An Introduction to Japanese Seaweed: Different Varieties and Health Benefits
Do you know your kombu from your wakame? In Japan, not all seaweed is considered equal, with different varieties used in a range of products found in everything from miso soup to sushi rolls. In this article we’ll introduce the main kinds of seaweed you are likely to encounter in everyday Japanese cuisine including:
- Nori: most common type of Japanese seaweed used in sushi rolls and often sold as sheets, strips, and flakes.
- Kombu: popular type of kelp used as the key ingredient in dashi stock for making miso soups and hotpots.
- Hijiki: type of seaweed found in rocky coastal areas used in Japanese salads and side dishes.
- Mozuku: Okinawa superfood seaweed with many health benefits, stringy in texture and brown in color.
- Wakame: deep green seaweed found commonly in miso soup and pickled cucumber salads.
- Aonori: popular topping used for okonomiyaki, takoyaki, and yakisoba.
The most common type of Japanese seaweed you may have heard of is nori. Nori is a type of edible seaweed that is traditionally used in sushi dishes and is often sold as nori sheets or strips in supermarkets. You probably recognize it as the dark green sheets used to wrap sushi rolls and onigiri (Japanese rice balls). In addition to using nori to make sushi rolls, you can use it as a wrap for sandwiches or use nori flakes as a healthy topping for salads and soups, giving them an extra crunch!
The history of nori in Japanese cooking is rooted deep in tradition. The earliest records of nori use date back to the 12th century. Nori was originally eaten wet, but as demand grew to preserve the nori for longer, it was shredded and dried in the sun, to create thin paper like sheets.
Consuming nori has several health benefits. It contains sodium, protein, magnesium, and calcium, and helps to prevent strokes and heart disease by lowering cholesterol levels. Other health benefits of nori include helping your thyroid to function, thanks to its iodine content, and helping to regulate and purify blood.
There are two types of nori available: toasted and raw. Toasted nori is more commonly found because it is already dried and ready to use, whilst raw nori must be frozen for at least three days before it can be eaten without being cooked first. Toasted nori is used in sushi rolls because it has the crispy texture and umami flavor.
Kombu can be found in dishes such as miso soup, dashi, and suimono. It can also be simply boiled or blanched to make it more tender for eating. Kombu seaweed is found in cold currents such as the North Sea and the Sea of Japan. It has high levels of iodine and can be used in many dishes or eaten raw. Kombu seaweed is also known to help with fatigue, headaches, insomnia, urinary tract infections, allergy symptoms, cancer prevention, and weight loss.
In Japan, kombu is usually sold as dried strips or pickled, and can also be eaten as a snack called su kombu. Kombu is one of the main ingredients in dashi, a popular stock used to make Japanese soups and hotpots like shabu shabu. To use kombu seaweed in miso soup, boil one piece of dried kombu with three cups of water and then remove it after 10 minutes.
Kombu is also used in kombu cha (seaweed tea), which uses powdered kombu as one of its main ingredients. This is not to be confused with the kombucha drink that has become popular in western countries in recent years, which is a fermented tea made from yeast.
Hijiki seaweed is a type of edible seaweed that has been used in Japanese culture for centuries. It is high in fiber, protein, and minerals like calcium, potassium, and magnesium. It contains lignans (compounds found in plants) which are thought to help the body fight against cancer. Hijiki can be eaten raw or cooked; the flavor is described to be savory with a peppery taste.
In Japanese cuisine, hijiki seaweed is often used as an ingredient in salads or as a side dish as part of a set meal complementing other dishes such as grilled fish, rice, and miso soup. It is mostly sold in packets in dried form, resulting in a black color.
Consuming hijiki seaweed is said to have positive mental health benefits including improved moods and cognitive performance for up to four hours after eating it. This is due to hijiki containing an amino acid called GABA which acts as a neurotransmitter in the brain which helps us to relax.
Hijiki seaweed is also used as an ingredient in skin care. It has anti-aging properties that can help moisturize skin and relieve irritation, while the antioxidant power makes it ideal for helping individuals with sensitive or acne prone skin as it protects the skin from free radicals that cause damage to the cells.
Mozuku is a type of brown Japanese seaweed which is mostly found in the Okinawa region of Japan. Harvested in the region’s crystal-clear oceans during the springtime, mozuku has a thick, stringy texture and is often credited as being a superfood that forms part of the famous Okinawa diet that sees many people live exceptionally long lives to 100 years old compared to other parts of the world.
Mozuku seaweed is low in calories and contains compounds called fucoidan, which is said to promote several health benefits like supporting the immune system against viruses, reducing inflammation, assisting with digestion and gut health, and helping to promote weight loss and healthy metabolism.
Mozuku is a very versatile ingredient that can be used in many Japanese dishes. It can be used dried by adding directly to soup, fresh by washing before cooking, or salted by washing out the excess salt through a colander before use and mixed with vinegar. Some ideas for Japanese dishes you can easily add mozuku to include tempura, gyoza, mabo tofu, miso soup, seaweed pancakes, rice dishes, and salads.
Wakame seaweed is a plant-like algae that has been used for centuries in Japan as a health food to help people fight illness, improve their immune system, and maintain healthy blood pressure levels. The benefits of Wakame seaweed are that it can help to build up your immune system by supplying an abundance of vitamin C and also keep you hydrated because it contains over 90% water.
Deep green in color, wakame creates a texture that is crunchy and chewy at the same time and can be used as a garnish in dishes like salads, soups, noodle dishes, and sushi rolls. Wakame can be purchased fresh in Japan during the harvesting months of February to June but can be bought in dried form all year round. It is usually purchased in dried form and requires rehydrating in water for a few minutes before it expands and is ready for use. Wakame is popular for its umami flavor and ability to absorb liquid flavors such as soy sauce or vinegar.
Grown mainly in Japan and Korea, wakame is also consumed in a soup called miyeokguk by pregnant women in Korea and after giving birth as the high calcium content is said to be beneficial when nursing babies.
Aonori is another versatile type of edible seaweed found mainly off the coast of Japan, and usually sold in dried or powdered form. It is used primarily as a topping or garnish, adding color and flavor to udon noodles, sushi, French fries, and other popular dishes like okonomiyaki, takoyaki, and yakisoba.
Aonori is usually sold in Japanese supermarkets in dried or powdered form. Japanese snacks like potato chips are often flavored with aonori and it is sometimes used in tempura batter to create isobe-age tempura, a tasty snack food popular with drinking beer.
Like other types of seaweed, aonori has a range of health benefits and is a good source of dietary fiber helping with digestion, along with vitamins and minerals such as folate, calcium, iron, and magnesium. Aonori is also said to help maintain healthy skin and eyes thanks to the presence of beta-carotene, a compound that the body converts into vitamin A.
Other Types of Japanese Seaweed
In addition to the main types of Japanese seaweed previously mentioned, there are several other varieties to look out for such as mekabu and kanten. Mekabu is part of the wakame plant but refers to the flowering part found just above the root. It has quite a slimy texture and is eaten with soy sauce, ponzu dressing, or as a topping over rice. Kanten or agar-agar is a gelatin type substance which is extracted from seaweed, making it a vegan friendly alternative to animal based gelatin products. It is often used in Japanese desserts such as anmitsu and confectionary products like wagashi.