Which Foods Are Bad for Thyroid Patients?

by Mary Shomon Patient Advocate

Some foods are better to eat — and others, worse — when you have hypothyroidism, and can have a real impact on your thyroid's function. Educate yourself on how what you eat could potentially effect you to minimize that impact.

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 cap levothyroxine, which is 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 found in wheat. There appears to be strong evidence to support a link between celiac disease (gluten allergy) and autoimmune thyroid disorders. You can be tested for gluten allergy or intolerance to determine whether you have a problem.

Some holistic practitioners recommend that anyone with autoimmune Hashimoto’s disease eliminate gluten.

Need advice on how to go gluten-free? The Celiac Disease Foundation has a helpful fact sheet, "What Can I Eat?"

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 the anti-inflammatory food pyramid from Andrew Weil, M.D..

soda in glass

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.”

Tin cans with food in a box

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.

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.

Mary Shomon
Meet Our Writer
Mary Shomon

Mary Shomon is a patient advocate and New York Times bestselling author who empowers readers with information on thyroid and autoimmune disease, diabetes, weight loss and hormonal health from an integrative perspective. Mary has been a leading force advocating for more effective, patient-centered hormonal healthcare. Mary also co-stars in PBS’ Healthy Hormones TV series. Mary also serves on HealthCentral’s Health Advocates Advisory Board.