scholarly journals Colon Carcinogenesis: The Interplay Between Diet and Gut Microbiota

Author(s):  
Yean Leng Loke ◽  
Ming Tsuey Chew ◽  
Yun Fong Ngeow ◽  
Wendy Wan Dee Lim ◽  
Suat Cheng Peh

Colorectal cancer (CRC) incidence increases yearly, and is three to four times higher in developed countries compared to developing countries. The well-known risk factors have been attributed to low physical activity, overweight, obesity, dietary consumption including excessive consumption of red processed meats, alcohol, and low dietary fiber content. There is growing evidence of the interplay between diet and gut microbiota in CRC carcinogenesis. Although there appears to be a direct causal role for gut microbes in the development of CRC in some animal models, the link between diet, gut microbes, and colonic carcinogenesis has been established largely as an association rather than as a cause-and-effect relationship. This is especially true for human studies. As essential dietary factors influence CRC risk, the role of proteins, carbohydrates, fat, and their end products are considered as part of the interplay between diet and gut microbiota. The underlying molecular mechanisms of colon carcinogenesis mediated by gut microbiota are also discussed. Human biological responses such as inflammation, oxidative stress, deoxyribonucleic acid (DNA) damage can all influence dysbiosis and consequently CRC carcinogenesis. Dysbiosis could add to CRC risk by shifting the effect of dietary components toward promoting a colonic neoplasm together with interacting with gut microbiota. It follows that dietary intervention and gut microbiota modulation may play a vital role in reducing CRC risk.

2015 ◽  
Vol 6 (4) ◽  
pp. 431-439 ◽  
Author(s):  
M. Remely ◽  
I. Tesar ◽  
B. Hippe ◽  
S. Gnauer ◽  
P. Rust ◽  
...  

Genetics, lifestyle, and dietary habits contribute to metabolic syndrome, but also an altered gut microbiota has been identified. Based on this knowledge it is suggested that host bacterial composition tends to change in response to dietary factors and weight loss. The aim of this study was to identify bacteria affecting host metabolism in obesity during weight loss and to correlate them with changes of the body composition obtained from bioelectrical impedance analysis (BIA). We recruited obese individuals receiving a dietary intervention according DACH (German, Austrian, and Swiss Society of Nutrition) reference values and guidelines for ‘prevention and therapy of obesity’ of DAG e.V., DDG, DGE e.V., and DGEM e.V. over three months. Faecal microbiota and BIA measurements were conducted at three time points, before, during, and after the intervention. Gut microbiota was analysed on the basis of 16S rDNA with quantitative real time PCR. Additionally, a food frequency questionnaire with questions to nutritional behaviour, lifestyle, and physical activity was administered before intervention. After weight reduction, obese individuals showed a significant increase of total bacterial abundance. The ratio of Firmicutes/Bacteroidetes significantly decreased during intervention. Lactobacilli significantly increased between the first and the second time point. These differences also correlated with differences in weight percentage. During the intervention period Clostridium cluster IV increased significantly between the second and the third time point. In contrast Clostridium cluster XIVa showed a decreased abundance. The dominant butyrate producer, Faecalibacterium prausnitzii, significantly increased as did the abundance of the butyryl-CoA: acetate CoA-transferase gene. Archaea and Akkermansia were significantly more prevalent after weight reduction. Our results show a clear difference in the gut bacterial composition before and after dietary intervention with a rapid change in gut microbial composition after a few weeks, but also indicate that a major shift requires long term dietary treatment.


Author(s):  
Umama Khan ◽  
S M Niazur Rahman ◽  
Nazmun Nahar Alam

With the ever-increasing rate, obesity has become an epidemiological problem throughout the globe comprising about 39% of the world population as of now. Among several reasons, disruption of the gut microbial ecosystem might contribute to the pathogenesis of metabolic disorders, including obesity, metabolic syndrome, type 2 diabetes, and other associated comorbidities. Though the mechanisms related to dysbiosis are unclear, diet might play a modulating role where different dietary approaches manipulate microbial richness and abundance as well as stability. For instance, shifting of Firmicutes and Bacteroidetes ratio in the gut might have a role in association with the dietary approaches and ingestion duration. Along with altered gut microbial composition, microbial metabolites such as short-chain fatty acids (SCFA) after ingestion of non-digestible dietary starches may have an impact on host metabolism by regulating lipogenesis, gluconeogenesis, and inflammation with potential associations to health and obesity. The dietary approaches like carbohydrates, fibre, protein, and/or fat diet at various arrangements can make a shift in the composition of gut microbiota if introduced for a short period. However, the unique pattern of the gut microbes usually remains the same along with the longer period of habitual diet. Though the short-term dietary intervention or circadian rhythm influences a transient change in gut microbes, other than habitual diet, the understanding related to long-term dietary change-induced permanent alterations is minimum. Alternatively, the usage of prebiotics, probiotics as well as postbiotics could be beneficial to overcome dysbiosis. This review highlights the current knowledge and the interaction between the human intestinal microbiota and diet as a modifying factor, in obesity allowing the scientists to uncover novel targets and tools to use as customized therapy.


Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 919
Author(s):  
Susan E. McCann ◽  
Meredith A. J. Hullar ◽  
David L. Tritchler ◽  
Eduardo Cortes-Gomez ◽  
Song Yao ◽  
...  

Lignans are phytochemicals studied extensively as dietary factors in chronic disease etiology. Our goal was to examine associations between the gut microbiota and lignan metabolism and whether these associations differ by ethnicity. We conducted a flaxseed (FS) dietary intervention in 252 healthy, postmenopausal women of African ancestry (AA) and European ancestry (EA). Participants consumed ~10 g/d ground flaxseed for 6 weeks and provided overnight urine collections and fecal samples before and after intervention. The gut microbiota was characterized using 16S rRNA gene sequencing and differences in microbial community composition compared by ethnicity and intervention status. We observed a significant difference in the composition of the microbiota measured as beta diversity (p < 0.05) between AA and EA at baseline that was attenuated with FS consumption. Genera that were significantly associated with ENL production (e.g., Klebsiella, Lactobacillus, Slackia, Senegalimassilia) were unique to each group. Bacteria (e.g., Fusobacteria, Pyramidobacter and Odoribacter) previously associated with colorectal cancer and cardiovascular disease, both diet-related chronic diseases, were unique to either AA or EA and were significantly reduced in the FS intervention. This study suggests that ethnic variation in ENL metabolism may be linked to gut microbiota composition, and its impact on disease risk deserves future investigation.


2008 ◽  
Vol 28 (01/02) ◽  
pp. 85-88 ◽  
Author(s):  
D. Fuchs ◽  
H. Daniel ◽  
U. Wenzel

SummaryEpidemiological studies indicate that the consumption of soy-containing food may prevent or slow-down the development of cardiovascular disease. In endothelial cells application of a soy extract or a combination of the most abundant soy isoflavones genistein and daidzein both inhibited apoptosis, a driving force in atherosclerosis development, when applied in combination with oxidized LDL or homocysteine. Proteome analysis revealed that the stressorinduced alteration of protein expression profile was reversed by the soy extract or the genistein/daidzein mixture. Only few protein entities that could be functionally linked to mitochondrial dysfunction were regulated in common by both application forms of isoflavones. A dietary intervention with isoflavone-enriched soy extract in postmenopausal women, who generally show strongly increased cardiovascular risk due to diminished estrogen production, led to significant alterations in the steady state levels of proteins from mononuclear blood cells. The proteins identified by proteome analysis revealed that soy isoflavones may increase the anti-inflammatory response in blood mononuclear cells thereby contributing to the atherosclerosispreventive activities of a soy-rich diet. Conclusion: By proteome analysis protein targets were identified in vitro in endothelial cells that respond to soy isoflavones and that may decipher molecular mechanisms through which soy products exert their protective effects in the vasculature.


2020 ◽  
Vol 17 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Pavan K. Mujawdiya ◽  
Suman Kapur

: Quorum Sensing (QS) is a phenomenon in which bacterial cells communicate with each other with the help of several low molecular weight compounds. QS is largely dependent on population density, and it triggers when the concentration of quorum sensing molecules accumulate in the environment and crosses a particular threshold. Once a certain population density is achieved and the concentration of molecules crosses a threshold, the bacterial cells show a collective behavior in response to various chemical stimuli referred to as “auto-inducers”. The QS signaling is crucial for several phenotypic characteristics responsible for bacterial survival such as motility, virulence, and biofilm formation. Biofilm formation is also responsible for making bacterial cells resistant to antibiotics. : The human gut is home to trillions of bacterial cells collectively called “gut microbiota” or “gut microbes”. Gut microbes are a consortium of more than 15,000 bacterial species and play a very crucial role in several body functions such as metabolism, development and maturation of the immune system, and the synthesis of several essential vitamins. Due to its critical role in shaping human survival and its modulating impact on body metabolisms, the gut microbial community has been referred to as “the forgotten organ” by O`Hara et al. (2006) [1]. Several studies have demonstrated that chemical interaction between the members of bacterial cells in the gut is responsible for shaping the overall microbial community. : Recent advances in phytochemical research have generated a lot of interest in finding new, effective, and safer alternatives to modern chemical-based medicines. In the context of antimicrobial research various plant extracts have been identified with Quorum Sensing Inhibitory (QSI) activities among bacterial cells. This review focuses on the mechanism of quorum sensing and quorum sensing inhibitors isolated from natural sources.


Author(s):  
Xiang Zhou ◽  
Jixing Guo ◽  
Mingxia Zhang ◽  
Chunxiu Bai ◽  
Zheng Wang ◽  
...  

Abstract Crematogaster rogenhoferi (Hymenoptera: Formicidae), an omnivorous ant, is one of the dominant predatory natural enemies of a soft scale pest, Parasaissetia nigra Nietner (Homoptera: Coccidae), and can effectively control P. nigra populations in rubber forests. Olfaction plays a vital role in the process of predation. However, the information about the molecular mechanism of olfaction-evoked behaviour in C. rogenhoferi is limited. In this study, we conducted antennal transcriptome analysis to identify candidate olfactory genes. We obtained 53,892 unigenes, 16,185 of which were annotated. Based on annotations, we identified 49 unigenes related to chemoreception, including four odourant-binding proteins, three chemosensory proteins, 37 odourant receptors, two odourant ionotropic receptors and three sensory neuron membrane proteins. This is the first report on the molecular basis of the chemosensory system of C. rogenhoferi. The findings provide a basis for elucidating the molecular mechanisms of the olfactory-related behaviours of C. rogenhoferi, which would facilitate a better application of C. rogenhoferi as a biological control agent.


Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1348
Author(s):  
Pratibha V. Nerurkar ◽  
Krupa Gandhi ◽  
John J. Chen

Metabolic syndrome (MetS) is prevalent not only among the overweight and obese but also normal weight individuals, and the phenotype is referred to as a metabolically unhealthy phenotype (MUHP). Besides normal weight individuals, overweight/obese individuals are also protected from MetS, and the phenotype is known as a metabolically healthy phenotype (MHP). Epidemiological studies indicate that coffee and micronutrients such as plasma folate or vitamin B12 (vit. B12) are inversely associated with MetS. However, correlations among coffee consumption metabolic phenotypes, plasma folate, and vit. B12 remain unknown. Our objective was to investigate the correlation between coffee consumption, metabolic phenotypes, plasma folate, and vit. B12 as well as to understand associations between plasma folate, vit. B12, and metabolic phenotypes. Associations among coffee consumption metabolic phenotypes, plasma folate, and vit. B12 were assessed in a cross-sectional study of 2201 participants, 18 years or older, from 2003–2004 and 2005–2006 National Health and Nutrition Examination Surveys (NHANES). MUHP was classified as having > three metabolic abnormalities. Coffee consumption was not associated with metabolic phenotypes, but negatively correlated with several metabolic variables, including BMI (p < 0.001). Plasma folate was positively associated with MUHP (p < 0.004), while vit. B12 was inversely associated with MUHP (p < 0.035). Our results suggest the potential protective impact of coffee on individual components of MetS and indicate a positive correlation between coffee consumption and MUHP among overweight individuals. Identifying possible dietary factors may provide practical and low-cost dietary intervention targets, specifically for early intervention. Larger and randomized intervention studies and prospective longitudinal studies are required to further evaluate these associations.


Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2428
Author(s):  
Małgorzata Guz ◽  
Witold Jeleniewicz ◽  
Anna Malm ◽  
Izabela Korona-Glowniak

A still growing interest between human nutrition in relation to health and disease states can be observed. Dietary components shape the composition of microbiota colonizing our gastrointestinal tract which play a vital role in maintaining human health. There is a strong evidence that diet, gut microbiota and their metabolites significantly influence our epigenome, particularly through the modulation of microRNAs. These group of small non-coding RNAs maintain cellular homeostasis, however any changes leading to impaired expression of miRNAs contribute to the development of different pathologies, including neoplastic diseases. Imbalance of intestinal microbiota due to diet is primary associated with the development of colorectal cancer as well as other types of cancers. In the present work we summarize current knowledge with particular emphasis on diet-microbiota-miRNAs axis and its relation to the development of colorectal cancer.


Author(s):  
Jonas Hauser ◽  
Edoardo Pisa ◽  
Alejandro Arias Vásquez ◽  
Flavio Tomasi ◽  
Alice Traversa ◽  
...  

AbstractBreastmilk contains bioactive molecules essential for brain and cognitive development. While sialylated human milk oligosaccharides (HMOs) have been implicated in phenotypic programming, their selective role and underlying mechanisms remained elusive. Here, we investigated the long-term consequences of a selective lactational deprivation of a specific sialylated HMO in mice. We capitalized on a knock-out (KO) mouse model (B6.129-St6gal1tm2Jxm/J) lacking the gene responsible for the synthesis of sialyl(alpha2,6)lactose (6′SL), one of the two sources of sialic acid (Neu5Ac) to the lactating offspring. Neu5Ac is involved in the formation of brain structures sustaining cognition. To deprive lactating offspring of 6′SL, we cross-fostered newborn wild-type (WT) pups to KO dams, which provide 6′SL-deficient milk. To test whether lactational 6′SL deprivation affects cognitive capabilities in adulthood, we assessed attention, perseveration, and memory. To detail the associated endophenotypes, we investigated hippocampal electrophysiology, plasma metabolomics, and gut microbiota composition. To investigate the underlying molecular mechanisms, we assessed gene expression (at eye-opening and in adulthood) in two brain regions mediating executive functions and memory (hippocampus and prefrontal cortex, PFC). Compared to control mice, WT offspring deprived of 6′SL during lactation exhibited consistent alterations in all cognitive functions addressed, hippocampal electrophysiology, and in pathways regulating the serotonergic system (identified through gut microbiota and plasma metabolomics). These were associated with a site- (PFC) and time-specific (eye-opening) reduced expression of genes involved in central nervous system development. Our data suggest that 6′SL in maternal milk adjusts cognitive development through a short-term upregulation of genes modulating neuronal patterning in the PFC.


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