Seaweed is a general term used to categorize a group of marine plants found in oceans, lakes, rivers and other bodies of water. These underwater plants can be microscopic in size or grow to the size of trees found in above-water forests. Seaweed plants are essential for the health and vitality of marine life as well as the underwater ecosystem, and humans have consumed this nutritious plant for over 1,500 years. While the exact nutritional value of seaweed depends on its species, most versions of the plant contain a high concentration of vitamins, minerals and other essential nutrients.
Commonly Consumed Seaweed
While there are a plethora of seaweed types, some of the most commonly consumed are wakame, spirulina, laver, Irish moss, agar and kelp. Though each is slightly different, they all have a similar nutritional profile. Other versions of seaweed used in traditional Chinese medicine include porphyra, sargassum and ecklonia.
Minerals
Most forms of seaweed contain a total of 10 different minerals, including selenium, sodium, zinc, copper, manganese, magnesium, iron, calcium, potassium and phosphorus. While the most commonly consumed forms of seaweed contain similar minerals, the concentrations vary. For example, agar contains 54 mg calcium per 100 g, while wakame seaweed has a total of 150 mg calcium per 100 g.
Vitamins
The vitamin concentration in seaweed varies according to the plant species. The vitamin counts for the six most commonly consumed versions are 15 vitamins for kelp; 11 for agar, 15 for Irish moss, 15 for laver, 11 for spirulina and 15 for wakame. As with minerals, the amounts of each vitamin vary from one type of seaweed to another. For example, kelp contains 3 mg vitamin C per 100 g, while laver has 30 mg vitamin C per 100 g.
Other Nutrients
All versions of seaweed except agar and Irish moss contain varying concentrations of lipids, or fatty acids, as well as amino acids. Iodine is a prominent compound in seaweed, and this constituent is vital for thyroid health. Kelp has the highest iodine concentration, which can range in various seaweeds from 500 to 8,000 mcg per gram. The daily recommended intake of iodine for adults aged 18 and older is 150 mcg to 1,100 mcg; the latter is the upper limit intake.
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