I recently harvested sea lettuce on the Breton coast. Eating animals from the sea, such as mussels, shrimps and fish, is a given for everyone, but eating sea vegetables is less well known.
Sea lettuce is nevertheless easy to harvest. It thrives in the Wadden Sea and North Sea. In fact, it is growing so fast that beaches in Brittany have been closed because mountains of lettuce wash up, rot and then spread toxic gases. Nevertheless, sea lettuce is good to eat. In Roscoff, a town on the Breton North coast, it is sold dried in the Center de découverte des algues, but it can also be fresh, chopped into thin strips in macoroni, for example, or mixed with cucumber lettuce or cooked with a vegetable such as spinach. Salting is then no longer necessary. It is also processed in various types of pasta
It could be useful in many other ways. Sea lettuce beds could potentially counteract the acidification of the oceans. And according to some biologists, that lettuce could also solve the world food problem. Growing sea lettuce lowers the acidity of water. Linking the cultivation of sea lettuce to fish farming creates a closed cycle of nutrients. The waste products from fish farming form the food for the sea lettuce.
Sea lettuce botanical
Sea lettuce is an annual green algae that is common in the tidal areas around the North Sea. The plant has leaves of up to 1 meter in diameter. They are flat and thin, but firm, two cell layers thick. The smooth blade can be round or irregular in shape and can have all kinds of lobes. The color is pale green to dark green. Usually the young plant is fixed at 1 point on a shell or stone and as it grows larger, it is carried along by the current. Floating freely in the water, it can continue to grow and form large slabs.
Sea lettuce healthy
To start with, sea lettuce contains about 20% protein. It also contains a lot of calcium and a lot of iron. Iron is needed for the transport of oxygen, for the absorption of oxygen in the cells. Sea lettuce contains a high content of fiber which helps to improve digestion and bowel movements. It has a low fat content and mainly contains polyunsaturated fatty acids (omega 3 fatty acids, EPA).
- Proteins 15-25%
- Fatty acids 0.6-1%
- Polysaccharide, carbohydrate 42-46%
- Vitamin A 4286 IU
- Vitamin C 100-200 ppm
- Vitamin B3 100 ppm
- Vitamin B12 6 ppm
- Calcium 8000 ppm
- Iodine 250 ppm
- Iron 1000-1370 ppm
Dodonaeus about sea lettuce
Ancient herbal books such as Dodonaeus already describe seaweed species The first genus we call broad-leaved green sea moss, in Latin Muscus marinus virens latifolius, is the Muscus of Theophrastus which he describes with grass-colored large leaves that look a lot like lettuce leaves, rougher, however, and as drawn together and wrinkled, without a stalk producing many animal leaves as if from one origin or collection, and sometimes also gathered in different piles and growing on the stones and shells, for all these signs are remarkably described in our first sea moss. Aristotle also appears to have admonished this sea moss in his sixth book of the description of the animals where he states that this moss is an abundance or throwing up of the sea and is usually floated and thrown to the beach in the beginning of summer so that the oysters and other fish are fed with it.
The other genus we now call green sea moss with narrow leaves, in Latin Muscus marinus virens tenuifolius, and this should be taken for nothing but one of those sea herbs that Elian says is eaten from fish. The same moss or some goose animal like that is called woer en wt in Zeeland which, as Levinus Lemnius declares, has very thin and hair-like fennel-like leaves.
A recipe
Traditionally, a kind of bread or cake is made with it in Wales. Let fresh sea lettuce simmer for a few hours, mix the obtained dark green mass with oat flour and then bake cookies in a pan.
As a medicine
Traditionally, many types of seaweed are used because of their iodine content and slightly stimulating effect on the thyroid gland in case of an underactive thyroid gland, with some metabolic problems and in weight loss regimens.
In summary: use of sea lettuce
- to be used as food
- to be used as a medicine
- fertilizer in agriculture
- possibly counteracts the acidification of the environment
- is dried and pressed also used as fuel
For further research
- Phytother Res. 2000 Dec; 14 (8): 641-3. Biologically active steroid from the green alga Ulva lactuca.
- J Environ Biol. 2009 Sep; 30 (5 Suppl): 899-902. A preliminary study on the anti-inflammatory activity of methanol extract of Ulva lactuca in rat. Margret RJ, Kumaresan S, Ravikumar S.
- Plant Foods Hum Nutr. 2009 Sep; 64 (3): 218-23. Antioxidant activities of four edible seaweeds from the southern coast of Thailand. Yangthong M, Hutadilok-Towatana N, Phromkunthong W.
- Planta Med. 1999 Aug; 65 (6): 527-31. Biological properties of ulvan, a new source of green seaweed sulfated polysaccharides, on cultured normal and cancerous colonic epithelial cells.