Kelp, or brown algae, is an anti-inflammatory, low-calorie food that contains high fiber and a wide range of trace elements such as iron, potassium, magnesium, calcium and iodine. It is also rich in vitamins and proteins, and low in fat.
Besides being an excellent source of nutrients, the presence of fucoxanthin, a pigment which gives brown seaweeds their characteristic color, may also boost the production of protein that helps to burn fat (1).
Early studies also indicate that a sulfated polysaccharide called fucan or fucoidan found mainly in kelps may exert anti-tumor (2), antiviral (3), anti-inflammatory (4) and anticoagulant (5) effects. It could even be a potential protective agent against the harmful effects of anticancer drugs (6), radiation (7) and neurological disorders (8) such as Alzheimer’s disease.
However, like land vegetables, kelps are also prone to contamination, and in this case, by waters polluted with heavy metals and industrial waste. So the same caution should be taken when you are buying sea vegetables. Whenever possible, choose certified organic kelps harvested from minimally polluted waters.
Now let us take a look at five species of sea vegetables that would add healthful varieties to your diet:
- Kombu refers to not just one, but a few types of kelp from the Laminaria species. Some commonly used kombu are ma-kombu (Laminaria japonica) and naga-kombu (Laminaria longissima), each having its own unique taste. Kombu has been an integral part of Japanese cuisine since ancient times. It is mostly often used in soups to impart a subtleumami (savory) taste. This thick, long seaweed is also cut into thin strips, pickled and enjoyed as a side dish, or further processed to make kombu powder and kombu tea (not related to kombucha, a fermented drink). Dried individually packed kombu as well as processed kombu products can be found in supermarkets, Asian stores, health food stores…
- Commonly found floating in miso soup, wakame (Undaria pinnatifida) is not as hard and thick as kombu, making it ideal for salads.Wakame is most popular in Korean where it is traditionally boiled in soup and served to recovering new mothers. It is also a Korean custom to eatmiyeok guk, as the wakame soup is called, on birthdays.Like other brown algae, wakame is high in dietary fiber, iodine, calcium, and fucoidan. Wakame also contains small amount of omega-3 fatty acids eicosapentaenoic acid (EPA) which may be an important source of EPA for people who do not eat fish and other seafood.
- Other than kombu, arame (Eisenia bicyclis) is another traditional food that has been a part of Japanese diet for centuries.In dried and cooked forms, arame looks like hijiki, a thin, black, twig-like seaweed. But arame actually tastes softer and milder than hijiki. This makes arame a good choice for those who find the taste of other seaweeds too strong for their liking.Besides using arame in soups and broths, you can also stuff it in pie and quiche in place of spinach, and stir fry it with other vegetables or slices of meat.
Outside of Japan, is usually available in small dried leaves which soften and expand a few times their size after soaking in water.
- Ecklonia cava is not a common brown seaweed you can pick off the shelves. Beyond its places of origin, which are mainly Japan and Korea, it is usually only available in the form of dietary supplements. If you are lucky, you may be able to find dried Ecklonia cava, or known as noro kajime by the Japanese, in some Asian stores.Ecklonia cava is well-known for its high phlorotannin contents, which are actually a group of tannins that scientists are only beginning to understand in recent decades. In the laboratory, phlorotannins certainly look promising. Here is just a partial list of beneficial biological activities that phlorotannins are capable of: anti-inflammatory, antioxidative, anti-cancer, anti-diabetic, anti-HIV, anti-hypertensive, radioprotective and anti-allergic (9). But do note that these results have yet to be replicated in humans and they would need more in-depth research to prove their worth.Meanwhile, if you are eager to get some phlorotannins from your food, you can also find them in other species of brown algae such as arame (Eisenia bicyclis) and bladder wrack (Fucus vesiculosus).
- Strictly speaking, dulse (Palmaria palmata) is not a kelp, but a red algae. But its excellent nutritional profile deserves mention.While lacking in fucan and fucoxanthin, dulse makes it up with higher levels of EPA. In fact, one study which compares seven different seaweeds revealed that dulse has the highest EPA content among them, accounting for 59% of its total fat content. Like kelps, dulse also contains all the trace elements needed by the human body, and is especially rich inpotassium. For this reason, those who are suffering from impaired kidney function should limit their intake of seaweeds, including dulse, to prevent mineral overdose.Harvested mainly in Ireland and Canada, freshly picked dulse is available in places where it is found. Elsewhere, dried dulse can be purchased inshort strips or flakes.
Note: Kelps are high in iodine and therefore, should not be consumed in large quantities by people who suffer from an overactive thyroid.