Long-term Consumption of Resistant Starch Type-4 (RS4)

Description

This study will investigate the metabolic effects of daily RS4 consumption in overweight and obese adults. The investigators will recruit approximately 50 (BMI: 23-34.9kg/m2) adults ages 18-65yrs, who have elevated to borderline-high LDL-cholesterol (116-159mg/dL) to an 8-week randomized controlled intervention. Participants will be recruited in three waves of 16 participants each. Following a 7-10-day run-in where fiber intake is monitored, participants will be randomized to either the control or the RS4 group. The RS4 group will consume a high fiber bar, daily, for 8-weeks that will contain approximately 60-70% of the daily reccomended allowance of fiber. The primary outcome for this study will be fasting plasma LDL-Cholesterol (LDL-c). Secondary outcomes include body composition following daily RS4 consumption for 8-weeks. All health assessments will be conducted before the intervention begins, at the 4-week mid-point, and immediately following the 8-week intervention. Participants will fast for 10 -12 hrs. before reporting to the PAN-CRC for each testing session. The meal consumed prior to each testing session will be standardized so that it does not vary within the individual between testing sessions.

Treatments. The two treatment conditions are RS4 and control. Participants will be asked to consume one nutrition bar as part of their breakfast each day with no other changes to their diet. The control group will consume one native wheat starch bar per day. The RS4 group will consume one nutrition bar per day formulated using Fibersym RW containing 20g fiber. This amount would likely put individuals in the recommended dietary fiber intake range according to the dietary recommended intake ( Institutes of Medicine: 14g fiber/1000 kcal). All nutrition bars will contain the same ingredients and be matched for calories; however, fiber will vary between the bars.

Health assessments. The KSU Nutrition team will conduct all health assessments at each time point. Height (cm), weight (kg), and waist circumference (cm) will be measured to determine basic anthropometrics, and a dual-energy X-ray absorptiometry scan (DXA) will be used to determine body composition (body fat percentage and non-fat mass). Blood pressure (systolic and diastolic (mmHg) will be measured using a standard automated monitor. Fasting total cholesterol (TC), triglycerides (TRG), glucose, LDL-c, and HDL-c will be measured via an LDX Cholestech using a single venous blood draw for assessment. Plasma glucose and insulin will be determined via the same venous sample. Satiety will be measured during each testing session to determine how Fibersym RW impacts feelings of fullness and hunger.

Compliance Checks. To ensure compliance with consumption of the nutrition bars provided, participants will be asked to return to the PAN-CRC to return any leftover bars at the end of each intervention week (if any remain), and to pick up a new supply of their assigned bar. Participants will also be given a checklist that indicates their daily consumption of the given bars. The checklist will include options such as: I consumed the 100% of the bar, forgot to consume, consumed part of the bar (with options to check a percent of the bar consumed). To ensure that habitual dietary intake is maintained, participants will be instructed to complete a 3-day dietary record (two weekdays and 1 weekend day) prior to each testing session, allowing the investigators to determine any dietary changes that may occur during the 8-week intervention.

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