Hypothyroidism can be a tricky condition to manage, and what you eat can interfere with your treatment. Some nutrients heavily influence the function of the thyroid gland, and certain foods can inhibit your body’s ability to absorb the replacement hormones you may take as part of your thyroid treatment.
Is your diet working against your thyroid gland? Find out which foods interfere with healthy thyroid function and how to minimize your risk.
- Soy: The hormone estrogen can interfere with your body’s ability to use thyroid hormone, says Stephanie Lee, MD, PhD associate chief of endocrinology, nutrition, and diabetes at Boston Medical Center and an associate professor at the Boston University School of Medicine. Soy is loaded with plant-based phytoestrogen, and some researchers believe too much soy may increase a person’s risk for hypothyroidism. People with hypothyroidism should moderate their intake of soy.
- Cruciferous Vegetables: Cruciferous vegetables can interfere with the production of thyroid hormone, particularly people who have an iodine deficiency. They block the thyroid’s ability to absorb iodine, which is essential for normal thyroid function. People with hypothyroidism should limit their intake of broccoli, Brussels sprouts, cabbage, cauliflower, kale, turnips, and bok choy to less than 4 ounces a day.
- Gluten: People with hypothyroidism may want to consider minimizing their intake of gluten, a protein found in foods processed from wheat, barley, rye, and other grains, says Ruth Frechman, RDN, a dietitian and nutritionist in the Los Angeles area and a spokesperson for the Academy of Nutrition and Dietetics. Gluten can irritate the small intestine and may hamper absorption of thyroid hormone replacement medication.
- Fatty Foods: Fats have been found to disrupt the body’s ability to absorb thyroid hormone replacement medicines, Dr. Lee says. Fats may also interfere with the thyroid’s ability to produce hormone as well. Some health care professionals recommend that you cut out all fried foods and reduce your intake of fats from sources such as butter, mayonnaise, margarine, and fatty cuts of meat.
- Sugary Foods: Hypothyroidism can cause the body’s metabolism to slow down, Frechman says. That means it’s easy to put on pounds if you aren’t careful. “You want to avoid the foods with excess amounts of sugar because it’s a lot of calories with no nutrients,” she says. It’s best to reduce the amount of sugar you eat or try to eliminate it completely from your diet.
- Processed Foods: “Processed foods tend to have a lot of sodium, and people with hypothyroidism should avoid sodium,” Frechman says. Having an underactive thyroid increases a person’s risk for high blood pressure, and too much sodium further increases this risk. Read the Nutrition Facts label on the packaging of processed foods to find options lowest in sodium.
- Coffee: Caffeine has been found to block absorption of thyroid hormone replacement, Lee says. “People who were taking their thyroid medication with their morning coffee had uncontrollable thyroid levels, and we couldn’t figure it out,” she says. “I now have to be very careful to tell people, ‘Only take your medication with water.'” You should wait at least 30 minutes after taking your medication before having a cup of joe.
- Alcohol: Alcohol consumption can wreak havoc on both thyroid hormone levels in the body and the ability of the thyroid to produce hormone. Alcohol appears to have a toxic effect on the thyroid gland and suppresses the ability of the body to use thyroid hormone. Ideally, people with hypothyroidism should cut out alcohol completely or drink in careful moderation.