Spirulina, sea lettuce... for a few years now, these aquatic plants have found their way onto our plates. And that's good! Because, whether they come from the sea or from fresh water, seaweeds contain many beneficial substances for our body.

Seven, edible, seaweeds, and, their, benefits

Consumed and produced for thousands of years in Asia, seaweed has only been part of the European food scene for about 50 years. To think that during all this time we have missed their extraordinary nutritional potential!

Whether they are micro (spirulina, chlorella...) or macroscopic (sea lettuce, dulse...), brown, red or green, seaweeds, like all plants, are full of beneficial substances, some of which have interesting properties (color, texture...) for the food industry, and even for the pharmaceutical industry. In addition, like vegetables, they can be used in many preparations, both savory and sweet, and are on the menu of gastronomic establishments.

Royal kombu, the slimming ally

Firm and crunchy, it satiates thanks to its richness in fibers and contains a brown pigment, fucoxanthin, which promotes the degradation of triglycerides. With a good potassium content, it has a slight diuretic action. Beware of its particularly high iodine content!

How to consume kombu ? It is blanched for a few minutes in boiling water to reduce its iodine content and eaten in salads, with pasta, rice, potatoes, or used to coat meat or fish and bake them.

Wakame, while waiting for baby

This brown seaweed is distinguished by its high levels of vitamin B9 (folic acid), calcium and iron, nutrients that are beneficial during pregnancy. However, be careful not to overdo it, because the iodine it contains can also have a deleterious effect on the fetus!

How to consume wakame? We use the blade (leaf) minced in miso soups and the ribs, just blanched, in salads. It can also be sprinkled on cold dishes with lemon juice or vinegar.

The sea bean, protector

This bean-shaped brown algae is particularly rich in tannins with antioxidant effects. It is also a source of magnesium and fiber, and is distinguished by its high vitamin C content.

How to consume the sea bean? Like green beans: in mixed salads or with fish. It can also be incorporated into flourless custards: the alginates will gel the preparation. 

Dulse, remineralizing

Rich in proteins, iron, manganese, magnesium, calcium, iodine, vitamins K, C, B9 and K1, it has a sodium/potassium ratio of less than 0.5: as a result, it gives a slightly salty taste without the disadvantages of salt.

How to consume dulse? Delicious in chips, dried for a long time then grilled in a pan. In flakes, in sauces, soups and savory cakes, sliced with mascarpone, whipped cream or fruit.

Sea lettuce in case of fatigue

This green seaweed is particularly rich in minerals, especially in anti-stress magnesium and anti-fatigue iron. Its sulfated sugars, ulvans, strengthen immunity and have an antimicrobial action.

How to consume sea lettuce? A little hard to chew, it is best mixed in soups or smoothies, or served as a chiffonade with fish. 

Nori, a boost for vegetarians

It is the richest macro-alga in proteins: 35 to 50%. This is good when you eat little or no animal food, especially since it also contains a significant amount of iron. It also has good manganese and beta-carotene content.

How to consume nori? With parsimony, because it is the most expensive seaweed in the world! It is best enjoyed as flakes lightly grilled in a pan, then sprinkled on dishes to give them a light smoky taste and crunch. Fresh, it is used as a wrapper to cook fish in the oven. 

Spirulina, the pick-me-up for weakened organisms

This microalga, which is mostly cultivated in fresh water, is ultra-rich in beta-carotene, iron, calcium, phosphorus, magnesium, zinc, copper, chlorophyll... and contains up to 70% of well assimilated proteins. Ideal in case of malnutrition or deficiencies.

How to consume spirulina? It is mostly taken as a food supplement, but it can also be added, dried in twigs or powder, in soups, salads and juices. Contrary to macro-algae, it does not have a sought-after flavor and may even repel some palates... 

New health benefits of red algae revealed

In a study published in April 2021 in the journal Marine Drugs researchers looked specifically at red seaweed and its health benefits. Although several studies have shown that Asians who frequently eat seaweed have a lower risk of colon, rectal and breast cancer, scientists have not been able to identify the component of their diet responsible for a possible "anti-cancer effect." In this study, researchers broke down the structure of different types of red algae with enzymes and tested the sugars produced to see which one was beneficial to health.

Of the six different sugars produced, agarotriose and 3,6-anhydro-L-galactose, or AHG, showed the most promise. After producing these sugars, they tested their prebiotic activity (food for intestinal bacteria) using the bacterium Bifidobacterium longum ssp. Infantis. This is a "good" intestinal bacteria, i.e. a probiotic: living microorganisms that confer a health benefit on the host. Among the sugars derived from the algae, these good bacteria could only consume agarotriose, indicating that this component functions as a prebiotic: it improves the growth of probiotic bacteria.

"These results show that when we eat red algae, they break down in the gut and release these sugars that serve as food for the probiotic bacteria. This could help explain why Japanese populations are healthier than others," notes the scientific team. The team also tested the sugars for anti-cancer activity and found that AHG inhibits the growth of colon cancer cells. The hypothesis to explain AHG's anti-cancer activity is that it triggers a process called "apoptosis" or programmed cell death. 

Where to buy edible seaweed?

Seaweed can be found on the Internet, in organic and health food stores, in some supermarkets, in the fish section (fresh seaweed), in the grocery section (canned food, flakes) and in the food supplements section (spirulina, fucus...).

    "It is necessary to verify that they come from France (mainly Brittany) and not from Asia, especially China, emphasizes Régine Quéva, seaweed specialist. Algae fix heavy metals that are toxic for the body. By buying local, we ensure compliance with health regulations.

We also avoid dull or white seaweed: "This means that they have lost their antioxidants by staying too long in the light." 

 Knowing how to prepare and preserve them

"It is better to start with dehydrated seaweed, in flakes, to be sprinkled on salads, soups, dishes or to be rehydrated and then incorporated into various preparations ..., advises Régine Quéva. They have the same nutritional benefits as fresh seaweed, except of course for the vitamin C. Once familiar with their particular flavor, we move on to the fresh versions preserved in salt: we desalinate them in two waters, we sponge them, we slice them and we add them to savory preparations (cakes, salads...) as well as sweetened by making them candied in a syrup like fruits (cakes, mousses...). We also find frozen ones, very practical.

As for conservation, no worries, because the seaweed is robust: the flakes can be stored for several months, provided they are protected from light and heat, and the fresh seaweed, several weeks in the refrigerator. More and more, you can also buy products containing seaweed such as fish rillettes, seaweed salt, seaweed tartar, aperitif snacks (chips, for example)...