Effects of Soluble Corn Fiber Alone or in Synbiotic Combination with GG and the Pilus-Deficient Derivative GG-PB12 on Fecal Microbiota, Metabolism, and Markers of Immune Function: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Elderly (Saimes Study).

BACKGROUND

The aging process leads to a potential decline in immune function and adversely affects the gut microbiota. To date, many and studies focused on the application of synbiotics (prebiotics combined with probiotics) as a promising dietary approach to affect gut microbiota composition and improved functioning of the immune system. However, studies using synbiotic preparations often have the limitation that it remains unclear whether any effect observed is a result of the prebiotic or probiotic or a synergistic effect of the combined supplement.

OBJECTIVES

We investigated the effects of a probiotic GG and pilus-deficient GG-PB12 combined with Promitor™ Soluble Corn Fiber (SCF, a candidate prebiotic) on fecal microbiota, metabolism, immunity, and blood lipids in healthy elderly persons. A prospective, double-blind, placebo controlled, randomized, single-centered, crossover study in 40 healthy elderly subjects (aged 60-80 years) was carried out. Volunteers were randomized to consume either probiotic and prebiotic as synbiotic, prebiotic or placebo (maltodextrin) during 3 weeks. Three-week washout periods separated all the treatments. We assessed effects upon blood lipids, glucose, cytokines, natural killer (NK) cell activity, phenotype, and intestinal microbiota composition. SCF decreased IL-6, which was not observed with the synbiotics.

RESULTS

Consumption of GG combined with SCF increased NK cell activity compared to baseline in females and the older group. In the fecal microbiota analyses, the strongest community shifts were due to GG combined with SCF and SCF treatments. GG combined with SCF and GG-PB12 combined with SCF significantly increased the genus . GG combined with SCF and SCF increased concentrations of . and slightly decreased in the GG combined with SCF group, whereas decreased also in the GG-PB12 combined with SCF group. GG combined with SCF reduced total cholesterol and LDL-cholesterol in volunteers with initially elevated concentrations. C-reactive protein significantly decreased during GG-PB12 combined with SCF intervention compared to baseline.

CONCLUSION

In conclusion, the synbiotic combination of GG with SCF showed a tendency to promote innate immunity by increasing NK cell activity in elderly women and in 70 to 80-year-old volunteers and decreased TC and LDL-c in hypercholesterolemic patients. In addition, GG-PB12 combined with SCF demonstrated an increase in NK cell activity compared to SCF alone in older volunteers. We also found significant positive effects on the immune response, evidenced by a decrease of the pro-inflammatory cytokine IL-6. Therefore, dietary intervention with GG combined with SCF could be of importance in elderly as an attractive option for enhancement of both the microbial and immune systems.