Sea vegetables, more commonly called seaweed, are used by manufacturers as thickeners and stabilizers in such products as ice cream, instant pudding, whipped topping, salad dressing and toothpaste. However, they're also full of important vitamins and minerals and are low in calories and, as such, can be eaten like any other vegetable as part of a healthy diet.
History
Archaeologists in Asia have discovered evidence dating the use of sea vegetables in the Japanese diet going back 10,000 years, and the vegetables have been used in other cultures around the world since ancient times. Because Japan has traditionally been the largest consumer, producer and exporter of sea vegetables, most of these vegetable species have Japanese names.
Identification
Sea vegetables grow in marine salt waters, typically around coral reefs or in rocky landscapes, and in some fresh-water lakes. They are neither plants nor animals, but rather listed in the same family as algae. There are thousands of types of sea vegetables categorized by color that include brown, red or green. Some of the most popular varieties are agar-agar, arame, dulse, hijiki, kelp, kombu, nori and Irish moss, also known as carrageen.
Benefits
Sea vegetables are excellent sources of magnesium, iron, calcium, vitamin A, vitamin C, various B vitamins vitamin K and plant compounds called lignans. They are also nature's richest source of iodine, a mineral required by healthy thyroid function, and contain carbohydrate-like substances called fucans, which have anti-inflammatory properties. Although sea vegetables don't contain vitamin D, they do have a substance called ergesterol that converts to vitamin D in the body. Sea vegetables are also high in various enzymes and dietary fiber.
Expert Insight
A study led by Kazuo Miyashita, Ph.D., a chemistry professor at Hokkaido University in Japan, discovered that a compound in brown seaweed, called fucoxanthin, promotes weight loss and has potent anti-diabetes effects by promoting the production of docosahexaenoic acid, or DHA, in the liver. Sea vegetables also show promise in helping to fight heart disease. Researchers from National Research Institute of Fisheries Science in Japan investigated the effects of brown seaweed on triglycerides in laboratory animals and found the seaweed significantly lowered serum and liver triacylglycerol levels. In addition, two separate studies, one published by K. Suetsuna et al in the "Journal of Nutritional Biochemistry" in September 2000 and the other, led by M. Sato and published in the "Journal of Agricultural Food Chemistry" in 2002, identified an antihypertensive peptide from the brown sea vegetable wakame, lowering blood pressure and having a potential beneficial effect on cerebrovascular diseases in stroke-prone spontaneously hypertensive rats. Various studies have also shown promise for sea vegetables to have a part in cancer prevention and treatment.
Warning
There has been considerable concern among scientists and nutrition experts in recent years regarding the levels of pollution in ocean waters, including heavy metal elements - including arsenic, lead, and cadmium. Sea vegetables can act like a sponge and absorb these potentially toxic substances. Hijiki seaweed in particular has been shown to have high levels of arsenic. If you have thyroid disease, you should also use caution in eating sea vegetable foods or supplements, due to the high iodine content. Reports in Brazil indicate that five years of excessive iodine intake by some Brazilians may have increased the prevalence of chronic autoimmune thyroiditis and hypothyroidism in people who were genetically predisposed to those diseases.
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