The History of Sushi And Seaweed: A Closer Look

What do you know about the history of sushi and seaweed?

The history of sushi would not exist without seaweed. Seaweed has been part of many Asian diets for thousands of years. It is especially popular in Japan where it is known as nori and used primarily for sushi. In makizushi, sushi rice and various other ingredients such as raw fish and vegetables are wrapped into a roll of nori seaweed with the help of a bamboo mat. Nori can also be used in dishes beyond sushi such as ramen, seasoning for rice or noodles, and it can even be eaten as aonori which is essentially just fresh seaweed eaten entirely on its own, though it tends not to be the most aesthetically pleasing of meals since it looks like something that the tide brought in. While seaweed may not be on everyone’s menu, it nevertheless is an extremely healthy food. 

Nori is high in minerals, vitamins, fiber, and protein while remaining very low in calories. Unsurprisingly, Japan is the world’s largest producer of nori, harvesting 350,000 tons annually (“”). As such, it is quite important in the typical history of sushi as well as Japanese diet and culture. It grows rapidly, reaching maturity in about 45 days. It is a type of red seaweed (which is technically algae) that includes the species Pyropia yezoensis and Pyropia tenera. The reason why nori does not appear red when served as part of a meal is because of the drying, roasting, and shredding processes that it undergoes before it is ready to eat (“”). While there are several different kinds of edible seaweed throughout the history of sushi, nori tends to be one of the most popular. Furthermore, it seems that it has been popular for a long time.

history of sushi
Photo by Rajesh TP from Pexels.

It is believed that the Japanese have been making nori since at least 794 C.E., though they were most likely consuming different types of seaweed for hundreds or even thousands of years previous to that. Additionally, the Chinese have been using seaweed since 2700 B.C.E. (“NaturalKnowledge247”).

History of Sushi and Seaweed

Around the Mediterranean and on the islands of Hawaii, seaweed was used less for food and more for medicine, food for animals, and dye for clothing and material. Some of the ancient Hawaiians believed that a particular red seaweed was deadly and coated their spearheads with it before going into battle, however, there is no evidence of any seaweed being fatal or even remotely toxic upon human exposure or consumption. Ireland has a long history of using seaweed for fertilizer, the practice of which began around 1200 C.E. (“NaturalKnowledge247”).

Image result for seaweed

Certain types of seaweed such as kelp possess fucons—also known as sulfated polysaccharides or large carbohydrate molecules with added sulfate groups—which have been shown in studies to have properties that inhibit cell growth. Inhibiting cell growth is an important factor in slowing or stopping the growth of cancer cells which are characterized by their uncontrolled reproduction of malignant cells. Fucoidan—another component of seaweed and also a sulfated polysaccharide—has been reported to interfere with the stages of viral attacks including the attachment of the virus to a cell, the penetration of the cell membrane by the virus, and viral intracellular penetration (“NaturalKnowledge247”).

Certain seaweeds may also be beneficial in the treatment of the herpes simplex virus (genital herpes) and the Herpes Zoster virus (shingles). While seaweed isn’t the magical cure to cancer and viruses, studies have shown that it may have very important properties when it comes to the maintenance of one’s health and the reduction of aberrant cell growth. It’s hard to imagine that so much significant chemical nutrients can be packed into something that doesn’t really look all that spectacular. After all, seaweed primarily looks like giant leafy weeds that grow (you guessed it) in the sea. How does seaweed grow when submerged by so much water and how does it keep itself from being swept away by the currents?

An interesting thing to note about seaweed is that it is, in fact, not a plant; it’s a type of algae. Algae are believed to be the earliest ancestors of plants. They are photosynthetic, meaning they take energy from the sun to provide themselves with nutrients and release oxygen as a byproduct which allows oxygen-breathing creatures on earth to survive. Some algae produce blooms, also known as the infamous “red tides,” which actually reduce the amount of oxygen in the air and turn the water toxic, resulting in many wildlife fatalities including marine animals and waterfowl (Lewin & Andersen, 2019).

history of sushi

Fortunately, seaweed does not tend to create any awful algae blooms or toxic environments. Seaweed can grow up to 100 feet long and interestingly, while needing light, nutrients, and water just the same as plants, seaweed does not have any roots. Plants need roots to absorb water and nutrients from the soil, but seaweed is constantly surrounded by water and nutrients brought in by the water currents which can passively diffuse into its leafy tissues, eliminating the need for roots. Seaweed also lacks an internal conducting system for water and nutrients because of this (Norris).

However, seaweed still needs something to keep it anchored in one place lest the whole seaweed stalk float hopelessly out to sea. Luckily, seaweed has holdfasts which anchor to the seafloor, rocks, boats, or hard-shelled mollusks. Because seaweed is photosynthetic, it tends to grow in somewhat shallow bodies of water in contrast to the deep ocean where it is difficult for light to penetrate. Like plants, seaweed uses a pigment called chlorophyll which not only gives the leaves their green color but also allows the seaweed to capture sunlight as energy. Unlike most plants, seaweed tends to have different pigments that help it to absorb even more light and therefore create more energy for itself and more oxygen for the atmosphere (Norris).

Seaweed does not look like anything too special. If a clump of green, slimy leaves were to wash up on the beach, most people wouldn’t care to look at it twice. It’s hard to imagine that such a mundane-looking alga can have so many important capabilities and uses. It is popularly used as nori in Japanese cuisine, it was used as medicine, dye, and fertilizer by ancient civilizations, it has potentially anti-viral and anti-cancer properties, and it provides our atmosphere with plenty of oxygen so we can breathe soundly. Seaweed might not be in everyone’s diet and some people might think it’s just gross, but nonetheless, seaweed is an important part of the planet’s ecosystem and a significant component of human civilizations.

Now, you know all about the history of seaweed and sushi.


Lewin, R. A. & Andersen, R. A. (2019). “Algae.” Encyclopaedia Britannica. Retrieved from

(n.d.).“Seaweed: A Brief History.” NaturalKnowledge247. Retrieved from

Norris, Lori. (n.d.). “What Causes Seaweed to Grow?” Home Guides | SF Gate. Retrieved from

(n.d.). “What is Nori (Seaweed Wrap)?” Retrieved from  

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