Unagi is a nutrient-dense food packed with protein, healthy fats, and an unusually high concentration of vitamins. A 100-gram serving of grilled freshwater eel (the classic kabayaki preparation) delivers about 257 calories, 19 grams of protein, and 16 grams of fat. That’s a solid nutritional profile, but the full picture includes some important caveats about how it’s prepared, who should limit it, and where it comes from.
Vitamin A and B12 Stand Out
Unagi’s most remarkable nutritional feature is its vitamin A content. A single cooked fillet provides roughly 1,808 micrograms of retinol, which is about twice the daily recommended intake. Vitamin A in this form (preformed retinol, not the plant-based beta-carotene found in carrots) is highly bioavailable, meaning your body absorbs and uses it efficiently. It supports vision, immune function, and cell growth.
Eel is also rich in vitamin B12, containing around 7 micrograms per 100 grams. That’s several times the daily requirement for most adults. B12 plays a central role in energy metabolism and red blood cell production, making unagi a particularly good choice for people who struggle to get enough of this vitamin from other sources.
The fat in unagi includes meaningful amounts of DHA and EPA, the same omega-3 fatty acids found in salmon and mackerel. DHA makes up about 5% of the total fat content, with EPA adding another 1%. These fats are linked to heart health, brain function, and reduced inflammation throughout the body.
Vitamin E and Skin Protection
Eel contains vitamin E, a fat-soluble antioxidant that plays a specific and well-documented role in skin health. Vitamin E is the most abundant fat-soluble antioxidant naturally found in human skin, where it helps neutralize damage from UV light, reduces inflammation after sun exposure, and limits the breakdown of skin lipids. Your body delivers vitamin E to the skin surface through the oils produced by sebaceous glands, so dietary intake directly contributes to the skin’s defense system.
This doesn’t mean eating unagi will transform your skin overnight. But as part of a diet that includes adequate fat-soluble vitamins, eel contributes meaningfully to the nutrients your skin relies on for repair and protection.
The Kabayaki Sauce Problem
Most unagi you’ll encounter at a restaurant or grocery store comes in kabayaki style: brushed with a thick, sweet glaze and grilled. That sauce changes the nutritional equation considerably. A typical kabayaki sauce contains about 44 grams of sugar per 100 grams, along with 4.7 grams of salt. The sauce is roughly 56% added sugars by weight, combining table sugar with glucose syrup.
You’re not eating 100 grams of sauce with your eel, of course. But a generous brushing adds a significant amount of sugar and sodium on top of what is otherwise a clean protein source. If you’re watching your sodium or sugar intake, it’s worth being aware that the health benefits of unagi can be partially offset by its most common preparation. Ordering unagi shirayaki (grilled without sauce) or using the sauce sparingly makes a noticeable difference.
Unagi vs. Anago
Japanese cuisine features two types of eel: unagi (freshwater) and anago (saltwater conger eel). They differ more than you might expect. Unagi runs about 255 calories per 100 grams with a higher fat content, while anago comes in at just 151 calories per 100 grams and is considerably leaner. If you’re looking for the omega-3s and fat-soluble vitamins, unagi is the better choice. If you want a lighter option with fewer calories, anago delivers eel flavor without as much richness.
Who Should Be Careful
The same vitamin A density that makes unagi nutritious also makes it a concern during pregnancy. Raw eel contains about 1,200 micrograms of preformed retinol per 100 grams, and cooked fillets can be even higher. Excessive preformed vitamin A during pregnancy has been linked to an increased risk of neural tube defects and other developmental problems. UK health authorities specifically recommend that pregnant women and those considering becoming pregnant avoid foods rich in preformed vitamin A, placing eel in the same category as liver. This doesn’t apply to beta-carotene from vegetables, only to the retinol form found in animal foods like eel.
For most other adults, eating unagi occasionally poses no vitamin A risk. Your body stores excess retinol in the liver, and toxicity typically requires consistently high intake over time. Having unagi once or twice a week is well within safe limits for non-pregnant adults.
Sustainability and Sourcing Concerns
The Japanese eel (Anguilla japonica) has been classified as Endangered on the IUCN Red List since 2014, a status that was reaffirmed in 2020. Wild populations have declined significantly, and most unagi sold today is farmed. However, farmed eel still depends on wild-caught juvenile eels (called glass eels) because the species is extremely difficult to breed in captivity at commercial scale.
Sourcing quality matters for safety reasons too. In 2007, the US government banned eel imports from China after detecting prohibited antimicrobial agents in the products. Mislabeling has also been an issue: in 2008, several Japanese businesses were prosecuted for falsely labeling imported eels as domestically produced. If you’re buying unagi at a store, looking for reputable brands and clear country-of-origin labeling is worth the extra moment of attention.
The Bottom Line on Nutrition
Unagi is genuinely nutritious. It delivers high-quality protein, omega-3 fats, and exceptional amounts of vitamins A, B12, and E in a single serving. The main downsides are the sugar and sodium from kabayaki sauce, the vitamin A concern for pregnant women, and the environmental cost of eating an endangered species. For most people eating it occasionally at a sushi restaurant, it’s one of the more nutrient-rich items on the menu.