Clinical trial NCT01681173: OPTIFIT-Optimal Fiber Trial for Diabetes Prevention
Official title: Investigation of the Effect of Insoluble Dietary Fiber on Carbohydrate and Lipid Metabolism and the Prevention of Diabetes Mellitus Type 2 in Subjects With Impaired Glucose Tolerance
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Diabetes
Nutrition Disorders
Obesity
Overweight
Metabolic Syndrome x
Body Weight
Glucose Metabolism Disorders
Metabolic Diseases
Keywords: Nutritional support
Diet therapy
Diabetes prevention
Insoluble fiber
Healthy life style
Weight loss
Lead sponsor: German Institute of Human Nutrition
Sponsor class: OTHER
Collaborators: name: Charite University, Berlin, Germany
name: German Diabetes Foundation, Munich, Germany
name: Ernst von Bergmann Hospital
name: University Hospital Tuebingen
First posted: 2012-09-07
Enrollment: 200
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: High intake of insoluble fiber is strongly associated with a reduced incidence of diabetes and cardiovascular events in prospective observation studies. Our primary objective is to compare a life style diabetes prevention program(PRAEDIAS) with and without added insoluble fibers in its effectiveness to prevent incident diabetes type 2 in high risk individuals with impaired glucose tolerance. Subjects with IGT not willing to participate in the intervention will be used as independent controls. Secondary aims are to identify mechanisms of action with regard to body composition, anti-inflammatory and metabolic effects of fibers. We propose a randomized, prospective intervention study. The results will be of general relevance for guidance of fiber intake in the population and will help the food industry to design healthy high fiber foods. Fiber can be added at low cost to numerous foods. Increased fiber intake may therefore provide a simple non-cognitive prevention strategy effective at the population level.

Detailed description: The overall objective is to investigate whether insoluble fibers added to standard nutrition can reduce the progression of impairment of glucose metabolism in a high risk population with impaired glucose metabolism. Large prospective cohort studies clearly show that mainly insoluble cereal fiber from whole grains is associated with reduced risk of type 2 diabetes and cardiovascular disease. However, there is a lack of evidence from prospective intervention studies targeted to evaluate the potential of dietary fibers to reduce diabetes and cardiovascular disease as recently stated by the Cochrane Foundation. Dietary fiber intake is generally much lower than currently recommended, which may in part be related to side effects of whole grain nutrients and their gustatory properties. Intestinally uncomfortable effects are at least partly related to fermentation which is much less induced by insoluble non-fermentable fibers than by soluble fermentable fibers. The prospective demonstration of beneficial effects of insoluble fibers in preventing diabetes type 2 will allow detailed nutritional recommendations. This may serve to support the consumption of metabolically beneficial constituents of fiber-rich diets and help to increase fiber intake by high fiber natural nutrients or everyday nutrients enriched in insoluble natural fibers.

Eligibility criteria: Inclusion Criteria:

* Impaired glucose tolerance
* Age\>18years old
* both gender

Exclusion Criteria:

* Diabetes type 1 and type 2
* chronic or malignant disease
* Intake of metabolic influence drugs
* Food allergies, fiber intolerance

Primary outcomes:
measure: Change of 2h-postprandial blood glucose from IGT to diabetes mellitus type 2 or normal glucose tolerance (NGT)
timeFrame: 0, 12, 24 months
Secondary outcomes:
measure: Change of insulin sensitivity
timeFrame: 0, 12, 24 months
measure: Change of insulin secretion
timeFrame: 0, 12, 24 months
measure: Expression of inflammatory markers in blood
timeFrame: 0, 6, 12, 18, 24 months
measure: Biometric data
timeFrame: 0, 6, 12, 18, 24 months
measure: Assessment of cognitive performance
timeFrame: 0, 12, 24 months
measure: Development of indices for the prediction of fat mass
timeFrame: 0, 12, 24 months
measure: Determination of gene expression in adipose tissue
timeFrame: 0, 12, 24 month
Other outcomes:
Locations:
city: Potsdam-Rehbruecke
country: Germany
facility: German Instiute of Human Nutrition
state: Nuthetal
city: Berlin
country: Germany
facility: Charite University
Study officials:
affiliation: German Institute of Human Nutrition Potsdam-Rehbruecke
name: Andreas FH Pfeiffer, Prof.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Honsek C, Kabisch S, Kemper M, Gerbracht C, Arafat AM, Birkenfeld AL, Dambeck U, Osterhoff MA, Weickert MO, Pfeiffer AFH. Fibre supplementation for the prevention of type 2 diabetes and improvement of glucose metabolism: the randomised controlled Optimal Fibre Trial (OptiFiT). Diabetologia. 2018 Jun;61(6):1295-1305. doi: 10.1007/s00125-018-4582-6. Epub 2018 Feb 28.