Department of Ecology and Evolutionary Biology
University of Connecticut
1 University Place
Stamford , Connecticut
06901-2315 USA Charles.email@example.com
People have been eating fresh and sun-dried seaweeds for health purposes in oriental countries for thousands of years. However, in recent years, many new compounds with medicinal values have been identified in different types of seaweeds. Interestingly, most of these pharmaceutical compounds and nutraceuticals come from traditionally edible seaweeds like nori, kombu, wakame, and hiziki.
The annual value of cultivated, managed and wild-harvested seaweeds exceeds over U.S. $6.0 billion, with 87% of that amount derived from aquaculture. With worldwide production of approximately 14 billion sheets, the most valued of the Mari cultured seaweeds is the red alga Porphyra popularly known as “nori” in Japan. It is a source of food for humans throughout the world, although it is primarily cultivated in China , Japan , and South Korea .
Other economically important edible seaweeds include Laminaria (kombu), Undaria (wakame), Hizikia (hiziki), and Caulerpa (sea grapes). Additional seaweed species are industrial sources of carrageenans, alginates, and agars. These important polysaccharides are used in the food, textile, paint, biotechnological, and biomedical industries.
Seaweeds have significant value in agriculture as soil additives, fertilizers, and seaweed meals. There is also renewed interest in using seaweeds as biological nutrient
44 August 2005 G LOBAL A QUACULTURE A DVOCATE
Removal system in the integrated aquaculture of finfish and crustaceans.
The bioremediation potential of several Porphyra , Gracilaria, and Laminatia species has been assessed for open water and land-based systems.
Many seaweeds and their polysacchatides have demonstrated antibacterial, antiviral, and antitumor effects. Recently, some seaweeds have shown antioxidant and anti HIV potential. The sulfated polysaccharide Carraguard, now in clinical trials in Africa , appears tobe a safe and cost-effective microbiocide that may reduce the transmission of HIV and possibly other sexually transmitted infections, according to the Population Council.
Porphyra is rich in dietary fiber, contains 25-50% protein, ,more vitamin C than oranges, and trace minerals. Seventeen types of free amino acids have been reported in Porphyra . Its very high taurine levels of cholesterol. Porphyra and Undaria are promising seaweeds for preventing cardiovascular disease.
Consumption of Undaria pinnatifida can decrease blood pressure in humans. Enteromotpha, Monostroma and Caulerpa are other edible seaweeds with several health benefits. Recent epidemiological studies suggested a link between the consumption of seaweeds and a reduction in prostrate, colorectal, and breast cancers. A variety of antioxidant compounds including polyphenols have been identified in several brown seaweeds.