DIETARY FERMENTABLE CARBOHYDRATE (FC) CONSUMPTION AND ASSOCIATIONS WITH DIET QUALITY AND HEALTH PARAMETERS

Abstract

Excessive body fat and related dysmetabolic complications concern both emerging and developed countries. An important environmental cause of these conditions is the altered composition of gut microbiota, which is influenced by the host diet. A number of clinical trials target gut microbiome composition or functions with fermentable carbohydrates (FCs) to promote a healthier profile. Total dietary fiber, which includes both FC and non-fermentable carbohydrates, is considered a promising tool for the prevention of chronic diseases. This has led to significant changes in food and health recommendation with an increase in dietary fiber intake advised. However, reference to other FCs such as resistant starches, non-starch polysaccharides, polyols (lactitol, sorbitol, mannitol, etc.), soluble dietary fibers (SDF), and oligosaccharides (fructo- and galacto- oligosaccharides, etc.) are still lacking. Intakes of FC in free-living adults remain largely under-investigated, but the limited work to date suggests that they tend to be low. Determining overall dietary components and patterns associated with FCs might allow adjustment for diet in many future studies and can eventually help increase the habitual consumption of all FCs. Identifying the average consumption of all types of FCs and their associations with health outcome sin free-living populations might inform treatment practices that include all types of FCs to improve clinical outcomes and help to include them in dietary guidelines than just dietary fiber. Based on this background, the objectives, hypotheses, methods, and results of this dissertation are threefold: Manuscript-1: The goal of this study was to analyze the association between the consumption of FCs and the total healthy eating index 2015 (HEI-2015) as well as HEI-2015 components. The study involves a US college student population, considering they are at the decisive stage of their dietary choices and at high risk of developing metabolic diseases. The Diet History Questionnaire-II (DHQ-II) was used to estimate dietary intake of FCs, and a simple HEI algorithm scoring method, which is a publicly available statistical code from the Division of Cancer Control and Population Sciences of the National Cancer Institute, was used to calculate the HEI-2015 total score and component scores. The relationship between FC intake and total HEI-2015 and the component score was assessed using a simple linear regression model. The result concluded that the higher total FCs intake was related to a higher HEI-2015 score and hence higher diet quality. Furthermore, the HEI adequacy components such as vegetables, sea/plant proteins, and fruits (total and whole) are associated