Seaweed Supplements, Iodine and Thyroid Function
In recent years, seaweed supplements have gained recognition for their wide range of health benefits. Seaweed is commonly known for its natural iodine content, which plays a crucial role in thyroid function. Let's dive into the world of seaweed supplements, exploring the iodine content of different seaweeds and how these elements can benefit, or impact, your health.
How Much Iodine is Found in Seaweed?
Different varieties of seaweed have differing amounts of iodine, and therapeutic benefits depend on factors such as species, area of the plant, stage of growth, season, and geographical location.[1] More on seaweed’s health benefits can be found in this article: Exploring the Health Benefits of Seaweed Supplements. Iodine is water-soluble in cooking and may vaporise in humid storage conditions, making the average iodine content of prepared foods difficult to estimate. Below is a list of commonly consumed seaweeds, alongside the average iodine content contained in each:[2]
|
Genus and species |
Common name |
Location |
Form |
|
Iodine |
Variance +/- |
Number of samples |
|
Alaria esculenta |
American wakame |
Maine |
Whole |
|
110 |
30 |
7 |
|
Ascophyllum nodosum |
Knotted wrack |
Maine |
Whole |
|
646 |
392 |
3 |
|
Ecklonia maxima |
Paddle weed |
Namibia |
Whole |
|
2123 |
352 |
6 |
|
Fucus vesiculosis |
Bladderwrack |
Maine |
Whole |
|
276 |
82 |
3 |
|
Hizikia fusiforme |
Hijiki |
Japan |
Whole |
|
629 |
153 |
6 |
|
Laminaria angustata |
Mitsuishi-kombu |
Japan |
Powdered |
|
2353 |
65 |
4 |
|
Laminaria digitata |
Fingered tangle |
Maine |
Whole |
|
1997 |
563 |
6 |
|
Laminaria digitata |
Fingered tangle |
Maine |
Whole |
|
2984 |
910 |
6 |
|
Laminaria longicruis |
Oarweed |
Maine |
Whole |
|
746 |
26 |
3 |
|
Laminaria sp. |
Kelp |
British Columbia |
Capsule |
|
1259 |
200 |
5 |
|
Laminaria sp. |
Kombu |
Washington |
Whole |
|
1350 |
362 |
7 |
|
Laminaria sp. |
Wild kelp |
Maine |
Capsule |
|
1356 |
665 |
7 |
|
Laminaria sp. |
Kelp |
British Columbia |
Whole |
|
1513 |
117 |
5 |
|
Porphyra tenera |
Nori, Purple Laver |
Japan |
Sheet |
|
16 |
2 |
3 |
|
Postelsia palmaeformis |
Sea palm |
California |
Whole |
|
871 |
231 |
7 |
|
Sargassum |
Horsetail tangle |
Washington |
Whole |
|
30 |
1 |
5 |
|
Undaria pinnatifida |
Wakame |
Tasmania |
Powder |
|
32 |
4 |
5 |
|
Undaria pinnatifida |
Wakame |
Tasmania |
Whole |
|
41 |
14 |
4 |
|
Undaria pinnatifida |
Wakame |
Japan |
Whole |
|
42 |
17 |
6 |
|
Undaria pinnatifida |
Wakame |
New Zealand |
Whole |
|
115 |
42 |
6 |
|
Undaria pinnatifida |
Mekabu (sprout) |
Tasmania |
Tablets |
|
22 |
1 |
4 |
|
Undaria pinnatifida |
Mekabu (sprout) |
Tasmania |
Powder |
|
53 |
3 |
5 |
Kombu (Laminaria japonica): Kombu is a natural flavour enhancer with health benefits. It adds a savoury umami taste to foods and is usually made from dried Laminaria japonica.[3] Kombu kelp has been reported to contain up to 2,984 mcg of iodine per seaweed sheet (1 gram).[4]
Bladderwrack (Fucus vesiculosus): Fucus seaweeds have nutritional value and are considered good sources of dietary fibre and minerals, especially iodine. The content of iodine in the Fucus species can vary between 130 to 730 mcg per 1 gram of dry weight, with the maximal concentration contained in Fucus vesiculosus.[5]
Mekabu (Undaria pinnatifida): Compared to other seaweeds, Undaria contains a relatively low amount of iodine. SeaQuo® Immune contains organic Undaria seaweed spore (mekabu) which grows wild in Tasmania’s pristine waters. The capsules contain approximately 36.57 mcg of iodine per capsule, resulting in a total iodine content of approximately 73.14 mcg per recommended dosage of 2 capsules a day. While our latest test results indicate this value, it's important to note that the iodine content may vary due to the natural nature of our product, with a maximum potential range of 50 mcg per capsule based on the seaweed's iodine content.
Contrary to wakame (the leaves of Undaria pinnatifida), SeaQuo® Immune capsules contain mekabu which is the ruffled-shaped spore located at the base of the Undaria plant. This part of the plant contains the highest concentration of fucoidan, known for its medicinal and therapeutic benefits. More about the benefits of fucoidan can be found in this article: Discover Fucoidan: 5 Key Health Benefits.
Note: quality and variety matter when selecting your seaweed supplements.Not all seaweed supplements are created equal. Where the seaweed is grown and how it is processed matters for contaminants and heavy metals. The seaweed in SeaQuo® Immune contains wild-grown Tasmanian Undaria pinnatifida. The harvesting and processing of the Undaria seaweed adhere to world best practices, ensuring that the seaweed used in SeaQuo® Immune is organic and free from harmful contaminants and heavy metals. Read more about how to choose a quality natural health supplement here.
The Role of Iodine and Thyroid Function
Iodine is an essential nutrient required for human health, most importantly for its role in producing thyroid hormones. We know that the minimum amount of iodine that our bodies need to function is 150 mcg a day (250 mcg in pregnancy and 90 mcg for young children).[6]
The major dietary sources of iodine include seafood (especially seaweed), dairy milk, iodised salt and packaged bread. Inadequate amounts of iodine in your diet may lead to a range of conditions, including goitre and hypothyroidism.[7] Pregnant and breastfeeding individuals and children are the populations requiring the most iodine.[8]
Mandatory iodine fortification of bread with iodised salt was implemented in 2009, intending to address the re-emergence of iodine deficiency in some areas of Australia and New Zealand,[9] mainly attributed to the diminishing levels of iodine in our soils.[10] However, iodine intake has a ‘sweet spot’ in healthy individuals, as too much iodine intake is not ideal either.
What is the Role of your Thyroid?
The thyroid is a butterfly-shaped gland in the front of your neck. The thyroid gland is part of your endocrine system and is responsible for making hormones that help control many of your body’s functions.
The roles of the hormones secreted by your thyroid gland include:[11]
- Controlling the metabolic rate of almost all cells in the body
- Controlling the metabolism of fat and carbohydrates
- Regulating heart rate and blood flow to organs
- Energy production and oxygen consumption in cells
- Promoting linear growth and brain development in children
- Needed for normal reproductive function in adults
- Important in bone and calcium metabolism[12]
Iodine and Thyroid Function
Iodine is required to make the thyroid hormones thyroxine (T4) and triiodothyronine (T3), responsible for regulating metabolism, energy levels, and overall hormonal balance listed above.[13]
Seaweed and Autoimmune Thyroid Conditions: Can I Take Seaweed Supplements if I have a Thyroid Condition?
If you have an autoimmune thyroid condition, such as Hashimoto's thyroiditis or Graves' disease, you may have been advised to avoid seaweed supplements due to their iodine content. A person with hyperthyroidism, for example, should monitor or avoid eating excessive amounts of iodine, as the amount of iodine you consume plays a role in how much thyroid hormone your thyroid produces. In some cases, too much iodine can exacerbate thyroid issues.
As different seaweeds contain varying levels of iodine, always enquire about the iodine content of a seaweed supplement and consult a healthcare provider who can help you determine the allowable dietary intake of iodine and if seaweed supplements are a suitable addition to your supplement routine.
Seaweed and Thyroid Health
Iodine-containing seaweed offers a range of benefits due to its pivotal role in supporting thyroid function. The thyroid gland relies on iodine to produce essential hormones that regulate metabolism, energy levels, and overall bodily functions.
By incorporating seaweed into your diet, you can help ensure adequate iodine intake, which is crucial for maintaining optimal thyroid health and helping to prevent deficiencies. However, it's important to select high-quality seaweed supplements and consider the iodine content to avoid excessive intake if you are part of the population with thyroid disease.
Balancing iodine levels through mindful consumption of seaweed can contribute to overall wellbeing in many ways as well as supporting the complex functions of your thyroid gland. It’s always best to follow the advice of your medical practitioner, as they can give you personalised advice about your health.
SeaQuo Immune contains Undaria seaweed, which supports overall wellness, immune, gut and skin health.
References
[1] Catarino MD, Silva AMS, Cardoso SM. Phycochemical Constituents and Biological Activities of Fucus spp. Mar Drugs. 2018 Jul 27;16(8):249. doi: 10.3390/md16080249. PMID: 30060505; PMCID: PMC6117670.
[2] Teas, J., Pino, S., Critchley, A., & Braverman, L.E. (2004). Variability of iodine content in common commercially available edible seaweeds. Thyroid 14(10).
[3] Cherry P, O'Hara C, Magee PJ, McSorley EM, Allsopp PJ. Risks and benefits of consuming edible seaweeds. Nutr Rev. 2019 May 1;77(5):307-329. doi: 10.1093/nutrit/nuy066. PMID: 30840077; PMCID: PMC6551690.
[4] Teas J, Pino S, Critchley A, Braverman LE. Variability of iodine content in common commercially available edible seaweeds. Thyroid. 2004 Oct;14(10):836-841. [PubMed abstract]
[5] Van Netten C., Hoption Cann S.A., Morley D.R., Van Netten J.P. Elemental and radioactive analysis of commercially available seaweed. Sci. Total Environ. 2000;255:169–175. doi: 10.1016/S0048-9697(00)00467-8.
[6] Nutrient Reference Values for Australia and New Zealand https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/iodine Last accessed 17/8/2024
[7] World Health Organization, UNICEF, ICCIDD, 2007, Assessment of iodine deficiency disorders and monitoring their elimination, http://www.who.int/nutrition/publications/micronutrients/iodine_deficiency/9789241595827/en/, Last accessed 17/8/2024
[8] Hatch-McChesney A, Lieberman HR. Iodine and Iodine Deficiency: A Comprehensive Review of a Re-Emerging Issue. Nutrients. 2022 Aug 24;14(17):3474. doi: 10.3390/nu14173474. PMID: 36079737; PMCID: PMC9459956.
[9] Food standards Australia and New Zealand, Iodine fortification, https://www.foodstandards.gov.au/consumer/food-fortification/iodine-fortification Last accessed 17/8/2024
[10] Jones E, McLean R, Davies B, Hawkins R, Meiklejohn E, Ma ZF, Skeaff S. Adequate Iodine Status in New Zealand School Children Post-Fortification of Bread with Iodised Salt. Nutrients. 2016 May 16;8(5):298. doi: 10.3390/nu8050298. PMID: 27196925; PMCID: PMC4882711.
[11] Shahid MA, Ashraf MA, Sharma S. Physiology, Thyroid Hormone. [Updated 2023 Jun 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK500006/
[12] Australian Thyroid Foundation, Iodine Deficiency, https://thyroidfoundation.org.au/Iodine-Deficiency Last accessed 17/8/2024
[13] Mikaela M. Sifuentes, James D. Lechleiter, Chapter Eight - Thyroid Hormone Stimulation of Adult Brain Fatty Acid Oxidation, Editor(s): Gerald Litwack, Vitamins and Hormones, Academic Press, Volume 106, 2018,Pages 163-193, ISSN 0083-6729, https://doi.org/10.1016/bs.vh.2017.05.006. (https://www.sciencedirect.com/science/article/pii/S0083672917300377)