Can dietary fructans lower serum glucose?

BACKGROUND: Convincing evidence indicates that the consumption of inulin-type fructans, inulin, and oligofructose has beneficial effects on blood glucose changes in animal models, although data in humans have been considered equivocal. As such, a systematic review of available literature on humans was conducted to evaluate the effectiveness of dietary inulin-type fructans on serum glucose. METHODS: Thirteen eligible randomized controlled trials (RCT), published from 1984 to 2009, were identified using a comprehensive search strategy involving the PubMed, Medline, and Cochrane Library databases. Exclusion criteria, such as the absence of a control group, lack of information on the quantity of inulin-type fructans used, and lack of glucose values at outcome, were established. RESULTS: Upon review, only four of the 13 trials (31%) showed a decrease in serum glucose concentration and only one of these was statistically significant. The remaining nine trials showed no significant changes in serum glucose concentration. CONCLUSION: Based on the present systematic review, it does not appear that inulin-type fructans have a significant lowering effect on serum glucose in humans. More RCT are needed to determine whether inulin-type fructans, inulin, and oligofructose have beneficial effects on blood glucose in humans.