Objective: To evaluate the effect of oral nutritional supplementation with and without oligosaccharides on gut bacteriology, in particular the bifidogenic flora, and on immunology and inflammatory parameters in older persons at risk of malnutrition.
Design: Prospective, randomized, double-blind, controlled study.
Setting: Division of Geriatric Medicine, St. Louis University, Missouri, United States.
Participants: Seventy-four community dwelling elderly and/or nursing home subjects (age superior 70 y; 84 +/- 7 years) either undernourished or at risk of undernutrition.
Intervention: Daily liquid supplements, with (1.3 g/250 ml) and without oligosaccharides (OS) for 12 weeks.
Measurements: Nutritional evaluation, serum immunoglobulins, lymphocyte subsets, various cytokines and the endotoxin soluble receptor CD14 (sCD14) in serum, and cytokines specific mRNA in peripheral blood mononuclear cells at baseline and 12 weeks, and fecal bacteriologicy.
Results: Specific mRNA extracted from blood leucocytes showed a different level of pro-inflammatory gene activation: TNF-alpha mRNA and IL-6 mRNA diminished in the OS group after 12 weeks, while no changes were detected in the control group (P=0.05 and P=0.04 respectively). Serum levels of sCD14, a product shed by activated macrophages, decreased only in the OS group without reaching statistical significance (P=0.08). No significant differences were detected in the fecal gut flora or in the nutritional parameters.
Conclusions: This study shows that the administration of supplements in older persons at risk of malnutrition may benefit from the addition of prebiotics that can improve the low noise inflammatory process frequently observed in this population.