Hypothyroid Foods: What to Eat, Limit and Time Around Levothyroxine

There is no single hypothyroidism diet. The two food issues with the strongest support are iodine, which can be a problem in excess for people with Hashimoto's disease, and timing, because some foods and supplements reduce how much levothyroxine your body absorbs. Most other advice you will see online has weaker evidence than it sounds.

This guide separates what NIDDK and published research say from the myths, and gives the timing details that are easy to miss. It is educational and does not replace advice from your doctor, and you should never change or stop your medicine because of something you read online.

Take levothyroxine consistently

NIDDK says some foods and supplements affect how well you absorb levothyroxine, and that taking it on an empty stomach helps. Doctors typically advise taking it in the morning, 30 to 60 minutes before your first meal. A systematic review of levothyroxine interactions concluded that tablets need about 60 minutes before food, while liquid formulations can be taken with meals.

Foods and supplements that can interfere

The same review summarizes what research found. Your doctor may give you different instructions, and those come first.

• Coffee: espresso lowered the average rise in thyroxine by 29 to 36% in studies. The review suggests waiting about 1 hour after levothyroxine.
• Calcium: calcium carbonate significantly reduced absorption. The review suggests spacing it 2 to 4 hours after levothyroxine.
• Iron: ferrous sulfate raised TSH in most participants in one study. The review suggests a 2 to 4 hour gap or a different formulation.
• Soy: soy protein and isoflavones reduced effectiveness. The review suggests separating soy from levothyroxine by 1 hour.
• Fiber: whole-wheat bread and psyllium were linked to reduced absorption in studies.
• Grapefruit juice, aluminum hydroxide and chromium picolinate also reduced absorption.

The American Thyroid Association also lists antacids, calcium, iron supplements, biotin and estrogen as things that can affect thyroid medicine, and advises calling your doctor if you start or stop a medicine that does.

Iodine: too little and too much

The thyroid uses iodine to make hormones, but NIDDK says people with Hashimoto's disease and other autoimmune thyroid conditions may be sensitive to harmful effects from iodine. Foods with large amounts of iodine, such as kelp, dulse and other seaweed, and iodine-rich medicines or supplements, may cause hypothyroidism or make it worse. Do not start or stop an iodine supplement without asking your doctor. Our Hashimoto's iodine page and iodized salt page look at these ingredients in more detail.

Cruciferous vegetables

Broccoli, cabbage, kale and similar vegetables contain compounds called goitrogens, which is why they have a reputation for harming the thyroid. The Linus Pauling Institute says the thiocyanate they release does not appear to increase the risk of hypothyroidism unless iodine intake is also low, and notes a human study in which 150 grams a day of cooked Brussels sprouts for four weeks had no adverse effects on thyroid function. Its discussion is about risk, not about managing existing hypothyroidism, so if you eat very large amounts every day, mention it to your doctor.

Gluten

A review of the gluten-free diet in Hashimoto's disease reports that celiac disease occurs in about 5% of adults and 8% of children with Hashimoto's, compared with about 1% of the general population. It concludes there is currently no evidence that a gluten-free diet helps Hashimoto's in people without celiac disease or gluten sensitivity, and that the diet does not change thyroid hormone concentrations. Because celiac disease is more common in Hashimoto's, ask your doctor about testing before you remove gluten, since cutting it out first can make testing less reliable.

Selenium and vitamin D

NIDDK says researchers are looking at how diet and supplements such as vitamin D and selenium may affect Hashimoto's disease, but no specific guidance is currently available. Supplements can interact with thyroid medicine and with each other, so check with your doctor before starting one.

Check ingredient labels against your own needs

Foodsage lets you choose Hashimoto's and hypothyroid as a condition during setup, along with your own sensitivities, then checks a scanned product's ingredients and shows which ones matched. Our Hashimoto's ingredient guide lists ingredients such as iodine, gluten and iodized salt with a plain-language verdict for each. It does not tell you when to take your medicine, so keep following your doctor's instructions.

Foodsage and the other MetricPoint apps are educational tools, not medical devices or medical advice. For decisions about your health, allergies, or a specific condition, talk to a qualified doctor or registered dietitian.