Maintaining optimal breast health is a priority for many women, and iodine plays a crucial role in achieving this. While iodine is commonly associated with thyroid function, it’s also essential for breast health. This blog will explore the relationship between iodine and breast health, the risks of iodine deficiency, and actionable steps for improving your iodine intake.

The Importance of Iodine for Breast Health

Iodine is an essential nutrient that is often overlooked in discussions about breast health. Not only does it support the thyroid, but it is also vital for maintaining healthy breast tissue. Adequate iodine levels may help prevent conditions like fibrocystic breast changes and could potentially lower the risk of breast cancer.11, 13

Iodine’s Role in Cellular Function

Breast tissue requires significant amounts of iodine for normal cellular function. Iodine helps regulate estrogen metabolism, supporting healthy hormone balance. When iodine levels are sufficient, the body directs estrogen down protective pathways. In contrast, low iodine leads to imbalances that may increase the risk of breast issues.11,13

In particular, molecular iodine (I2) has been shown to neutralize free radicals, induce the production of antioxidant enzymes, and reduce inflammation. In cancerous cells, iodine activates apoptotic pathways (programmed cell death) and inhibits markers related to chemoresistance and cancer cell survival.1 A small pilot study in women with early and advanced breast cancer found that molecular iodine, when combined with chemotherapy, not only enhanced treatment response but also reduced side effects and prevented chemoresistance in all patients. After five years, patients who received iodine before and after surgery had a significantly higher disease-free survival rate compared to those who only received it after surgery.10

How Iodine Supports Estrogen Balance and Breast Health

Iodine plays a key role in metabolizing estrogen, guiding it through pathways that can either protect against or may raise the risk of cancer.5,12 It is especially important to note that iodine works best in synergy with selenium, a powerful antioxidant. Selenium protects iodine-rich tissues, such as the breasts and thyroid, by neutralizing free radicals.8

Studies suggest that breast cancer-protective effects of iodine are most prominent in people with higher selenium levels. Therefore, maintaining adequate levels of both iodine and selenium is critical for optimal breast health.8

The richest foods sources of selenium include Brazil nuts, organ meats, seafood, and muscle meats (from farmed animals who are supplemented with selenium in their feed).7

Fibrocystic Breast Changes and Iodine

Many women experience fibrocystic breast changes, characterized by lumpy, tender, and often painful breasts, due to hormonal fluctuations. Research indicates that iodine deficiency can exacerbate these symptoms. Increasing iodine intake has been shown to improve breast tissue health and reduce discomfort associated with fibrocystic changes.9

Why Are So Many People Still Deficient in Iodine?

Despite iodine being added to table salt, iodine deficiency remains common. Here are some reasons why:

  • Dietary Deficiencies: In my practice, I find iodine deficiencies in patients who do not consume little if any dairy, seafood and/ or sea vegetables and who are not supplementing with iodine. Recent research has found that those with vegan, vegetarian and paleolithic diets tend towards iodine deficiency. Recently, I have also found functional deficiency of iodine due to vitamin A deficiency (read more on the importance and connection between vitamin A and iodine below).4
  • Halides: Found in common products like baked goods, tap water, flame retardants, halides (chlorine, fluoride, and bromine) compete with iodine in the body, blocking its absorption.9
  • Soil Depletion: Modern farming practices have depleted iodine levels in the soil, meaning our food contains less iodine than it did decades ago.9
  • Less Effective Forms: The form of iodine found in table salt (iodide) is not as easily used by breast tissue, making it less beneficial for overall breast health.1,9

The Importance of Testing for Iodine Deficiency

Before supplementing with iodine, it's crucial to test your levels. A 24-hour urine iodine test is considered the most accurate method.6 Testing ensures you're taking the right dose of iodine and prevents over-supplementation, which could aggravate conditions like Hashimoto's thyroiditis.

Iodine Supplementation Guidelines

The World Health Organization (WHO) recommends the following iodine daily intake:

  • Adults and adolescents: 150 mcg/day
  • Pregnant and lactating women: 250 mcg/day
  • Children aged 6–12 years: 120 mcg/day
  • Infants up to 6 years: 90 mcg/day

It's important to work with a healthcare provider to determine an appropriate supplementation plan based on your test results.

The Connection Between Vitamin A, Iodine, and Breast Health

The Sodium Iodide Symporter (NIS) and Pendrin (PDS) are transport proteins that help move iodine into sensitive tissues, such as thyroid, breast and prostate. NIS levels are higher in about 80% of breast cancers, particularly HER2+, whereas pendrin has been found to be low in breast cancer tissues.2,3 Researchers are exploring how NIS can be used in breast cancer imaging and treatment.2

Vitamin A, specifically in the form of all-trans retinoic acid, helps boost NIS activity, improving how well breast tissue utilizes iodine.6 This suggests that keeping both iodine and vitamin A levels optimal may provide added protection against breast issues like fibrocystic changes.

What You Can Do

  1. Test Your Iodine Levels: Always test before supplementing with iodine. Work with a healthcare provider to determine the best type of test for you —24-hour urinary iodine testing is generally preferred.6
  2. Test Your Selenium Levels: Since selenium is crucial for iodine metabolism and breast tissue protection, consider testing your selenium levels too.7
  3. Consult a Professional: If you're considering iodine supplementation for breast health, consult your healthcare provider or naturopathic doctor for personalized advice based on your test results.
  4. Read Labels: Many multivitamins contain adequate iodine, but prenatal vitamins often fall short. Be mindful of the iodine content in your supplements to ensure you’re getting enough.

Final Thoughts

Iodine is a vital nutrient for both thyroid and breast health. By testing your levels, ensuring adequate selenium intake, and eating a balanced diet rich in antioxidants, you can take proactive steps to support breast health and hormone balance. Always consult with your healthcare professional to determine the best approach for your unique needs.

Take charge of your breast health today by understanding your body’s iodine needs and working with a trusted healthcare provider to achieve optimal wellness.

 

Dr. Sarah Giardenelli is a naturopathic doctor, acupuncturist, herbalist, and owner of the Collective Health Center in Leesburg, Virginia. With a focus on holistic health and wellness, Dr. Giardenelli is dedicated to helping patients achieve their health goals through personalized care and evidence-informed practices.

References

  1. Aceves C, Mendieta I, Anguiano B, Delgado-González E. Molecular Iodine Has Extrathyroidal Effects as an Antioxidant, Differentiator, and Immunomodulator. Int J Mol Sci. 2021 Jan 27;22(3):1228. doi: 10.3390/ijms22031228. PMID: 33513754; PMCID: PMC7865438. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865438/
  2. Arczewska KD, Godlewska M, Krasuska W, Łyczkowska A, Kiedrowski M, Czarnocka B. Expression of pendrin and NIS iodide transporters in human breast tumor and peri-tumoral tissue. Arch Med Sci. 2019 Nov 25;18(4):1041-1050. doi: 10.5114/aoms.2019.89980. PMID: 35832691; PMCID: PMC9266960. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9266960/
  3. Elliyanti A, Rusnita D, Afriani N, Susanto YDB, Susilo VY, Setiyowati S, Harahap WA. Analysis Natrium Iodide Symporter Expression in Breast Cancer Subtypes for Radioiodine Therapy Response. Nucl Med Mol Imaging. 2020 Feb;54(1):35-42. doi: 10.1007/s13139-019-00632-8. Epub 2020 Jan 3. PMID: 32206129; PMCID: PMC7062960. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062960/
  4. Greger, M. (2023, March 31). Are vegans at risk for iodine deficiency? org. https://nutritionfacts.org/video/are-vegans-at-risk-for-iodine-deficiency/
  5. He S, Wang B, Lu X, Miao S, Yang F, Zava T, Ding Q, Zhang S, Liu J, Zava D, Shi YE. Iodine stimulates estrogen receptor singling and its systemic level is increased in surgical patients due to topical absorption. 2017 Sep 4;9(1):375-384. doi: 10.18632/oncotarget.20633. PMID: 29416620; PMCID: PMC5787473. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5787473/
  6. Linus Pauling Institute. (2023). Oregon State University. https://lpi.oregonstate.edu/mic/minerals/iodine#:~:text=Vitamin%20A%20deficiency%20in%20animal,thyroid%20gland%20and%20impairing%20the
  7. Linus Pauling Institute. (2023). Oregon State University. https://lpi.oregonstate.edu/mic/minerals/selenium#selenoproteins
  8. Manjer J, Sandsveden M, Borgquist S. Serum Iodine and Breast Cancer Risk: A Prospective Nested Case-Control Study Stratified for Selenium Levels. Cancer Epidemiol Biomarkers Prev. 2020 Jul;29(7):1335-1340. doi: 10.1158/1055-9965.EPI-20-0122. Epub 2020 May 26. PMID: 32457181. https://pubmed.ncbi.nlm.nih.gov/32457181/
  9. Meletis CD. Iodine: Health Implications of Deficiency. Journal of Evidence-Based Complementary & Alternative Medicine. 2011;16(3):190-194. doi:10.1177/2156587211414424. https://journals.sagepub.com/doi/full/10.1177/2156587211414424
  10. Moreno-Vega A, Vega-Riveroll L, Ayala T, Peralta G, Torres-Martel JM, Rojas J, Mondragón P, Domínguez A, De Obaldía R, Avecilla-Guerrero C, Anguiano B, Delgado-González E, Zambrano-Estrada X, Cuenca-Micó O, De La Puente Flores O, Varela-Echavarría A, Aceves C. Adjuvant Effect of Molecular Iodine in Conventional Chemotherapy for Breast Cancer. Randomized Pilot Study. 2019 Jul 17;11(7):1623. doi: 10.3390/nu11071623. PMID: 31319484; PMCID: PMC6682905. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682905/
  11. Rappaport J. Changes in Dietary Iodine Explains Increasing Incidence of Breast Cancer with Distant Involvement in Young Women. J Cancer. 2017 Jan 13;8(2):174-177. doi: 10.7150/jca.17835. PMID: 28243321; PMCID: PMC5327366. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5327366/
  12. Stoddard FR 2nd, Brooks AD, Eskin BA, Johannes GJ. Iodine alters gene expression in the MCF7 breast cancer cell line: evidence for an anti-estrogen effect of iodine. Int J Med Sci. 2008 Jul 8;5(4):189-96. doi: 10.7150/ijms.5.189. PMID: 18645607; PMCID: PMC2452979. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2452979/
  13. Winder M, Kosztyła Z, Boral A, Kocełak P, Chudek J. The Impact of Iodine Concentration Disorders on Health and Cancer. 2022 May 26;14(11):2209. doi: 10.3390/nu14112209. PMID: 35684009; PMCID: PMC9182735. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9182735/
  14. ZRT Laboratory. (2021, July 7). Curious about iodine? Part 2: The history, uses, and forms of iodine. ZRT Laboratory. https://www.zrtlab.com/blog/archive/curious-about-iodine-2/#B9

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