Thyroid Health by Clinicians Technical Info

The thyroid is a hormone-producing gland in your neck shaped like a butterfly (see picture). It is one of the largest glands in the body.

What is its job?

The thyroid gland is part of the endocrine system, whose primary function is to make hormones.  Hormones pass messages around the body to make specific things happen. So for the thyroid it regulates metabolic rate (how fast we burn up food), temperature, growth in children and affects how much calcium is in the bones and in the blood stream.  To make these hormones it needs the key ingredients of iodine and selenium.

What can go wrong?

Basically thyroid malfunction can cause the body to run too fast (Hyper) or too slow (Hypo).

The negative effects of low thyroid function on general health are remarkable. For those of you who are interested, the thyroid hormone is produced under the direction of the pituitary gland that lies in the brain. The pituitary gland produces thyroid stimulating hormone (TSH), instructing the thyroid gland to make thyroid hormone T4. With the help of the minerals zinc, copper and selenium, T4 is converted to the active thyroid hormone T3 in the body, where it is taken up into the cells, and used in the body’s numerous metabolic processes. Hypothyroidism may result from both a T4 and/or a T3 deficiency.

Hyperthyroidism – too fast

Some symptoms of Hyperthyroidism include; racing heart, trembling hands, being constantly much hotter than everyone else, anxiety, thinning hair, hyperactive, difficulty sleeping.

These symptoms can also be created by having too much iodine.  This is why we are urging caution as everyone has gone iodine crazy with the current radiation fears from Japan.  You can have too much of a good thing!

Hypothyroidism – too slow

Some symptoms of Hypothyroidism include: weight gain, always cold, depression, hair loss, thinning outer eyebrows, puffy eyes, hands and feet, memory problems, lack of energy.

This is common in New Zealand as the soils are deficient in iodine and selenium; the basic ingredients required to make thyroid hormones.  It tends to be more common in women and can be hereditary.

Causes of Hypothyroidism

• Iodine Deficiency - historically, the cause of hypothyroidism was an iodine deficiency. The thyroid gland adds the trace mineral iodine to the amino acid tyrosine to create the thyroid hormones. This deficiency of iodine may lead to an enlarged thyroid gland or goiter. The incidence of goiter has decreased with the addition of iodine to table salt.

• Autoimmune Disease - autoimmune disorders such as Hashimoto’s disease are a cause of more severe forms of hypothyroidism. Here, the body’s immune system produces antibodies that block the action of thyroid hormones. Iodine is an essential nutrient for the production of the body’s thyroid hormones and is therefore required for normal thyroid function. The thyroid hormones are responsible for our basal metabolic rate (BMR) that reflects the body’s use of energy. The thyroid hormones are also needed for normal growth and development, protein synthesis, cholesterol synthesis, carbohydrate absorption, energy metabolism, nerve and bone formation, reproduction, the condition of the skin, hair, nails and teeth, and our speech and mental state

• Research shows that iodine may be effective in the prevention of fibrocystic breast disease (mildly uncomfortable, to severe painful swelling of the breasts). In 1924, in an effort to decrease the high incidence of iodine deficiency, iodine was added to table salt, a substance that was already in wide use. The most well-known manifestation of chronic, long-term iodine deficiency is goiter, an enlargement of the thyroid gland. This condition develops when the thyroid gland does not have enough iodine to manufacture thyroid hormones. As the gland increases its cell size to try and capture more iodine, its overall size increases, creating the characteristic goiter swelling in the neck.
• Suboptimal iodine intake is still considered to be a major problem in parts of the New Zealand population. Iodine deficiency is also thought to increase the risk of certain cancers, such as those of the breast, ovary and uterus. Iodine levels may also be low in people with fibrocystic breast problems.
• Metabolic - hypothyroidism leads to a general decrease in the rate at which fat, protein and carbohydrates are utilised. Weight gain and sensitivity to cold weather (experienced as cold hands and cold feet) is common. Cholesterol and triglyceride levels are increased in mild forms of hypothyroidism and studies have shown that individuals with hypothyroidism have an increased risk of cardiovascular disease. Lymphatic drainage also becomes impaired resulting in tissue swelling or oedema. Hypothyroidism can also cause hypertension.
• Hormonal - the most common hormonal symptom is lack of libido in men and menstrual abnormalities in women. Women with mild hypothyroidism have prolonged heavy menstrual bleeding with a shorter menstrual cycle. Infertility may be a problem as is an increased risk of miscarriages, premature births and stillbirths.
• Psychological - depression, along with weakness, fatigue and anxiety, are usually the first signs of hypothyroidism. This may later include difficulty in concentrating and extreme forgetfulness. Other signs - skin may be rough and dry while the hair may be coarse, dry and brittle. Hair loss can be quite severe while nails become thin, brittle and typically show transverse grooves. Muscle weakness and joint stiffness and sometimes muscle and joint pain and tenderness may be present.

Testing for Hypothyroidism

• Blood Tests - traditionally, testing for thyroid function involves testing for levels of T4 and Thyroid Stimulating Hormone (TSH). Using this blood test, it is estimated that 1- 4% of the adult population have moderate to severe hypothyroidism , while 10 -12% have mild hypothyroidism. However, these blood tests do not include T3 levels and therefore a large number of hypothyroid patients go undetected. People with a mild state or “sub-clinical hypothyroidism” will not be picked up in a routine blood test.
• Temperature Testing - a better way of assessing thyroid function is to measure its effect on the body. This is done by measuring an individual’s basal temperature when the body is at rest. This test, developed by Broda Barnes, is a good way of testing basal metabolic rate and thus the body’s response to the thyroid hormones regardless of their blood levels.

Dietary Recommendations

Dietary intake of some foods should be reduced in cases of hypothyroidism. These “goitrogen” foods reduce thyroid function by blocking iodine utilisation and include the brassica vegetables (turnips, cabbage,cauliflower, broccoli), cassava root, soybeans, peanuts, pine nuts and millet. These foods should be cooked before being eaten.