Whey Protein Hydrolysate Fortified with Iodine and Zinc against Stress-Induced Iodine Deficiency in C57BI/6N Mice

Insufficient iodine intake is recognized by the World Health Organization as one of the most significant nutritional problems of our time. More than half of the global population suffers from iodine deficiency, which is often aggravated by chronic stress. This combination leads to endocrine, nervous, cognitive, and immune disorders. This article describes the functional efficacy of a fortified whey protein hydrolysate in mitigating the consequences of chronic stress in laboratory animals. The research featured an experimental sample of whey protein hydrolysate fortified with iodine and zinc. Unfortified protein hydrolysate served as the control. The study determined acute toxicity (via a single intragastric dose of 5,000 mg/kg) and acute irritant effects (via skin application with reaction monitoring for 72 h). Efficacy was evaluated in C57Bl/6N laboratory mice under chronic stress conditions using Open Field and O-Maze behavioral tests. Other parameters included body weight changes, hormonal profiles (cortisol, TSH, T4, T3), and the relative weight of internal organs. The fortified sample exerted no acute toxic or irritant effects (LD50 > 5,000 mg/kg) and was classified as low-hazard (Hazard Class IV). The experimental hydrolysate containing organic iodine and zinc significantly reduced chronic anxiety. The median distance in the Open Field test reached 14.35 m (compared to 11.30 m in the control); the time spent in the open zones of the O-Maze increased to 36.31 s. Furthermore, the product contributed to body weight recovery and partial hormonal normalization, maintaining active T3 at a level comparable to the intact control. Unlike the stress-control group, the relative brain weight of the experimental animals did not decrease. Whey protein hydrolysate with organic iodine and zinc proved to be a safe food ingredient, capable of preventing stress-induced iodine deficiency and maintaining neuroendocrine stability. Further clinical trials will follow to validate its use in functional foods.