Octopus: Nutrition Facts, Health Benefits, and One of the Most Nutritionally Dense Seafoods Available

Octopus is one of the most nutritionally extraordinary yet most overlooked protein foods in Western fitness nutrition. At just 82 calories per 100g, it provides 833% of the daily Vitamin B12 requirement — more than eight times the daily amount in a single 100g serving — alongside 81% of selenium, 67% of copper, 29% of iron, 29% of riboflavin, 27% of phosphorus, and 14.9g of complete lean protein. No animal product on this site delivers a more concentrated combination of B12, copper, and selenium at this calorie level. Understanding what makes octopus so nutritionally exceptional — and why those numbers are genuine rather than surprising — requires understanding what octopus actually is biologically and how it lives.

Octopus Nutrition Facts (per 100g, cooked)

Octopus Nutrition Facts (per 150g serving — a standard cooked portion)

A standard 150g cooked octopus portion provides over 12 times the daily B12 requirement and the full daily copper requirement at just 123 calories.

Vitamins in Octopus (per 100g, cooked)

Standout: Octopus’ Vitamin B12 content — 833% of the daily value per 100g, rising to over 1,250% in a standard 150g serving — is one of the most extraordinary single-nutrient figures in this collection. The daily B12 requirement is just 2.4µg; 100g of octopus provides 20µg — more than eight days’ worth in a single serving. Combined with riboflavin at 29% DV, niacin at 13% DV, and B6 and pantothenic acid both at 10% DV, octopus delivers one of the most complete B vitamin profiles of any seafood.

Minerals in Octopus (per 100g, cooked)

Multiple standouts: Octopus’ mineral profile rivals the most mineral-dense foods on this site. Selenium at 81% DV supports glutathione peroxidase antioxidant defense and thyroid hormone activation. Copper at 67% DV is exceptional — copper is the mineral required for ceruloplasmin-mediated iron metabolism, lysyl oxidase-driven collagen crosslinking, and cytochrome c oxidase in mitochondrial energy production. Iron at 29% DV in highly bioavailable haem form directly supports oxygen transport. At just 82 calories per 100g, these figures represent one of the most impressive mineral-to-calorie ratios of any food in this entire collection.

Why Octopus Has 833% of Daily B12: The Biology Behind the Number

The B12 figure surprises almost everyone — and understanding why it’s real explains something genuinely fascinating about octopus biology.

Octopus as a Cephalopod: A Different Kind of Animal

Octopus belongs to the class Cephalopoda — the most neurologically complex invertebrates on earth. Octopuses have three hearts, blue blood (from haemocyanin, a copper-based oxygen-carrying protein rather than the iron-based haemoglobin found in vertebrate blood), distributed nervous systems with a majority of their neurons located in their arms rather than their brain, and documented problem-solving and tool-use behaviors more sophisticated than many vertebrates.

This unusual biology is directly relevant to their nutritional profile in two ways: their copper-based circulatory system explains the extraordinary copper concentration in their tissues, and their metabolically active, highly oxygenated musculature accumulates B12 and other nutrients at concentrations that reflect an active marine predator’s physiology.

The Haemocyanin Connection to Copper

Unlike vertebrates whose blood is red from iron-containing haemoglobin, octopus blood is blue because it uses haemocyanin — a copper-containing protein — to transport oxygen. Haemocyanin requires large amounts of copper to function, and this metabolic requirement means octopus tissue accumulates copper at concentrations far exceeding most other seafood. The 67% DV copper per 100g is a direct consequence of octopus’ fundamental circulatory biology.

B12 Accumulation in Marine Predators

B12 is produced exclusively by bacteria and archaea. In marine food chains, B12-producing bacteria colonize the ocean sediments and the digestive systems of marine animals throughout the food web. Octopuses, as active predators consuming shellfish, crustaceans, and other marine organisms throughout their lives, bioaccumulate B12 from their prey to levels that reflect the entire nutritional history of their marine diet — similar in mechanism to the extraordinary B12 concentrations found in clams and mussels, though octopus achieves this through active predation rather than filter feeding.

The Copper Story: Haemocyanin and Its Nutritional Implications

Octopus’ 67% DV of copper per 100g — rising to 100% DV in a standard 150g serving — deserves specific attention, because it connects directly to the animal’s physiology in a way that makes the figure genuinely meaningful rather than incidental.

What Copper Does in Both Octopus and in You

In octopus, copper is the oxygen-carrying element in haemocyanin — performing the same function that iron performs in human haemoglobin. When you eat octopus, you are consuming tissue that is saturated with copper-containing proteins from an animal that relies on copper for the same fundamental purpose your body relies on iron.

In the human body, dietary copper from octopus serves several critical functions:

Iron metabolism — ceruloplasmin, a copper-dependent enzyme, oxidizes ferrous iron to ferric iron, the form required for incorporation into transferrin (the blood’s iron transport protein) and ultimately into haemoglobin. Without adequate copper, iron metabolism is impaired even when dietary iron intake is sufficient. Octopus provides both copper (67% DV) and iron (29% DV) simultaneously — a nutritionally complementary pairing.

Collagen and elastin synthesis — lysyl oxidase, a copper-dependent enzyme, crosslinks collagen and elastin molecules into the mature fibers that give connective tissue its structural integrity. Adequate copper from foods like octopus directly supports tendon resilience, skin elasticity, and arterial wall strength.

Mitochondrial energy production — copper is a component of cytochrome c oxidase (Complex IV of the electron transport chain), the final enzyme in aerobic energy production that generates the majority of cellular ATP.

Antioxidant defense — copper is a component of Cu/Zn superoxide dismutase, one of the body’s primary antioxidant enzymes.

Health Benefits of Octopus

Extraordinary B12 for Neurological Health

At 833% DV per 100g, a single serving of octopus provides vastly more B12 than required for even optimal neurological health maintenance. B12 is essential for myelin synthesis (the protective sheath surrounding nerve fibers), red blood cell formation in bone marrow, DNA synthesis, and homocysteine regulation. Deficiency causes progressive, potentially irreversible neurological damage — adequate B12 from foods like octopus is genuinely important for long-term neurological health, and a single weekly octopus serving provides more than sufficient B12 to maintain optimal status.

Exceptional Selenium for Antioxidant and Thyroid Support

At 81% DV per 100g, octopus is one of the more concentrated selenium sources of any food, supporting the glutathione peroxidase enzyme system that neutralizes oxidative damage throughout the body and the deiodinase enzymes that convert thyroid hormone T4 to active T3.

Iron for Oxygen Transport

At 29% DV per 100g in haem form, octopus is a meaningful and highly bioavailable iron source, directly supporting haemoglobin synthesis and the oxygen-carrying capacity that underlies aerobic performance and daily energy.

Exceptional Lean Protein

At 14.9g of protein per 82 calories — a protein-to-calorie ratio of approximately 0.18g per calorie — octopus is one of the leanest whole-food protein sources available, containing all 9 essential amino acids in good proportions.

Taurine for Cardiovascular and Neurological Health

Octopus is one of the richest natural sources of taurine with concentrations among the highest of any seafood. Taurine has documented roles in cardiovascular function (blood pressure regulation, cardiac contractility, antiarrhythmic effects), neurological function (inhibitory neurotransmitter activity, neuroprotection), and muscle function (calcium sensitivity and force production in muscle fibers).

Heart Health

Octopus supports cardiovascular health through its taurine content, the B12 and folate that regulate homocysteine, the selenium that protects LDL from oxidative modification, and its very low saturated fat content (just 0.2g per 100g). The modest sodium content (230mg per 100g) is worth noting for people monitoring sodium intake, though it is considerably lower than many processed seafood products.

Omega-3 Contribution

At approximately 0.35g of EPA and DHA per 100g, octopus provides a modest but genuine long-chain omega-3 contribution — directly available without the ALA-to-EPA/DHA conversion limitation of plant-based omega-3 sources. Its very favorable omega-6 to omega-3 ratio (the polyunsaturated fat is heavily omega-3 dominated) makes octopus a clean addition to any dietary omega-3 strategy.

Octopus for Athletes and Active People

Copper and Iron Together for Maximum Oxygen Delivery

Octopus’ combination of 67% DV copper and 29% DV iron in the same food is particularly valuable: copper activates ceruloplasmin, which is required for the iron metabolism that ultimately produces haemoglobin. Eating a food that provides both minerals together — rather than supplementing them separately — ensures that the iron can be properly metabolized and incorporated into red blood cells.

B12 for Red Blood Cell Production

B12 is required alongside iron and folate for red blood cell formation. Athletes with marginal B12 status may have reduced red blood cell production that impairs oxygen-carrying capacity — a single weekly octopus serving provides vastly more than sufficient B12 to support optimal erythropoiesis.

Selenium for Exercise Recovery

Intense training generates significant oxidative stress; octopus’ 81% DV selenium per 100g contributes to the glutathione peroxidase antioxidant defenses that help manage exercise-induced oxidative damage.

A Calorie-Efficient Protein Source for Cutting Phases

At 14.9g of protein for just 82 calories, octopus competes directly with the leanest whole-food proteins available — comparable to cod and halibut in efficiency — making it a genuinely useful cutting-phase protein for athletes maximizing protein per calorie during calorie restriction.

How to Cook Octopus

Octopus has a reputation for being difficult to cook, primarily because it can become extremely tough and rubbery if not prepared correctly. The cooking challenge is real but entirely solvable with the right approach.

Why Octopus Gets Tough

Octopus muscle is different from fish muscle — it has more connective tissue and a different myofibril structure. When briefly cooked, the proteins contract firmly. Extended high-heat cooking then tightens the collagen further. The window for tender octopus requires either very short, very high-heat cooking (searing for just minutes) or long, slow, low-temperature cooking that breaks down the connective tissue — the same principle that makes braised beef shoulder tender after hours of slow cooking.

The Most Reliable Methods

Slow braising or simmering — the most consistent method for beginners. Submerge octopus in water or stock (with onion, garlic, wine, bay leaf), bring to a barely simmering 85–90°C, and cook for 45–90 minutes depending on size, until a knife slides into the thickest tentacle without resistance. Pull from the liquid and allow to rest.

Pressure cooking — dramatically reduces the time required; 15–25 minutes in a pressure cooker at high pressure produces tender octopus reliably and is arguably the most foolproof method available.

Freezing before cooking — a traditional Mediterranean technique with genuine scientific basis: freezing ruptures the muscle cells and begins to break down connective tissue before cooking even starts, making the braising phase faster and more reliable. Many fishmongers sell octopus that has already been frozen for this reason.

Grilling after braising — the most common restaurant approach and genuinely excellent; braise first until fully tender, then char briefly on a very hot grill or cast iron pan to develop caramelization and smokiness. The braise provides tenderness; the grill provides flavor.

Preparation Steps

Remove the beak (a hard, parrot-like structure in the center of the tentacles) and the ink sac before cooking. The skin is edible and becomes pleasantly tender when cooked correctly. No need to peel it before cooking.

Octopus in Global Cuisine

Octopus has been eaten across the Mediterranean, East Asia, and Pacific Island cultures for millennia, and its culinary tradition reflects this:

Mediterranean — grilled octopus with olive oil, lemon, and herbs is one of the most iconic dishes of Greek, Italian, and Spanish coastal cuisine. Galician octopus (pulpo a la gallega) — boiled, sliced, drizzled with olive oil, smoked paprika, and sea salt — is considered one of Spain’s great dishes.

Japan — takoyaki (octopus balls) are among the most popular street foods in Japan; octopus sashimi and octopus sushi are widely eaten; dried octopus is consumed as a snack.

Korea — live octopus sannakji is a dish of freshly killed, immediately served octopus tentacles, still moving from residual nerve activity, typically eaten with sesame oil.

Hawaii and Pacific Islands — octopus (he’e in Hawaiian) has been harvested and eaten by Pacific Island cultures for centuries, traditionally prepared by simmering in coconut milk or stewing.

Practical Ways to Include Octopus in Your Diet

Grilled octopus — braise until tender, pat dry, brush with olive oil, and grill or char for 2–3 minutes per side. Serve with lemon, capers, and fresh herbs.

Mediterranean octopus salad — braised, cooled, and sliced octopus tossed with olive oil, lemon, celery, parsley, and capers; a practical, nutrient-dense make-ahead dish.

Octopus in pasta — sliced octopus in a tomato-based sauce over pasta creates a nutritionally exceptional complete meal combining octopus’ extraordinary micronutrient profile with pasta’s carbohydrate energy.

Spanish tapas style — simple braised and sliced octopus with olive oil, sweet paprika, and sea salt over boiled potato; one of the most classic octopus preparations globally, requiring minimal preparation skill.

Octopus ceviche — tender braised octopus marinated in citrus juice, chilli, and herbs; the acid continues to “cook” the surface slightly and the flavor combination is excellent.

Potential Considerations

Sodium content — at 230mg per 100g, octopus carries moderate sodium reflecting the natural mineral content of its marine environment; comparable to other fresh seafood and well below processed seafood products. People with strict sodium targets should account for this.

Shellfish allergy category — octopus is a mollusc, falling under the shellfish allergy category along with clams, mussels, and oysters. People with shellfish allergy must avoid it; importantly, mollusc allergy and crustacean shellfish allergy (shrimp, crab, lobster) are distinct — some people react to one but not the other, though cross-reactivity exists.

Cholesterol — at 48mg per 100g, broadly comparable to other seafood and not a specific outlier by current nutritional guidance.

Sourcing — octopus is caught globally with significant variation in fishing practices; choosing products from well-managed fisheries or certified sustainable sources is worthwhile given overfishing concerns in some regions.

Cooking skill — octopus requires more preparation knowledge than most proteins on this site; following the slow braise method is genuinely reliable for first-time preparation.