Recent advances and health implications of dietary fasting regimens on the gut microbiome

Abstract

Calorie restriction is a primary dietary intervention demonstrated over many decades in cellular and animal models to modulate aging pathways, positively affect age-associated diseases, and, in clinical studies, to promote beneficial health outcomes. Because long-term compliance with daily calorie restriction has proven problematic in humans several intermittent fasting (IF) regimens, including alternate day fasting (ADF) and time-restricted feeding (TRF), have evolved revealing similar clinical benefits as calorie restriction. Despite significant research on the cellular and physiological mechanisms contributing to, and responsible for, these observed benefits, relatively little research has investigated the impact of these various fasting protocols on the gut microbiome (GM). Reduced external nutrient supply to the gut may beneficially alter the composition and function of a 'fed' gut microflora. Indeed, the prevalent, obesogenic Western diet can promote deleterious changes in the GM, signaling intermediates involved in lipid and glucose metabolism, and immune responses in the gastrointestinal tract. This review describes recent preclinical and clinical effects of varying fasting regimens on GM composition and associated physiology. Although the number of preclinical and clinical interventions are limited, significant data thus far suggest fasting interventions impact GM composition and physiology. However, there are considerable heterogeneities of study design, methodological considerations, and practical implications. Ongoing research on the health impact of fasting regimes on GM modulation is warranted.

Intermittent fasting two days versus one day per week, matched for total energy intake and expenditure, increases weight loss in overweight/obese men and women

“…As noted previously, we postulate IF2-P participants experienced enhanced ketogenesis compared to IF1-P participants, and previous research suggests a complex ketone-mediated suppression of some measures of hunger or appetite [ 46 ]. Finally, our findings may be mediated through gut microbiome alterations as the gut-brain axis is emerging as an important regulator of appetite and food reward signaling [ 47 ], an understudied and nascent topic of intense investigation [ 48 ].…”

Lipopolysaccharide and the gut microbiota: considering structural variation

“…Importantly, different microbial taxa within the GM have different abundance and may localize in a diverse manner. For example, during periods of significant energy restriction or dietary fasting, some taxa may congregate proximal to the intestinal epithelium, feeding off host‐derived mucin [49]. Conversely, during periods of increased nutrient intake, there may be less competition between microbes for energy substrate and less encroachment.…”

Microbiota and body weight control: Weight watchers within?

“…Recent literature reviews have summarized the effects of IF on the gut microbiota [ 304 , 305 ] ( Figure 4 ). In healthy mice, one month of ADF intervention led to an increase Lactobacillaceae , Bacteroidaceae , and Prevotellaceae family bacteria, whereas one month of 16-hour TRF was linked with an increase in A. muciniphila and a decrease in Alistipes genus bacteria [ 306 , 307 ].…”