Some Call Them Weeds

By Awake! correspondent in Japan

SEAWEEDS​—the very name suggests a sense of contempt and annoyance. To most people, they are just the slimy, entangling nuisance that spoils their fun at the beach. But are they so worthless?

In Japan they are viewed in a quite different light. The islands of Japan are skirted by both warm and cold currents of the ocean. For this reason, there is an abundance of seaweeds of many kinds in the surrounding waters. Over the years the Japanese people have found many uses for these marine plants.

More Than Ten Thousand Species

One reason for their many uses is the great variety​—more than ten thousand species have been identified! They flourish in waters from the icy polar regions to the warm tropical seas. Scientifically, they are what biologists call marine algae, the simplest form of plant life, although the term “seaweed” generally refers to the larger varieties. Their “roots” are only for anchorage; seaweeds take in minerals and water through the surface of the entire plant. Their leaves and stems, properly called fronds, are soft and pliable; they can sway back and forth with the waves without breaking, as in a graceful ballet. Some seaweeds have small balloonlike swellings on their fronds that keep them afloat on the surface of the water.

Within this general family resemblance, however, there is an endless variety in their appearance. There are seaweeds that look like tender lettuce leaves or fussy moss or beautiful red corals. The masses of brown gulfweeds floating in the North Atlantic Sargasso sea are so enormous that they generated legends of fearsome sea monsters and lost ships, dreaded by ancient mariners.

Even though seaweeds may appear brown, red, or green, they contain chlorophyll, the substance that enables them to carry on photosynthesis to produce their own food. It is estimated that these simple marine plants along with microscopic algae carry out about ten times as much photosynthesis as all land plants put together. It is not surprising that a host of marine creatures find their favorite shelter in seaweed beds, where there is an abundant supply of oxygen and nutrients.

Not for Fish Only

Seaweed is attractive not only to fish; in Japan some 200,000 tons of marine algae is served annually as food on the dinner table. “Sea vegetables are low-​caloric, highly nutritious foods that help promote health and longevity,” says the book Vegetables From the Sea, by Japanese authors Seibin and Teruko Arasaki. Incidentally, the writers’ choice of the term “sea vegetables” rather than “seaweeds” is a clear indication of their high regard for these plants. And why not? In terms of protein, minerals, and vitamins, there are few other foods that can compare with these ‘vegetables from the sea.’

Consider, for example, one of the favorites, nori. When processed, this seaweed looks like sheets of dry, greenish-​black paper and is prized for its aroma. Some 8,500 million sheets of it are consumed each year, which works out to about 70 letter-​pad-​sized sheets per person. What is so remarkable about nori? From 35 to 40 percent of it, by dry weight, is good protein that is easily digested. It is also a storehouse of vitamins. Compared to spinach, nori has 8 times more vitamin A, 9 times more vitamin B₁, 15 times more vitamin B₂, and 1.5 times more vitamin C. In addition, it is one of the few foods that is rich in vitamin B₁₂, and it contains six other types of B vitamins.

Seaweeds are richer in minerals than almost any other food. It is calculated that from 7 to 38 percent of the seaweed’s dry weight is made up of “the minerals required by human beings, including calcium, sodium, magnesium, potassium, phosphorus, iodine, iron, and zinc.” For instance, wakame, another favorite, contains 13 times more calcium than milk does. Anemia sufferers will be interested to know that the iron content of edible marine algae is from two to more than ten times that of egg yolks or spinach. And the iodine in seaweeds may be the reason why the thyroid disease goiter is rare among the Japanese.

There are still other benefits. The fibers of marine plants are softer than those of land vegetables. So they are good for intestinal regulation. Japanese scientists have recognized laminin, an agent that prevents high blood pressure, in seaweeds. They are also investigating certain ingredients in seaweeds that are found to lower blood cholesterol and lipids in animal tests.

Virtues Unsung

Even if you think you will never be able to stomach seaweed, every time you gulp down a spoonful of ice cream or yogurt or pour on your favorite syrup or savor your favorite cheese, you may well be doing just that. Moreover, every time you dispense a dab of facial lotion or toothpaste or swallow a fast-​release tablet of some kind, you may also be benefiting from the lowly seaweed.

This is so because the cell walls in most brown seaweeds contain a substance called algin, or alginate. This substance has a number of very special properties that help it find its way into a wide range of consumer products. It is a good stabilizer of emulsions and suspensions. So it is used in soft foods, cosmetics, and pharmaceuticals. Alginate is also used in the manufacture of water-​based paints, textiles, paper, and so on.

Kelp can be fermented to produce methane gas, and researchers believe that as much as 10 percent of Japan’s energy needs could be filled from this source. Agricultural chemical makers are investigating an agent found in red seaweed that is highly effective as an insecticide, yet completely harmless to humans. Japan’s biotechnology industry is developing a novel biopaper from alginate that can be used as artificial skin and in other medical uses. Animal feed, fertilizers, antibiotics, and a host of other products are being made from seaweeds.

So the next time you see the slimy, troublesome nuisance on the beach or entangled around your feet, just remember that there is a storehouse of goodness in these lowly marine plants that is waiting to be explored and utilized. After all, they are not so worthless that they should be called weeds!

[Box on page 27]

Delicious Ways to Sample Seaweeds

Various kinds of seaweeds may be purchased from Japanese, Korean, or Chinese grocery stores, health-​food shops, or even some of the larger grocery markets. They usually come in packages of dried sheets. Some stores may sell them marinated in soy sauce. The most common varieties are wakame, nori, and kombu.

The easiest way to try wakame is to add them to your salad or soup. Simply soak them in water, rinse off the salt, cut them in small pieces, and toss them in. Marinated seaweed may be added to steamed rice or other dishes.

The very popular sushi is simply rice wrapped in nori, with the addition of cucumber, egg, or different seafoods​—tuna, salmon, shrimp, lobster, and so on. If you find the raw fish a little too much, try rolling cheese or cucumber sticks in seasoned sheets of nori.

Children will enjoy the crispy, deep-​fried kombu. Wipe off the salt, and dip it in oil at medium temperature for a second or two, or simply toast small pieces of it until they become crispy.

[Pictures on page 26]

Above: Temaki (hand rolled) sushi with sea urchin in the center

Left: Nori, or laver, is used abundantly in sushi, a favorite dish in Japan