Effects of fiber supplementation on glycemic excursions and incidence of hypoglycemia in children with type 1 diabetes

International Journal of Pediatric Endocrinology Effects of fiber supplementation on glycemic excursions and incidence of hypoglycemia in children with type 1 diabetes Nicole Nader 0 Amy Weaver 2 Susan Eckert 1 Aida Lteif 0 0 Division of Pediatric Endocrinology, Mayo Clinic , 200 1st St SW, Rochester, MN 55905 , USA 1 Division of Endocrinology, Mayo Clinic , Rochester, MN 55905 , USA 2 Biomedical Statistics and Informatics, Mayo Clinic , Rochester, MN 55905 , USA Background: Nutritional therapy is an important component of diabetes management. There is data to suggest that fiber content of foods may affect glycemic response. Materials and methods: 10 children, diagnosed with type 1 diabetes, participated. In the first phase of the study, children followed their usual meal plan. In the second phase, subjects followed the same meal plan except that fiber was added to the diet using a powder supplement (wheat dextrin). Data was collected using a continuous glucose monitoring device. The blood glucose excursion level following each meal was compared between the two phases of the study by fitting a repeated measures regression model. The incidence of hypoglycemia was also compared by fitting a logistic regression model. Results: There was no difference in the mean blood glucose excursion after meals or the incidence of hypoglycemia between the two phases. There was a strong negative correlation between the amount of fiber supplemented and the mean maximum post-prandial blood sugar after the lunch and breakfast meals (Spearman rank correlation coefficient = 0.86 lunch and 0.76 breakfast). Conclusion: Our study did not show an overall decrease in glucose excursion or incidence of hypoglycemia with fiber supplementation. We did find a strong negative correlation between the amount of fiber added during the supplemental phase and the mean maximum post-prandial blood sugar after the lunch and breakfast meals. We speculate that different types of fiber may have different effects on blood glucose with wheat dextrin having a greater dampening effect. - Introduction Nutritional therapy is an important component of diabetes management. The American Diabetes Association currently recommends that patients with type 1 diabetes monitor their carbohydrate intake either by carbohydrate counting or by the use of exchange diets and match prandial insulin to carbohydrate intake [1]. This method implies that equal portions of carbohydrate have equivalent effects on blood sugar levels. However, there is data to suggest that other factors such as the molecular structure of the carbohydrate and its fiber content result in differential blood glucose responses [2]. High fiber foods as a preferred source of carbohydrate and higher amount of fiber per day are currently recommended [3,4]. Fibers are known to slow down the absorption of carbohydrates after a meal [5]. Despite the fact that children with type 1 diabetes are known to have sub-optimal fiber intake [6,7] and have a tendency towards greater glycemic excursions, there is limited data looking at the effects of a fiber on metabolic control in children. In a cross over study of 23 patients who consumed either a low glycemic diet or a standard diet for two days, it was shown that the low glycemic diet contained more fiber than the standard diet and resulted in lower mean daytime blood glucose values [8]. Rami et al. demonstrated that giving a high-fiber bedtime snack to children with type 1 diabetes flattened the blood glucose curve until midnight [9]. It currently remains unclear what effects a diet rich in fiber would have on diabetes control and glycemic excursions in children with type 1 diabetes. The aim of this study was to determine whether the addition of a fiber supplement to the diet of pediatric patients with type 1 diabetes has an effect on the magnitude of glucose excursions and or the incidence of hypoglycemia. We hypothesized that children with type 1 diabetes receiving a high fiber diet will have lower glucose excursions and a lower incidence of hypoglycemia. Research design and methods Recruitment Ten children with type 1 diabetes were recruited from a pediatric endocrinology clinic in Rochester, MN between September 2008 and March 2010. Study staff approached potential participants during their routine diabetes clinic visit and invited them to participate. Inclusion criteria were: diagnosis of type 1 diabetes for at least two years prior to enrollment in the study and 416 years of age. Exclusion criteria were: any other associated medical conditions that could potentially affect absorption of nutrients such as celiac disease or inflammatory bowel disease and intercurrent illness during the study period. The study protocol was approved by the Mayo Clinic Institutional Review Board. Study subjects signed assent or consent forms (depending on their age) and both parents signed consent forms prior to participation. Study procedure The study was a prospective interventional observation study with a within-subject cross over design. During the study period the subjects were asked to maintain their usual level of activity. All subjects were asked to present to the outpatient diabetes clinic for an initial study visit. They first met with a dietitian who worked with them on a 3 day meal plan which was representative of their typical daily intake. The subjects were asked to follow that meal plan very closely. They then met with a physician who performed a brief physical exam including an Ears/Nose/Throat, heart, lung, and abdominal exam. Subjects were also asked about the presence of the following signs and symptoms in the preceding 3 days: upper respiratory infection symptoms, vomiting, diarrhea, and fever. If subjects had any signs or symptoms of an infection, upon presentation or during the study period, they were excluded from the study. Subjects were then connected to a continuous blood glucose monitoring device (Medtronic CGMD gold system). Subjects were instructed to continue using their own reflectance meters to check their blood sugars at least four times per day. They were also asked to keep a detailed food diary. Three days later, subjects returned to the clinic and the monitoring device was removed. The study dietitian analyzed the food diary to determine daily caloric intake and fiber intake using the Nutritionist Pro program. Subjects were instructed to contact the study team if they developed any symptoms or signs of infection at any time during the study period. During the washout period, subjects were asked to lower their insulin dose for unexplained hypoglycemia and increase it for a pattern of hyperglycemia that lasts for three days. For the second phase of the study which was conducted on similar days of the week, the subjects again returned to the outpatient diabetes clinic and met with a dietitian. There was a two to four week washout period between the study phases. The same meal plan was given ex (...truncated)