Overview: Hypothyroidism

• Hypothyroidism is the insufficient synthesis of thyroid hormone, necessary for metabolic processes throughout the body.

• Worldwide, iodine deficiency is the most common cause of primary hypothyroidism, the most common type of hypothyroidism.

• In iodine-sufficient countries, autoimmune destruction of the gland (Hashimoto disease) is the leading cause of primary hypothyroidism.

• The second leading cause of primary hypothyroidism is iatrogenic, including surgery, radioactive iodide, medications (i.e., lithium, amiodarone), overconsumption of goitrogens, and external-beam radiation.

• Primary hypothyroidism accounts for approximately 95% of cases compared with less than 5% from secondary and tertiary types. Secondary hypothyroidism results from decreased thyroid- stimulating hormone (TSH) secretion from pituitary tumors (adenomas most commonly), pituitary surgery, or other pituitary disease, such as Sheehan syndrome.

• Hypothalamic or tertiary hypothyroidism results in decreased thyrotropin-releasing hormone secretion related to infiltrative processes such as sarcoidosis, infection, or congenital defect.

• Transient hypothyroidism may occur after abrupt withdrawal of long-term thyroid hormone therapy or from silent or subacute thyroiditis.

Important Points to Consider

• Serum triiodothyronine (T3) is generally not used to confirm the diagnosis of hypothyroidism. It may be useful for guiding thyroid hormone dose titration in patients taking a combination of thyroxine (T4) and T3 medication.

• Reduce chronic stress from physical, emotional, nutritional, and environmental sources that
  can promote an overactive immune system, particularly in patients with positive antithyroid antibodies.

• Provide nutrients that are needed for adequate thyroxine (T4) manufacture, proper T4 to triiodothyronine (T3) conversion, and optimal T3 binding activity to intracellular receptors.

• Exercise and follow a heart-healthy nutrition program to increase energy and maintain weight (or at least stop gaining weight).

• Use appropriate testing, monitoring, and medications as needed to treat hypothyroidism.

• Steaming or cooking Brassica vegetables and soy briefly may help reduce their goitrogenic effect while preserving their nutrient content.

• Iodine: Too much or too little can cause hypothyroidism; too much can also cause hyperthyroidism.

• Soy, calcium, and iron supplements should be consumed at least 2 to 3 hours separately from thyroid medication because they may interfere with their bioavailability.

  • Thyroid medication is typically most effective when taken on an empty stomach in the morning, at least 30 minutes before eating breakfast for maximum absorption.

  
  

The 24-hour unprovoked urine iodine test is the standard test for checking iodine status.

Prevention Prescription

• Consume a diet with adequate amounts of iodine, selenium, iron, vitamin A, and zinc.

• Do not consume excessive amounts of iodine for long periods of time.

• Avoid substances that block thyroid hormone synthesis, such as chlorine, bromine, perchlorate, and certain medications, as well as radiation to the head and neck area when possible.

Integrative Therapeutic Review

Exercise

• Maintain a regular aerobic and weight-bearing exercise routine.

Nutrition

• Eat a heart-healthy, antiinflammatory diet to maintain proper body weight and reduce cardiovascular risk.

• Limit goitrogenic foods and avoid substances that interfere with thyroid activity.

• Limit vegetables from the Brassica family (cabbage, turnips, Brussels sprouts, rutabagas, broccoli, cauliflower, bok choy), millet, peaches, peanuts, pine nuts, strawberries, spinach, and cassava root. Cook vegetables briefly to reduce goitrogenic substances and consume at least 2 to 3 hours separately from thyroid medication.  

• Avoid the following medications and toxins, if possible: lithium, thionamides, amiodarone, interferon-alpha, interleukin-2, cholestyramine, perchlorate, expectorants, aluminum hydroxide, raloxifene, heavy metals, chlorine, fluoride, and bromine.

• Avoid topical antiseptics (Betadine) and radiocontrast dyes when possible.

Supplements

• Vitamins and minerals (preferably consumed in food)

  • Iodine*: 150 to 1100 mcg/day

  • Iron: 8 to 45 mg/day

  • Selenium: 55 to 400 mcg/day

  • Vitamin A†: 2300 to 10,000 units/day

  • Zinc: 8 to 40 mg/day

    
    

Botanicals

• Seaweed: Total iodine content should not exceed 1100 mcg/day for the general population unless on targeted megadose therapy. See Table 33-2 for assistance in determining allowable grams per day, depending on the variety of seaweed.

• Guggulu: Consider using it in the context of an Ayurvedic treatment regimen and not as an isolated treatment for hypothyroidism or hyperlipidemia. Take care to avoid heavy metal toxicity in certain Asian formulations.

  
  

Pharmaceuticals

• Levothyroxine alone (T4): gold standard of therapy

• Synthetic combination T4 plus T3: considered if T4 alone fails to control symptoms adequately; may use compounded formulations

• Desiccated porcine thyroid: considered if synthetic T4 plus T3 fails to control symptoms adequately or based on patient preference or physician experience

Traditional Chinese Medicine

• Qi and yang tonics include codonopsis, astragalus, epimedium, curculigo, cinnamon bark, and cuscata. A traditional Chinese medicine practitioner with a strong background and certification in Chinese herbalism should prescribe these combinations.

Mind-Body Therapy

• Advise yoga therapy with an emphasis on thyroid-enhancing poses such as the shoulder stand (Sarvāngāsana) if the patient has no contraindications.

• Yoga practice may be helpful even without challenging poses such as the shoulder stand, for the purposes of stress reduction, meditation, enhanced flexibility, and strength.

*Consider testing for iodine deficiency. Use Lugol solution or Iodoral tablet for documented deficiency for a limited time when the patient is unable to increase iodine through diet or is unable to reduce exposure to iodine-depleting medications or substances.

†Most people in the United States receive an adequate supply of preformed vitamin A (retinol) in milk, liver, margarine, and fortified cereals. Beta-carotene from plants is an excellent source of vitamin A.

Key Web Sources

• MedlinePlus information on thyroid diseases. http://www.nlm.nih.gov/medlineplus/thyroiddiseases.html.

• American Thyroid Association. http://www.thyroid.org.

• About.com information on thyroid disease. http://www.thyroid. about.com

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