The Health-Promoting Properties of Seaweeds: Clinical Evidence based on <i>Wakame</i> and <i>Kombu</i>

Abstract

In this review, the botany, uses, bioactive metabolites, and health-promoting benefits of Undaria pinnatifida (wakame) and Saccharina japonica (kombu) are highlighted. Their clinical evidence is focused on clinical studies conducted in Japan and in other countries. These two species are brown seaweeds (Phaeophyta). In Japan, wakame and kombu seaweeds are popular food items consumed almost daily. Laboratory evidence shows that carotenoids (fucoxanthin and fucoxanthinol), polysaccharides (fucoidan) and sterols (fucosterol) are bioactive metabolites in wakame and kombu. Wakame displays antioxidant, anti-inflammatory, anticancer, antihypertensive, antidiabetic, antiviral, anticoagulant, antiosteoporotic, hepatoprotective, and antiobesity properties. Kombu possesses anticoagulant, antithrombotic, anticancer, hypolipidemic, hypoglycemic, antiobesity, antithrombotic, antiatherosclerosis, renal protective, vascular protective, antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, gut biota regulatory, hypoglycemic, hypolipidemic, and neuroprotective activities. Clinical evidence on the effects of wakame intake was based on eight studies in Japan and eight studies in other countries. Clinical evidence on the effects of kombu intake was based on five studies in Japan. One case study on kombu dealt with severe alopecia areata. Some areas for future research on wakame and kombu are suggested. Information and data used in this review were from databases such as Google, Google Scholar, PubMed, PubMed Central, Science Direct, J-Stage, PubChem, China Academic Journals, and ClinicalTrials.gov.