Prevention of Postoperative Malnutrition with Oral Nutritional Supplements in Patients Undergoing Gastrointestinal Surgery.

Oral nutritional supplements (ONSs) offer support for the nutritional needs of surgical patients. However, their efficacy is contingent upon the nutrient composition, absorption efficiency, and postingestion tolerance. Our study included a cohort of 84 patients who underwent elective open surgery involving at least one intestine anastomosis. To mitigate the risk of malnutrition, 2 groups of 28 patients each received either a high-protein low-osmotic ONS (Group I) or a high-calorie high-osmotic ONS (Group II). A standard diet was used in the control group (Group III). The metabolic effects were evaluated by measuring body weight and relative change in body weight (Δkg) from 24 h (-1 day) presurgery to 28 days postprocedure. Subjective tolerance following ONS consumption on the second postoperative day was also assessed. Our findings showed that, across all groups, the average body weight decreased during the initial 2 weeks postsurgery, subsequently stabilizing or returning to baseline levels by the third and fourth week of observation. Patients receiving ONS demonstrated greater weight gain between days 14 and 28, with Group I exhibiting the highest rate of gain. Low-osmotic ONS displayed superior tolerance and elicited fewer patient complaints postconsumption. Postoperative hospitalization duration did not differ significantly among the nutritional strategies. In conclusion, early administration of ONS supplies essential nutrients and facilitates refeeding, thereby reducing the risk of malnutrition. Low-osmotic preparations are better tolerated and contribute more effectively to the restoration of preoperative body weight, despite their lower caloric content.