Mechanisms Linking Dietary Fiber, the Microbiome and Satiety
Design: Using fiber derived from peas, Aim 1 will test the effect of a HiFi diet on appetite, satiety, and cardiometabolic health and whether elevated SCFA concentration mediates improved satiety in 44 overweight/obese subjects randomly assigned to receive either a high fiber or a low fiber dietary intervention for four weeks in a parallel arm-repeated measures design. Aim 2 will quantitate the changes in microbial composition and colonic SCFA production rate during HiFi feeding and whether any changes are potential mediators of observed benefits on satiety and cardiometabolic risk factors in 26 subjects assigned to receive a high fiber intervention for 3 weeks in a repeated measures design. Relevance: These studies will significantly expand the understanding of mechanisms by which dietary fiber improves satiety and cardiometabolic health in humans.
• Men and women (premenopausal only)
• Age 20-55y (Aim 1); 45-55y (Aim 2)
• BMI ≥25 or ≤35 kg/m2 (Aim 1); ≥25 or ≤40 (Aim 2)
• Weight stable (no fluctuations in body weight of greater than 4 kg in the last 3 months)
• Willing to consume a research diet
• Willing to provide blood and fecal samples
• At least one characteristic of the metabolic syndrome (but not diabetic)
• 1\. A large waistline: 35 inches or more for women 40 inches or more for men 2. High triglycerides: 150 mg/dL or higher 3. Low HDLc level: \<50 mg/dL for women \<40 mg/dL for men 4. High blood pressure ≥130/85 mmHg 5. Fasting blood sugar ≥100 mg/dL
• Pre-diabetes acceptable (glucose \<125 mg/dL or HbA1c \<6.5%)
• Stably treated with statin drugs, anti-hypertensives, and anti-depressants. These are acceptable as long as the drug category does not alter appetite, body weight, or the microbiome (if known)