Last update: July 31, 2018


Low Risk probable for breastfeeding

Moderately safe.
Mild risk possible. Follow up recommended.
Read the Comment.

Seaweed is traditionally an important source of food in several countries, especially Asian ones. Its consumption has spread to other regions of the world.
It contains amino acids, unsaturated fatty acids, docosahexaenoic acid (DHA), omega 3, mucilages, vitamins and numerous minerals and essential trace elements, among which is found iodine in very variable quantities but large in some of them (EC 2018, Romarís 2012 , Kikuchi 2008, Moon 1999), so much that its excessive consumption can produce symptoms of hyperthyroidism: anxiety, insomnia, tachycardia, palpitations (Leung 2012, Picco 2006, Salas 2002).

Consumption of algae increases the levels of iodine in plasma, urine and breastmilk (Moon 1999, Kim 1998).
There have been reports of hypothyroidism in infants of East Asian mothers who include in their diet significant amounts of marine algae rich in iodine such as Undaria Pinnatifida, Laminaria japonica or others (Hulse 2012, Emder 2011, Rhee 2011, Nishiyama 2004).

The maximum daily intake of iodine should not exceed 600 micrograms (μg) per day in adults and 200 μg/day in children under 3 years of age, which is 0.6 and 0.2 mg of iodine respectively (EC 2018).

Bear in mind that the bioavailability of iodine contained in algae is very low, meaning that the total iodine that reaches plasma circulation after being cooked, digested and metabolized in the liver is much less than that contained in algae. For example (Romarís 2012):
• Spirulina (Spirulina platensis), Agar-agar (from Gelidium sesquipedale), canned seaweed (prepared from Himanthalia elongata and Saccorhiza polyschides), nori (Porphyra umbilicalis), sea lettuce (Ulva rigida) and dulse (Palmaria palmada): contain less than 100 μg/g of iodine of which less than 6 μg/g are bioavailable
• Sea spaghetti (Himanthalia elongata): 120 μg/g of iodine, bioavailable 4 μg/g
• Wakame (Undaria pinnatifida): 300 μg/g, 9 μg/g bioavailable
• NIES 09 Sargasso: 525 μg/g, 23 μg/g bioavailable
• Kombu (Laminaria ochroleuca): 6,000 μg/g, 1,000 μg/g bioavailable

It is advisable to inquire about the composition of each particular algae and avoid them or consume moderately if the amount of iodine is large: Kombu algae in particular, Sargasso and, in general, dried algae products containing more than 20 mg of iodine per kilo (20 μg/g) of dry matter.

Algae can also contain heavy metals such as arsenic (Lynch 2014, Farré 2009), cadmium, iodine, lead and mercury (EC 2018, Romarís 2012).

The FAO and WHO have established a Provisional Tolerable Weekly Intake (PTWI) for inorganic arsenic at 15 μg/kg body weight (Farré 2009).

The most toxic form of arsenic is inorganic. Most algae contain the organic form, except for Hiziki or Hijiki brown alga (Sargassum fusiforme, Hizikia fusiformis) which contains very high concentrations of inorganic arsenic (80,000 μg/Kg) and its consumption has not been recommended (EFSA 2014, Farré 2009). Other algae contain an average of 270 μg/ Kg, with Wakame (Undaria spp.) having the highest content with 280 μg/Kg and Kombu (Laminaria spp.) with 350 μg/Kg (EFSA 2014).

Nevertheless, arsenic is ubiquitous and is present in water and all the foods we consume in varying quantities: 2 μg/L of water, 5 μg/kg in tomato, potato and apple, 100-150 μg/kg in rice, some mushrooms, molluscs and thyme, and 260 μg/Kg in ginger.
It should be noted that many dietary products labeled as nutritional supplements containing minerals, pollen, algae, fibre, etc. contain more than 1,000 μg/Kg of arsenic (EFSA 2014).

It is advisable to consume algae of known and reliable origin, with correct labeling and from companies which meet all the requirements of existing legislation, in particular the recommendations of the European Commission (EC 2018) regarding the concentration of iodine and heavy metals, with periodic analyses transmitted regularly to the EFSA (European Food Safety Authority).
Do not consume quantities above those indicated by the manufacturer, which range between 3 and 6 grams per day.

The levels of docosahexaenoic acid (DHA) in breastmilk increased when mothers consumed a nutritional supplement of algae (Jensen 2000).

Although in some cultures it is used as a galactogogue, there is no evidence of its effectiveness in increasing milk production. The best galactogogue is frequent on demand breastfeeding with correct technique in a mother who is self-confident (Mannion 2012, Forinash 2012, ABM 2011).

External treatments with algae, whether in the form of massages or body wraps on the skin, involve no or very little systemic absorption and are compatible with breastfeeding.

See below the information of these related products:

Suggestions made at e-lactancia are done by APILAM´s pediatricians and pharmacists, and are based on updated scientific publications.
It is not intended to replace the relationship you have with your doctor but to compound it.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Seaweed is also known as

Seaweed in other languages or writings:


Seaweed belongs to this group or family:


Main tradenames from several countries containing Seaweed in its composition:


  1. ABM: Brodribb W. ABM Clinical Protocol #9: Use of Galactogogues in Initiating or Augmenting Maternal Milk Production, Second Revision 2018. Breastfeed Med. 2018 Jun;13(5):307-314 Abstract Full text (link to original source) Full text (in our servers)
  2. CE - Comisión europea. RECOMENDACIÓN (UE) 2018/464 DE LA COMISIÓN de 19 de marzo de 2018 relativa al control de metales y yodo en las algas marinas, las plantas halófilas y los productos a base de algas marinas. Diario oficial de la Unión Europea 2018 Full text (link to original source) Full text (in our servers)
  3. EC - The European Commission. COMMISSION RECOMMENDATION (EU) 2018/464 of 19 March 2018 on the monitoring of metals and iodine in seaweed, halophytes and products based on seaweed. Official Journal of the European Union 2018 Full text (link to original source) Full text (in our servers)
  4. Lynch HN, Greenberg GI, Pollock MC, Lewis AS. A comprehensive evaluation of inorganic arsenic in food and considerations for dietary intake analyses. Sci Total Environ. 2014 Abstract
  5. EFSA (European Food Safety Authority). Dietary exposure to inorganic arsenic in the European population. EFSA Journal. 2014 Full text (link to original source) Full text (in our servers)
  6. Forinash AB, Yancey AM, Barnes KN, Myles TD. The use of galactogogues in the breastfeeding mother. Ann Pharmacother. 2012 Oct;46(10):1392-404. Abstract
  7. Mannion C, Mansell D. Breastfeeding self-efficacy and the use of prescription medication: a pilot study. Obstet Gynecol Int. 2012;2012:562704. Abstract Full text (link to original source) Full text (in our servers)
  8. Hulse T. Transient neonatal hypothyroidism resulting from maternal ingestion of a traditional Korean seaweed soup. Horm Res Paediatr. 2012;78 (Suppl 1):127. Abstract P1-d3-405 Thyroid 1. 2012 Full text (link to original source) Full text (in our servers)
  9. Romarís-Hortas V, Bermejo-Barrera P, Moreda-Piñeiro J, Moreda-Piñeiro A. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry. Anal Chim Acta. 2012 Abstract
  10. Leung AM, Braverman LE. Iodine-induced thyroid dysfunction. Curr Opin Endocrinol Diabetes Obes. 2012 Abstract
  11. ABM. Academy Of Breastfeeding Medicine Protocol Committee. ABM Clinical Protocol #9: Use of galactogogues in initiating or augmenting the rate of maternal milk secretion (First Revision January 2011). Breastfeed Med. 2011 Abstract Full text (link to original source) Full text (in our servers)
  12. 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 Abstract
  13. 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 Abstract
  14. ABM. Comité de Protocolos de la Academia Médica de Lactancia Materna. ABM Protocolo Clínico #9: Uso de Galactogogos para Iniciar o aumentar la tasa de secreción de Leche Materna. Breastfeed Med. 2011 Full text (link to original source) Full text (in our servers)
  15. 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 Abstract Full text (link to original source) Full text (in our servers)
  16. Farré Rovira R, Cacho Palomar JF, Cameán Fernández AM, Más Barón A, Delgado Cobos P. Informe del Comité Científico de la Agencia Española de Seguridad Alimentaria y Nutrición (AESAN) relativo a la evaluación del riesgo asociado a la posible presencia de arsénico en algas desti- nadas al consumo humano. (Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) related to the risk assessment associated to the possible presence of arsenic in algae intended to human consumption). Revista del comité científico AESAN, nº 10 2009 Full text (link to original source) Full text (in our servers)
  17. Kikuchi Y, Takebayashi T, Sasaki S. [Iodine concentration in current Japanese foods and beverages]. Nihon Eiseigaku Zasshi. 2008 Abstract Full text (link to original source) Full text (in our servers)
  18. Picco G, de Dios-Romero A, Albanell N, Badia J. Ingestión habitual de algas e hipertiroidismo. [Regular intake of seaweed and hyperthyroidism]. Med Clin (Barc). 2006 Abstract
  19. Nishiyama S, Mikeda T, Okada T, Nakamura K, Kotani T, Hishinuma A. Transient hypothyroidism or persistent hyperthyrotropinemia in neonates born to mothers with excessive iodine intake. Thyroid. 2004 Abstract
  20. Salas Coronas J, Cruz Caparrós G, Laynez Bretones F, Díez García F. Hipertiroidismo inducido por consumo de algas marinas. [Hyperthyroidism secondary to kelp tablets ingestias]. Med Clin (Barc). 2002 Abstract
  21. Jensen CL, Maude M, Anderson RE, Heird WC. Effect of docosahexaenoic acid supplementation of lactating women on the fatty acid composition of breast milk lipids and maternal and infant plasma phospholipids. Am J Clin Nutr. 2000 Abstract
  22. Moon S, Kim J. Iodine content of human milk and dietary iodine intake of Korean lactating mothers. Int J Food Sci Nutr. 1999 Abstract
  23. Kim JY, Moon SJ, Kim KR, Sohn CY, Oh JJ. Dietary iodine intake and urinary iodine excretion in normal Korean adults. Yonsei Med J. 1998 Abstract

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