Hypothyroidism occurs when the thyroid gland produces too little thyroid hormone, when there is decreased conversion from T4 to T3, when there is an overproduction of reverse T3 (Wilson's syndrome), or when the body is not efficiently using thyroid hormone. It can take several forms.

• In Hashimoto's thyroiditis, the most common type, the gland shrinks and loses its function.
• Post-therapeutic hypothyroidism may follow overzealous treatment for hyperthyroidism (excess production of thyroid hormone). Medical and surgical treatments for hyperthyroidism can leave patients' thyroids incapable of producing enough thyroid hormone.
• Goitrous hypothyroidism results from an extreme shortage of iodine in the diet. Almost unknown in the United States since the introduction of iodized salt, it produces a goiter in the neck.

Other types of hypothyroidism can stem from inherited enzymatic deficiencies or the failure of other glands in the body. According to some estimates, as many as 11 million Americans suffer some degree of hypothyroidism. However, the majority of those cases go undiagnosed.

Hypothyroidism can occur in either sex at any age, although middle-aged women are most commonly affected. Note that infants, adolescents, and adults show different sets of symptoms. The disease has a wide variety of symptoms, and they often reveal themselves slowly and subtly. Untreated, hypothyroidism can cause anemia, a low body temperature, heart failure and, ultimately, a condition known as myxedema coma. This type of coma, triggered by exposure to cold, infection, or drugs such as sedatives, is potentially fatal. It leads to a slowdown in breathing, seizures, and a reduction in the flow of blood to the brain. Myxedema coma is extremely rare in warm climates, but not uncommon in cold regions.

• In Hashimoto's thyroiditis, often called primary hypothyroidism, an autoimmune response occurs in which antibodies in the blood destroy tissues in the thyroid gland. As a result, the thyroid decreases in size and reduces its production of thyroid hormones.
• Post-therapeutic hypothyroidism results from the treatment of hyperthyroidism with radioactive iodine or surgical removal of part or all of the thyroid gland. The treatment can leave the patient's thyroid unable to produce sufficient amounts of thyroid hormone.
• Goitrous hypothyroidism is caused by a lack of iodine in the diet, a problem in some developing countries. (The thyroid requires a steady supply of iodine to operate correctly.)

• Treatment for hyperthyroidism
• Chronic lack of iodine in the diet
• Inherited enzymatic defects
• For women, reaching middle age

• Slow pulse
• Lethargy
• Hoarse voice
• Slowed speech
• Puffy face
• Loss of eyebrows from the sides
• Drooping eyelids
• Intolerance to cold
• Weight gain
• Constipation
• Dry, scaly, thick, coarse hair
• Raised, thickened skin over the shins
• Carpal tunnel syndrome
• Confusion
• Depression
• In children, growth retardation, delayed teething, and mental deficiency
• Dementia
• Headaches
• Menstrual cramps or other menstrual disorders

• Euthyroid sick syndrome
• Depression
• Alzheimer's disease or other types of dementia
• Carpal tunnel syndrome

Patients typically report muscle aches and the inability to stay warm in cool or cold temperatures. Tests of reflexes indicate brisk contraction and slow relaxation times. As symptoms progress, patients show puffy faces, dry, thickened skin, hoarseness, and hearing loss. The palms and soles have slightly orange hues, evidence of carotene deposits. The heart is enlarged.

Blood tests may show decreased levels of thyroid hormone, increased thyroid-stimulating hormone, and the presence of autoantibodies, differentiating between primary and secondary hypothyroidism. Patients with primary hypothyroidism, for example, will not respond to radioactive iodine uptake tests, while most of those with secondary hypothyroidism will show a brisk response. Blood tests can also indicate the presence of anemia, a symptom of untreated hypothyroidism.Hypercholesterolemia may be found with hypothyroidism.

When necessary, perform two radioactive iodine uptake tests four days apart.

Providers can prescribe several thyroid hormones as replacement therapy. Typically, condition improves within two to three weeks of the start of daily hormone therapy, and all symptoms disappear within a few months. However, patients must continue this treatment for the rest of their lives.

Health care providers must initially choose between synthetic preparations of the human thyroid hormone and dried forms of animal thyroid hormone. Providers generally prefer synthetic versions of thyroxine, liothyronine, or combinations of the two. They typically prescribe 100 to 125 mcg of the medication daily, to be taken orally. Evidence suggests that patients absorb about 90% to 95% of the dose.

Key to effective treatment is calibration of the medication. Particularly in older patients, treatment should start with small doses of thyroid hormone. Providers then gradually increase the dose until the individual's blood level of thyroid-stimulating hormone returns to normal. With appropriate calibration of doses, the patient will reach this stage about eight weeks after the start of daily therapy.

Specialists recommend that providers not prescribe liothyronine alone over long periods. It tends to cause chemical hyperthyroidism for at least several hours per day, thereby exposing the patient to above normal cardiac risks. Since myxedema coma represents an emergency situation, providers should administer replacement hormones intravenously.

Thyroid function can be effectively supported with nutrition and herbs, although concurrent treatment with conventional medicine may be necessary in moderate to severe cases.

Avoid foods that suppress thyroid function, including broccoli, cabbage, brussels sprouts, cauliflower, kale, spinach, turnips, soybeans, peanuts, linseed, pine nuts, millet, cassava, and mustard greens. Avoid refined foods, dairy products, wheat, caffeine, and alcohol.

• Essential fatty acids (1,000 to 1,500 mg bid) are necessary for hormone production. It may be wise to avoid flaxseed oil due to high levels of cyanogenic glycosides. A better choice for omega-3 oils for the hypothyroid patient would be cold-water fish oils or borage oil.
• Vitamin C (1,000 mg tid to qid), vitamin A (10,000 to 25,000 IU/day), B complex (50 to 100 mg/day), augmented with vitamins B2 (riboflavin, 15 mg), B3 (niacin, 25 to 50 mg), and B6 (pyridoxine, 25 to 50 mg), selenium (200 mcg/day), iodine (300 mcg/day), vitamin E (400 IU/day), and zinc (30 mg/day) are necessary for thyroid hormone production.
• L-tyrosine (500 mg bid to tid) also supports normal thyroid function. In a small percentage of patients it may cause caffeine-like symptoms. Patients with insomnia should avoid taking L-tyrosine in the evening. (May rarely exacerbate hypertension.)
• Calcium (1,000 mg/day) and magnesium (200 to 600 mg/day) are cofactors for many metabolic processes.

Herbs are generally a safe way to strengthen and tone the body's systems. Ascertain a diagnosis before pursuing treatment. Herbs may be used as dried extracts (capsules, powders, teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, teas should be made with 1 tsp. herb per cup of hot water. Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for roots. Drink 2 to 4 cups/day.

A combination that would support thyroid function includes herbs rich in minerals. Combine equal parts of the following herbs for a tea (3 to 4 cups/day) or tincture (20 to 30 drops tid). Horsetail (Equisetum arvense), oatstraw (Avena sativa), alfalfa (Medicago sativa), and gotu kola (Centella asiatica).

Seaweeds such as kelp (Laminaria hyperborea), bladderwrack (Fucus vesiculosus), Irish moss (Chondrus crispus) may be taken as foods or in capsule form due to their salty and unfamiliar taste. Many patients would not tolerate the seaweed taste in a tea beverage.

Coleus foreskohlii (1 to 2 ml tid) stimulates thyroid function with an increase in thyroid hormone production. Also, herbs such as guggul (Commiphora mikul, 25 mg of guggulsterones tid) and hawthorn (Crataegus monogyna, 500 mg bid) are taken to counteract hypercholesterolemia which often attends hypothyroidism.

For patients that do not want to take whole tissue glandulars, homeopathic glandulars are available for hypothyroidism.

Contrast hydrotherapy to the neck and throat may stimulate thyroid function. Alternating hot and cold applications brings nutrients to the site and diffuses metabolic waste from inflammation. The overall effect is decreased inflammation, pain relief, and enhanced healing. Alternate three minutes hot with one minute cold. Repeat three times to complete one set. Do two to three sets/day.

Exercise helps sensitize thyroid gland to hormones and improves its function. Stress reduction techniques such as yoga, meditation, or tai chi help to lower cortisol levels. High cortisol levels may decrease T3/reverse T3 ratios.

Acupuncture may be helpful in correcting hormonal imbalances and addressing underlying deficiencies involved in hypothyroidism.

Therapeutic massage may be useful in relieving stress, improving circulation, and increasing the overall sense of well-being.

Monitor patients carefully during and after any treatment.

A diet using small amounts of iodized salt may help prevent goitrous hypothyroidism.

Watch out for brief swings into hyperthyroidism with certain treatments.

Expect to see beneficial effects of hormone replacement therapy within two to three weeks of starting the course of treatment. Symptoms should disappear within a few months, by which time patients will have settled into a maintenance dose of hormone.

Thyroid testing during pregnancy may have variable and unreliable results. Mild pathology may not be detected until after pregnancy. Thyroid treatment in pregnancy should be done with the supervision of a physician.

Bartram T. Encyclopedia of Herbal Medicine. Dorset, England: Grace Publishers; 1995:304.

Berkow R. Merck Manual. 16th ed. Whitehorse Station, NJ: The Merck Publishing Group; 1992.

Murray MT, Pizzorno JE. Encyclopedia of Natural Medicine. 2nd ed. Rocklin, Calif: Prima Publishing; 1998:386-390.