Serum potassium and sodium levels and nutrient intake in population exposed to radiation from the Semipalatinsk nuclear test site.

The relationship between serum electrolyte levels and nutrient intake in environmentally exposed populations has received little attention in the international literature. This study aimed to investigate serum potassium and sodium levels and nutrient intake in populations exposed to radiation from the former Semipalatinsk Nuclear Test Site compared with non-exposed populations. A cross-sectional study was conducted in four settlements of East Kazakhstan and Pavlodar provinces, with three classified as exposed and one as non-exposed. A total of 907 adults with lifelong residency were enrolled, and exposure status was verified using official residency documents and the state automated medical registry. Dietary intake was assessed using the validated EPIC-Norfolk Food Frequency Questionnaire, and fasting blood samples were collected to measure serum potassium and sodium using ion-selective electrodes. Compared with the non-exposed group, exposed individuals reported significantly lower consumption of nearly all macro- and micronutrients, except for vitamin A. Serum potassium levels did not differ significantly between groups (median 4.3 mmol/l, p = 0.337), whereas median serum sodium levels were significantly higher in the non-exposed group (141 vs. 140 mmol/l, p = 0.02). The sodium-to-potassium ratio was not significantly different between groups (32.56 in exposed vs. 32.79 in non-exposed, p = 0.156). Correlation analysis showed a moderate positive association between serum sodium levels and sodium intake (rho = 0.495, p < 0.001), and a strong positive association between sodium and potassium intake (rho = 0.642, p < 0.001). These findings underscore the need for further investigation into dietary patterns and possible physiological adaptations in environmentally exposed populations.