Triiodothyronine (T3, Free)

Changes in triiodothyronine levels in the body can affect health and wellbeing. The thyroid gland can become underactive and overactive causing increases or decreases in hormone secretion into the blood.

An overactive thyroid happens if the thyroid gland produces too many hormones or underactive thyroid is where the thyroid gland doesn’t produce enough hormones. The imbalance in these hormones can both cause several symptoms.

If you are worried about your thyroid function or just want to check where you fall on the range, you can test your triiodothyronine level with a simple at-home blood test.

Thyroid dysfunction is often caused by an autoimmune condition and although it may require medical intervention, lifestyle changes can help to restore its function. Changes to diet and lifestyle can help to control the symptoms of an over or underactive thyroid.

Although iodine is essential for the function of the thyroid gland, too much or too little can have negative effects. [6] Adults need 150 micrograms of iodine per day, most of which should be able to be obtained through eating a healthy, balanced diet. Individuals who are already taking thyroid medication like levothyroxine for an underactive thyroid, then you should not need to supplement your diet with iodine. [7]

Individuals with a thyroid condition are susceptible to vitamin B12 deficiency. It is particularly prevalent in hypothyroidism possibly because of their nutritional status. Plus, autoimmune thyroid disease is associated with autoimmune disorders such as pernicious anaemia which can lead to vitamin B12 malabsorption. [8] Therefore, an adequate intake of B vitamins is essential. Vegans and vegetarians are also susceptible to deficiency because vitamin B12 is found in animal products. Although some foods are fortified with the vitamin, susceptible groups may need supplementation. Good sources of vitamin B12 are:

• liver
• beef
• haddock
• tuna
• salmon
• trout
• eggs
• milk
• cheese
• fortified breakfast cereals [9]

Physical exercise has great effects on energy metabolism by increasing energy expenditure as well as increasing the body’s resting metabolic rate for hours following exercise. Some research has shown that exercise performed at 70% of maximum heart rate increases the level of T3 and FT4. [10]

However, some studies contradict this and state exercise doesn’t have any major effect on circulating levels of thyroid hormones. Yet, exercise has other beneficial advantages for weight loss, psychological symptoms like depression and anxiety, all of which can affect individuals with a thyroid issue.