Comparison of the Postprandial Glycemic and Insulinemic Response After a Fibersym Containing Cookie With a Control

Fibersym® is a RS4-type resistant modified wheat starch in which over 85% of the total starch is resistant starch as measured by AOAC method 991.43. It is meant to be consumed on a regular basis and doses up to 33g/day can be tolerated. The effect of a Fibersym-containing meal on postprandial glucose and insulin levels when compared to a control meal, where both meals contain the same amount of available carbohydrate, is not known. This study therefore investigated the acute effect of a Fibersym cookie and a control cookie matched for available carbohydrate after a 3-day habituation period.

The study used a double-blind, randomized, cross-over design. Visit 1: Participants willing to be considered were invited to come to the research centre to have the study procedures explained to them and be given a copy of the consent form which they may either sign then, take away to sign at a later date, or decline to participate. Participants were encouraged to ask any questions they may have and not to sign the consent form until all of their questions have been answered to their satisfaction. Those who consented to participate came to the research centre for a pre-selection visit when subject eligibility will be determined. A number of parameters were assessed including blood pressure, weight, height, BMI, and brief medical history. Visit 2-3: Each eligible subject received one of the treatments at visit 2 and the other at visit 3. The order of the 2 treatments was randomized using an online randomization calculator. The interval between visits was no less than 6 days and no more than 4 weeks. Prior to each visit there was a 3-day pre-feeding period during which subjects consumed either 108.9g Control Cookies (approx. 3.5 cookies) per day or 136.2 g of Fibersym Cookies (approx. 4 cookies) per day (delivering 29 g fiber from Fibersym/day) according to the randomized order. Cookies were consumed with each main meal (breakfast, lunch and dinner). Subjects were provided with a calorie appropriate, standard frozen dinner to be consumed on the evening before each visit. On the day of each visit, participants came to GI Labs in the morning after a 10-12 h overnight fast (except for water). Two (2) fasting fingerprick blood samples were collected at -5 min and 0 min. Each sample consisted of 2 vials, one for glucose analysis and one for insulin analysis (4-8 drops of blood each). Questionnaires to record satiety and GI symptoms were administered. Participants were then a 40g available carbohydrate protion of the same type of cookie (Control or Fibersym) they had been consuming over the past 3 days containing together with 250 ml of water and instructed to consume them over 15 minutes. Additional blood samples were collected 15, 30, 45, 60, 90 and 120 min after the start of the test meal. Satiety questionnaires were administered at the same time intervals. GI symptom questionnaires were filled out at 2 h in addition to fasting. Test Foods: The sugar snap cookie formula (Control) was obtained from the American Institute of Baking (AIB) International (Manhattan, KS). Fibersym RW (Appendix 1) was added as an extra portion to the Control Cookie recipe, amounts were adjusted so that both the control and Fibersym cookie portions contained the same amount of available carbohydrate (ingredients are listed in appendix 1). Both cookies were baked at the facilities of AIB. The macronutrient composition of baked cookies was determined by an independent laboratory and the final weights of the cookies fed were adjusted accordingly. To maintain blinding, the cookies were re-packaged by a GI Labs staff member not involved in the clinical trial. Product label displayed the subject number, subject initials, product ID, ingredients statement, GIL repacked date, expiration date, researcher name and telephone number, investigational use statement, and allergy warnings (if needed). Study Product Intake Logs were completed upon dispensation of study product to each subject. After the data had been entered, checked for errors and the database locked, the code was broken. Participants were asked to maintain stable dietary and activity habits throughout their participation and to refrain from drinking alcohol and from unusual levels of food intake or physical activity for 24 h before each test. Subjects were asked to complete a 3- day record of supplement consumption and whether they consumed the standard evening meal, in addition to a 3-day symptom diary before each test visit. If any subject was not feeling well or had not complied with the preceding experimental conditions, the test was not carried out and was rescheduled for another day.