Response

Tofu, made from soybeans, contains isoflavone compounds like genistein and daidzein. Isoflavones can affect the activity of enzymes involved in thyroid hormone production. This leads many to worry that consuming tofu might cause hypothyroidism or worsen existing thyroid conditions.

However, there is currently no conclusive evidence that individuals with normal thyroid function or those with thyroid disease need to completely avoid tofu and soy foods. Patients with hypothyroidism, Hashimoto's thyroiditis, hyperthyroidism, or thyroid nodules should not arbitrarily remove tofu from their diet. Tofu remains a valuable source of plant-based protein and can be part of a diverse, balanced diet.

Tofu provides plant-based protein for people with thyroid disease. Photo: Duy Anh

Tofu provides plant-based protein for people with thyroid disease. Photo: Duy Anh

Nevertheless, doctors often advise caution for individuals taking levothyroxine, an active ingredient that supplements thyroid hormones after surgery or for hypothyroidism treatment, regarding a soy-rich diet. This is because soy and soy protein can reduce the absorption of thyroid hormone medication if taken concurrently or too close to the time of medication. If a meal contains soy, patients should take their medication at least 4 hours apart from eating to minimize any impact on drug absorption.

Some thyroid cancer patients prescribed radioactive iodine (I-131) therapy must follow a low-iodine diet before treatment. This aims to reduce iodine levels in the body and enhance the thyroid cells' ability to absorb radioactive iodine. During this stage, patients may be advised to avoid or limit soy products, including tofu.

Each thyroid condition has distinct causes and treatment methods. Therefore, you do not necessarily need to avoid tofu, soy milk, or other soy products. Instead, you should consult your doctor for personalized dietary and lifestyle advice.

Master. Doctor Pham Thi Hong

Department of Endocrinology and Diabetes

Tam Anh General Hospital Hanoi