Food DNA Digestion

Overview

This pilot study investigates the digestion rate of naturally occurring food DNA through the human digestive tract by detecting residual food DNA in stool samples. The investigators hypothesize that food DNA primarily transits through the digestive system within 24 hours, with maximal detection in stool samples collected the day after ingestion. Previous research has focused on food DNA digestion in human gastric juices, leaving digestion through the entire gut largely unexplored. This study employs a fixed-order within subjects design involving healthy participants. Each participant will submit a baseline stool sample, consume a single dose of a study-specific powdered food (reconstituted in water) differing from their usual diet, and provide the subsequent five stool samples. If five samples are collected in fewer than five days, an additional sample will be obtained on the fifth day post-consumption. The presence and decline of food specific DNA in these samples will be quantified using qPCR, enabling us to determine the digestion rate of food DNA. The study design poses with minimal risk as it non-invasively monitors the natural process of food DNA digestion and transit through stool sample analysis.

Transit time, the duration for ingested food to travel from ingestion to excretion, is crucial because it influences nutrient absorption, digestion efficiency, gut microbiome composition and the overall health of the gastrointestinal system. While numerous studies have focused on the breakdown of food components such as protein, fat and carbohydrates, the fate of food DNA, an integral part of the cells constituting these foods, remains less explored. Mouse studies indicate that food DNA can be traced in various sections of the digestive tract, with the greatest amount of degradation seen in the stomach. Human studies have supported these reports through showing significant dietary DNA degradation in the stomach and other food components in the stomach not significantly impact the efficiency of this degradation. However, this process is not 100% efficient as residual DNA has been shown to be detectable in stool in levels that are informative for health and epidemiological purposes. How long this residual DNA remains in the digestive tract and as such, the overall transit time and digestion rate for food DNA to be completely depleted from the digestive tract remain an open question. In this study, the investigators will carry out a behavioral intervention in healthy human participants designed to investigate the transit time of dietary DNA. The design of this study is informed by the PI's previous experience with dietary interventions in human cohorts to better understand the human gut microbiome. This prior experience includes conducting a longitudinal study where samples as well as behavioral and dietary metadata were collected from human volunteers in addition to interventional studies of dietary supplements or fully controlled diets.