ByGemma Alexander

Nov 6, 2023

Eating lower on the food chain is one of the most effective ways individuals can lower their carbon footprints. Many people find the shift challenging; fake meat is highly processed, and insects require an adventurous palate. But learning about tasty vegan ingredients makes it easier. Legumes and peanuts are great sources of protein for a plant-based diet. And for people who worry that vegetarian food is bland, there’s a nutritious umami-filled ingredient with a long, if underappreciated, culinary tradition – seaweed.

Seaweed is a form of algae that, like mushrooms, are a unique group of organisms that fall between better known classifications. Algae contain chlorophyll like plants, but lack plant structures like true stems, roots, leaves, and vascular tissue. Fungi make up their own kingdom in between plants and animals. Just as some mushrooms can be poisonous, some algae, like the ones that cause toxic blooms in summertime, are harmful.

There are well over a quarter million species of algae, which includes all types of seaweed. Just as fungi can be a delicious option for eating lower on the food chain, seaweeds like spirulina and kelp are environmentally beneficial, nutritious, or both.

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Eating Seaweed

Most people are familiar with seaweed as a food thanks to the popularity of sushi. Sheets of dried Porphyra seaweed called nori are used to wrap sushi rolls and rice balls. Nori can also be used as a condiment on rice, as when the sheets are shredded and mixed with other ingredients, like bonito flakes and sesame seeds, in furikake.

Seaweed is even eaten plain as a snack. Japanese food utilizes several other types of seaweed as well. Kombu is made from kelp and used to flavor soup stocks; hijiki is served in salads and noodle dishes, like cabbage; and wakame is often served in soups or even by itself as a salad. Wakame seaweed is also the basis of miyeokguk, a soup traditionally served to celebrate birthdays in Korea.

In Western cuisine, however, seaweed is almost unheard of. In the 18th century, seaweed was considered a famine food. But researchers have recently discovered that Europeans used to eat seaweed. Dental samples have shown it was a common food from Spain to Lithuania throughout the period between 6400 BC all the way into the early Middle Ages.

Benefits of Culinary Seaweed

Although every species of seaweed has its own unique combination of nutrients, in general, seaweed is surprisingly nutritious. Seaweed is a low-fat, often low-calorie food that contains micronutrients like iodine, as well as being rich in vitamins and minerals, antioxidants, and fiber. Some seaweeds, like spirulina, contain all of the amino acids, while many are rich in B12 (although there is some dispute about how readily this is absorbed). If you don’t consume dairy, seaweed contains about half as much calcium as milk (with a fraction the calories) per serving.

Seaweed is also a sustainable crop. Farming seaweed has been demonstrated to support ocean recovery, lowering ocean acidification, and removing nutrients from eutrophic waters while reducing pressure on land-based resource production. Seaweed farms do not require large investments in equipment and materials to set up and require no fertilizer or synthetic inputs to maintain. Seaweed farms can support cultural sustainability, too, offering economic opportunities for tribal communities who have been forced to rely on now-declining extractive industries since colonization. But these operations will only survive if the Western market for seaweed grows.

Savoring Seaweed

Just as different species of seaweed contain different nutrients, each species has its own texture and a unique flavor profile – if you don’t like one, you may still find others delicious. If you are new to the taste of seaweed, some of the value-added products created from Alaska kelp farms might be a good place to start. To start cooking with kelp, try the recipe website Yummly, which lets you filter results by your favorite types of cuisine. One of the easiest seaweed-based foods to make is miso soup, a savory, probiotic soup that uses both nori and kombu. For the best results, be sure to start your miso soup with a miso paste instead of dried base.

If you want to really explore the possibilities of seaweed as an ingredient, “The Seaweed Cookbook,” by Nicole Pisani and Kate Adams (one of several books with that title) contains 50 seaweed recipes. The New Seaweed Cookbook by Crystal June Maderia goes into depth on different types of seaweed and their health benefits and includes recipes for familiar foods augmented by seaweed. And if you are interested in seaweed more generally, Kaori O’Connor’s microhistory “Seaweed: A Global History” looks at the historical and potential use of seaweed as a sustainable foodstuff.

By Gemma Alexander

Gemma Alexander has an M.S. in urban horticulture and a backyard filled with native plants. After working in a genetics laboratory and at a landfill, she now writes about the environment, the arts and family. See more of her writing here.