Clinical zinc deficiency during long-term total enteral nutrition

Zinc deficiency during long-term total parenteral nutrition has been well reported in the literature. However, there is limited information available on zinc deficiency occurring during total enteral nutrition. Two cases of clinical zinc deficiency in patients on long-term enteral feedings are presented. Nutritional assessment of these two patients on admission revealed hypoalbuminemic malnutrition. Nutritional support in the form of nasogastric tube feedings were initiated in both patients due to altered mental status. The formula used was Ensure (Ross Labs, Columbus, OH), which provided greater than 150% of the RDA for zinc. However, four months and seven months after initiation of adequate nutritional support, both patients developed skin rashes around the groin and under the breasts and axilla. Serum zinc levels were depressed in both patients, to 42 and 54 mg/dL, respectively (normal for the authors' laboratory, 66 to 120 mg/dL). Supplementation with zinc sulfate 220 mg per day via nasogastric tube resulted in disappearance of the rash with return of serum zinc to normal levels. The authors suggest close observation of patients on long-term enteral nutrition for clinical manifestation of zinc deficiency, especially an unexplained skin rash. Further studies are needed to establish minimum daily zinc requirements in patients on long-term enteral feedings.