The thyroid, a gland located in the lower front of the neck, is widely misunderstood despite its crucial role in human physiology. Shaped like a butterfly, this small gland produces hormones that orchestrate communication with every cell in the body. These hormones profoundly influence metabolism speed, impacting body weight significantly. Various health issues can arise from thyroid irregularities, but regular exercise and sufficient intake of vitamin A and zinc can enhance cellular responsiveness to these hormones.
Understanding Thyroid Disorders
Thyroid disorders affect millions of Americans and hundreds of millions worldwide. Two common issues involve hormone imbalances: hyperthyroidism, where the thyroid overproduces hormones, and hypothyroidism, where it underproduces them. Hypothyroidism, affecting up to 10 percent of the global population, will be the primary focus here.
Causes of Hypothyroidism
Iodine deficiency stands as the leading global cause of hypothyroidism, with an estimated one in three individuals worldwide lacking sufficient iodine intake. This deficiency often manifests in goiter (thyroid enlargement) or thyroid nodules. Research indicates iodine insufficiency affects over half of pregnant women in Norway and more than half of children and pregnant or breastfeeding women in Australia. In the United States, nearly one in five individuals may have moderate to severe iodine deficiency.
Autoimmune attacks on the thyroid, known as Hashimoto’s thyroiditis, represent the second major cause of hypothyroidism. Specific antibodies target the thyroid gland, impairing its ability to produce enough T4 thyroid hormone. Other factors contributing to inadequate thyroid function include stress, trauma, infections, pesticide exposure, fluoride, and celiac disease.
Diagnosis and Symptoms
Doctors typically diagnose hypothyroidism through elevated levels of TSH (thyroid-stimulating hormone) in blood tests. Optimal TSH levels range between 0.4 and 2.0 mIU/L, according to many integrative physicians. Symptoms of hypothyroidism can include fatigue, weight gain, depression, dry skin, constipation, hair loss, menstrual irregularities, and elevated cholesterol, among others.
Risk Factors and Prevention
Risk factors for thyroid dysfunction include being female, iodine deficiency, autoimmune conditions like Hashimoto’s thyroiditis, irritable bowel syndrome, non-celiac gluten sensitivity, and leaky gut syndrome. Preventive measures include ensuring adequate iodine intake, with recommended daily levels ranging from 150 µg for non-pregnant adults to 290 µg during lactation. Low iodine levels have been linked to learning difficulties in children.
Iodine-rich foods (per serving) include a variety of options:
- Navy beans (32 mcg)
- Codfish (99 mcg per 3 grams of fish)
- Eggs (24 mcg per egg)
- Iodized salt (71 mcg)
- Lobster (100 mcg)
- Milk (56 mcg)
- Pineapples (45 mcg)
- Potatoes (60 mcg)
- Prunes (13 mcg per 5 prunes)
- Seaweed (16 to 2900 mcg)
- Shrimp (35 mcg per 3 ounces)
- Strawberries (13 mcg)
- Turkey Breast (34 mcg)
- Yogurt (75 mcg)
Ensuring optimal gut health is paramount for thyroid well-being. Individuals with irritable bowel syndrome should prioritize repairing a leaky gut to facilitate proper absorption of vitamins and minerals. Research indicates that those sensitive to gluten face an elevated risk of thyroid disease. Moreover, maintaining a healthy digestive system and balanced microbiome is crucial for fostering an appropriate immune system response, thus aiding in the prevention of autoimmune-induced thyroid disorders. It's worth noting that approximately 80 percent of our immune system resides in our gut.
Conventional Treatment
While modern medicine has made significant strides, the recognition of goiter, denoting thyroid enlargement, dates back millennia. In 40 BC, Pliny, Vitruvius, and Juvenal of Rome described treating goiter with burnt seaweed, rich in iodine. Leonardo Da Vinci's sketches in 1500 AD marked the first depiction of the butterfly-shaped thyroid gland alongside detailed human anatomy. Thomas Warton coined the term "thyroid" in 1656, derived from the Greek word thureoeidēs, meaning shield. In 1820, Jean Francois Coindet of France pioneered goiter treatment using iodine.
In the late 1890s, desiccated thyroid formulas containing both T4 and T3 hormones were introduced to treat hypothyroidism. However, the trend shifted towards prescribing synthetic levothyroxine (T4 only), exemplified by the introduction of Synthroid in 1955. Presently, conventional medicine often adopts a wait-and-see approach for Hashimoto’s thyroiditis, intervening with thyroid medication once the gland's function diminishes. Integrative physicians may recommend addressing underlying leaky gut issues to manage Hashimoto’s.
Nutrition and Supplements for Thyroid Health
Research suggests that diets rich in fruits, vegetables, and seeds may reduce the risk of autoimmune thyroid diseases. These dietary choices also support gut microbiome health.
Key nutrients aiding thyroid hormone production include selenium, which serves as a cofactor for enzymes involved in hormone synthesis. Selenium supplementation may lower TPO antibodies during autoimmune attacks and facilitate the conversion of T4 to active T3 hormone. A suggested dose is 200 mcg daily.
Iodine
A deficiency in iodine is the primary cause of goiters, thyroid nodules, and hypothyroidism worldwide. It's recommended to maintain an iodine-rich diet (see above for food list). According to the World Health Organization (WHO), the preferred method for assessing iodine deficiency is through a random urine sample (preferably in the morning). A result below 100 mcg/L indicates deficiency by WHO standards. It's suggested to take a multivitamin and mineral supplement containing at least 150 mcg of iodine. Some individuals may opt for iodine supplements or kelp, but intake should not exceed 500 mcg daily to avoid exacerbating thyroid issues.
Iron
Iron deficiency is prevalent among menstruating women and can impair thyroid metabolism. A 2017 study in Thyroid recommended clinicians check iron levels and aim for a ferritin level of 50 to 75 ng/ml or higher. The suggested iron dose varies depending on individual needs and should be determined by a physician or as indicated on the label.
Vitamin D
Vitamin D deficiency affects 80% of people globally and is associated with increased risks of cancers and autoimmune diseases, including autoimmune thyroid disease. A 2018 study linked lower vitamin D levels to a heightened risk of Hashimoto’s thyroiditis. Daily supplementation of 1,000 IU to 5,000 IU is recommended.
Zinc
Inadequate zinc intake affects nearly 45% of Americans and over 15% of people worldwide, with significant prevalence in Sub-Saharan Africa and South Asia. Aging, poor dietary choices, and alcohol consumption can contribute to zinc deficiency, which is linked to thyroid disorders, skin and blood issues, and increased infection risk. Daily doses of 15 to 50 mg are recommended, often available in quality multivitamins.
In addition to the above nutrients, maintaining a balanced diet rich in tyrosine, vitamins B2, B3, B6, C, and E are essential for thyroid health. B-complex supplements can provide these B vitamins.
Summary
Optimal thyroid health requires a well-balanced diet and attention to gut microbiome health. Avoiding problematic foods and considering a quality probiotic can further support thyroid function. Balancing nutrition through diet and supplements is crucial, but any changes should be discussed with a healthcare provider, especially for those currently undergoing thyroid treatments.