Prevalence of Idiopathic Reactive Hypoglycaemia and Impact of Fructo-Oligosaccharide Supplementation on Blood Glucose Variability

Abstract

BACKGROUND: The term idiopathic reactive hypoglycaemia (IRH) applies when a meal-induced dip in blood glucose, or symptoms of hypoglycaemia, follows high-starch, low-fibre meals in otherwise healthy individuals. Due to inconsistency of its definition and debated clinical value, reported prevalence of this state varies. No consensus exists on optimal treatment of IRH, hence we wanted to investigate 1) the prevalence and characteristics of IRH, and 2) if diet supplementation of fibre could improve the reactive glucose response in IRH. METHODS: 362 subjects (71 + 9 years, 146 females), all previously undiagnosed of dysglycaemia, who had participated in on of two case-control studies involving a oral glucose tolerance test (OGTT), were classified according to WHO standards (type 2 diabetes mellitus (T2DM), impaired glucose tolerance (IGT), normoglycaemia (NGT)) or categorized as IRH if OGTT 1h- or 2h- capillary blood glucose (cBG) levels were ≤ 3.9 mmol/L or 1h- or 2h- glucose were < fasting cBG, with no evidence of T2DM or IGT. Characteristics of the IRH group were aligned with T2DM, IGT and NGT groups through a case-control evaluation of lipids, inflammatory- and IGF system parameters, cardiovascular complications, medications and anthropometric measures. Further, twelve (56 + 8 years, 6 females) subjects from the IRH minority were recruited in a 4-week, randomized, crossover intervention, to evaluate the glucometabolic and anthropometric effects of fructo-oligosaccharides (FOS), a dietary soluble fibre with texturising properties (10g bid for 2 weeks, no treatment the following 2 weeks). At the end of each 2-week treatment sequence, fasting laboratory samples, a 4h-OGTT (blood glucose (BG) measures every 30th minute) and anthropometric measures were conducted. RESULTS: IRH was found in 12.4% of the subjects whom characteristics were: younger, a more favourable inflammatory- and IGF system axis profile and lower coronary artery disease (CAD) prevalence, compared to all other groups. FOS leveraged a significant improvement in several of the glucometabolic parameters. Although some fasting parameters were significantly reduced (plasma glucose and total cholesterol levels; 5.4 + 0.6 vs. 5.1 + 0.5 mmol/L, p < 0.05 and 5.3 + 1.1 vs. 4.9 + 1.1 mmol/L, p < 0.04, respectively), most benefits were seen in the 4h OGTT trajectory during the last two hours of the 4h-OGTT. FOS significantly reduced glycaemic exposure (AUC) between 180 and 210 minutes (p = 0.03) and reduced the proportion of capillary blood glucose measurements < 3.9 mmol/L from 21 to 11(χ2 = 4.26, p = 0.04) in this period. Moreover, favorable alternations in the shape of the OGTT curve were seen, with less pronounced zeniths and nadirs. CONCLUSION: A reactive hypoglycaemic response during an OGTT is prevalent in older adults and this phenomenon could be modulated by dietary supplementation of FOS. The stabilizing effects of fructo-oligosaccharides on blood glucose should be assessed in patient groups where BG variability plays a role, e.g. in T1DM or T2DM.