Thyroid health is crucial in the intricate relationship between the endocrine system and the ageing process, particularly through its impact on metabolic regulation. This involves the conversion of food into energy, mediated by the thyroid hormones thyroxine (T4) and triiodothyronine (T3). There was a prevailing belief that the signs of ageing are similar to the symptoms of hypothyroidism, suggesting that lowered thyroid function could be a hallmark of getting older.
In older adults, thyroid disorders are prevalent, yet their symptoms can significantly differ from those seen in younger people, often being subtler and masked by other illnesses. This makes interpreting thyroid function tests in the elderly particularly complex, as it becomes challenging to separate normal age-related changes from those arising from acute or chronic nonthyroidal illnesses and the effects of medications frequently prescribed to older patients. Additionally, treating thyroid diseases in older patients requires special medical attention due to the higher risk of complications. Several controversies are still unresolved on "when" and "how" to treat. To support thyroid health, supplementation with nutrients such as iodine, zinc, selenium, and spermidine can be beneficial.
Age-Related Changes of the Thyroid Gland
The functional core of the thyroid gland is the thyroid follicle- made up of follicular cells surrounding intrafollicular colloids. The follicles' size and the epithelium's height change with the gland's activity level. With ageing, the thyroid's weight may decrease, stay the same, or increase. Age-related changes include more fibrosis (thickening or scarring) between follicles, smaller follicle size, and degenerated cells with lymphocytic infiltration. Ageing leads to structural and functional alterations in the thyroid, reducing its ability to maintain balance. In older adults, especially those over 60, the thyroid often experiences fibrosis and atrophy, decreasing its volume. (J. Lee et al., 2016; Mariotti et al., 1995)
Hypothyroidism becomes more prevalent with age due to various changes that suggest a decline in thyroid function in older individuals. Additionally, certain biochemical abnormalities associated with ageing, such as an increase in serum total and low-density lipoprotein (LDL) cholesterol, suggest that reduced thyroid function might contribute to the ageing process.
In elderly people, there's a consistent reduction in iodine thyroid uptake. Radioisotopic studies reveal age-related decreases in T4 distribution, increased T4 half-life, and reduced thyroid hormone production. Serum-free T4 remains stable, but total and free T3 decline with age. Recent research suggests that, despite a complex array of changes in various functional aspects, normal ageing is associated with essentially normal thyroid function. However, in older people, thyroid activity is often complicated by the higher occurrence of primary hypothyroidism and concurrent nonthyroidal illnesses. (J. Lee et al., 2016; Mariotti et al., 1995)
Common Thyroid Disorders in Elderly Patients
As individuals age, the dynamics of their health undergo significant changes, and the thyroid gland is not immune to this process. Thyroid disorders become increasingly relevant in the context of elderly patients, presenting unique challenges and considerations.
Hyperthyroidism
Hyperthyroidism, aka overactive thyroid, occurs when the thyroid gland produces an excess of thyroid hormones. It is more prevalent in women and individuals aged 60 and above. In older adults, hyperthyroidism can be misdiagnosed as depression or dementia, displaying distinct symptoms like loss of appetite and social withdrawal. Approximately 30% of older individuals with atrial fibrillation may have hyperthyroidism. The prevalence rises with age, reaching up to 10% in the older age groups.
Symptoms
The symptoms include weight loss despite an increased appetite, rapid or irregular heartbeat, nervousness, irritability, difficulty sleeping, fatigue, trembling hands, muscle weakness, excessive sweating, or intolerance to heat. Other common signs can encompass frequent bowel movements and the development of a goitre, characterised by neck enlargement.
Complications
If left untreated, hyperthyroidism can result in severe health complications, such as stroke, heart failure, cardiac issues, osteoporosis, muscle-related problems, menstrual cycle irregularities and fertility issues.
Causes of Hyperthyroidism
Graves' disease, an autoimmune condition, often triggers hyperthyroidism by causing the thyroid gland to produce too much hormone. Thyroiditis, or inflammation of the thyroid, can lead to a temporary surge in hormone levels, eventually causing reduced activity. High iodine intake from certain medications or foods like seaweed may also stimulate excessive thyroid hormone production. Overuse of thyroid hormone replacements or certain drug interactions can further elevate these levels. In rare instances, benign tumours of the pituitary gland can induce hyperthyroidism.
Hypothyroidism
Hypothyroidism, or underactive thyroid, occurs when the thyroid gland produces insufficient thyroid hormones to meet the body's requirements. The prevalence of hypothyroidism in India is 11%, compared with only 2% in the UK and 4·6% in the USA with most cases being mild and exhibiting few noticeable symptoms. In the elderly, Hashimoto's disease is often a leading cause of hypothyroidism.
Symptoms
Hypothyroidism symptoms vary and can include fatigue, weight gain, cold sensitivity, joint and muscle pain, dry skin, hair thinning, menstrual irregularities or fertility issues, a slow heart rate, and depression. These symptoms often develop slowly, possibly taking months or years to become noticeable. Common symptoms like fatigue and weight gain don't always signal thyroid problems.
Complications
Hypothyroidism symptoms vary and can include fatigue, weight gain, cold sensitivity, joint and muscle pain, dry skin, hair thinning, menstrual irregularities or fertility issues, a slow heart rate, and depression. These symptoms often develop slowly, possibly taking months or years to become noticeable. Common symptoms like fatigue and weight gain don't always signal thyroid problems.
Complications
Untreated hyperthyroidism can lead to serious complications, including elevated cholesterol levels. In severe cases, untreated hypothyroidism can escalate to myxedema coma, a critical state where bodily functions significantly slow down, requiring immediate medical attention.
Causes of Hypothyroidism
Hashimoto's disease, an autoimmune disorder, is the leading cause of hypothyroidism, with inflammation impairing thyroid hormone production. The risk escalates with age, especially between 40 and 60. Thyroiditis causes inflammation that releases hormones, initially leading to thyrotoxicosis, which can last for months before potentially transitioning to an underactive thyroid, often necessitating lifelong hormone therapy. In newborns, untreated congenital hypothyroidism can result in intellectual and growth impairments. While partial thyroidectomy might maintain hormone levels, total removal definitively leads to hypothyroidism.
Supplements For Thyroid Health
Explore supportive supplements for managing thyroid dysfunction and promoting overall thyroid health.
Iodine
Iodine is crucial for thyroid hormone synthesis, and its deficiency can cause brain impairment. Currently, around 800 million individuals suffer from iodine deficiency disorders, leading to conditions like goitre, hypothyroidism, cognitive impairment, and various developmental issues. Iodine supplementation, such as iodised salt and vegetable oil, significantly improves thyroid health. The recommended daily iodine intake varies from less than 10 milligrams in deficient conditions to 150 grams for adults, higher for pregnant or lactating women, and lower for children and neonates, with no significant age-related changes. (Triggiani et al., 2009)
Selenium
Selenium is a crucial micronutrient necessary for regular development, growth, and metabolism. Additionally, selenium plays a role in the antioxidant system. This amino acid is present in the catalytic centre of numerous enzymes engaged in cellular defence against free radicals, as well as in the metabolism and functions of thyroid hormones. Recommended daily intake ranges from 20-40 mcg/day in infancy to 55 mcg in adulthood, with 60 mcg for pregnant and 70 mcg for lactating women.(Triggiani et al., 2009)
Iron
Iron is a crucial element for the synthesis and metabolism of thyroid hormones in the human body. The conversion of thyroxine (T4) into the active hormone triiodothyronine (T3) relies on iron. Consequently, insufficient iron levels can hinder thyroid function, leading to symptoms resembling hypothyroidism in patients. (Ghiya & Ahmad, 2019)
Zinc
Zinc has a crucial role in thyroid hormone metabolism, particularly in controlling the activity of deiodinase enzymes, the synthesis of thyrotropin-releasing hormone (TRH) and thyroid-stimulating hormone (TSH), and the modulation of key transcription factors essential for thyroid hormone synthesis. Additionally, the concentrations of serum zinc seem to impact the levels of serum T3, T4, and TSH. (Silva et al., 2019)
Vitamin A
Vitamin A enhances TSH stimulation and thyroid enlargement while decreasing the risk of hypothyroidism. Vitamin A supplementation enhances iodide efficiency. In adults, vitamin A and its metabolites, including retinoic acid (RA), are crucial for vision, immune function, brain function, tissue remodelling, and metabolism. (Brossaud et al., 2017)
Spermidine
Spermidine (SPD) and spermine (SPM), crucial polyamines in living cells, regulate ion channels, gene transcription, and translation, and protect against oxidative damage. Dietary spermidine converts to spermine in the body, entering the systemic circulation. Enzymes like spermine oxidase (SMOX) or spermine synthase (SMS) then convert spermine back to spermidine. The decreased spermine to spermidine ratio in Graves disease (GD), Hashimoto's thyroiditis (HT), and thyroperoxidase antibody (pTAb) patients suggests a potential link to thyroid autoimmunity. This emphasises the importance of spermine in thyroid health, suggesting that spermidine supplementation may enhance thyroid functioning and support overall thyroid health.(Song et al., 2019)
In conclusion
The ageing process significantly impacts thyroid health, leading to morphological and physiological changes. Elderly individuals face challenges in diagnosing and treating thyroid diseases due to overlapping symptoms and complexities. Hyperthyroidism and hypothyroidism pose distinct risks, with causes ranging from autoimmune conditions to iodine imbalances. It's crucial to address these issues promptly to prevent complications. Additionally, incorporating or avoiding specific foods and supplements can support thyroid health. Navigating these aspects is vital for optimal well-being in the ageing population, requiring careful consideration and personalised medical attention.
FAQ
1) How does the thyroid affect ageing?
Thyroid disorders, especially hyperthyroidism and hypothyroidism, are more prevalent in older individuals and can be deceptive, as their symptoms may be confused with other conditions or attributed to ageing. Altered thyroid function significantly impacts the well-being of older people, potentially impairing their ability to perform daily activities.
2) What is the best supplement for thyroid problems?
Selenium and iodine are key for thyroid health, aiding in hormone production and protection from damage. Spermidine supplements may also benefit thyroid function due to their respective antioxidant properties and potential to reduce autoimmunity.
3) What are the common symptoms of thyroid disorders in adults?
Thyroid disorders in adults exhibit varied symptoms, including weight loss, rapid heartbeat, nervousness, muscle weakness, excessive sweating, and intolerance to heat. Other signs encompass goitre, fatigue, weight gain, difficulty tolerating colds, joint pain, dry skin, thinning hair, and irregular periods. A slowed heart rate and feelings of depression can also occur. Recognising these symptoms is crucial for prompt medical attention, ensuring an accurate diagnosis and effective management of thyroid disorders.
4) How does diet impact hyperthyroidism and hypothyroidism?
Diet plays a crucial role in managing hyperthyroidism and hypothyroidism. For hyperthyroidism, limit iodine-rich foods and caffeine to reduce thyroid activity. In hypothyroidism, ensure sufficient iodine intake and focus on a balanced diet with nutrients like selenium and zinc. Both conditions benefit from avoiding excessively processed foods.
5) At what age do thyroid problems start?
An overactive thyroid can impact individuals, leading to potential health issues requiring treatment. While it can affect anyone, it is around 10 times more prevalent in women than men, and it typically occurs between the ages of 20 and 40.
References:
Lee, J., Yi, S., Kang, Y. E., Kim, H., Joung, K. H., Sul, H. J., Kim, K. S., & Shong, M. (2016). Morphological and functional changes in the thyroid follicles of the aged murine and humans. Journal of Pathology and Translational Medicine, 50(6), 426–435. https://doi.org/10.4132/jptm.2016.07.19
Mariotti, S., Franceschi, C., Cossarizza, A., & Pinchera, A. (1995). The aging thyroid. Endocrine Reviews, 16(6), 686–715. https://doi.org/10.1210/edrv-16-6-686
Dedon, J. (2022). Thyroid Disease in Aging. Missouri Medicine, 119(4), 351-353. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9462896/
Babiker, A., Alawi, A., Atawi, M. A., & Alwan, I. A. (2020). The role of micronutrients in thyroid dysfunction. Sudanese Journal of Paediatrics, 13–19. https://doi.org/10.24911/sjp.106-1587138942
Triggiani, V., Tafaro, E., Giagulli, V. A., Sabbà, C., Resta, F., Licchelli, B., & Guastamacchia, E. (2009). Role of iodine, selenium and other micronutrients in thyroid function and disorders. Endocrine, Metabolic & Immune Disorders, 9(3), 277–294. https://doi.org/10.2174/187153009789044392
Ghiya, R., & Ahmad, S. (2019). SUN-591 Severe Iron-Deficiency anemia leading to hypothyroidism. Journal of the Endocrine Society, 3(Supplement_1). https://doi.org/10.1210/js.2019-sun-591
Silva, J., Morais, J. B. S., De Freitas, T. E. C., Andrade, A. L. P., Feitosa, M. M., Fontenelle, L. C., De Oliveira, A. R. S., & Cruz, K. J. C. (2019). The role of zinc in thyroid hormones metabolism. International Journal for Vitamin and Nutrition Research, 89(1–2), 80–88. https://doi.org/10.1024/0300-9831/a000262
Brossaud, J., Pallet, V., & Corcuff, J. (2017). Vitamin A, endocrine tissues and hormones: interplay and interactions. Endocrine Connections, 6(7), R121–R130. https://doi.org/10.1530/ec-17-0101
Mackawy, A. M., Al-Ayed, B. M., & Al-Rashidi, B. M. (2013). Vitamin D Deficiency and Its Association with Thyroid Disease. International Journal of Health Sciences, 7(3), 267–275. https://doi.org/10.12816/0006054
Song, J., Shan, Z., Mao, J., & Wang, T. (2019). Serum polyamine metabolic profile in autoimmune thyroid disease patients. Clinical Endocrinology, 90(5), 727–736. https://doi.org/10.1111/cen.13946
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