, nutrient density — defined as the ratio of nutrients per calorie — is high for protein, selenium, and vitamin D in swordfish. Yet the absence of carbohydrates and fiber means that complementary foods like vegetables, legumes, and whole grains are needed in meals to provide a full spectrum of dietary needs, particularly for digestive and metabolic health. The raw values change slightly when swordfish is cooked: moisture loss concentrates nutrients, and cooking methods can influence the retention of heat‑sensitive vitamins and some omega‑3s. For example, grilling tends to preserve nutrient levels better than deep‑frying, which can introduce excess fats and reduce omega‑3 content. Taken together, swordfish’s nutritional profile supports a variety of health outcomes when consumed as part of a balanced pattern that includes plant foods and varietal seafood choices.

Source: USDA FoodData Central (FDC ID: 173703)