Eel is a nutrient-dense fish that delivers high-quality protein, heart-healthy fats, and a strong mineral profile. A 100-gram serving contains roughly 18.7 grams of protein and 285 calories, making it a solid choice nutritionally, though it comes with a few important caveats around preparation and sourcing.
Protein and Calorie Breakdown
Eel is leaner than most people expect. That same 100-gram portion (about 3.5 ounces) has only 0.9 grams of fat in its raw form, though this number climbs significantly depending on the species and how it’s prepared. Japanese unagi, for instance, is typically grilled with a sweet soy-based sauce and basted in oil, which raises both the fat and calorie count well beyond the baseline. If you’re eating eel at a sushi restaurant, you’re getting a richer dish than the raw numbers suggest.
The protein content is comparable to other popular fish like tilapia or cod, and the amino acid profile is complete, meaning it provides all the building blocks your body can’t make on its own.
Omega-3 Fatty Acids
Where eel really stands out is its omega-3 content. European eel contains about 12.68 milligrams of EPA and DHA combined per gram of muscle tissue. For a typical 100-gram serving, that translates to roughly 1,268 milligrams of these two fatty acids, which is well above the 250 to 500 milligrams most health organizations recommend per day.
EPA and DHA are the forms of omega-3 your body uses most efficiently. They reduce inflammation, support blood vessel function, and play a central role in brain health. While salmon and mackerel get most of the attention as omega-3 sources, eel belongs in that same conversation. Preliminary animal research has also shown that oil extracted from eel significantly lowers total cholesterol, LDL (“bad” cholesterol), and triglycerides at rates comparable to commercial fish oil supplements, though human studies are still needed to confirm the same effect in people.
Key Vitamins and Minerals
Eel provides a broad spectrum of micronutrients. It’s notably rich in vitamin A, which supports vision, immune function, and skin health. In fact, eel contains far more vitamin A than most other fish, enough that eating it regularly can make a meaningful contribution to your daily intake.
It also supplies phosphorus, which works alongside calcium to maintain bone density, and vitamin E, which acts as an antioxidant protecting cells from damage. The B vitamins in eel, particularly B12, support red blood cell production and nervous system function. A single serving can cover a significant portion of your daily B12 needs.
Eel Blood Is Toxic When Raw
One thing that sets eel apart from other seafood: its blood contains a protein-based toxin. Research on Japanese eel has identified this as a specific protein with a molecular mass of 100 kilodaltons that is lethal when injected into the bloodstream of lab animals. For humans, the practical risk is limited to contact with raw eel blood, which can cause irritation if it gets into your eyes or an open wound, and nausea if consumed uncooked in significant amounts.
The good news is that this toxin is a protein, and like most proteins, heat destroys it. Cooking eel to a safe internal temperature completely neutralizes the toxin, which is why eel is always served cooked. You will never find raw eel on a sushi menu. The nigiri labeled “unagi” or “anago” has been grilled or steamed before it reaches your plate.
How Preparation Affects Nutrition
The way eel is prepared changes its nutritional value dramatically. Grilled eel (kabayaki style) is basted repeatedly in a sauce made from soy, sugar, and mirin, adding a significant amount of sodium and simple sugars. Deep-fried eel, common in some European dishes, absorbs extra oil and can double the calorie count. Smoked eel, popular in the Netherlands and Scandinavia, retains its omega-3 content well but tends to be high in sodium.
If you’re eating eel primarily for its health benefits, grilled or steamed preparations with minimal added sauce give you the best nutritional return. When ordering unagi at a restaurant, you can ask for the sauce on the side to control how much you’re adding.
Mercury and Contaminant Considerations
Like most predatory fish, eel can accumulate mercury and other environmental contaminants. However, the ratio of beneficial omega-3s to mercury in European eel is favorable, with research showing an EPA+DHA to mercury ratio of 17.46, meaning the omega-3 benefits substantially outweigh the mercury risk for most people. That said, eel is not a fish to eat daily. A few servings per month is a reasonable frequency, particularly for pregnant women and young children who are more sensitive to mercury exposure.
Freshwater eels tend to accumulate more contaminants than their saltwater counterparts because rivers and lakes concentrate pollutants more than open ocean waters. Where the eel was caught or farmed matters.
Sustainability Is a Real Concern
The biggest downside of eating eel has nothing to do with nutrition. European eel populations are in critical decline, and the European Commission maintains a six-month ban on all eel fishing along with a full prohibition on recreational eel fishing in marine and brackish waters of the northeast Atlantic. Japanese eel faces similar pressure and is classified as endangered.
Most eel served in restaurants is farmed, but eel farming depends on catching wild juvenile eels (called glass eels) because the species doesn’t breed reliably in captivity. This means even farmed eel puts pressure on wild populations. If sustainability matters to you, eel is a fish to enjoy occasionally rather than as a dietary staple, and choosing eel from well-managed farms is worth the extra effort.
Who Benefits Most From Eating Eel
Eel is a particularly good choice if you’re looking to increase your omega-3 intake without relying on supplements or eating salmon every week. Its combination of high-quality protein, vitamin A, B12, and anti-inflammatory fats makes it useful for supporting cardiovascular health, brain function, and bone maintenance. People who enjoy Japanese or European cuisine already have eel in their rotation, and the nutritional data supports keeping it there.
For people managing cholesterol or triglyceride levels, eel’s fat profile is genuinely beneficial. For those watching their sodium or sugar intake, paying attention to preparation method matters more than the fish itself. The eel is healthy; the sweet glaze less so.