Nutritional Aspects of Wakame: Minerals, Calsium, Iron, Iodine

5) Minerals

The food group to which Wakame belongs contains the largest quantity of minerals of any food group.The surface tissues selectively absorb important minerals from sea water, and as a result Wakame contains all the minerals essential to the human body, including calcium, sodium, magnesium, potassium, phosphorus, sulfur, iodine, iron, zinc and various trace elements.

Mineral Content, Dried Wakame and Other Foods(Unit:mg/100g)
Source: Japan National Institute of Resources the Science and Technology Agency Standard Tables of Food Composition in Japan, 1983.
  Calcium Sodium Phosphorus Iron Potassium
Wakame 960 6,100 400 7.0 5500
Broccoli 49 6 120 1.9 530
Pumpkin 17 1 35 0.4 330
Carrot 39 26 36 0.8 400
Parsley 190 14 55 9.3 810
Spinach 55 21 60 3.7 740
Green pepper 10 2 23 0.6 200
Cucumber 24 2 37 0.4 210
Celery 34 24 34 0.2 360
Tomato 9 2 18 0.3 230
Milk 100 50 90 0.1 150
Oyster 55 280 130 3.6 230


The adult human body contains about one kilogram (2.2 lb.) of calcium, 99% of which forms solid tissues such as bones and teeth as calcium phosphate and calcium carbonate. The remaining 1% is contained in the blood, muscles and nerves in the form of ions and salts. Besides helping maintain proper blood alkalinity and promoting contraction of the myocardium, calcium also helps control muscle tension and reduces the sensitivity of the nerves to stimulation. All in all, calcium plays a large role in the body's physiology. Additionally, calcium contained in the bones and teeth is constantly being metabolized: when old calcium is eliminated, new calcium is replaced in quantity.

Calcium content in the blood is maintained by hormones at a constant level of 9-11mg/dl. When calcium deficiency occurs, reducing the calcium content in the blood, calcium contained in the bones and teeth may be dissolved into the blood. For this reason, calcium should be constantly replenished.


Nutritional imbalances caused by dieting for weight control can lead to dystrophy and anemia, especially if iron intake is insufficient. The adult human body contains about 3g of iron, most of which is contained in the hemoglobin of the red blood cells, myoglobin of the muscles and ferritin of the liver. The remaining small amount is distributed throughout the body.
Iron is important for metabolism. The iron in hemoglobin carries oxygen in the blood, and that in myoglobin takes it into the cells. The amount of iron in the cell affects oxygen utilization, and iron deficiency can cause anemia, fatigue, and poor memory.
The high iron content of Wakame makes it an important source of necessary iron.


The adult body contains about 25 mg of iodine.During youth, iodine promotes growth, while in adults it helps maintain the basal metabolic rate.Iodine is known to be one of the components of the thyroid hormone (thyroxine). The minimum recommended daily requirement is 0.l-0.2mg a day for adults and 0.2 mg a day for children and pregnant women.
Iodine deficiency causes goiter and symptoms such as obesity, fatigue and reduced metabolism, which stops the growth of the body. Because of the habit of eating sea vegetables such as Wakame, iodine deficiency is rare in Japan. People in areas located far away from the sea, in inland continental areas for example, are more likely to suffer from iodine deficiency. Indeed, in some countries like the United States and Canada iodine is added to salt to ensure adequate daily intake. It has been known for centuries that sea vegetables such as Wakame are rich in iodine; in Europe, even now, iodine is extracted from seaweeds.

Iodine Content of Foods(Unit:mg/100g)
Source:"Tales of Seaweeds" by S. Arasaki and T. Arasaki, Tokai University Press, 1978.
Wakame, dried
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