The thyroid is a butterfly-shaped gland located just below the Adam’s apple. It is responsible for running the body’s metabolism. This means it affects how fast processes run inside every single cell.
The thyroid gland produces a hormone called thyroxine (T4). This is converted by an enzyme to the active form – tri-iodothyronine (T3), which is used by the body’s cells.
The amount of thyroid hormones produced each day is controlled by two other glands – the hypothalamus and pituitary. They constantly measure the amount of circulating thyroid hormones and tell the thyroid gland when to produce more using thyroid stimulating hormone (TSH).
If there is a break down in this monitoring system, or the thyroid is damaged or is there are insufficient raw materials to make thyroid hormones, or the T4 isn’t properly converted to T3, then thyroid dysfunction can occur.
Underproduction of thyroid hormones is called hypothyroidism. It results in a slowing of metabolism. This leads to symptoms such as:
- Weight gain
- Feeling cold
- Coarse, dry hair
- Dry, rough pale skin
- Hair loss
- Muscle aches
- Low mood or irritability
- Memory problems
- Abnormal menstrual cycles
- Decreased libido
Overproduction of thyroid hormones is called hyperthyroidism. This results in the metabolism going into overdrive, causing:
- Restlessness and agitation
- Weight loss despite an increased appetite
- Rapid heart rate
- Intolerance to heat
- Frequent bowel movements
Thyroid imbalances can be caused by a problem with the pituitary or hypothalamus, damage to the thyroid, nutritional deficiencies, or by the immune system attacking or accidentally stimulating the thyroid gland.
The thyroid tests carried out by GP usually only measure the levels of TSH and T4. This will indicate if there is a serious thyroid pathology but it doesn’t give any information about the cause of the problem. These tests also won’t pick up problems that occur as a result of T4 not being properly converted to T3.
The thyroid plus screen gives a much more complete analysis of thyroid function. It includes:
- TSH – This hormone comes from the pituitary to stimulate the thyroid gland into making more hormone. TSH rises when the thyroid is struggling.
- Total T4 – T4 lowers when the thyroid is struggling and goes up in hyperthyroidism.
- Free T4 – The unbound form of T4, this lowers when the thyroid is struggling and will be high if the thyroid has gone into overdrive.
- Free T3 – T3 is the active thyroid hormone used by the body’s cells. Low levels of T3 could indicate a problem with thyroid hormone conversion.
- Reverse T3 – This is a ‘non-active’ form of T3 that if produced in high amounts can stop the normal T3 from functioning correctly.
- Anti-thyroglobulin and Anti-thyroid peroxidase antibodies – These antibodies are present when the immune system is attacking and damaging the thyroid. High levels indicate an autoimmune cause of thyroid dysfunction.
A Thyroid Plus Screen is recommended for those who:
- Suffer with the symptoms of thyroid dysfunction
- Are struggling to lose weight
- Have been diagnosed with a thyroid problem but would like to investigate and address the root cause
- Present with all the symptoms of an underactive thyroid but GP blood tests have come back normal for TSH and Total T4.