Seaweed, It’s a Low-Calorie and Nutritious Sea Vegetable

Seaweed is a traditional Japanese food and is now eaten all over the world. It is also called “sea vegetable” and it is one of the healthiest foods, as it is low in calories but rich in nutrition.


1. Kinds of Seaweed

There are 3 major edible kinds of seaweed; Brown algae, Green algae and Red algae.

Brown Algae

Kombu (kelp): grows on rocks in the sea. Used to make dashi (a soup stock) or in stewed dishes.

Wakame: grows to around 2 meters on rocks. Used in soup or stewed dishes.

Hijiki: grows a lot on rocks near the shore with strong waves. Used in stewed dishes.

Mozuku: attaches to other seaweed. Usually eaten marinated with vinegar.

Mekabu: the holdfast part of wakame. Eaten marinated with vinegar or used in soup.


From the left, Mozuku Salad, Wakame and Mekabu

Green algae

Aosa: often washed up on the shore.  Used as Furikake (rice seasoning mix) or in soup.

Umibudo (sea grapes): mostly produced in Okinawa. Also called green caviar and used in salad.



Aonori (green laver) : grows on the shore. Used in soup or as sprinkles for decoration.

Red algae

Nori: paper-like dried seaweed sheets. Used for sushi.

Tengusa (gelidium): main ingredient for Kanten (agar) or Tokoroten (agar noodles)

2. Seaweed Health Benefits

Japanese people have a particular bacteria that digests seaweed in their intestines. As Japan is surrounded by sea, seaweed has been a part of the Japanese diet for a long time. The bacteria has been genetically inherited. Since many people consider their health nowadays, seaweed is now being eaten around the world due to its health benefits. It is expected that those people will have the intestinal bacteria too. Seaweed is rich in soluble fiber which absorbs and removes the cholesterol in the intestines, and controls blood pressure after eating.    The nutrient has a sticky component called fucoidan that activates the immune system so it is now being used as an anticancer drug.  Seaweed is very helpful to lose weight as it has low sugar and low calories. It also contains a lot of vitamins, minerals, iron and calcium; especially Hijiki, which has 10 times more calcium than milk.


3. How People Eat Seaweed in Japan

Kombu is mainly used in miso soup and other kinds of soup and also as a stock for stewed dishes. For example, to make miso soup, firstly, make the stock from kombu, boil vegetables and tofu and then mix and melt the miso paste. Wakame and Aosa can be ingredients in miso soup.


Aosa Miso Soup

Using seaweed as a stock and ingredient is a great way to have all the nutrition of seaweed, even coming out of the soup.   Wakame, Mozuku and Mekabu are usually marinated with vinegar (as the above photos). Washed seaweed and vegetables like cucumbers are normally marinated together in vinegar and soy sauce. The vinegary taste refreshes your mouth. Hijiki is usually stewed or cooked together with rice. Stewed Hijiki with vegetables, deep-fried bean curd, mince, beans and konjac is a traditional Japanese dishes. Nori is commonly used to wrap rice balls or sushi. Nori goes well with rice and is the favorite seaweed of many people. Sushi has never been unpopular in Japan, and nori is always necessary to make any kind of sushi, such as Gunkan (submarine sushi) which is salmon roe or urchin on top of the vinegared rice wrapped in nori, and Maki-zushi (rolled sushi) with fresh fish like tuna inside and nori outside.


Maki-Zushi wrapped in a Nori


4. Processed Seaweed Products

Shio Kombu… flavored kombu cut into strips. Used as an ingredient for rice balls, salad and pasta.

Kombu-no-Tsukudani…Stewed kombu with seasonings like soy sauce. Eaten alone as a side dish or used in fried rice.

Tororo-kombu…dried kombu that is softened in vinegar and then pressed. Used in soup or rice balls.

Tokoroten… Shaped agar that comes out from the red algae such as Tengusa by boiling. Great to eat it with brown sugar syrup.



Kanten…Frozen and dried Tokoroten. It works like gelatin and is used to make jelly and Yokan (red bean jelly).


Yokan, Made With Red Bean Paste and Kanten

Seaweed has a lot of uses, as mentioned above. Simply flavored, stewed, or dried… You can take the nutrition of seaweed from not only meals but also desserts! How wonderful is that!?