Diet, the Gut Microbiome, and Epigenetics

Abstract

Increasingly, the gut microbiome is implicated in the etiology of cancer, not only as an infectious agent, but also by altering exposure to dietary compounds that influence disease risk. While the composition and metabolism of the gut microbiome is influenced by diet, the gut microbiome can also modify dietary exposures in ways that are beneficial or detrimental to the human host. The colonic bacteria metabolize macronutrients, either as specialists or in consortia of bacteria, in a variety of diverse metabolic pathways. Microbial metabolites of diet can also be epigenetic activators of gene expression that may influence cancer risk in humans. Epigenetic involves heritable changes in gene expression via post translational and post transcriptional modifications. Microbial metabolites can influence epigenetics by altering the pool of compounds used for modification or by directly inhibiting enzymes involved in epigenetic pathways. Colonic epithelium is immediately exposed to these metabolites, although some metabolites are also found in systemic circulation. In this review, we discuss the role of the gut microbiome in dietary metabolism and how microbial metabolites may influence gene expression linked to colon cancer risk.

EGCG Prevents High Fat Diet‐Induced Changes in Gut Microbiota, Decreases of DNA Strand Breaks, and Changes in Expression and DNA Methylation of Dnmt1 and MLH1 in C57BL/6J Male Mice

“…However, above small-intestinal absorption, tea catechins could reach the large intestine and be processed by gut microbiota into gallic acid and epigallocatechin (EGC) [26, 27]. Alterations in gut microbiota composition and differences in gut microbial metabolite profile due to different dietary feeding offer insights that may be relevant for several chronic conditions, including obesity.…”

Broad-Spectrum Antibiotic Abuse and its Connection to Obesity

“…In 1900, 30.4% of all deaths occurred in children less than the age of 5. The leading causes of death were pneumonia, tuberculosis, and diarrhea, accounting for one third of all deaths [12 a].…”

“…In recent years, it has been discovered that microbiome composition is a key environmental factor that drives human genetic expression, with the power to turn genes on and off based on the ratios of microbes present [30]. In this regard, there are no good or bad bacteria when they are maintained in normal ratios.…”

The Impact of Traditional Food and Lifestyle Behavior on Epigenetic Burden of Chronic Disease

“…[211] Consumption of higher amounts of dietary fiber has been linked with a distinct gut microbiome often leading to production of higher amounts of butyrate, which is a histone deacetylase inhibitor that could potentially induce epigenetic modifications. [227,228] There is evidence that short chain fatty acids (SCFA) like butyrate can be absorbed after production in the gut, [229] thereby potentially reaching the placenta and growing fetus in pregnant women to induce placental histone modifications and possibly other epigenetic effects [230] and fetal epigenetic reprograming with consequently increased risk of adult NCCDs. [231] In general, dietary factors can influence the gut microbiota through promoting the preferential growth of some microbiota over others, with resultant production of metabolites such as SCFA and methyl donors that circulate through the blood to reach their target organs and induce DNA methylation changes or histone modifications.…”