What is Hypothyroidism
Hypothyroidism (Underactive Thyroid) refers to the common pathological condition of thyroid hormone deficiency. If untreated, it can lead to serious adverse health effects and ultimately death.The thyroid controls how your body's cells use energy from food, a process called metabolism.
Hypothyroidism can be classified as:
Primary (due to thyroid hormone deficiency)
Secondary (due to TSH deficiency)
Tertiary (due to thyrotropin-releasing hormone deficiency)
Peripheral (extra-thyroidal; panel)
Primary hypothyroidism:
Iodine is an essential component of thyroid hormone. Iodine deficiency can result in goitre, thyroid nodules, and hypothyroidism
Iodine-containing drugs (eg, amiodarone) can restrict thyroid hormone production through iodine overload, immediately blocking thyroid hormone synthesis
About 14% of patients treated with amiodarone develop hypothyroidism
Central hypothyroidism:
Biochemically, central hypothyroidism is defined by low or low-to-normal TSH concentrations and a disproportionately low concentration of free thyroxine
Peripheral hypothyroidism:
Consumptive hypothyroidism is caused by aberrant expression of the deiodinase 3 enzyme (which inactivates thyroid hormone) in tumour tissues. Very rare.
Because of the large variation in clinical presentation and general absence of symptom specificity, the definition of hypothyroidism is pre-dominantly biochemicalBiochemically
Overt or clinical primary hypothyroidism is defined as thyroid-stimulating hormone (TSH) concentrations above the reference range and free thyroxine concentrations below the reference range.
Mild or subclinical hypothyroidism, which is commonly regarded as a sign of early thyroid failure, is defined by TSH concentrations above the reference range and free thyroxine concentrations within the normal range.
Common Symptoms of hypothyroidism in adults
Fatigue
Lethargy
Cold intolerance
Weight gain
Constipation
Change in voice
Dry skin
The clinical presentation can include a wide variety of symptoms that differ with age, sex, and time between onset and diagnosis
Standard Treatment
Thyroid hormone replacement with levothyroxine (for patients with hypothyroidism).
Hypothyroidism in children and pregnant women are considered separate topics
Heritability
The heritability of TSH and free thyroxine concentrations in serum is estimated to be 65% and 23–65%, respectively
In iodine-sufficient areas, the most common cause of hypothyroidism is chronic autoimmune thyroiditis (also known as Hashimoto’s disease)
Factors implicated in autoimmune thyroiditis:
Vitamin D and selenium deficiency
Moderate alcohol intake
Smoking (incidence of autoimmune thyroiditis increases after smoking cessation)
15% of patients with autoimmune hypothyroidism are asymptomatic or report only one hypothyroidism-associated symptom, whereas 70% of euthyroid controls have one or more thyroid- associated complaints.The thyroid uses iodine, a mineral in some foods, to make thyroid hormones. However, if you have Hashimoto’s disease or other types of autoimmune thyroid disorders, you may be sensitive to harmful side effects from iodine. Eating foods that have large amounts of iodine—such as kelp, dulse, or other kinds of seaweed, and certain iodine-rich medicines—may cause hypothyroidism or make it worse. Taking iodine supplements can have the same effect.
Hashimoto (HT) is an autoimmune disease in which destruction of the thyroid occurs as a result of lymphocyte infiltration.
Nutritional tips to balance diet in Hashimoto’s Disease
Regular consumption of 4–5 meals daily which provide nutrients, the deficits of which are observed in patients:
vitamin D: fatty fish, fish oil, sun-dried mushrooms, Agaricus (and solar bath), chicken eggs;
B group vitamins: meat, fish, chicken eggs, wholegrain cereal products;
vitamin A: kale, carrot, pumpkin, liver, spinach, egg yolk, butter, dried apricot;
vitamin C: (although not a rich source, it raises the level in blood), black currant, kiwi, strawberry, orange, mango, lemon, melon, kale, spinach, tomatoes, peppers (especially red peppers); vegetables and fruit are basically the main sources;
vitamin E: avocado, fish oil, whole-grain cereal products, vegetable oils;
magnesium: cocoa and bitter chocolate, pumpkin seeds, avocado, nuts, whole grain cereal products, some fatty fish (salmon) and green vegetables, yogurt, kefir;
zinc: cocoa and bitter chocolate, meat, kefir, yogurt, pumpkin seeds, nuts, spinach, mushrooms, whole-grain cereals;
iron: meat, animal offal, cocoa and bitter chocolate, spinach, sardines, seafood, pumpkin seeds;
iodine: iodized salt, fish (cod, tuna) and seafood as well as seaweed, iodized milk and dairy products, if elimination is not required, chicken eggs, plum, especially dried plums, maize;
selenium: Brazilian walnut, fish (sardines, halibut, salmon, tuna), meat, spinach, liver.
Adjusting the energy value to the individual needs of the patient, as the caloric restriction or low-fat diet may affect the thyroid function
Preferable sources of fats are: olive oil, avocado oil, avocado, rapeseed oil, walnut oil or walnuts, oily fish and seafood.
Increasing the supply of protein from the recommended 10–15% total dietary energy intake to 15–20% or even 25%, recommended total dietary energy intake. Oily fish, chicken eggs from organic farming and organic cow meat is good sources of both protein, iodine, iron, zinc and omega-3 acids.
Providing carbohydrates from whole grains; characterized by a higher nutritional density and dietary fibre.
Increasing the intake of soluble fibre supports intestinal microbiota and can improve defecation and bowel function, which is a common problem in hypothyroidism. Plantbased food, such as cocoa, fruit and vegetables, as well as whole-grain cereal products, are good sources of fibre.
Taking care of nourishing the microbiota by eating vegetables and fruit, dietary fibre and silage products.
Limiting the consumption of processed products, including sweets, chilled beverages and other sources of sucrose or simple sugars.
Eliminating gluten is not recommended if coeliac disease or other forms of gluten intolerance are not present.
Adopting a diet that eliminates food allergens when food allergy is diagnosed.
References:
Chaker, L., Bianco, A. C., Jonklaas, J., & Peeters, R. P. (2017). Hypothyroidism. Lancet (London, England), 390(10101), 1550–1562. https://doi.org/10.1016/S0140-6736(17)30703-1
National Institute of Diabetes and Digestive and kidney diseases https://www.niddk.nih.gov/health-information/endocrine-diseases/hashimotos-disease?fbclid=IwAR2P7vfwgGXwBVPiJ-e7zjXq1p72aG4v12eTNGUJKsiNct4btY_tXfyu16k#diet
Ihnatowicz, P., Drywień, M., Wątor, P., & Wojsiat, J. (2020). The importance of nutritional factors and dietary management of Hashimoto's thyroiditis. Annals of agricultural and environmental medicine : AAEM, 27(2), 184–193. https://doi.org/10.26444/aaem/112331