Octopus is one of the most nutrient-dense seafoods you can eat. It’s high in protein, extremely low in fat, and packed with vitamins and minerals that are hard to get in such concentrated amounts from other foods. A 100-gram serving of raw octopus contains just 82 calories, and even cooked, it comes in at around 164 calories for the same portion.
Protein and Calorie Breakdown
Octopus is almost pure protein. When cooked, most of its moisture evaporates, which concentrates the protein, fat, and mineral content. Boiled octopus lands around 120 calories per 100 grams, with protein making up the bulk of those calories. Fat content stays minimal. For anyone looking for a lean protein source that isn’t chicken breast, octopus is a strong option.
Vitamins and Minerals
The micronutrient profile is where octopus really stands out. A single serving delivers roughly 1,275% of your daily value for vitamin B12, which is essential for nerve function, red blood cell production, and DNA synthesis. That’s not a typo. Octopus is one of the richest natural sources of B12 in any food category.
Beyond B12, a serving provides about 139% of your daily selenium (important for thyroid function and antioxidant defense), 70% of your daily copper (which supports iron absorption and immune health), and 45% of your daily iron. If you struggle with low iron or B12, octopus delivers both in a single meal without supplements.
Omega-3 Fatty Acids
Octopus contains omega-3s in the forms your body actually uses for heart and brain health. A 100-gram serving of steamed octopus provides about 0.38 grams of these fats, covering more than 20% of recommended intake. That’s less than salmon or mackerel, but significantly more than most land-based proteins. For people who eat seafood occasionally rather than daily, octopus contributes meaningful omega-3s alongside its other benefits.
Taurine and Blood Vessel Health
Octopus meat is naturally rich in taurine, an amino acid that plays a role in cardiovascular protection. Lab research has shown that taurine-rich octopus extract helps protect blood vessel cells from damage caused by methylglyoxal, a harmful byproduct of blood sugar metabolism that accumulates in people with diabetes or consistently high blood glucose. The extract reduced cell toxicity and DNA damage in both human cell cultures and animal models. While this doesn’t translate directly to “eat octopus, prevent heart disease,” it does suggest that the taurine content adds a layer of benefit beyond basic nutrition.
Mercury and Safety
Mercury is a reasonable concern with any seafood. Octopus generally falls on the safer end of the spectrum. Studies measuring mercury levels in common octopus found concentrations within the range legally defined as safe for human consumption. Most mercury accumulates in the digestive gland rather than the arm muscle, which is the part people actually eat. The arm muscle carries about 56% of the total mercury in the animal, but the overall concentrations remain well below levels considered risky. Octopus is not in the same category as swordfish, shark, or king mackerel when it comes to mercury exposure.
Purines and Gout Risk
If you have gout or high uric acid levels, octopus deserves some attention but not alarm. It contains about 137 mg of total purines per 100 grams, which falls into the moderate range. Japanese dietary guidelines for gout prevention recommend staying under 400 mg of purines per day, and foods classified as high risk contain more than 200 mg per 100 grams. Octopus sits below that threshold. Its purine composition leans toward hypoxanthine, which is worth noting because hypoxanthine is considered more problematic for gout than other purine types. A reasonable serving as part of a varied diet shouldn’t be an issue for most people, but if you’re actively managing gout flares, it’s worth factoring in.
How Cooking Changes the Nutrition
The way you prepare octopus matters more than you might expect. Boiling causes moisture loss, which concentrates everything: protein, fat, fatty acids, amino acids, and minerals like zinc, phosphorus, and iodine all increase per gram of cooked meat. Raw octopus starts at about 81 calories per 100 grams, and boiled octopus rises to around 120 calories for the same weight. That’s not because boiling adds calories. It’s because the water leaves and everything else stays behind in a denser package.
Grilling with a light brush of olive oil keeps the calorie count reasonable while adding flavor. Deep-frying, predictably, adds fat and calories that offset the lean advantage octopus naturally has. Preparations in oil or brine (common in canned or jarred versions) also add sodium and fat that aren’t present in the fresh product. If you’re eating octopus specifically for its nutritional profile, stick with boiling, grilling, or steaming.
Who Benefits Most
Octopus is particularly useful for people who need more B12 or iron without a lot of extra calories or saturated fat. That includes people following calorie-controlled diets, those with B12 deficiency (common in older adults and people who’ve recently reduced their meat intake), and anyone trying to increase iron from food rather than supplements. It’s also a solid choice for people managing blood sugar, given its negligible carbohydrate content and its taurine-related benefits for blood vessel health.
The main practical downside is availability and cost. Fresh octopus can be expensive and isn’t stocked at every grocery store. Frozen octopus is widely available and nutritionally comparable. Canned versions work in a pinch but check labels for added sodium.