Foods to Avoid When Taking Thyroid Medication

According to Harvard Medical School, about 12 million people in the United States have some form of thyroid disease: either hypothyroidism (9.6 million), wherein not enough thyroid hormone is produced; or hyperthyroidism (2.6 million), where there is too much hormone produced. Mayo Clinic staff say women over the age of 50 are most likely to have hypothyroidism. People with hypothyroidism take synthetic thyroid hormone to help balance hormone production.There are certain foods to avoid while taking thyroid medication because they may block proper absorption of the medication into the bloodstream.

Medicate on an Empty Stomach

Mayo Clinic staff say there is no special diet needed to aid thyroid function or help thyroid medication work properly. They do say, however, it is best to take thyroid medication on an empty stomach and wait at least 1/2 hour before eating. Dr. Mark Lupo of the Thyroid and Endocrine Center recommends eating a well-balanced diet. He said it is also important to keep calories balanced between intake and outgo so that there is no unusual weight fluctuation in the patient.

Dietary Fiber

Drugs & Foods to Avoid for Hypothyroidism

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Certain dietary fiber sources can impede absorption of the thyroid hormone replacement medication. Mayo Clinic staff say it is best to avoid dietary fiber in foods like walnuts, soy products, iron supplements and multivitamins containing iron.


Dr. Lupo of the Thyroid and Endocrine Center says that a diet high in soy products may cause a decrease in thyroid function.

Calcium Supplements

Levothyroxine & Soy

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Todd B. Nippoldt, M.D., of the Mayo Clinic advises steering clear of calcium supplements and medications. He says antacids and magnesium supplements may also contain calcium and should be avoided when taking thyroid medications. If unable to totally avoid these supplements, Nippoldt advises taking them several hours before or after taking thyroid medications.