Chewing the Fat with Microbes: Lipid Crosstalk in the Gut

Abstract

It is becoming increasingly important for any project aimed at understanding the effects of diet on human health, to also consider the combined effect of the trillions of microbes within the gut which modify and are modified by dietary nutrients. A healthy microbiome is diverse and contributes to host health, partly via the production and subsequent host absorption of secondary metabolites. Many of the beneficial bacteria in the gut rely on specific nutrients, such as dietary fiber, to survive and thrive. In the absence of those nutrients, the relative proportion of good commensal bacteria dwindles while communities of opportunistic, and potentially pathogenic, bacteria expand. Therefore, it is unsurprising that both diet and the gut microbiome have been associated with numerous human diseases. Inflammatory bowel diseases and colorectal cancer are associated with the presence of certain pathogenic bacteria and risk increases with consumption of a Western diet, which is typically high in fat, protein, and refined carbohydrates, but low in plant-based fibers. Indeed, despite increased screening and better care, colorectal cancer is still the 2nd leading cause of cancer death in the US and is the 3rd most diagnosed cancer among US men and women. Rates are rising worldwide as diets are becoming more westernized, alongside rising rates of metabolic diseases like obesity and diabetes. Understanding how a modern diet influences the microbiota and how subsequent microbial alterations effect human health will become essential in guiding personalized nutrition and healthcare in the future. Herein, we will summarize some of the latest advances in understanding of the three-way interaction between the human host, the gut microbiome, and the specific class of dietary nutrients, lipids.

Research progress of gut microbiota and obesity caused by high-fat diet

“…Previous research has provided evidence that a HFD can lead to obesity, inflammation, and enhance gut epithelial cell permeability ( Lemons and Liu, 2022 ). The mechanism through which HFD induces increased gut permeability involves several processes ( Figure 1 ).…”

From Gut Microbiota through Low-Grade Inflammation to Obesity: Key Players and Potential Targets

“…Indeed, studies in mice demonstrated that increased Firmicutes abundance is related to a greater fat deposition despite the lower chow intake, likely through the reduction of energy expenditure. This suggests that the gut microbiota is a key regulator of body fat storage [ 8 , 9 ]. In addition, as recently reviewed [ 10 , 11 ], the gut microbiota might influence the endocrine signals to the hypothalamus (both orexigenic and anorexigenic hormones), thus influencing food intake.…”