Dr. Ayşe Betül Bilen, Assistant Professor at the Department of Nutrition and Dietetics, Faculty of Health Sciences, Istanbul Atlas University, provided an assessment on the importance of nutrition in hypothyroidism. Dr. Bilen gave the following information:
Hypothyroidism is more common in women.
“Hypothyroidism is a common endocrine disorder characterized by insufficient production of thyroid hormones. Current data indicate that the prevalence of hypothyroidism in the general population ranges from approximately 3,8–4,6 percent. It is known that hypothyroidism is more common in women than in men and tends to increase with age.”
In addition to clinical hypothyroidism, subclinical hypothyroidism, characterized by elevated TSH but normal T4 levels, is also quite common, with a prevalence ranging from 3–20 percent.
There is no specific diet plan for hypothyroidism.
Hypothyroidism management often focuses on pharmacological treatment, but nutritional approaches are an important complement to this process. However, the key point to emphasize here is that there is no single 'special diet' model for hypothyroidism. Current scientific literature clearly shows that nutrition in hypothyroidism is not a treatment method; rather, it is a tool that influences the course of the disease, can alleviate symptoms, and supports treatment effectiveness. Therefore, the main goal of the nutritional approach is not to directly replace thyroid hormones, but to ensure micronutrient balance, reduce accompanying metabolic risks, control the inflammatory burden, and maintain the effectiveness of drug therapy.
The Mediterranean Diet contributes to the management of inflammation and metabolic disorders.
In this context, the Mediterranean diet stands out as the most rational nutritional model. Rich in olive oil, vegetables, fruits, whole grains, fish, and antioxidant components, this model has been shown to make significant contributions to the management of low-grade inflammation and metabolic disorders, particularly those accompanying hypothyroidism, thanks to its anti-inflammatory and immunomodulatory effects. Therefore, rather than strict restrictive diets, a sustainable and balanced nutritional model should be adopted in patients with hypothyroidism.”
Goitrogenic foods should not be consumed in excessive amounts or raw.
Drawing attention to the goitrogenic effects of some nutrients, Assistant Professor Ayşe Betül Bilen stated the following:
“Goitrogenic foods are foods that contain components that can affect thyroid hormone synthesis steps and, in particular, impair iodine utilization. These foods primarily include cruciferous vegetables (broccoli, cauliflower, cabbage), soy products, and some types of millet. However, the clinically significant point is that when these foods are consumed in normal amounts and cooked, they generally do not cause a significant adverse effect in healthy individuals or in hypothyroid patients with adequate iodine intake.”
The goitrogenic effect becomes more pronounced in cases of excessive consumption, raw consumption, and iodine deficiency. Furthermore, cooking largely inactivates these compounds. Therefore, in patients with hypothyroidism, it is recommended that these foods be consumed cooked, in a balanced and controlled manner, rather than being completely restricted.
Beware of Iodine Excess!
Adequate and balanced iodine intake is crucial in hypothyroidism. Micronutrients are one of the most critical components of nutritional management in hypothyroidism. Iodine is an essential element for thyroid hormone synthesis, and its deficiency is one of the most important causes of hypothyroidism. However, an important point often overlooked in clinical practice is that excess iodine can also suppress thyroid function. It is known that chronically high iodine intake, in particular, can lead to temporary or permanent suppression of thyroid hormone synthesis. Therefore, the approach should not be "the more iodine, the better," but rather ensuring adequate and balanced iodine intake.
Uncontrolled supplementation should be avoided.
Similarly, selenium is involved in the conversion of thyroid hormones to their active form and plays an important role in the antioxidant defense system. However, there is no strong and consistent evidence to support routinely recommending selenium supplementation in all patients. While other micronutrients such as vitamin D, iron, zinc, and B12 have also been associated with thyroid function, the fundamental approach for these nutrients is not uncontrolled supplementation, but rather the identification of deficiencies and targeted replacement therapy. It should be noted that iron deficiency, in particular, can negatively affect the clinical picture by reducing the activity of the enzyme involved in thyroid hormone synthesis.
Thyroid-Gut Axis Interaction is Important
Another issue that has gained increasing importance in recent years is the relationship between gut microbiota and thyroid function. This interaction, defined as the "thyroid-gut axis," is not limited solely to nutrient absorption. A healthy microbiota supports the absorption of critical micronutrients such as iodine, selenium, and iron, as well as playing a role in the conversion of thyroxine (T4) to its active form, triiodothyronine (T3). Conversely, disruption of microbiota balance can negatively affect thyroid function by leading to increased intestinal permeability, systemic inflammation, and activation of the immune system. Therefore, maintaining gut health should be considered an important goal in the management of hypothyroidism.
Thyroid medications should be taken on an empty stomach.
"One of the most practical and clinically critical components of nutritional management in hypothyroidism is the correct application of medication. Drug absorption can be affected by many factors, including coffee, high-fiber foods, and calcium and iron supplements. Therefore, it is generally recommended that the medication be taken on an empty stomach and that sufficient time be allowed between doses and certain foods. Especially if iron and calcium supplements are being taken, leaving at least a 4-hour gap between doses is important for the effectiveness of the medication," he said.
A personalized nutrition plan should be implemented.
Dr. Ayşe Betül Bilen concluded her remarks as follows: “In conclusion, the nutritional approach in hypothyroidism should not be based on monotonous diets or random supplement use; rather, it should be based on an individualized, balanced, and scientifically grounded approach. Identifying and correcting micronutrient deficiencies, supporting gut health, and properly managing drug-food interactions are key elements that increase the effectiveness of hypothyroidism treatment.”
