For many patients with a thyroid problem , weight control is one of the most difficult complications, although it often represents an important warning sign. On the one hand, we find hyperthyroidism , a condition characterized by excessive production of thyroid hormones (thyroxine – T4 and triiodothyronine – T3 ), which can have serious consequences on metabolism , leading to sudden weight loss related to the severity of the overactive thyroid.
On the other hand, an underactive thyroid ( hypothyroidism ), which causes the normal production of thyroid hormones to be reduced , is generally associated with some weight gain , mainly due to excessive accumulation of salt and water.
Dr. Ieva Gailyte Grassano , endocrinologist and diabetologist at the Humanitas Medical Care clinics in Lainate and Arese, talks to us about it .
How does thyroid hormone regulate metabolism?
Thyroid hormone regulates metabolism through several mechanisms:
- By increasing oxygen consumption (they stimulate the production of enzymes involved in energy production in cells)
- Regulating protein synthesis (influence protein synthesis, increasing the production of proteins, which are essential for the maintenance and growth of tissues)
- Regulating carbohydrate and lipid metabolism (they can influence insulin sensitivity, increasing glucose uptake by cells, as well as promoting the use of lipids as an energy source)
- Stimulating thermogenesis (they can increase heat production in the body through thermogenesis, contributing to increased metabolism)
- Influencing the central nervous system, mood, attention, and stress response .
What are the symptoms of hyperthyroidism?
The symptoms that can appear in case of hyperthyroidism are different and include:
- weight loss and increased appetite
- tachycardia, arrhythmias , or palpitations
- anxiety, nervousness and irritability
- tremors and intense sweating
- menstrual irregularities
- erectile dysfunction
- heat intolerance
- intestinal disorders ( diarrhea )
- tiredness and muscle weakness
- sleep disorders
- thinning skin and brittle hair.
What causes hyperthyroidism?
Among the most common are Graves’ disease (an autoimmune disease that tends to occur mainly in young women), thyroid nodules ( toxic adenoma and toxic multinodular goiter, also known as Plummer’s disease), and thyroiditis (inflammation that leads to the release of hormone stored in the thyroid into the blood).
However, taking certain drugs (interferon, amiodarone) can also lead to hyperthyroidism.
What are the symptoms of hypothyroidism?
Symptoms vary depending on the age at which the disease begins, its duration, and its severity. Among the most common, in addition to weight gain, are:
- muscle weakness and excessive tiredness
- cold intolerance
- difficulty concentrating
- facial swelling and dry skin.
- constipation
- slowing of the heartbeat
- irregular menstrual cycle
- depressive tendencies (due to the lack of thyroid hormones it can also have an influence on mood ).
The weight lost during hyperthyroidism can be regained when the disease is treated.
What causes hypothyroidism?
The causes of hypothyroidism can be congenital , therefore present from birth, or acquired , that is, caused by other conditions (autoimmune thyroiditis; therapies with radioactive iodine or particular drugs; surgical removal of the thyroid).
How much weight should you expect to gain once hypothyroidism is treated?
As in the treatment of hyperthyroidism, treating the abnormal state of hypothyroidism with thyroid hormone results in a return of body weight to what it was before the development of hypothyroidism.
How are hyperthyroidism and hypothyroidism diagnosed?
Diagnosis involves an evaluation of the patient’s clinical history and physical condition and the measurement of circulating levels of FT3, FT4, TSH (the hormone that regulates the secretion of thyroid hormones) and anti-thyroid antibodies (TRAb, Ab-TPO, Ab-Tg).
Finally, it may also be necessary to proceed with thyroid scintigraphy and ultrasound study of the thyroid .
