Biomedical Sciences Program
Downers Grove IL MedicalResearch.com: What is the background for this study? What are the main findings? Dr. Martinez-Guryn: The original goal of this study was to understand why mice devoid of all microorganisms (germ free mice) are protected from diet-induced obesity. We demonstrate that these mice display severely impaired lipid absorption even when fed a high fat diet. Dr. Chang: We found that many of the processes of dietary lipid digestion and absorption are dependent on and modulated by the gut microbiome which itself responds to dietary cues to adjust the small intestine’s ability and capacity to handle dietary lipids appropriately. This interplay is important for general health, but the findings are also relevant to conditions of overnutrition (obesity, metabolic syndrome) and undernutrition (starvation, environmental enteropathy). In conditions of overnutrition, high fat, simple sugar, low fiber foods typical of western diets promote small intestinal microbes (which have been largely neglected by the scientific community) that promote fat digestion and absorption. This increases our capacity to assimilate dietary fats which can contribute to the overnutrition problem. In conditions of undernutrition, these types of gut microbes are lost or minimally represented. Thus, when nutritional repletion is started, the gut’s ability to upregulate its capacity for dietary lipid digestion and absorption is compromised.