Thyroid Patients: Are You Making These Supplement Mistakes?

Patient Expert
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Supplements — including vitamins, herbs, and botanical remedies — are increasingly popular components of a healthy lifestyle. When you have a chronic health condition like thyroid disease, you are even more likely to turn to over-the-counter, non-prescription supplements to help relieve symptoms and improve your health. Make sure that you are not making these common supplement mistakes.


Thinking a supplement can replace prescription medication

If you are hypothyroid and believe you can take supplements or vitamins instead of prescription thyroid hormone replacement medication, you’re wrong. You need actual thyroid hormone, and it’s only reliably available in prescription thyroid medication like levothyroxine or natural desiccated thyroid (NDT). Every cell, organ, tissue, and gland in your body requires thyroid hormone to function, and without it, you can even die.


Taking iron too close to thyroid medication

If you are taking a thyroid hormone replacement medication like levothyroxine, a common mistake is to take iron supplements too close to your medication. Unless you wait at least three or four hours after taking your thyroid medication, taking iron can interfere with your body’s ability to properly absorb your thyroid medication, making it less effective, and making you more hypothyroid. Keep in mind that this also applies to prenatal multivitamins, many of which contain iron.


Taking calcium too close to thyroid medication

If you are taking levothyroxine, be especially careful about calcium supplements, which can interfere with absorption of your medication. You should wait at least three or four hours after your thyroid medication before taking calcium supplements. The same rule goes for antacids like Tums, and calcium-fortified beverages like cow’s milk, orange juice, soy milk, and almond milk.


Taking a thyroid glandular supplement

There are dozens of supplements available online and in health food stores that are “thyroid glandulars.” These supplements claim to include actual thyroid glandular material from animals. The problem: You may not know which animals are being used in production. Experts caution against ingesting supplements that may be contaminated with brain matter — sometimes from cows — given the possible risk of prion-borne diseases.


Taking the wrong thyroid-support supplement

Research has shown that some supplements that are labeled as "thyroid support" illegally contain actual thyroid hormone as ingredients. The problem: There is no way to know which supplements contain the hormone, or if so, in what amounts. This means that if you are hypothyroid and taking a thyroid-support supplement along with your prescription thyroid hormone medication or antithyroid drug, you can be overmedicated into a hyperthyroid state, or become more hyperthyroid.


Taking too much iodine, kelp, or bladderwrack

Iodine is needed to produce thyroid hormone. Unfortunately, many health store clerks and uninformed practitioners recommend thyroid support supplements, iodine, kelp, or bladderwrack for everyone with a thyroid problem. This poses two problems:

  • If you’re hyperthyroid, iodine can make your condition worse.
  • If you have Hashimoto’s, iodine can worsen inflammation and make hypothyroidism worse.

Experts recommend that you supplement with iodine only if you have tests that show you are deficient.


Not taking iodine when it's needed

While too much iodine is a problem, too little is also a problem. Cutting salt and processed foods out of your diet increases your risk of iodine deficiency. If you are iodine deficient and still have a thyroid, you’re missing an ingredient you need to produce enough thyroid hormone. Consider having your iodine tested — the urinary iodine clearance test is considered most accurate — and supplement with iodine if you are deficient.


Taking a prenatal vitamin without iodine

Iodine is an essential nutrient before, during, and after pregnancy. It helps your thyroid meet the increased demands of pregnancy and breastfeeding. Like many women, you may take a prenatal vitamin and assume you are getting all the nutrients you need. Be careful. Many prenatal vitamins — including those available by prescription – do not include the recommended 150 mcg of iodine daily recommended by experts for women before, during, and after pregnancy.


Not getting enough selenium

The mineral selenium plays an important role in helping your body convert the storage hormone thyroxine (T4) into the active hormone triiodothyronine (T3), and in lowering autoimmune thyroid antibodies. Many of us don’t get enough selenium from our diet. (One of the only potent sources of dietary selenium is the little-known Brazil nut.) Consider supplementing with selenium, but not exceed 400 mcg from all sources (food and supplements) to avoid toxic side-effects at higher doses.


Taking too much carnitine

Carnitine, a supplement found in many weight-loss and energy formulations, can inhibit the activity of thyroid hormones, and worsen hypothyroidism. Read the labels on any weight-loss capsules, tablets, powders, or drinks, and consider avoiding any that contain l-carnitine and acetyl-l-carnitine as ingredients.


Not getting enough zinc

Zinc is an important mineral to help facilitate healthy thyroid function. It’s hard to get enough zinc from your diet, so zinc deficiency is common. Make sure your multivitamin includes zinc, or consider supplementing with zinc for optimal thyroid health.


Taking soy supplements

Supplement manufacturers tout soy as a remedy for everything from menopause to high cholesterol. The problem is that some soy supplements contain high concentrations of phytoestrogens. At higher doses, soy phytoestrogens act as endocrine disruptors and interfere with your body's proper use of thyroid hormone. While tofu, miso, or soy sauce aren’t likely to be problematic, regular use of high-potency soy supplements may negatively affect your thyroid function.