What is Hijiki? All About the Black Seaweed Used in Macrobiotic and Healthy Cooking

Dried Hijiki. Renee Shelton.
Dried Hijiki. Renee Shelton.

Hijiki, Hizikia fusiforme, is a seaweed which a plant that grows in marine or saltwater. Hijiki is also known as ‘hiziki’. While it comes in different forms, it is most commonly identified as a black, finely shredded-looking seaweed that is sold dried and sealed in packs. Hijiki is found with other dried seaweed varieties and is found in specialty and Asian supermarkets. Hijiki is stored at room temperature similar to other dried seaweed.

This black vegetable is a staple ingredient in macrobiotic cooking, and is often served as a vegetable by itself. It can be served with other vegetables, such as cucumbers, carrots and shredded lettuces as a salad, or served by itself with a flavorful dressing and sesame seeds.

Hijiki is a high-fiber food: a 10g dried portion contains 6 g fiber (or 22% daily values for fiber). It is also a good source of iron, calcium, and is fat-free. The same 10g dried portion has 40% and 10% daily values respectively for iron and calcium.

Inorganic and Organic Arsenic Levels in Hijiki

While many people enjoy hijiki in salads, soups and as an ingredient used in appetizers, some governmental agencies have placed notice to their citizens of limiting the amount of hijiki consumed or of avoiding it all together. New Zealand, Canada, the United Kingdom and Hong Kong are countries or areas with restrictions or have official notices for the limited use of hijiki as a food product for consumption.

Hijiki is singled out as the only seaweed used for cooking that contains high levels of inorganic arsenic. Arsenic is an element found in nature. Organic and inorganic arsenic is found in much of the seaweed used for cooking, including kombu, wakame and nori. Some governmental agencies, such as the Department of Health and Human Services Agency for Toxic Substances and Disease Registry, have found organic arsenic to be less toxic than inorganic arsenic.

As for the safety of using hijiki in cooking and eating it as a food source, every individual must make an independent decision and use their governmental agencies as guides. Soaking dried hijiki and draining it well afterwards does lower the total amount of inorganic arsenic that the hijiki contains. And hijiki is never served in its dried form, which contains the highest levels of inorganic arsenic of all seaweed.

References used, and resources for more information on the inorganic arsenic levels in hijiki:

  • Food.gov.uk; Hijiki: Your questions Answered. (Site accessed 10 July, 2010)
  • Interscience.wiley.com; Ingestion of Hijiki seaweed and risk of arsenic poisoning. Nakajima, Yoshiaki; Endo, Yoko; Inoue, Yoshinori; Yamanaka, Kenzo; Kato, Koichi; Wanibuchi, Hideki; and Endo, Ginji. 28 June, 2006. (Site accessed 10 July, 2010)
  • Ead.anl.gov; Arsenic. (Site accessed 10 July, 2010)