Recipient Organization
UTAH STATE UNIVERSITY
(N/A)
LOGAN,UT 84322
Performing Department
Nutrition, Dietetics and Food Sciences
Non Technical Summary
According to national diet surveys, the average American diet contains 60% of the Adequate Intake (AI) of dietary fiber. Evidence from human and animal studies suggests that increasing fiber intakes reduces gut and systemic inflammation and protects against the development of coronary heart disease (CHD) and type 2 diabetes.The difference between recommended and actual intakes of fiber has been called the 'fiber gap'. Evidence-based strategies to address the fiber gap are needed, such as increasing fiber intake via supplementation of processed foods. Dietary fiber may be characterized according to source (i.e. fruit, vegetable, and cereal), chemical composition (monosaccharide constituents) or functional properties (such as solubility and viscosity). Insoluble fiber increases fecal bulk, decreases gut transit time, but is not thought to be biologically active. Soluble fiber solutions are viscous and reduce digestion rate and absorption of nutrients, and tend to be highly fermented in the hind gut into short chain fatty acids, which affects the microbiome, gut and systemic physiology and metabolism.To date, many epidemiological studies have compared insoluble vs. soluble fiber intake on health outcomes. There is an apparent paradox with respect fiber intake and protection from metabolic diseases. Based on physical properties, soluble fiber intake would appear more likely to be associated with improved health, yet it is insoluble cereal fiber that is most often associated with protection against the development of CHD and T2D. If it is insoluble fiber in the diet that contributes to protection from developing chronic diseases, the mechanism(s) responsible is/are unknown.The primary goal of this project is to determine the feasibility of preventing and/or treating development of glucose insensitivity via optimizing intakes of physiologically and nutritionally relevant dietary fiber levels. The goal of this project is to investigate the potential mechanisms through which the composition of the dietary fiber improves metabolic health. In the gut, we will quantitatively profile the microbiome and measure inflammation, gut permeability and short-chain fatty acid production. Systemically, we will measure energy expenditure, inflammation and oxidative stress. Collectively, these data will provide targets for the supplementation of processed foods with added fiber, and will facilitate further grant submissions to federal agencies.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Goals / Objectives
We will test the hypothesis that insoluble fiber is more metabolically beneficial than soluble fiber. High fat, metabolically stressful rodent diets will be formulated at 60% of Adequate Intake (AI; average US intakes) and 100% (recommended level) of AI, but with either high insoluble, or high soluble fiber. Mice will be fed the diets for 16 weeks. Glucose sensitivity and body composition will be measured during the study, as will the energy expenditure via indirect calorimetry. Other endpoints measured will be related to the gut (microbiome composition, gut permeability, inflammation) and related to systemic metabolism (oxidative stress, metabolically responsive genes and gene products in liver and adipose), and to inflammation.
Project Methods
We will conduct a 16 week feeding study. We will measure glucose sensitivity with an oral glucose tolerance test and body composition during the study as well as energy expenditure via indirect calorimetry. After 16 weeks mice will be killed and we will measure the effects of the diets on the gut (microbiome composition, gut permeability and inflammation). Last, we will also measure indices of oxidative stress and metabolic health via gene and protein expression.