[The Story of Seaweed]

Seaweed is indispensable to the Japanese diet. Unique seaweed culinary cultures have developed not only in Japan, Korea, and China, but also around the world, including France, Ireland, the United States, Canada, and Chile. While referred to in English as “seaweed,” it has recently also been called “sea vegetable.” Its high nutritional value has made it a focus as a health food.

For example, in Wales, UK, laverbread—similar to simmered laver—is spread on toast with butter and eaten with a squeeze of lemon. In Ireland, desserts made with “carrageen moss” seaweed and soups using “dulse” red algae are well-known. Northwest Coast indigenous peoples, such as the Tlingit tribe in southeastern Alaska, have traditionally gathered and consumed kelp and herring roe kelp (kelp attached to herring eggs) as staple foods. In Brittany, France, fermented butter blended with seaweed is traditionally made. This shows how unique consumption methods have developed in each region, adapted to local climate, preservation techniques, and food culture.

Japan also has an ancient culture of eating raw seaweed, with approximately 1,500 species of seaweed said to grow naturally in its coastal waters. During the Asuka and Heian periods, people picked and ate fresh nori seaweed. In the Yamato court era, it was used as an offering in Shinto rituals, and the Taihō Code even designated it as a taxable item. Later, it evolved into preserved foods like sheet nori and dried nori, while seasonal ingredients like “fresh nori,” “fresh wakame,” “fresh akamoku,” and “fresh mozuku” circulated. Okinawan sea grapes and mozuku are prime examples, rooted in Japan's unique tradition of eating seaweed raw.

While certain seaweeds like fresh nori and wakame contain components difficult to digest, the gut bacterium Bacteroides plebeius, which can break them down, is reportedly more common among Japanese and some other Asians. This is thought to result from the seaweed-eating culture influencing gut bacteria through horizontal gene transfer (acquiring genes from external microorganisms), leading to the evolution of seaweed-digesting enzymes in human gut bacteria. People in other regions, such as Europe and America, have fewer of these bacteria and find raw seaweed difficult to digest, so they primarily consume heated or processed seaweed.

Common seaweeds (kombu, wakame, hijiki, mozuku, nori) are rich in marine minerals, primarily composed of carbohydrates with low fat content, and abundant in iodine, calcium, potassium, and other nutrients. They are gaining attention as low-calorie, highly nutritious, and healthy foods. Nori, in particular, is a rare food containing both glutamic acid (plant-based) and inosinic acid (animal-based), the components of umami. Some studies also report that these are present in the golden ratio of approximately 10:1, which humans perceive as the strongest umami taste.

Now, there's a saying that “children love nori,” and this also has scientific backing. Children are said to have about three times as many taste buds (taste sensors) as adults, making them more sensitive to umami. Furthermore, breast milk contains umami components, so infants become familiar with umami from a very young age. It makes sense that children have such sensitive taste buds. I, too, am drawn to the umami of roasted nori and often find myself munching on it straight out of the packet.

Kurikyu's Magewappa Lunch Box (Unpainted)
https://www.shokunin.com/en/kurikyu/mutosou.html

References
https://www.table-source.jp/column/seaweed-outside-japan/
https://www.maff.go.jp/j/keikaku/syokubunka/traditional-foods/bunrui/kaisou-seihin.html
https://www.kazusa.or.jp/dna/worlds_dna_research/腸内細菌の遺伝的アップグレード(nl79)/
https://www.asken.jp/info/1706
https://www.norino1.jp/post/海苔のうまみ成分は黄金比！！
https://shun-gate.com/roots/roots_127/
https://oishii-igirisu-ryori.com/2019/02/01/laver-bread/
https://precious.jp/articles/-/7103
https://hes.official.jp/images/kaishi_pdf/20/20-2-16-.pdf