Hypothyroidism occurs when levels of the two thyroid hormones, triiodothyronine (T3) and thyroxine (T4), are too low. Although changing your diet alone isn’t enough to restore normal thyroid hormone levels, avoiding some foods and eating more of others can help improve your body’s absorption of the hormones.

Foods to Avoid

Many common foods and supplements contain compounds that interfere with thyroid functions. In general, it’s best to avoid the following foods and supplements:

  • Soy: Studies suggest that phytoestrogens in soybeans and soy-rich foods may inhibit the activity of an enzyme that makes the thyroid hormones. One study found that women who consumed soy supplements were three times more likely to develop hypothyroidism.
  • Iodine-rich foods: Some forms of hypothyroidism are caused by a lack of sufficient iodine. In such cases, using iodized salt or iodine-enriched foods can be beneficial. But eating too much iodine can have the opposite effect and suppress thyroid gland activity. Check with your doctor before taking supplements.
  • Iron and calcium supplements: Taking iron or calcium supplements can also change the effectiveness of many thyroid medications.
  • High-fiber foods: Although a high-fiber diet is usually recommended, too much fiber may interfere with the absorption of thyroid medicines.
  • Certain vegetables: Cruciferous vegetables that are rich in fiber like broccoli, cabbage, spinach, kale, and Brussels sprouts can inhibit thyroid drug absorption. Reducing the amounts of such produce in your diet may help.

Caffeine, tobacco, and alcohol can also influence the effectiveness of thyroid medicine. Ask your doctor for tips on how to regulate or reduce your consumption.

Foods to Eat

Nutrient-rich foods that improve your health may also benefit your thyroid gland, including:

  • Antioxidant-rich fruits and vegetables: Blueberries, tomatoes, bell peppers, and other foods rich in antioxidants can improve overall health and benefit the thyroid gland. Eating foods high in B vitamins, like whole grains, may also help.
  • Selenium: Tiny amounts of selenium are needed for enzymes that make thyroid hormones to work properly. Eating selenium-rich foods, such as sunflower seeds or Brazil nuts, can be beneficial.
  • Tyrosine: This amino acid is used by the thyroid gland to produce T3 and T4. Taking a supplement may help, but ask your doctor beforehand.

Diet Plans and Herbal Supplements

Hypothyroidism doesn’t prevent or limit you from following a certain health lifestyle. People with hypothyroidism can choose to be vegetarian, eat protein-rich foods, or avoid allergy-causing ingredients.

You may also decide to use alternative medicines. Some plant extracts, like ashwagandha (Withania somnifera), coleus (Coleus forskohlii), gotu kola (Centella asiatica), and guggul (Commiphora mukul) have been suggested to benefit some symptoms of hypothyroidism. But evidence to support these claims are limited. Always speak with your doctor before making any big changes to your eating habits or before taking any supplements.