Thyroid Autoimmune Disease

Autoimmune thyroid disease occurs when the immune system attacks its own thyroid cells. This may result in reducing or even destroying the thyroid. Factors that may contribute to endocrine disease of the thyroid include viral infection, underlying disease, autoimmunity, congenital factors, gender, ethnicity, dietary iodine intake, and environmental factors among others. Thyroid disorders are often treated with drug therapy, which often have serious side effects and do not necessarily treat the underlying condition leading to the thyroid dysfunction. In recent years there has been increased interest in herbs and supplements as individuals take more interest in their health and well being.

Caloric Restriction & Fasting

It has been established that nutrition and caloric restriction impact thyroid metabolism centrally and possibly peripherally. In the case of caloric restriction, T3 levels decrease and rT3 increase suggesting a modulation of hepatic 5′ -deiodinase activity. However, the effects of caloric restriction on thyroid hormone metabolism appear to reverse, returning to a normal balance, after three continuous weeks of dieting. Several factors may influence the response during caloric restriction including macronutrient content of the diet, genetics, weight and gender.

Fasting also impacts thyroid hormone metabolism possibly due to elevated cortisol levels. Studies suggest that the modulation may be due to influences on central as well as peripheral metabolism. Similar to the typical response to stress, fasting serum rT3 levels increase and T3 levels decrease compared to the non-fasting state. Prolonged periods of fasting or caloric deprivation result in a similar thyroid hormone profile.

Herbs & Dietary Supplements

Thyroid disorders are often treated with drug therapy. In the case of Hashimoto’s disease, the standard medical protocol is thyroid hormone replacement. For Graves’ disease, anti-thyroid drugs, operations to partially or fully remove the thyroid gland and use of radioactive iodine are standard recommendations of physicians. Due to potential side effects associated with many medications some people seek complementary and alternative therapies. Others may seek alternative therapies due to their cultural backgrounds. Some commonly used natural products for autoimmune thyroid disorders include rosmarinic acid, blue flag, guggul, selenium, iodide and vitamin D3 supplements.

Rosemarinic Acid

Based on in vivo research, rosmarinic acid is hypothesized to prevent TSH effects on receptor sites, block immunoglobulin effects on TSH receptors, and inhibit peripheral conversion of thyroxine to T3. These findings suggest that rosmarinic acid may be beneficial in Graves’ disease. Rosmarinic acid has been shown to be capable of inducing T cell apoptosis of only actively proliferating T cells, direct T cell activity, inhibit T cell activation and proliferation and modulate T cell promotion of pro-inflammatory cytokine release, suggesting potential application in autoimmune disorders.

Blue Flag (Iris Versicolor)

Adding adaptogenic herbs, like Blue Flag, is often helpful in the treatment of Hashimoto’s disease because they act as endocrine tonics that help mitigate autoimmune diseases. It is used as an alternative therapy due to its reported lymphatic anti-inflammatory effects, and has been used in liver and spleen enlargement (hepato-splenomegaly) and thyroid enlargement (thyromegaly).76 Although clinical research is lacking, blue flag has a long history of medicinal use for treatment of goiters and thyroid enlargement.

Guggul (Commiphora Mukul)

Guggul has demonstrated biological effects on thyroid homeostasis and lipid lowering properties. It has been shown to improve both thyroid function and structure in melatonin induced hypothyroidism in mice. Studies have identified a ketosteroid present in the oleo-resin of C. mukul (Z -guggulsterone) which has strong thyroid stimulatory activity. In vivo , administration of Z -guggulsterone increased iodine-uptake by the thyroid and increased activities of both thyroid peroxidase and protease. Guggulsterone also seems to increase T3 synthesis by increasing the conversion of T4 to T3 and significantly decrease hepatic lipid peroxidation. Since serum thyroxine (T4) is converted to T3 in the liver, researchers concluded that hormone levels and peroxidation are related. It is believed that Guggul’s effect on thyroid regulation is responsible for the therapeutic effects seen in cholesterol levels.

Selenium

Selenium, a constituent of selenoproteins, has been implicated in the autoimmune thyroiditis by increasing the duration and exacerbating disease severity. It is possible that this is due to reduced activity of the selenoprotein glutathione peroxidase leading to increases in hydrogen peroxide production. Iodothyronine selenodeiodinases D1 and D2, are another class of selenoproteins which produce active T3 through deiodination in peripheral tissues. During selenium supplementation serum selenium has been reported to increase by 45%, plasma glutathione peroxidase by 21% and TPO antibody decreased by 76%. On withdrawal of supplementation, a sharp decrease was seen in selenium and glutathione peroxidase accompanied by marked increase in TPO. Extracellular glutathione peroxidase is secreted by thyrocytes and primarily modulates hydrogen peroxidase and organification of iodine. Its secondary function is to prevent oxidation damage to the thyrocytes themselves.

Proper usage of iodine

Iodine is a crucial constituent of thyroid function and is a component of thyroxine and T3. It is well established that the highest prevalence of thyroid disorders is seen in populations where iodine deficiency is prevalent. Autoimmune hypothyroidism is not commonly seen in mild to moderate iodine deficiency. However, thyrogloblin antibody is more common in iodine deficiency, suggesting that thyroid globulin antibodies are generated in response to thyroid globulin release from an iodine deficient thyroid. Goiter is usually endemic in areas where daily iodine intake is <50 mg and congenital hypothyroidism is seen in areas where intake is <25 mg/day. Potassium iodide and T4 therapy are often used for treating thyroid disorders as they have been shown to inhibit and prevent the growth of benign thyroid nodules in 66% of patients. However, caution must be used when prescribing iodine in the presence of a hot nodule. Ingested iodide is organified to iodine and bound to thyroglobulin in the follicle by thyroid peroxidase and hydrogen peroxide. Premature organification of iodine in the follicular cell is prevented by glutathione peroxidase. Low levels of glutathione peroxidase in the thyroid tissue can lead to damage to the NIS. High doses of iodide can lead to an over saturation of the NIS and lead to iodothyronine suppression. Vitamin D

In individuals with Hashimoto’s disease, circulating vitamin D3 levels are low, similarly, vitamin D deficiency has been associated with other autoimmune conditions. Animal models have demonstrated that vitamin D3 supplementation has been shown to prevent the development of autoimmune conditions including autoimmune thyroiditis. Vitamin D plays a role in immunity, with low intake resulting in enhanced immune response and high intake resulting in suppression of the immune response. Vitamin D3 modulates T cell responses, inhibiting Th1 cell cytokines including IFN-g and IL-2. Th1 cell activation and production of cytokines is necessary for cell mediated immune responses, which, in autoimmune diseases is misdirected. Blood levels of vitamin D3 should be monitored when treating patients with vitamin D3 to ensure sufficiency is achieved (50–70 nM) and levels associated with hypercalciuria (250 nM) are not reached.