The thyroid gland and its functions have been compared to the conductor of the orchestra of the human body. If something goes wrong with our thyroids, practically every other system and function in the body will be out of kilter. Considering that 27 million Americans are estimated to suffer from thyroid-related disorders, then it is evident that thyroid problems are extremely common and that they play a complex role in health and disease (Mahan et al, 2011).
The thyroid is a small gland situated just below the Adam’s apple. Patients with goitre, will know that the thyroid is capable of enlarging alarmingly to the point where swallowing becomes a problem.
This small gland produces two hormones, namely thyroxine (T4- which contains 4 molecules of iodine) and triiodothyronine (T3- which contains 3 molecules of iodine and is the most active form of thyroid hormone in the body). These hormones are responsible for the following functions:
- Regulation of carbohydrate and fat metabolism
- Regulation of body temperature
- Regulation of heart rate
Thyroid-stimulating hormone (TSH) which is produced by the pituitary gland stimulates the thyroid gland to produce T4 and T3 from tyrosine (an amino acid) and iodine (a trace mineral).
Although thyroid malfunction, particularly hypothyroidism (underproduction of thyroid hormones), has been known and described since the times of Hippocrates in Ancient Greece, it is only more recently that researchers have identified that up to 50% of the cases of underactive thyroid function are due to an autoimmune disorder called Hashimoto’s thyroiditis. In such patients, the autoimmune system of the body attacks and destroys thyroid tissue thus decreasing the thyroid’s capacity to produce sufficient thyroid hormones to meet the needs of metabolism and health.
Typical symptoms of Hashimoto’s thyroiditis:
- Lack of energy and exhaustion
- Cold hands and feet
- Increased blood cholesterol levels
- Muscle pains
- Forgetfulness and lack of mental acuity
The disadvantaged sex
It is unfortunate that women are 5 to 8 times more prone than men to develop hypothyroidism. In addition, many women tend to develop hypothyroidism after one or more pregnancies.
Links with other diseases
a) Coeliac disease
There are indications that patients who suffer from coeliac disease (gluten intolerance), may be more prone to developing hypothyroidism and that the use of a gluten-free diet will not only improve the symptoms of the coeliac disease, but in some cases rectify thyroid function. So if you suffer from gluten intolerance or coeliac disease and have also been diagnosed with hypothyroidism, then it is important to apply a gluten-free diet as strictly as possible with the assistance of registered dietitian and to monitor if your thyroid function is improving with the gluten-free diet.
b) Schmidt’s syndrome
This syndrome refers to hypothyroidism combined with other derangements of the endocrine system such as Addison’s disease (insufficiency of the adrenal glands), underactive parathyroid gland and diabetes, which can also all be due to autoimmune malfunctions.
The thyroid gland is capable of overproduction of thyroid hormones (hyperthyroidism) and as mentioned above, underproduction of thyroid hormones (hypothyroidism).
Both conditions are characterised by a variety of symptoms that can be used as warning signals if you suspect that you are suffering from thyroid malfunction.
Typical symptoms of Hypothyroidism (underactive thyroid):
- Fatigue and weight gain
- Forgetfulness and loss of mental acuity
- Depression and mood swings
- Very heavy menstruation
- Dry, coarse hair and a hoarse voice
Typical symptoms of Hyperthyroidism (overactive thyroid):
- Intolerance to heat, excessive sweating
- Weight loss
- Changes in appetite
- Frequent bowel motions
- Changes in vision
- Fatigue and muscle weakness
- Menstrual disturbances and infertility
- Mental and sleep disturbances
- Tremor - trembling hands
- Thyroid enlargement
Factors that can trigger thyroid malfunction:
The following factors have been identified as triggers that can lead to low thyroid function:
a) Adrenal stress and oxidative stress
According to Mahan and coworkers (2011), so-called ‘adrenal fatigue’ is often associated with hypothyroidism. In our modern world where stresses of all types are the norm, rather than the exception, it is not surprising that our bodies eventually stop trying to adapt to stress and succumb to adrenal fatigue. Once chronic adrenal fatigue sets in, it has a negative influence on signalling between the pituitary and the thyroid gland, it hampers thyroid hormones from doing their job and the conversion of T4 to active T3 hormones, it can cause thyroid hormone resistance and weakens the body’s immune function, all of which can trigger Hashimoto’s thyroiditis.
To achieve healthy ageing, it is necessary to maintain healthy thyroid function throughout life - something that is easier said than done. Hypothyroidism is know to increase with age and up to 17% of women over the age of 60 years, suffer from an underactive thyroid.
As mentioned above, many women develop hypothyroidism during or after pregnancy. In the USA 1 in 50 women is diagnosed with hypothyroidism during pregnancy and up to 25% of women develop permanent hypothyroidism after pregnancy.
1) Medical drug therapy
From a medical point of view, hypothyroidism which is caused by autoimmune disease, or treatment with radioactive iodine, congenital defects and/or surgical removal of thyroid tissue, is treated with thyroid hormone supplementation. Your medical doctor or endocrinologist will prescribe products such as Eltroxin, Diotroxin or Euthyrox at specific doses to treat your hypothyroidism.
2) Dietary factors
The most important nutrients involved with thyroid hormone production are iodine and selenium. However, other deficiencies of micronutrients such as iron, vitamin A and zinc, may also affect how iodine is incorporated into the thyroid hormones.
In South Africa, table salt has been iodated for decades as a measure to prevent iodine-deficiency goitre and cretinism in children. In view of this fortification programme, it is not generally necessary for patients to take other iodine supplements (e.g. kelp, etc). In fact, if patients suffering from autoimmune Hashimoto’s hypothyroidism take iodine supplements, this can worsen their condition leading to flare-ups of antibody production.
Selenium is used by the human body as a cofactor for the enzyme 5'-deiodinase which is involved in the production of T3 hormone. Recent studies suggest that supplementation with selenium may help in Hashimoto’s and Grave’s disease. However, excessive intakes of selenium can suppress the enzyme and should be avoided. At present, the safe level of selenium intake is believed to be 500 microgram of selenium per day or less. This is an example where a small amount of a nutrient, such as selenium, has highly beneficial effects, whereas excessive intakes of selenium may be detrimental. More is not necessarily better when it comes to selenium supplementation in hypothyroidism.
Patients suffering from coeliac disease and hypothyroidism may find that adherence to a strict gluten-free diet not only improves their symptoms of gluten intolerance, but also restores their thyroid hormone production.
3) Weight loss
In most cases, the medical treatment of hypothyroidism with thyroid hormone replacement therapy should assist with weight loss. Patients who do not react to a moderately energy restricted diet and an increase in physical activity to boost energy expenditure, should consult a registered dietitian for additional dietary support.
- (January 2012)
(References: Mahan LK et al (2011). Krause’s Food & the Nutrition Care Process. Ed. 13. Elsevier, USA.)
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