Hypothyroidism (underactive thyroid)

  • image.alt
  • With Mayo Clinic endocrinologist

    Todd B. Nippoldt, M.D.

    read biography

Mayo Clinic Health Manager

Get free personalized health guidance for you and your family.

Get Started

Free

E-Newsletter

Subscribe to receive the latest updates on health topics. About our newsletters

  • Housecall
  • Alzheimer's caregiving
  • Living with cancer

Question

Soy: Does it worsen hypothyroidism?

Is it true that people who have hypothyroidism should avoid soy?

Answer

from Todd B. Nippoldt, M.D.

Hypothyroidism is generally treated with synthetic thyroid hormone — and soy has long been thought to interfere with the body's ability to absorb the medication. However, there's no evidence that people who have hypothyroidism should avoid soy completely.

If you have hypothyroidism, take thyroid hormone replacement as directed by your doctor — typically on an empty stomach. Generally, it's best to wait four hours after taking thyroid medication to consume any products that contain soy. The same guidelines apply to other products that may impair the body's ability to absorb thyroid medication, including high-fiber foods, iron and calcium supplements, and antacids that contain aluminum or magnesium.

Next question
Coconut oil: Can it cure hypothyroidism?
References
  1. ATA hypothyroidism booklet. American Thyroid Association. http://www.thyroid.org/patients/brochures/Hypothyroidism%20_web_booklet.pdf. Accessed Sept. 17, 2008.
  2. Thyroid hormone treatment FAQ. American Thyroid Association. http://www.thyroid.org/patients/faqs/hormonetreatment.html. Accessed Sept. 17, 2008.
  3. Messina M, et al. Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: A review of the relevant literature. Thyroid. 2006;16:249.
  4. Teas J, et al. Seaweed and soy: Companion foods in Asian cuisine and their effects on thyroid function in American women. Journal of Medicinal Food. 2007;10:90.

AN00454

Dec. 18, 2008

© 1998-2009 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "EmbodyHealth," "Reliable tools for healthier lives," "Enhance your life," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.

Print Share Reprints

Text Size: smaller largerlarger