About
Kelp is a group of large brown seaweeds of the order Laminariales, consumed as whole food and used as a food ingredient globally—especially in East Asian cuisines—for its high iodine, mineral, and dietary fibre content; its extracted polysaccharides (alginates, fucoidan, laminarin) are also used as thickeners and gelling agents. It is not a single chemical compound and carries no INS/E number as a whole food.
Safety summary
Kelp preparations are generally recognised as safe (GRAS) in the US and broadly approved as food worldwide; however, Laminaria/Saccharina species accumulate extraordinarily high iodine concentrations—a single portion of some kelp products can exceed the EFSA tolerable upper intake level of 600 µg iodine/day many-fold, with iodine-induced hypo- and hyperthyroidism both documented in kelp-consuming populations. Kelp also bioaccumulates heavy metals (arsenic, cadmium, lead, mercury) from seawater, and regular or high-dose consumption can elevate exposure to these contaminants to potentially harmful levels.
Regulatory landscape
| Jurisdiction | Status | Note |
|---|---|---|
| FSANZ (Food Standards Australia New Zealand) (Australia) | Approved | Kelp and seaweed are approved as food in Australia. FSANZ has established maximum levels for inorganic arsenic in seaweed; imported food compliance data (2006–2014) showed a 21.5% failure rate for inorganic arsenic in seaweed samples. Use of generic terms like 'kelp' on product labels has been flagged as problematic for arsenic risk communication. France, New Zealand, and Australia permit iodine content up to 1000–2000 mg/kg DW in seaweed products.source |
| EFSA (European Food Safety Authority) (European Union) | Approved | Kelp/seaweed is approved as a food. EFSA's Scientific Committee on Food (SCF, 2002) established a tolerable upper intake level (UL) for iodine of 600 µg/day for adults. The 0.6 mg/day figure reflects the iodine UL, not an ADI for kelp per se. EU Commission Recommendation 2018/464 requires monitoring of metals and iodine in seaweed. EFSA 2023 scientific report quantified heavy metal and iodine exposure from seaweed consumption across 19 European countries and recommended further work to consider setting maximum levels.source |
| MHLW (Ministry of Health, Labour and Welfare) (Japan) | Approved | Kelp (kombu, Laminaria spp.) is a staple food with a long history of safe use in Japan. Average dietary iodine intake from seaweed in Japan (1–3 mg/day) far exceeds EFSA and WHO upper tolerable limits, yet the Japanese population appears to have adapted to high iodine intake; no formal maximum level for iodine in kelp is established.source |
Who should approach with care
Research citations
- 1other. Kelp – LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, 2024. ncbi.nlm.nih.gov
- 2EFSA. Dietary exposure to heavy metals and iodine intake via consumption of seaweeds and halophytes in the European population, 2023. efsa.europa.eu
- 3WHO. Report of the Expert Meeting on Food Safety for Seaweed – Current Status and Future Perspectives, 2022. openknowledge.fao.org
- 4PubMed. Commercially available kelp and seaweed products – valuable iodine source or risk of excess intake?, 2021. pmc.ncbi.nlm.nih.gov
- 5PubMed. Risks and benefits of consuming edible seaweeds, 2019. pmc.ncbi.nlm.nih.gov
- 6PubMed. Potential Risks of Excess Iodine Ingestion and Exposure: Statement by the American Thyroid Association Public Health Committee, 2015. pmc.ncbi.nlm.nih.gov
