Sargassum seaweed

 

A weed from the sea

Sargassum seaweed is a type of seaweed found along the coasts of Japan and China. Two species, Sar-gassum fusiforme and Sargassum pallidum, are both re-ferred to as sargassum seaweed or gulfweed in English and hai zao in Chinese.

Sargassum seaweed is a brown algae with leafy seg-ments supported at the surface of the ocean by air blad-ders. Many species of sargassum are found worldwide. In fact, the Sargasso Sea, an area of the Caribbean near the West Indies, is named for its large floating masses of sargassum seaweed. However, sargassum used in healing is usually of Asian origin.

General use

Sargassum seaweed, or Hai zao, has been used in traditional Chinese medicine (TCM) since at least the eighth century A. D. In TCM it is characterized as having a cold nature and a salty, bitter taste.

 

1782    GALE ENCYCLOPEDIA OF ALTERNATIVE MEDICINE 2
 
The primary use of sargassum seaweed is to treat goiters. A goiter is a nodule in the neck caused by en-largement of the thyroid gland. The thyroid needs io-dine to produce a critical hormone, thyroxin, that regu-lates body metabolism. When not enough iodine is con-sumed in the diet, the thyroid gland enlarges. The pri-mary natural sources of dietary iodine are sea salt, fish, and vegetables that live in the ocean. In the days before mechanical refrigeration, it was often difficult for peo-ple living far from the ocean to get enough iodine in their diets. Today, widespread refrigeration or freezing of fish and rapid transportation to inland markets has made iodine deficiency and goiters rare in the developed world. In addition, commercial salt manufacturers often produce a version of their product, called iodized salt, that is available in supermarkets and has iodine artifi-cially added. However, iodine deficiency is still a world-wide problem and a major cause of mental and learning disabilities.

Using sargassum seaweed as a source of iodine to treat goiters is a scientifically sound practice. In TCM, sar-gassum seaweed is also used to treat such other thyroid dis-orders as Hashimoto’s disease. In addition it is prescribed as a diuretic to increase the production of urine and reduce edema. It is also used to treat pain from hernia and swollen testes. Sargassum seaweed is found in many com-mon Chinese formulas. In combination with silkworm, prunella, and scrophularia, it is used to treat scrofuloderma. When sargassum seaweed is combined with water chest-nut, it is used to treat silicosis, a lung disease.

Sometimes modern herbalists use sargassum sea-weed to promote weight loss because it encourages the body to discharge water through the urine. This can be risky because of the role iodine plays in setting the metabolic rate of the body. In China and Japan, fresh sargassum seaweed is sometimes stir-fried and eaten as a vegetable.

Reliable scientific evidence shows that sargassum seaweed provides enough dietary iodine to make it use-ful as a treatment for goiter. There is little scientific evi-dence that sargassum seaweed is useful in treating such other thyroid problems as Hashimoto’s disease. Research shows that sargassum seaweed also has mild diuretic and anti-fungal properties. Studies done in Japan (1998) and Hong Kong (2000) using different but related species of sargassum seaweed showed that sargassum seaweed con-tained antioxidants that helped protect the livers of rats when they were subjected to chemical damage in labora-tory experiments. In general, antioxidants are thought to slow aging and protect the body from damage caused by free radicals.
 





































Sargassum seaweed. (© Lawson Wood/Corbis. Reproduced by permission.)


Preparations

Sargassum seaweed is collected from the ocean through-out the year and dried at cool temperatures away from direct sunlight for future use. This plant is a component of several Chinese formulas, including haizao yuhu tang, used to treat goiter and neixiao lei li wan, used to treat scrufuloderma. Dosage varies depending on the condition being treated.

Precautions

Because thyroid problems are serious, people with enlarged thyroid or nodules in their neck should seek pro-fessional help from a physician and not try to treat these problems solely with alternative remedies. Sargassum sea-weed should be used with caution for weight loss because of the interactions of this product and the thyroid gland.

Side effects

No side effects have been reported when using sar-gassum seaweed in recommended dosages.