Effect of enteral formula infusion rate, osmolality, and chemical composition upon clinical tolerance and carbohydrate absorption in normal subjects

It is a common clinical practice to initiate enteral hyperalimentation using low flow rates or diluted formula. These adjustments are made in an effort to minimize patient intolerance. Using complex and elemental enteral formulas, we investigated whether various flow rates or osmolalities effected clinical intolerance or carbohydrate malabsorption in 20 healthy volunteers. Our infusion rates ranged between 50 and 150 kcal/hr and the osmolalities ranged between 325 and 690 mOsm/Kg of water. Even at the maximal flow rate and osmolality, our results show that both types of enteral formulas were well tolerated as assessed by the frequency of abdominal pain, bloating, passage of rectal gas and stooling. No carbohydrate malabsorption was detected as measured by breath hydrogen. In well nourished subjects, our findings do not support the common clinical practice of initiating alimentation with low flow rates or diluted formula.