Which Foods are Bad for Thyroid Patients?

Patient Expert
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Goitrogenic vegetables

Goitrogenic vegetables contain a chemical that slows your thyroid gland. Some of the popular goitrogenic vegetables include kale, spinach, broccoli, cabbage, Brussels sprouts, and bok choy.

You don’t need to stop eating these healthy foods, but if you are hypothyroid or iodine-deficient, avoid overconsuming these vegetables raw, in large or concentrated form, i.e., raw smoothies.

Steaming or cooking, however, makes these vegetables much less likely to negatively affect your thyroid.



Soy is a goitrogen. It also has the ability — especially if you do not get enough iodine — to block your body’s absorption of thyroid hormone. If you are hypothyroid, you don’t have to stop eating soy, but experts recommend that you don’t overdo it, and eat it in its fermented forms — miso or tofu — as a high-protein condiment. Avoid the soy protein isolate found in shakes, powders, supplements, soy burgers, processed soy, and soy milk, as well as genetically modified (GMO) soy.



Don’t worry! You don’t have to stop drinking your morning cup of joe! But if you are taking the levothyroxine tablets (Synthroid, Levoxyl), be aware that coffee contains an acid that can impair your absorption of your thyroid medication.

Wait at least an hour after you’ve taken your medication before drinking coffee, including decaf. If you have to have your levothyroxine and coffee at the same time, ask your doctor about Tirosint gel caps or liquid levothyroxine, which are not affected by coffee.


Milk and calcium-fortified juice

If you are hypothyroid, it’s important to know that calcium has the ability to impair your ability to absorb your thyroid hormone replacement medication. If you want to drink milk (skim, 1 percent, 2 percent, or full-fat), or calcium-fortified juice, wait for at least three to four hours after taking your thyroid medication.



Gluten is a protein that can confuse your immune system, causing it to attack your thyroid. You can be tested for gluten intolerance to determine whether you have a problem. Some holistic practitioners, however, recommend that anyone with autoimmune Hashimoto’s disease should eliminate gluten.

Need advice on how to go gluten-free? Gluten Free Living has a great overview, "The Basic Gluten-Free Diet," and the Celiac Disease Foundation has a helpful fact sheet, "What Can I Eat?" to help.


Inflammatory foods

The majority of thyroid disease in the United States is caused by the autoimmune disease Hashimoto’s thyroiditis. Inflammation is a key factor in autoimmune disease, and certain foods promote inflammation. Experts recommend thyroid patients avoid pro-inflammatory foods, including:

  • Sugar
  • Fried foods
  • Refined flours (bread, etc.)
  • Additives
  • Trans-fats, partially hydrogenated oils, margarine
  • Processed meats (i.e., sausage, bologna)

For help, read Dr. Andrew Weil’s anti-inflammatory food pyramid.


Artificial sweeteners and diet drinks

It’s time to get rid of those pink, blue, and yellow packets of artificial sweeteners, as well as the diet sodas and drinks that include them as ingredients. Research shows that they can have a negative effect on your thyroid and immune function.

Reporting to the American Association of Clinical Endocrinologists (AACE), endocrinologist Isaac Sachmechi, M.D. said: “An overabundance of sugar-substituted beverages could pose a serious health risk if you are a thyroid patient.”


Many canned foods

Many canned foods are contaminated with BPA (bisphenol-A), which is used to coat the cans. BPA is a synthetic estrogen that disrupts normal thyroid function.

You should avoid using BPA-contaminated food cans. You can find a list of brands that use BPA — which include popular brands like Carnation, Del Monte, Hunt's, and more — in their cans at the Environmental Working Group website, as well as a list of brands that have eliminated BPA from their food cans and packaging.


A special note about the “Low-Iodine Diet”

If you have papillary or follicular thyroid cancer, your doctor may recommend a low-iodine diet for two weeks before radioactive iodine (RAI), to make it more effective. To follow the low-iodine diet, stay under 50 mcg of iodine daily by avoiding iodized salt, seafood, dairy, and other foods and ingredients. The Thyroid Cancer Survivor’s Association (ThyCa) has all the details on the low-iodine diet. You can also download a free copy of their Low-Iodine Cookbook.