Conditions Centre

Hypothyroidism

Hypothyroidism refers to the low or under functioning of the thyroid gland, resulting in the deficiency of thyroid hormones being produced. This gland is located in the front of the neck, and is the hormones produced are active in the control of metabolism and growth in virtually every cell of the body, so a deficiency can affect all body functions. 

When the thyroid gland is working properly, it uses the amino acid tyrosine and iodine to make the thyroid hormone called thyroxine or T4. The other important thyroid hormone is triiodothyronine or T3. T3 is actually the major active thyroid hormone, being much more active than T4. T4 is produced within the thyroid gland and is later converted to the active T3 outside the thyroid gland in peripheral tissues. 

The thyroid secretes its hormones in response to a thyroid-stimulating hormone (TSH) which is produced from the pituitary gland in the brain. At times when the thyroid hormones are low, the pituitary will secrete more stimulating hormone, but for some reason the thyroid gland does not respond. This is called primary hypothyroidism, and accounts for approximately 20% of females and 5% of males with in the population with thyroid disease. When both pituitary and thyroid hormones are low, it is termed secondary hypothyroidism. 

Iodine is needed by the thyroid gland to produce its hormones, and iodine deficiency can lead to hypothyroidism and to the development of an enlarged thyroid gland, commonly known as goiter. Goiters can develop in response to the stimulation from the pituitary gland hormone TSH, and the thyroid gland grows in response. In this situation the cells of the gland enlarge but the activity is not increased because of lack of iodine. 

Some foods can interfere with thyroid function. These are called goitrogens because excess ingestion may contribute to an imbalance of thyroid function and promote goiter formation. Foods in the cabbage family such as cabbage, turnips, Swede’s, Brussels sprouts, broccoli, and cauliflower, soy bean foods, maize, sweet potatoes, lima beans, soy, and pearl millet are all considered goitrogens because they contain chemicals that interfere with thyroid function or the utilization of iodine. 

Hashimoto's thyroiditis (also called chronic lymphocytic thyroiditis) is an autoimmune condition of the thyroid gland where white blood cells infiltrate the gland itself and cause glandular destruction. It is the most common cause of hypothyroidism in the United States. 

A form of congenital hypothyroidism can occur, called cretinism. The term cretinism was originally applied to infants in areas of low iodide intake and goiter, and these children have developmental delays and mental retardation. Testing for congenital hypothyroidism should happen at birth. Babies born to women with Hashimoto’s thyroiditis have an increased risk of cretinism. 

The toxins PCB and PBB have adverse effects on the thyroid, but it is not known how important a contributor it is to the incidence of thyroid disease in the general population. Preliminary studies have found an association between multiple chemical sensitivities and hypothyroidism. One study found a correlation between high blood levels of lead, a toxic heavy metal, and low thyroid hormone levels in people working in a brass foundry. Many of these people also complained of depression, fatigue, constipation, and poor memory (symptoms of hypothyroidism). Occupational exposure to polybrominated biphenyls and carbon disulfide has also been associated with decreased thyroid function.

A very excessive intake of iodine, often from sea vegetables, has been associated with higher incidence of thyroid diseases, including hypothyroidism and thyroid cancer. Excessive iodine intake can result in either hypothyroidism or hyperthyroidism (overactive thyroid). Sources of iodine include foods (iodized salt, milk, water, seaweed, ground beef), dietary supplements (multiple vitamin-mineral formulas, seaweed extracts), drugs (potassium iodide, amiodarone, topical antiseptics), and iodine-containing solutions used in certain laboratory tests. 

Symptoms

The clinical picture of hypothyroidism can range from minor irritating symptoms to the severe and life threatening. Skin changes are almost always seen, dry skin being the most common. Myxedema is also considered a skin sign; it is a particular kind of edema that can occur in the face with puffy eyelids and an enlarged tongue. It also appears on the hands and feet. There may be bruising due to poor healing and poor skin tone. Frequently a thinning of the eyebrows occurs. The face will be pale, and the voice may be hoarse. Gastrointestinal symptoms are common, especially constipation. Myxedema can also affect the heart and nervous system. The heart becomes enlarged and the nervous system may show a general slowing of the mental process, which can develop into depression or agitation and is term ‘myxedema madness’. 

Hashimoto’s thyroiditis has a slightly different clinical picture, in that initially the symptoms may appear to be related to over activity of the thyroid gland. There may be a painless enlargement of the thyroid, but it may shrink later in the course of the condition. Hashimoto’s disease is also associated with joint pain, pernicious anemia and other forms of autoimmune diseases such as rheumatoid arthritis.

Lifestyle and Dietary Modifications expandexpand

foods. Soy foods and products are used in many processed food, so avoidance of all processed foods containing soybean oil is advised. A whole food diet that emphasizes lower calories from fat and carbohydrate and good fiber and protein sources will help metabolism and encourage good thyroid function. 

Exercise is beneficial to increase metabolism for those with low thyroid. Not only will it promote weight loss, it will also decrease stress. Coritsol, a hormone that is produced in high stress situations, reduces thyroid hormones. 

Alcohol intake and conditions associated with high alcohol consumption such as liver cirrhosis can decrease the body’s ability to convert the thyroid hormones in the active form.

Nutritional Factors Shown to be Beneficial expandexpand

Zinc

Zinc may be involved in the thyroid hormones, and deficiency is common in people with hypothyroidism.
Dose: 15-50 mg a day

Vitamin A

People with hypothyroidism have been shown to have an impaired ability to convert beta-carotene to vitamin A.
Dose: 5,000–10,000 IU per day

Bladderwrack (Fucus vesiculosus)

Fucus is a type of brown seaweed that contains variable amounts of iodine. Hypothyroidism due to insufficient intake of iodine may possibly improve with bladderwrack supplementation, though human studies have not confirmed this.
Dose: 1-2 grams a day

Guggul (Commiphora mukul)

Guggul, which is shown to normalize thyroid function and increase weight loss by enhancing metabolism, also helps to promote the healthy metabolism of lipids
Dose: 25 mg of guggalsterones, usually about 300 mg of guggal three times a day

Coleus forskohii

Forskolin may thyroid hormone secretion. It should be avoided in people with ulcers, because it may increase stomach acid levels.
Dose: 50–100 mg twice to three times a day

Rhodiola rosea

Rhodiola which has a mild stimulant action, regulates brain functions, and enhances the functions of the thyroid gland, adrenals, and ovaries.
Dose: 300-600 a day

Ashwagandha (Withania somnifera)

Ashwagandha root extract stimulates thyroidal activity.
Dose: 3-6 grams of root extract, 300-500 mg of extract standardized to withanosides

Diagnosis and Pharmaceutical Interventions expandexpand

Diagnosis by conventional medical practitioners is made almost exclusively from blood tests. Generally, T4 and TSH are measured in the bloodstream. Additionally, a protein that binds T4 is also measured. From this protein and T4, the free T4 is calculated. A high TSH and low T4 indicate primary hypothyroidism; in secondary hypothyroidism the levels of TSH and T4 will be low. At times the levels of TSH and T4 will be normal or only slightly depressed; this may be diagnosed as ‘euthyroid sick syndrome’, ‘low T3 syndrome’ or Wilson’s hypothyroidism’. These conditions reflect the inability of the body to convert T4 to T3. Although the blood levels of the hormones are normal, the conversion is dampened by physical factors, some of which are aging, stress, liver disease, chronic alcohol intake, toxic metal exposure, severe or systemic illness and surgery. These factors can cause the body temperature to be lower than normal, and the enzyme needed for conversion is inactivated. 

The taking of a basal body temperature can be considered by some to be indicative of hypothyroidism. A lowered temperature can indicate the decreased activity of thyroid hormones, and the decreased conversion of T4 to T3. 

Hashimoto’s thyroiditis testing is similar to the testing for hypothyroidism but also includes testing for autoantibodies. 

Western Medications

Thyroxine is a synthetic version of T4 and is the most common pharmaceutical for the treatment of hypothyroidism worldwide. The dose used should be minimal, but for many it requires a long term usage, for some even life-long. Taking thyroxine with food may decrease its absorption. Thyroxine absorption is increased when taken on an empty stomach. High-fiber diets have been shown to decrease thyroxine absorption. Thyroid hormones should be taken an hour before eating, at the same time very day. The major toxic reactions to levothyroxine overdosage are symptoms of hyperthyroidism—particularly cardiac symptoms—and, in postmenopausal women, osteoporosis. 

Desiccated thyroid, also called thyroid extract (e.g., Armour Thyroid), is used by some doctors as an alternative to synthetic thyroid hormones (such as thyroxine [Synthroid® or other brand names]) for people with hypothyroidism. Thyroid extract contains two biologically active hormones (thyroxine and triiodothyronine), whereas the most commonly prescribed thyroid-hormone preparations contain only thyroxine. One study has shown that the combination of the two hormones contained in desiccated thyroid is more effective than thyroxine alone for those with hypothyroidism. Some doctors report that thyroid extract works better than standard thyroid preparations for many of their patients with hypothyroidism. Glandular thyroid products, which are available from health food stores, have had most of the thyroid hormone removed and would therefore not be expected to be effective for people with hypothyroidism. Intact desiccated thyroid is available only by prescription. Hypothyroidism sufferers who want to use desiccated thyroid must first consult with a physician.