Evaluation of Serum Zinc Status in Patients With Neurologic Impairment Under Controlled Enteral Nutrition

Patients with neurologic impairment (NI) often require long-term enteral nutrition. Zinc plays a vital role in neurological and immune function, yet data on zinc intake and status in NI patients remain limited. This study aimed to evaluate whether serum zinc concentrations reflect standardized daily zinc intake in patients with NI receiving fixed-content enteral formulas (EFs) and to identify factors associated with serum zinc levels.

This retrospective study included bedridden NI patients aged ≥16 years who received EFs via nasogastric or gastrostomy feeding. Clinical parameters, serum biochemical markers, and daily nutrient intake were assessed. Patients were stratified by serum zinc levels (<60 μg/dL or ≥60 μg/dL). Univariate and multivariate linear regression analyses were performed to identify factors independently associated with serum zinc concentrations.

Of 31 patients analyzed, 8 (25.8%) exhibited serum zinc deficiency. Zinc intake was significantly lower in the low zinc group compared to the normal zinc group (9.2 vs. 13.5 mg/day, p = 0.0157). Notably, zinc deficiency was observed even in individuals whose zinc intake exceeded the Estimated Average Requirement (EAR) or Recommended Dietary Allowance (RDA). In regression analyses, both daily zinc intake (β = 1.28, p = 0.0273) and serum albumin (β = 14.87, p = 0.0407) were independently associated with serum zinc levels.

Despite controlled enteral nutrition, a substantial proportion of patients with NI exhibited zinc deficiency. Although limited by a small sample size, these findings highlight the importance of individualized monitoring and potential supplementation beyond standardized intake levels.