Iodine and Thyroid Dysfunction in Ageing: Nutritional, Pharmacologic, and Microbial Modifiers in Older Adults
Corina-Aurelia Zugravu1,2, Marta Petre2, Ciprian Constantin3,4
1Department of Hygiene and Nutrition, "Carol Davila" University of Medicine and Pharmacy, 050463 Bucharest, Romania.
Geriatrics (Basel, Switzerland)
|February 20, 2026
Summary
Ageing impacts thyroid function through altered iodine metabolism, influenced by diet, medications, and gut health. Monitoring iodine intake and using age-specific thyroid ranges are key for older adults.
Area of Science:
- Endocrinology
- Gerontology
- Nutritional Science
Background:
- Ageing alters endocrine regulation and nutrient metabolism, increasing thyroid dysfunction risk in older adults.
- Iodine's narrow physiological range makes aging individuals vulnerable due to interactions with nutrition, medications, renal function, and gut microbiota.
Purpose of the Study:
- Review how ageing affects iodine-thyroid homeostasis.
- Emphasize roles of diet, medications, gut microbiota, and metabolic changes in iodine handling and thyroid hormone economy.
Main Methods:
- Narrative review of existing evidence.
- Integration of data on physiological ageing, nutrient metabolism, and thyroid function.
Main Results:
- Physiological ageing decreases renal iodine clearance, thyroid reserve, and hormone conversion.
- Polypharmacy and chronic inflammation increase susceptibility to iodine imbalance and thyroid dysfunction.
- Age-related gut dysbiosis may link gut ecology to thyroid autoimmunity and impact nutrient absorption.
Conclusions:
- Iodine intake variations are key determinants of thyroid dysfunction in ageing.
- Nutritional, pharmacologic, and other factors modify iodine-related thyroid vulnerability.
- Age-adjusted thyroid ranges and monitoring can prevent overtreatment and enhance metabolic resilience.
Related Concept Videos
01:15Drug Dosing: Geriatric Patients
308
Elderly individuals encompass a diverse population with varying degrees of age-related physiological changes. Defining the elderly presents challenges, as the geriatric population is often arbitrarily categorized as individuals older than 65. However, many individuals in this group lead active and healthy lives, with an increasing number surpassing 85 years and falling into the older elderly category. Physiological changes associated with aging impact performance capacity and homeostatic...
308
01:27Pharmacodynamics in Geriatric Patients: Effects of Age
257
Age-related pharmacokinetic changes are extensively documented, but understanding age-related pharmacodynamic alterations is relatively limited. This knowledge gap can be partly attributed to the complexity of developing appropriate measures of drug responses compared to bioanalytical methods for determining drug concentrations.Most information regarding age-related differences in human pharmacodynamics originates from cross-sectional studies. However, these studies assume that observed mean...
257
01:18Pharmacokinetics in Geriatric Patients: Effect of Age on Drug Metabolism
249
Geriatric patients show significant variation in how their bodies process medications, which can change how effective and safe treatments are. The liver is the primary organ where drug metabolism occurs, involving two main types of chemical reactions: phase I and II. Phase I metabolism is driven by the cytochrome P450 enzyme system, which includes key types such as CYP3A, CYP2D6, and CYP2C9. Research indicates that while aging doesn't notably alter the levels or activity of these enzymes, it...
249
01:00Pharmacokinetics in Geriatric Patients: Effect of Age on Drug Distribution
287
Drug distribution in the human body is influenced by several factors, including plasma protein concentration, body composition, blood flow, tissue-protein concentration, and tissue fluid pH. Among these, changes in plasma protein concentration and body composition due to aging significantly affect how drugs are distributed within the body. Specifically, aging is associated with a decrease in albumin levels by about 10% and an increase in α1-acid glycoprotein levels. These alterations are...
287
01:22Pharmacokinetics in Geriatric Patients: Effect of Age on Drug Absorption
748
As individuals age, their body's physiology evolves, affecting drug pharmacokinetics. The most apparent changes occur in the gastrointestinal tract, where an increase in gastric pH, a delay in gastric emptying, and a reduction in gastrointestinal motility are observed. Remarkably, these changes do not substantially modify the absorption of orally administered drugs, particularly those absorbed via passive diffusion.Transdermal drug delivery emerges as a highly viable method for older adults due...
748
01:18Pharmacokinetics in Geriatric Patients: Effect of Age on Drug Excretion
274
In geriatric patients, renal physiology undergoes significant changes, including diminished renal blood flow and a lower glomerular filtration rate (GFR), leading to alterations in medication clearance. Drugs such as aminoglycoside antibiotics, lithium, and digoxin, which rely on glomerular filtration for removal from the body, particularly impact pharmacokinetics. These drugs tend to have slower clearance rates in older adults, necessitating careful dosage considerations.Evaluation of renal...
274