Selenium and the thyroid gland

The thyroid gland is found at the front of the neck, below the Adam’s apple. This butterfly-shaped gland secretes thyroid hormones that control our metabolic rate and protein synthesis.

The metabolic rate is the speed at which the body converts food into energy. We also refer to this as metabolism. Our metabolic rate is vital for a number of biological functions. It influences our body weight, body temperature, tissue growth (skin, hair, nails etc.) and a multitude of other things.

Many people suffer from slow metabolism (an underactive thyroid gland) without being aware of it. This may result in symptoms such as

  • fatigue
  • cold sensitivity
  • weight gain
  • poor concentration
  • saggy and dry skin
  • swelling of the throat and face.


Conversely, an overactive thyroid gland typically causes symptoms like

  • nervousness, anxiety and irritability
  • mood swings
  • sleeping problems
  • weakness and persistent tiredness
  • heat sensitivity (excessive body heat)
  • irregular and/or unusually fast heart rate (heart palpitations)
  • weight loss
  • trembling or twitching


Selenium’s role in metabolism

Selenium contributes to normal functioning of the thyroid gland and is therefore important for maintaining a normal metabolic rate. The thyroid gland produces two thyroid hormones, T3 (with three iodine atoms) and T4 (with four iodine atoms). T3 is much more actively involved in cellular metabolism than T4. Studies show that selenium regulates several enzymes that control the activity of these hormones. One of these enzymes, deiodinase, activates T4

by removing an iodine atom, thereby converting T4 to T3. If levels of T3 are too low, the metabolism slows down. On the other hand, with too much T3, the metabolic rate increases. Selenium’s role is to help the thyroid gland carry out its functions.

Therefore, making sure to get adequate amounts of selenium is essential for normal thyroid function and normal metabolism.