Commercially available kelp and seaweed products – valuable iodine source or risk of excess intake?

  • Inger Aakre Department of Seafood and Nutrition, Institute of Marine Research,Bergen, Norway
  • Dina Doblaug Solli Department of Seafood and Nutrition, Institute of Marine Research, Bergen, and Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
  • Maria Wik Markhus Department of Seafood and Nutrition, Institute of Marine Research,Bergen, Norway
  • Hanne K. Mæhre Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
  • Lisbeth Dahl Department of Seafood and Nutrition, Institute of Marine Research,Bergen, Norway
  • Sigrun Henjum Department of Nursing and Health Promotion, Oslo Metropolitan University (OsloMet), Oslo, Norway
  • Jan Alexander Division of Infection Control, Environment and Health, Norwegian Institute of Public Health, Oslo, Norway
  • Patrick-Andre Korneliussen Department of Seafood and Nutrition, Institute of Marine Research,Bergen, Norway
  • Lise Madsen Department of Seafood and Nutrition, Institute of Marine Research,Bergen, Norway, and Department of Biology, University of Copenhagen, Copenhagen Ø, Denmark
  • Marian Kjellevold Department of Seafood and Nutrition, Institute of Marine Research,Bergen, Norway
Keywords: Iodine, Recommended Intake, Tolerable Upper Intake Level, Public Health, Seaweed, Kelp, Macroalgae, Iodine ecxess, Novel Food

Abstract

Background: Seaweeds and kelps, also known as macroalgae, have long been common in the East-Asian diet. During recent years, macroalgae have entered the global food market, and a variety of macroalgae products are now available for consumers. Some macroalgae species are known to be particularly rich in iodine, but little data regarding the iodine content of macroalgae-containing foods exists.

Objective: The aim of this research study was to analyse the iodine content in a large variety of commercially available macroalgae-containing foods and supplements and to evaluate whether such products are sources of adequate dietary iodine.

Design: Ninety-six different products were collected after surveying the Norwegian market for commercially available macroalgae products, collected from three categories: 1) wholefood macroalgae products (n = 43), 2) macroalgae-containing foods (n = 39), and 3) dietary supplements containing macroalgae (n = 14). All products were analysed for iodine content by inductively coupled plasma-mass spectrometry (ICP-MS).

Results: The iodine content in one portion of wholefood macroalgae products ranged from 128 to 62,400 μg. In macroalgae-containing foods, the iodine content ranged from 30 to 25,300 μg per portion, and in supplements it ranged from 5 to 5,600 μg per daily dose. The species with the highest analysed iodine content were oarweed, sugarkelp and kombu, with mean iodine levels of 7,800, 4,469 and 2,276 μg/g, respectively. For 54 products, the intake of one portion or dose would exceed the tolerable upper intake level (UL) for iodine.

Discussion and conclusion: The iodine content in the included products was variable and for most products high, exceeding the tolerable upper intake level (UL) if consumed as a serving or portion size. The labelling of macroalgae species included, and declaration of iodine content, were inadequate or inaccurate for several products. As macroalgae-containing products are unreliable iodine sources, inclusion of such products in the diet may pose a risk of consuming excessive amounts of iodine.

Downloads

Download data is not yet available.

References


  1. Zava TT, Zava DT. Assessment of Japanese iodine intake based on seaweed consumption in Japan: a literature-based analysis. Thyroid Res 2011; 4(1): 14. doi: 10.1186/1756-6614-4-14

  2. Teas J, Braverman LE, Kurzer MS, Pino S, Hurley TG, Hebert JR. Seaweed and soy: companion foods in Asian cuisine and their effects on thyroid function in American women. J Med Food 2007;10(1):90–100. doi: 10.1089/jmf.2005.056

  3. Rhee SS, Braverman LE, Pino S, He X, Pearce EN. High iodine content of Korean seaweed soup: a health risk for lactating women and their infants? Thyroid 2011; 21(8): 927–8. doi: 10.1089/thy.2011.0084

  4. Mahadevan K. Seaweeds: a sustainable food source. In: Tiwari BK, Troy DJ, eds. Seaweed sustainability. San Diego, CA: Academic Press; 2015, pp. 347–64. doi: 10.1016/B978-0-12-418697-2.00013-1

  5. Rioux L-E, Beaulieu L, Turgeon SL. Seaweeds: a traditional ingredients for new gastronomic sensation. Food Hydrocolloids 2017; 68: 255–65. doi: 10.1016/j.foodhyd.2017.02.005

  6. Bouga M, Combet E. Emergence of seaweed and seaweed-containing foods in the UK: focus on labeling, iodine content, toxicity and nutrition. Foods (Basel, Switzerland) 2015; 4(2): 240–53. doi: 10.3390/foods4020240

  7. MacArtain P, Gill CIR, Brooks M, Campbell R, Rowland IR. Nutritional value of edible seaweeds. Nutr Rev 2007; 65(12): 535–43. doi: 10.1111/j.1753-4887.2007.tb00278.x

  8. FAO. The global status of seaweed production, trade and utilization. Globefish research programme. Rome: FAO; 2018.

  9. Holdt SL, Kraan S. Bioactive compounds in seaweed: functional food applications and legislation. J Appl Phycol 2011; 23(3): 543–97. doi: 10.1007/s10811-010-9632-5

  10. Teas J, Baldeón ME, Chiriboga DE, Davis JR, Sarriés AJ, Braverman LE. Could dietary seaweed reverse the metabolic syndrome? Asia Pac J Clin Nutr 2009; 18(2): 145.

  11. Brown EM, Allsopp PJ, Magee PJ, Gill CI, Nitecki S, Strain CR, et al. Seaweed and human health. Nutr Rev 2014; 72(3): 205–16. doi: 10.1111/nure.12091

  12. McHugh DJ. A guide to the seaweed industry. FAO Fisheries Technical Paper 441. Rome: FAO; 2003.

  13. Nitschke U, Walsh P, McDaid J, Stengel DB. Variability in iodine in temperate seaweeds and iodine accumulation kinetics of fucus vesiculosus and Laminaria digitata (Phaeophyceae, Ochrophyta). J Phycol 2018; 54(1): 114–25. doi: 10.1111/jpy.12606

  14. Teas J, Pino S, Critchley A, Braverman LE. Variability of iodine content in common commercially available edible seaweeds. Thyroid 2004; 14(10): 836–41. doi: 10.1089/thy.2004.14.836

  15. Duinker A, Roiha IS, Amlund H, Dahl L, Lock E-J, Kögel T, et al. Potential risks posed by macroalgae for application as feed and food – a Norwegian perspective. Bergen, Norway;2016.

  16. Mæhre HK, Malde MK, Eilertsen K-E, Elvevoll EO. Characterization of protein, lipid and mineral contents in common Norwegian seaweeds and evaluation of their potential as food and feed. J Sci Food Agric 2014; 94(15): 3281–90. doi: 10.1002/jsfa.6681

  17. Roleda MY, Skjermo J, Marfaing H, Jónsdóttir R, Rebours C, Gietl A, et al. Iodine content in bulk biomass of wild-harvested and cultivated edible seaweeds: inherent variations determine species-specific daily allowable consumption. Food Chem 2018; 254: 333–9. doi: 10.1016/j.foodchem.2018.02.024

  18. Küpper F, Schweigert N, Gall EA, Legendre J-M, Vilter H, Kloareg B. Iodine uptake in laminariales involves extracellular, haloperoxidase-mediated oxidation of iodide. Planta 1998; 207(2): 163–71. doi: 10.1007/s004250050469

  19. Brent GA. Mechanisms of thyroid hormone action. J Clin Invest 2012; 122(9): 3035–43. doi: 10.1172/JCI60047

  20. Zimmermann MB. Iodine deficiency. Endocr Rev 2009; 30(4): 376–408. doi: 10.1210/er.2009-0011

  21. Laurberg P, Pedersen I, Carlé A, Andersen S, Knudsen N, Ovesen L, et al. The U-shaped curve of iodine intake and thyroid disorders. In: Preedy V, Burrow G, Watson R, eds. Comprehensive handbook on iodine: nutritional, endocrine and pathological aspects. London: Elsevier; 2009, pp. 449–55.

  22. Leung AM. The effects of iodine excess. In: Pearce EN, ed. Iodine deficiency disorders and their elimination. Springer International Publishing; 2017, pp. 75–89. ProQuest Ebook Central. [cited 08 September 2020]. Available from: https://ebookcentral-proquest-com.ezproxy.hioa.no/lib/hioa/detail.action?docID=4795484

  23. WHO. Assessment of iodine deficiency disorders and monitoring their elimination. A guide for programme managers. Geneva, Switzerland: World Health Organisation, International Council for Control of Iodine Deficiency Disorders, United Nations Children’s Fund; 2007.

  24. Eastman CJ, Li M. Mild to moderate iodine deficiency. In: Pearce EN, ed. Iodine deficiency disorders and their elimination. Switzerland: Springer Nature; 2017, pp. 59–74.

  25. Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol 2014; 10(3): 136–42. doi: 10.1038/nrendo.2013.251

  26. Zimmermann MB, Jooste PL, Pandav CS. Iodine-deficiency disorders. Lancet 2008; 372(9645): 1251–62. doi: 10.1016/S0140-6736(08)61005-3

  27. SCF. Opinion of the scientific committee on food on the tolerable upper intake level of iodine. Scientific Committee on Food: Brussels; 2002.

  28. Lazarus JH. Iodine status in Europe in 2014. Eur Thyroid J 2014; 3(1): 3–6. doi: 10.1159/000358873

  29. Aakre I, Morseth MS, Dahl L, Henjum S, Kjellevold M, Moe V, et al. Iodine status during pregnancy and at 6 weeks, 6, 12 and 18 months post-partum. Matern Child Nutr 2021; 17(1): e13050. doi: 10.1111/mcn.13050

  30. Brantsæter A, Knutsen H, Johansen N, Nyheim K, Erlund I, Meltzer H, et al. Inadequate iodine intake in population groups defined by age, life stage and vegetarian dietary practice in a Norwegian convenience sample. Nutrients 2018; 10(2): 230. doi: 10.3390/nu10020230

  31. Haldimann M, Alt A, Blanc A, Blondeau K. Iodine content of food groups. J Food Compost Anal 2005; 18(6): 461–71. doi: 10.1016/j.jfca.2004.06.003

  32. National Food Institute TUoD, Denmark, Sá Monteiro M, Sloth J, Holdt S, Hansen M. Analysis and risk assessment of seaweed. EFSA J 2019; 17(S2): e170915. doi: 10.2903/j.efsa.2019.e170915

  33. Norwegian Food Safety Authority, The Norwegian Directorate of Health, University of Oslo. The Norwegian food composition table. Norwegian Food Safety Authority; 2020. [cited 08 September 2020]. Available from: https://www.matvaretabellen.no/?language=en

  34. NNR. Nordic nutrition recommendations 2012: integrating nutrition and physical activity. Copenhagen: Nordisk Ministerråd; 2014. doi: 10.6027/Nord2014-002

  35. Dalane JØ, Bergvatn TAM, Kielland E, Carlsen MH. Mål, vekt og porsjonsstørrelser for matvarer [Weights, measures, and portion sizes for foods] (in Norwegian). Oslo: Norwegian Food Safety Authority, University of Oslo, Norwegian Directorate of Health; 2015.

  36. Aakre I, Evensen LT, Kjellevold M, Dahl L, Henjum S, Alexander J, et al. Iodine status and thyroid function in a group of seaweed consumers in Norway. Nutrients 2020; 12(11): 3483. doi: 10.3390/nu12113483

  37. Katagiri R, Yuan X, Kobayashi S, Sasaki S. Effect of excess iodine intake on thyroid diseases in different populations: a systematic review and meta-analyses including observational studies. PLoS One 2017; 12(3): e0173722. doi: 10.1371/journal.pone.0173722

  38. Teng W, Shan Z, Teng X, Guan H, Li Y, Teng D, et al. Effect of iodine intake on thyroid diseases in China. N Engl J Med 2006; 354: 2783–93. doi: 10.1056/NEJMoa054022

  39. Chen R, Li Q, Cui W, Wang X, Gao Q, Zhong C, et al. Maternal iodine insufficiency and excess are associated with adverse effects on fetal growth: a prospective cohort study in Wuhan, China. J Nutr 2018; 148(11): 1814–20. doi: 10.1093/jn/nxy182

  40. Emder PJ, Jack MM. Iodine-induced neonatal hypothyroidism secondary to maternal seaweed consumption: a common practice in some Asian cultures to promote breast milk supply. J Paediatr Child Health 2011; 47(10): 750–2. doi: 10.1111/j.1440-1754.2010.01972.x

  41. Chung HR, Shin CH, Yang SW, Choi CW, Kim BI. Subclinical hypothyroidism in Korean preterm infants associated with high levels of iodine in breast milk. J Clin Endocrinol Metab 2009; 94(11): 4444–7. doi: 10.1210/jc.2009-0632

  42. Suzuki H, Higuchi T, Sawa K, Ohtaki S, Horiuchi Y. ‘Endemic coast goitre’ in Hokkaido, Japan. Eur J Endocrinol 1965; 50(2): 161–76. doi: 10.1530/acta.0.0500161

  43. Miyai K, Tokushige T, Kondo M. Suppression of thyroid function during ingestion of seaweed ‘Kombu’ (Laminaria japonoca) in normal Japanese adults. Endocr J 2008; 55(6): 1103–8. doi: 10.1507/endocrj.k08e-125

  44. Konno N, Makita H, Yuri K, Iizuka N, Kawasaki K. Association between dietary iodine intake and prevalence of subclinical hypothyroidism in the coastal regions of Japan. J Clin Endocrinol Metab 1994; 78(2): 393–7. doi: 10.1210/jcem.78.2.8106628

  45. Aakre I, Næss S, Kjellevold M, Markhus MW, Alvheim AR, Dalane JØ, et al. New data on nutrient composition in large selection of commercially available seafood products and its impact on micronutrient intake. Food Nutr Res 2019; 63: 10. doi: 10.29219/fnr.v63.3573

  46. Nerhus I, Wik Markhus M, Nilsen BM, Øyen J, Maage A, Ødegård ER, et al. Iodine content of six fish species, Norwegian dairy products and hen’s egg. Food Nutr Res 2018; 62. doi: 10.29219/fnr.v62.1291

  47. Lee SM, Lewis J, Buss DH, Holcombe GD, Lawrance PR. Iodine in British foods and diets. Br J Nutr 1994; 72(3): 435–46. doi: 10.1079/BJN19940045

  48. Zimmermann M, Delange F. Iodine supplementation of pregnant women in Europe: a review and recommendations. Eur J Clin Nutr 2004; 58(7): 979–84. doi: 10.1038/sj.ejcn.1601933

  49. American Thyroid Association. ATA statement on the potential risks of excess iodine ingestion and exposure. American Thyroid Association; 2013 [updated 05 June]. [cited 19 March 2021]. Available from: http://www.thyroid.org/ata-statement-on-the-potential-risks-of-excess-iodine-ingestion-and-exposure

  50. Norwegian Food Safety Authority. Is it safe to consume seaweed and kelp. [In Norwegian: Er det trygt å spise tang og tare] Norwegian Food Safety Authority; 2016 [updated 21 November 2019]. [cited 19 March 2021]. Available from: https://www.matportalen.no/uonskedestoffer_i_mat/tema/miljogifter/er_det_trygt_aa_spise_tang_og_tare.

  51. Nielsen CW, Holdt SL, Sloth JJ, Marinho GS, Sæther M, Funderud J, et al. Reducing the high iodine content of Saccharina latissima and improving the profile of other valuable compounds by water blanching. Foods 2020; 9(5): 569. doi: 10.3390/foods9050569

  52. Nitschke U, Stengel DB. Quantification of iodine loss in edible Irish seaweeds during processing. J Appl Phycol 2016; 28(6): 3527–33. doi: 10.1007/s10811-016-0868-6

  53. Mæhre HK, Edvinsen GK, Eilertsen K-E, Elvevoll EO. Heat treatment increases the protein bioaccessibility in the red seaweed dulse (Palmaria palmata), but not in the brown seaweed winged kelp (Alaria esculenta). J Appl Phycol 2016; 28(1): 581–90. doi: 10.1007/s10811-015-0587-4

  54. Murphy EW, Criner PE, Gray BC. Comparisons of methods for calculating retentions of nutrients in cooked foods. J Agric Food Chem 1975; 23(6): 1153–7. doi: 10.1021/jf60202a021

  55. Hou X, Chai C, Qian Q, Yan X, Fan X. Determination of chemical species of iodine in some seaweeds (I). Sci Total Environ 1997; 204(3): 215–21. doi: 10.1016/S0048-9697(97)00182-4

  56. Nordic Committee on Food Analysis [In Norwegian: Nordisk Metodikkomité for Næringsmidler]. NMKL-PROCEDURE NR 5Measurement uncertainty [In Norwegian: NMKL-PROSEDYRE NR 5 Måleusikkerhet]. Bergen, Norway: Nordic Committee on Food Analysis; 1997.

  57. Greenfield H, Southgate DA. Food composition data: production, management, and use. Food and Agriculture Organization (FAO): Rome; 2003.

Published
2021-03-30
How to Cite
Aakre, I., Doblaug Solli , D., Wik Markhus, M., K. Mæhre, H., 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. https://doi.org/10.29219/fnr.v65.7584
Section
Original Articles