The octopus available in the United States comes from two species. The giant north Pacific octopus, Enteroctopus dofleini, may weigh up to 100 lb., according to the Alaska Department of Fish and Game. The smaller Octopus vulgaris is a common species from the Atlantic Ocean. Both species are low-calorie seafoods, with fewer than 100 calories per 3 oz. serving, according to the U.S. Department of Agriculture.
Atlantic Octopus Macronutrients
A 3 oz. serving of common Atlantic octopus has 70 calories, with 13 g of protein and 2 g of carbohydrates. This species has 0.9 g of fat and 41 mg of cholesterol. The water content is 80 percent, with 68 g per serving. The Atlantic octopus contain no sugar and provides no fiber.
Pacific Octopus Macronutrients
The Pacific octopus has 48 calories per 3 oz. serving. This serving contains 10.5 g of protein and 0.7 g of fat. It has 2 mg of cholesterol. There are no carbohydrates in this serving. Pacific octopus is 84 percent water, with 72 g per serving. The USDA data for this species does not include its fiber or sugar content.
Atlantic Octopus Nutrients
Per serving, Atlantic octopus provides 54 percent of the recommended daily amount of selenium, with 38 mg, and 25 percent of the RDA for iron, with 4.5 mg. It provides 0.4 mg of copper, or 19 percent of the RDA, 16 percent of the RDA for phosphorus, with 158 mg, and 9 percent of the RDA for potassium, with 298 mg. It has 1.4 mg of zinc, or 9 percent of the RDA. Along with 196 mg of sodium, it provides 45 mg of calcium, 26 mg of magnesium and a trace amount of manganese. It has 1.8 mg of niacin, or 9 percent of the RDA, but provides less than 5 percent of the RDA for other vitamins.
Pacific Octopus Nutrients
Pacific octopus has 4.1 mg of iron per serving, or 23 percent of the RDA. It has 134 mg of phosphorus, or 13 percent of the RDA. The copper content of 0.32 mg is 16 percent of the RDA. The 1.2 mg of zinc provides 8 percent of the RDA. This serving also contains 30 mg of calcium, along with trace amounts of manganese. The most abundant vitamin in Pacific octopus is niacin. It has 1.7 mg, or 9 percent of the RDA. The other vitamins that it contains provide less than 5 percent of the RDA.