Evaluation of micronutrient adequacy in adult enteral formulas in Türkiye: a comparison with DRI, ESPEN, and National Guideline (TUBER-2022)

Objective: Enteral nutrition (EN) is a cornerstone of nutritional support for patients unable to meet their dietary needs orally, yet concerns remain regarding the adequacy of micronutrient provision in commercial enteral formulas. The aim of the study is to evaluate the micronutrient content of commonly used adult enteral formulas in Turkiye by comparing their composition with the recommendations provided in international and national guidelines. Methods: Thirty-eight commercially available adult enteral formulas, encompassing standard, immune-modulating, and disease-specific types were analyzed. The micronutrient content was calculated based on the labelled values and subsequently adjusted for daily energy intakes of 1500 and 1800 kcal. These values were then compared with Dietary Reference Intakes (DRIs), ESPEN micronutrient guidelines, and TUBER-2022 recommendations. Results: At a 1500 kcal/day EN intake, 89.1% of the formulas (33/37) failed to meet the recommended intake for vitamin K, 86.5% (32/37) for vitamin D, and 94.6% (35/37) for magnesium based on DRI and ESPEN guidelines. Additionally, 37.8% (14/37) of the formulas did not meet the iron requirement specifically for females according to DRI and ESPEN recommendations. According to ESPEN’s recommendations for high demand, all formulas were found to be insufficient in multiple micronutrients, including vitamins A, D, E and B-complex vitamins, as well as iron, zinc, selenium, chromium and molybdenum. Furthermore, one immune-modulating formula exceeded the tolerable upper intake levels for five micronutrients (folic acid, calcium, magnesium, zinc, and manganese) according to both the DRI and the TUBER-2022. Conclusion: Commonly used enteral formulas in Turkey may inadequately supply essential micronutrients, particularly to vulnerable populations with increased requirements. These findings emphasize the need for routine clinical monitoring, individualized supplementation strategies and reformulation of products, especially with regard to vitamin D and magnesium content, to align with ESPEN’s higher intake recommendations.