Hyperthyroidism is the most common endocrine disease in middle-aged and older cats, and dietary management has emerged as an effective adjunct or alternative treatment with significant welfare implications.
Hyperthyroid cats experience significant discomfort through multiple pathways: the metabolic effects of excessive thyroid hormone (including apparent anxiety, gastrointestinal upset, and cardiac stress), and the welfare impact of treatment side effects including medication-induced vomiting, anorexia, or skin reactions. Dietary management using strict iodine restriction requires that cats eat ONLY the prescription diet, which is challenging in multi-cat households. Welfare-focused management selects treatment based on individual cat circumstances - radioactive iodine offers the best long-term welfare outcome for appropriate candidates.