U.S. Department of Agriculture, Agricultural Research Service. (2019). FoodData Central: Seaweed, kelp, raw. A brown seaweed (Laminaria/Saccharina); source of iodine, alginate soluble fiber, and free glutamate. fdc.nal.usda.gov
Aakre, I., Solli, D. D., Markhus, M. W., Mæhre, H. K., Dahl, L., Henjum, S., Alexander, J., Korneliussen, P.-A., Madsen, L., & Kjellevold, M. (2021). Commercially available kelp and seaweed products – valuable iodine source or risk of excess intake? Food & Nutrition Research, 65, 7584. 96 commercial products; 54 exceeded the iodine UL in one portion/dose. Dried kombu mean iodine ~2,276 µg/g; oarweed ~7,800 µg/g. Highest listed portion 62,400 µg (~400× the 150 µg RDA, not 1000×). 10.29219/fnr.v65.7584
National Institutes of Health, Office of Dietary Supplements. (2022). Iodine — Fact Sheet for Health Professionals. Fact sheet (updated November 5, 2024; Wayback snapshot 16 September 2026): commercial seaweeds range from 16 to 2,984 mcg iodine per gram; dried nori, 2 tablespoons flaked (5 g), 116 mcg; US iodized salt is labelled 45 mcg iodine per gram (measured 47.5-50.7); two RCTs giving 150 or 200 mcg/day iodine from early pregnancy to delivery found no effect on child cognitive, language or motor scores at 1.5-2 years, and one found no benefit at 5-6 years either (fact sheet). ods.od.nih.gov/factsheets/Iodine-HealthProfessional
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2014). Scientific Opinion on Dietary Reference Values for iodine. EFSA Journal, 12(5), 3660. Adult adequate intake 150 µg/day; EFSA sets the adult tolerable upper intake level at 600 µg/day. 10.2903/j.efsa.2014.3660
Miyai, K., Tokushige, T., & Kondo, M. (2008). Suppression of thyroid function during ingestion of seaweed 'Kombu' (Laminaria japonica) in normal Japanese adults. Endocrine Journal, 55(6), 1103-1108. Short-term 15-30 g kombu/day (35-70 mg iodine) for 7-10 days raised TSH; daily 15 g for 55-87 days kept TSH elevated; values returned 7-40 days after stopping. 10.1507/endocrj.K08E-125
Zimmermann, M. B. (2009). Iodine deficiency. Endocrine Reviews, 30(4), 376–408. Review: an estimated 2 billion people have insufficient iodine intake; about 50% of Europe remains mildly deficient; deficiency in pregnancy and infancy may impair growth and neurodevelopment; optimal intakes from iodized salt are about 150-250 micrograms/day for adults; the small risks of iodine excess are far outweighed by the risks of deficiency (abstract, PMID 19460960). 10.1210/er.2009-0011
Ikeda, K. (1909/2002). New seasonings [translated]. Chemical Senses, 27(9), 847-849. Kikunae Ikeda identified glutamate in kombu dashi as the basis of the umami taste in 1908, founding the modern understanding of MSG. 10.1093/chemse/27.9.847
Jinap, S., & Hajeb, P. (2010). Glutamate: its applications in food and contribution to health. Appetite, 55(1), 1-10. Reviews glutamate/umami in food and the use of MSG to reduce added sodium while maintaining palatability. 10.1016/j.appet.2010.05.002
Brownlee, I. A., Allen, A., Pearson, J. P., Dettmar, P. W., Havler, M. E., Atherton, M. R., & Onsøyen, E. (2005). Alginate as a source of dietary fiber. Critical Reviews in Food Science and Nutrition, 45(6), 497-510. Alginate is a viscous gel-forming soluble fiber from brown seaweed that slows gastric emptying, raises satiety, and binds bile acids/lipids. 10.1080/10408390500285673
U.K. Food Standards Agency. (2010, reiterating 2004 advice). Consumers advised not to eat hijiki seaweed. Hijiki (Sargassum fusiforme) contains high levels of inorganic arsenic; a 2004 FSA survey found inorganic arsenic in hijiki but not in kombu, nori, wakame, or arame. Occasional past consumption is unlikely to significantly raise cancer risk. www.food.gov.uk/news-alerts
Rose, M., Lewis, J., Langford, N., Baxter, M., Origgi, S., Barber, M., MacBain, H., & Thomas, K. (2007). Arsenic in seaweed — forms, concentration and dietary exposure. Food and Chemical Toxicology, 45(7), 1263-1267. Hijiki carries high inorganic arsenic while other common edible seaweeds contain predominantly the less-toxic organic (arsenosugar) forms. 10.1016/j.fct.2007.01.007
International Agency for Research on Cancer. (2012). Arsenic, metals, fibres, and dusts. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 100C. Arsenic and inorganic arsenic compounds are classified as Group 1 (carcinogenic to humans). publications.iarc.fr/120
