Written by Dr. Ilana Halperin, an endocrinologist and internist at Sunnybrook Health Sciences Centre.
Have you ever noticed that the "health" magazines in the grocery store checkout are filled with thyroid cures and fixes? I often tell my patients that the thyroid is the most-blamed gland in the body. While 0.5 to two per cent of women are affected by thyroid conditions, most people are experiencing fatigue and weight gain due to lack of exercise, depression and poor diet.
What does the thyroid do?
The thyroid is a butterfly-shaped gland in the front of the throat just below your Adam's apple. Its function is to take iodine that is found in foods and convert it to T4 and T3. Every cell in the body depends upon thyroid hormones for regulation of their metabolism. Primary hypothyroidism is caused when your thyroid gland does not make enough circulating thyroid hormone, called T4 (because it has 4 iodine molecules on it). T4 usually enters the cells and is converted to T3 (it loses an iodine). T3 helps regulate your body's metabolism.
It makes hormones that can influence the function of your heart, bones, brain, digestive system, skin, and reproductive system.
How do you know if your thyroid is functioning properly?
The very best test for thyroid function is a blood test called a thyroid stimulating hormone (TSH). TSH is a hormone released by the pituitary gland, the master hormone gland in the brain. When the pituitary gland senses that there is too little circulating T3 and T4, it releases more TSH to tell the thyroid gland to make more. When the pituitary gland senses there is too much circulating thyroid hormones, it reduces the amount of TSH it releases.
When you present to your doctor with symptoms of an over or underactive thyroid, TSH should be the first test. If it is normal you can rule out a thyroid problem with 95 per cent certainty. If it is abnormal then additional tests like freeT4 and freeT3 should be considered.
What are the symptoms of an underactive thyroid?
When your thyroid gland does not make enough T4 you may experience a variety of symptoms including fatigue, feeling cold (body and/or hands and feet), weight gain, dry hair and skin, constipation, menstrual irregularities, an enlarged thyroid gland, depression and forgetfulness. When hypothyroidism (under function) is severe the heart may not pump as well and heart failure can set in.
What are the symptoms of an overactive thyroid?
When your thyroid makes too much hormone you may feel hot and sweaty, feel your heart racing, have shaky hands, feel anxious, have difficulty sleeping, and you may lose weight. It's important to realize that this weight loss is not fat but muscle and bone. Severe hyperthyroidism (over function) can result in high fevers, heart failure and confusion.
What about a thyroid ultrasound?
Thyroid ultrasound is the best test for the thyroid structure, but it doesn't tell us anything about thyroid function. There is no need for a thyroid ultrasound, unless your doctor feels a lump or an abnormality in the neck when they examine you.
How are thyroid problems treated?
Thyroid problems are generally treated with medication, though some types of overactive thyroid can be treated with radioactive iodine or surgery. For hypothyroidism, the safest treatment is with synthetic T4. Although desiccated thyroid (mashed up thyroid from animal) and synthetic T3 are available, research has shown that these therapies can cause more fluctuations in your thyroid hormone levels with a worsening of your symptoms.
What about diet and supplements?
Canada is an iodine sufficient country, so for the majority of patients, there is no need to increase iodine intake to manage their thyroid conditions. There are many supplements marketed to support your thyroid. These supplements are poorly regulated and have not been studied. I generally recommend my patients spend more money on healthy diet and exercise than on supplements.
So if I am worried about my thyroid what should I do?
See your doctor and discuss your symptoms. A TSH is an appropriate screening test. If the TSH is normal, but you still have symptoms that you think are related to your thyroid, then explore alternative causes including poor sleep, lack of exercise, stress, nutrition and mental health concerns.
Read more women's heath information from Sunnybrook experts at health.sunnybrook.ca
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