Feline hyperthyroidism is the most common endocrine disorder in older cats. Dietary iodine restriction offers an alternative treatment route when other options are unsuitable.
Untreated hyperthyroidism causes progressive deterioration over months to years. Affected cats experience a state of metabolic excess — constant hunger yet wasting, restlessness, increased heart rate, and hypertension that damages vital organs silently. Secondary hypertensive retinopathy causes sudden blindness, and hypertensive heart disease causes discomfort and reduced exercise tolerance. Diagnosis and treatment dramatically improve welfare: weight stabilises, restlessness resolves, and appetite normalises. Iodine-restricted diets require strict adherence — any other food source provides iodine that undermines the treatment — making owner compliance essential for therapeutic success.