scholarly journals Dietary Fiber, Gut Microbiota, and Metabolic Regulation—Current Status in Human Randomized Trials

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 859 ◽  
Author(s):  
Mari C. W. Myhrstad ◽  
Hege Tunsjø ◽  
Colin Charnock ◽  
Vibeke H. Telle-Hansen

New knowledge about the gut microbiota and its interaction with the host’s metabolic regulation has emerged during the last few decades. Several factors may affect the composition of the gut microbiota, including dietary fiber. Dietary fiber is not hydrolyzed by human digestive enzymes, but it is acted upon by gut microbes, and metabolites like short-chain fatty acids are produced. The short-chain fatty acids may be absorbed into the circulation and affect metabolic regulation in the host or be a substrate for other microbes. Some studies have shown improved insulin sensitivity, weight regulation, and reduced inflammation with increases in gut-derived short-chain fatty acids, all of which may reduce the risk of developing metabolic diseases. To what extent a dietary intervention with fiber may affect the human gut microbiota and hence metabolic regulation, is however, currently not well described. The aim of the present review is to summarize recent research on human randomized, controlled intervention studies investigating the effect of dietary fiber on gut microbiota and metabolic regulation. Metabolic regulation is discussed with respect to markers relating to glycemic regulation and lipid metabolism. Taken together, the papers on which the current review is based, suggest that dietary fiber has the potential to change the gut microbiota and alter metabolic regulation. However, due to the heterogeneity of the studies, a firm conclusion describing the causal relationship between gut microbiota and metabolic regulation remains elusive.

2020 ◽  
pp. 153537022097995
Author(s):  
Jisun HJ Lee ◽  
Jiangjiang Zhu

As an alternative to pharmacological treatment to diseases, lifestyle interventions, such as dietary changes and physical activities, can help maintain healthy metabolic conditions. Recently, the emerging analyses of volatile organic compounds (VOCs) from breath and short-chain fatty acids (SCFAs) from plasma/feces have been considered as useful tools for the diagnosis and mechanistic understanding of metabolic diseases. Furthermore, diet-induced changes of SCFAs in individuals with diagnosed metabolic abnormalities have been correlated with the composition changes of the gut microbiome. More interestingly, the analysis of exhaled breath (breathomics) has gained attention as a useful technique to measure the human VOC profile altered as a result of dietary interventions. In this mini-review, we examined recent clinical trials that performed promising dietary interventions, SCFAs analysis in plasma/feces, and VOC profile analysis in exhaling breath to understand the relationship between dietary intervention and metabolic health.


2020 ◽  
Vol 21 (3) ◽  
pp. 910 ◽  
Author(s):  
Jun-Li Liu ◽  
Irina Segovia ◽  
Xiao-Lin Yuan ◽  
Zu-hua Gao

In the past 15 years, gut microbiota emerged as a crucial player in health and disease. Enormous progress was made in the analysis of its composition, even in the discovery of novel species. It is time to go beyond mere microbiota-disease associations and, instead, provide more causal analyses. A key mechanism of metabolic regulation by the gut microbiota is through the production of short-chain fatty acids (SCFAs). Acting as supplemental nutrients and specific ligands of two G-protein-coupled receptors (GPCRs), they target the intestines, brain, liver, and adipose tissue, and they regulate appetite, energy expenditure, adiposity, and glucose production. With accumulating but sometimes conflicting research results, key questions emerged. Do SCFAs regulate pancreatic islets directly? What is the effect of β-cell-specific receptor deletions? What are the mechanisms used by SCFAs to regulate β-cell proliferation, survival, and secretion? The receptors FFA2/3 are normally expressed on pancreatic β-cells. Deficiency in FFA2 may have caused glucose intolerance and β-cell deficiency in mice. However, this was contrasted by a double-receptor knockout. Even more controversial are the effects of SCFAs on insulin secretion; there might be no direct effect at all. Unable to draw clear conclusions, this review reveals some of the recent controversies.


2017 ◽  
Vol 106 (4) ◽  
pp. 352-356 ◽  
Author(s):  
Gilles Mithieux

A large number of genomic studies have reported associations between the gut microbiota composition and metabolic diseases such as obesity or type 2 diabetes. This led to the widespread idea that a causal relationship could exist between intestinal microbiota and metabolic diseases. At odds with this idea, some compelling studies reported that global changes in microbiota composition have no effect on the host metabolism in obese mice or humans. However, specific bacteria are able to confer host metabolic benefits, such as Akkermansia muciniphila or Prevotella copri, when they are given by gavage in obese mice. A crucial link by which gut bacteria communicate with the host mucosa is based on metabolites or low-molecular-weight compounds. Among them, short-chain fatty acids produced from the fermentation of dietary fibers initiate beneficial effects on the host metabolism via the activation of intestinal gluconeogenesis (a mucosal function exerting antidiabetic and antiobesity effects through the activation of gut-brain neural circuits). However, fermentation of short-chain fatty acids is a function that is widespread among the main bacterial phyla and thus weakly depends on microbiota composition. Therefore, even if some bacteria may confer on the host metabolic benefits, the causal role of microbiota in metabolic diseases is not established.


2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Anna M. Malinowska ◽  
Marcin Schmidt ◽  
Malgorzata Majcher ◽  
Hanna Przydatek ◽  
Marta Szaban ◽  
...  

AbstractSome species of gut bacteria produce short-chain fatty acids (SCFAs) from dietary fiber—mainly acetate, propionate, and butyrate. The composition of human gut microbiota is dependent on dietary intake and health status. The aim of this study was to assess the effect of diet and anthropometric parameters on the potential of gut microbiota to metabolize dietary fiber and produce SCFA.A group of 200 men and women aged 31 to 50 years old participated in the study. The diet was assessed using three-day dietary records and the dietary pattern was determined using score methods. The potential to utilize water-insoluble fiber was assessed by measuring the β-glucosidase enzymatic activity of dissolved feces. To estimate the potential to metabolize water-soluble dietary fiber, cultures containing feces and pectin were incubated under anaerobic conditions for 24 hours. The amounts of fiber, acetic acid, propionic acid, and butyric acid before and after incubation were measured.Pectin utilization correlated positively with the amount of energy intake from fat (r = 0.19) and with the intake of nuts and seeds (r = 0.17) and was negatively correlated with the amount of energy from complex carbohydrates (r = -0.16) and its sources, such as refined grain products (r = -0.15). The dietary pattern did not affect the potential of the gut microbiota to metabolize pectin, but did influence the potential to digest insoluble dietary fiber, as the subjects following the western dietary pattern had lower potential than those following the rational pattern. β-glucosidase activity correlated positively with the intake of dietary fiber (r = 0.19) and intake of its sources, such as fruits (r = 0.18), vegetables (r = 0.21), and nuts and seeds (r = 0.18); it correlated negatively with nonalcoholic beverage intake (r = -0.15) and sugar and honey intake (r = -0.16). The potential to synthesize acetic acid correlated negatively with dietary indices and dietary fiber intake (r = -0.18). The potential to synthesize propionic acid correlated negatively with hip and waist circumference (r = -0.14, -0.15, respectively). The potentials to synthesize both propionic and butyric acid were affected by the intake of nuts and seeds (r = 0.18, 0.21, respectively).Diet affects the potential of gut microbiota to utilize dietary fiber and to produce SCFAs. The impact of anthropometry parameters was only seen on the potential to synthesize propionic acid.


2021 ◽  
Author(s):  
Ceren Gezer ◽  
Gözde Okburan

While all prebiotics are accepted as dietary fibers, not all dietary fibers are accepted as prebiotics. Fructo-oligosaccharides and galacto-oligosaccharides are significant prebiotic dietary fibers related with the regulation of weight management. They, selectively stimulate the growth of bifidobacteria and lactobacillus, thus help to modulate gut microbiota. Since bifiodobacteria population are responsible for energy scavenging they are playing a vital role in the weight management. In addition, prebiotics fermented to short chain fatty acids by gut microbiota, whose presence in the large intestine is responsible for many of the metabolic effects and prevent metabolic diseases such as obesity. Short chain fatty acids via different mechanisms also stimulate satiety hormones such as GLP-1 and PYY, and shift glucose and lipid metabolism. To conclude, prebiotic dietary fibers beneficially impact the gut microbiota thus can be effective on regulation of weight management. There is a need for further clinical trials to explain more comprehensively the effects of dietary prebiotics on weight management.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yeshun Wu ◽  
Hongqing Xu ◽  
Xiaoming Tu ◽  
Zhenyan Gao

Hypertension is a significant risk factor for cardiovascular and cerebrovascular diseases, and its development involves multiple mechanisms. Gut microbiota has been reported to be closely linked to hypertension. Short-chain fatty acids (SCFAs)—the metabolites of gut microbiota—participate in hypertension development through various pathways, including specific receptors, immune system, autonomic nervous system, metabolic regulation and gene transcription. This article reviews the possible mechanisms of SCFAs in regulating blood pressure and the prospects of SCFAs as a target to prevent and treat hypertension.


2020 ◽  
Vol 15 (1) ◽  
pp. 52-56
Author(s):  
Sri Winarti ◽  
Agung Pasetyo

The consumption of prebiotics is known to affect the balance of gut microbiota. The purpose of this study was to explore how a galactomannan-rich effervescent drink can affect the population of Lactobacillus, Bifidobacterium, E. coli, and the concentration of short-chain fatty acids in the cecum of rats. Twenty-eight male Wistar rats (aged 2 months) were divided equally into 7 groups and treated orally each day for 15 days with 2 mL effervescent drinks with increasing levels of prebiotic galactomannan. The dosage of 500 mg galactomannan increased the growth of Lactobacillus spp. and Bifidobacterium spp. with inhibition of the growth of E.coli with increased formation of short-chain fatty acids such as acetate, propionate, and butyrate in the cecum of rats.


2020 ◽  
Vol 70 ◽  
pp. 20-22 ◽  
Author(s):  
Daniel Grün ◽  
Valerie C. Zimmer ◽  
Jil Kauffmann ◽  
Jörg Spiegel ◽  
Ulrich Dillmann ◽  
...  

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