Not All “Superfoods” Are Super For Your Thyroid
It’s easy to get misled by all the overwhelming health information out there, thinking you need to jump on the newest health trends to stay “healthy”. And yes, some of these foods are healthy but I urge you to always educate yourself on the different spectrums of the food. It’s always about listening to your body and finding what’s right for your condition.
I’m sure you’ve heard people say, “it’s a superfood, it’s good for you!” But when it comes to optimal thyroid health, not ALL superfoods are necessarily good for your thyroid.
One food in specific are Sea Vegetables also known as Seaweed and Kelp. Yes, they are a type of algae that are loaded with nutrients but they are also the single food category with the highest amount of iodine, which can be harmful if eaten in excessive amounts.
How much iodine does your thyroid need?
The recommended daily amount for adults is 150 mcg. For pregnant women, 220-250 mcg and for breastfeeding women, 250-290 mcg [1]
How can excess iodine affect your thyroid?
It’s not to be mistaken that your thyroid doesn’t need iodine. In fact, iodine is vital for the creation of thyroid hormones like thyroxine (T4) and triiodothyronine (T3). But, excess amounts can have harmful effects on your thyroid gland too. When there is excess iodine in the body, it can actually slow down your thyroid gland and disrupt its normal functioning. This can lead to a decrease in thyroid hormone production and trigger your immune system to attack your thyroid gland.
A medical study done showed that it can even “increase your TPO levels and thyroglobulin antibodies, increasing incidences of autoimmune thyroiditis in women.”[6]
“Excess iodine intake including eating seaweed can lead to conditions in the form of goitre, thyroid autoimmunity, hypothyroidism, or hyperthyroidism.” [3, 4, 5] And not surprisingly, those conditions are very common in areas with heavy sea vegetable consumption.
“An increased prevalence of papillary thyroid cancer was reported in postpartum Japanese women that consumed daily seaweed dishes, compared to those whose consumption was 2 days per week or less.” [7]
While sea vegetables can be a nutritious addition to your diet, it is important to know your iodine levels to better understand how much iodine you really need. Also, be aware that iodine contains contaminants like arsenic, cadmium, lead, and mercury.
Like with anything, it is important to maintain a healthy balance of iodine in the body to support thyroid function and overall health.
TIP: If you have unpleasant thyroid symptoms or a thyroid condition, ask your doctor about taking the Iodine 24-hour Urine Test. The measurement of urinary iodine will “serve as an index of the adequate intake of iodine for your body.” [8]
Disclaimer: Always consult a medical professional before making any nutritional changes and ask them questions regarding your medical condition. This information is purely for educational purposes so you can become your own health advocates.
References:
https://www.thyroid.org/ata-statement-on-the-potential-risks-of-excess-iodine-ingestion-and-exposure/
https://pubmed.ncbi.nlm.nih.gov/15588380/
https://etj.bioscientifica.com/view/journals/etj/10/2/ETJ512971.xml
Mussig K. Iodine-induced toxic effects due to seaweed consumption. In: Preedy V, Burrow G, Watson R, editors. Comprehensive Handbook of Iodine. Academic Press; 2009. pp. p. 897–908
Farebrother J, Zimmermann MB, Andersson M. Excess iodine intake: sources, assessment, and effects on thyroid function. Ann N Y Acad Sci. 2019;1446((1)):44–65.
https://journals.lww.com/co-endocrinology/abstract/2018/10000/the_catalytic_role_of_iodine_excess_in_loss_of.13.aspx
Michikawa T, Inoue M, Shimazu T, Sawada N, Iwasaki M, Sasazuki S, et al. Seaweed consumption and the risk of thyroid cancer in women: the Japan Public Health Center-based Prospective Study. Eur J Cancer Prev. 2012;21((3)):254–60
https://testdirectory.questdiagnostics.com/test/test-detail/16602/iodine-24-hour-urine?cc=MASTER