Close-up of a woman's hands taking a piece of chocolate from a plate
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There are several foods that you should avoid if you have low thyroid or hypothyroidism. While chocolate does not directly affect the function of the thyroid gland, it may contain ingredients that worsen low thyroid or hinder the absorption of medication. Check with your nutritionist before eating low-fat and low-sugar chocolate -- in moderation -- as part of your weekly balanced diet.

Interactions With Iodine

Iodine is an essential mineral that is important for thyroid hormone production. Some foods such as cabbage, broccoli, cauliflower and other cruciferous vegetables can block the use of iodine, worsening a low thyroid condition. The Linus Pauling Institute notes that compounds in soybeans can also lead to low iodine uptake. Hence, if you are unsure if your chocolate contains soy milk or soy products, it is best to avoid it.

Reactions With Thyroid Medications

If you have low thyroid, your doctor has likely prescribed medication to help replace your thyroid hormones. According to Drugs.com, thyroid medications such as levothyroxine can adversely interact with certain foods and should be taken on an empty stomach for best results. While chocolate is not on the list of foods to avoid, it may contain ingredients such as soy milk and walnuts that do interfere with the absorption of levothyroxine.