Fecal microbiome as determinant of the effect of diet on colorectal cancer risk: comparison of meat-based versus pesco-vegetarian diets (the MeaTIc study)

Association of Life's Essential 8 with all-cause mortality and risk of cancer: a prospective cohort study

BACKGROUND

No study has concentrated on the association of LE8 with cancer risk and death. We aim to examine the association of LE8 with death and cancer.

METHODS

A total of 94733 adults aged 51.42 ± 12.46 years and 77551 participants aged 54.09±12.06 years were enrolled in longitudinal and trajectory analysis respectively. Baseline LE8 was divided into three groups based on the American Heart Association criteria and three trajectory patterns by latent mixture models. We reviewed medical records and clinical examinations to confirm incident cancer during the period from 2006 to 2020. Death information was collected from provincial vital statistics offices. Cox models were used.

RESULTS

12807 all-cause deaths and 5060 cancers were documented during a 14-year follow-up. Relative to participants with high LE8 at baseline, participants with lower levels of LE8 have a significantly increased risk of mortality and incident cancer. All these risks have an increasing trend with LE8 level decreasing. Meanwhile, the trajectory analysis recorded 7483 all-cause deaths and 3037 incident cancers after approximately 10 years. The associations of LE8 with death and cancer were identical to the longitudinal study. In the subtype cancer analysis, LE8 has a strong effect on colorectal cancer risk. Moreover, the cut point is 56.67 in the association between LE8 and death, while the cut point altered to 64.79 in the association between LE8 and incident cancers. These associations were enhanced among younger adults.

CONCLUSIONS

There was a significant association of LE8 with death and cancer risk, especially for the young population.

Surfeit folic acid, protein, and exercise modify oncogenic inflammatory biomarkers and fecal microbiota

Intestinal microbiota, diet, and physical activity are inextricably linked to inflammation occurring in the presence of tumor progression and declining neurocognition. This study aimed to explore how fecal microbiota, inflammatory biomarkers, and neurocognitive behavior are influenced by voluntary exercise and surplus dietary protein and folic acid which are common health choices. Dietary treatments provided over 8 weeks to C57BL/CJ male mice (N = 76) were: Folic Acid (FA) Protein (P) Control (FPC, 17.9% P; 2 mgFA/kg); Folic Acid Deficient (FAD); Folic Acid Supplemented (FAS; 8 mgFA/kg); Low Protein Diet (LPD, 6% P); and High Protein Diet (HPD, 48% P). FAS mice had decreased plasma HCys (p < 0.05), therefore confirming consumption of FA. Objectives included examining influence of exercise using Voluntary Wheel Running (VWR) upon fecal microbiota, inflammatory biomarkers C - reactive protein (CRP), Vascular Endothelial Growth Factor (VEGF), Interleukin-6 (IL-6), nuclear factor kappa ß subunit (NF-κßp65), Caspase-3 (CASP3), Tumor Necrosis Factor-alpha (TNF-α), and neurocognitive behavior. CRP remained stable, while a significant exercise and dietary effect was notable with decreased VEGF (p < 0.05) and increased CASP3 (p < 0.05) for exercised HPD mice. Consumption of FAS did significantly increase (p < 0.05) muscle TNF-α and the ability to build a nest (p < 0.05) was significantly decreased for both FAD and LPD exercised mice. Rearing behavior was significantly increased (p < 0.05) in mice fed HPD. An emerging pattern with increased dietary protein intake revealed more distance explored in Open Field Testing. At week 1, both weighted and unweighted UniFrac principal coordinates analysis yielded significant clustering (permanova, p ≤ 0.05) associated with the specific diets. Consumption of a HPD diet resulted in the most distinct fecal microbiota composition. At the phylum level-comparing week 1 to week 8-we report a general increase in the Firmicutes/Bacteroidetes ratio, characterized by an outgrowth of Firmicutes by week 8 in all groups except the HPD. MaAsLin2 analysis corroborates this finding and emphasizes an apparent inversion of the microbiome composition at week 8 after HPD. Explicit modification of oncogenic inflammatory biomarkers and fecal microbiome post high FA and protein intake along with voluntary exercise contributed to current underlying evidence that this diet and exercise relationship has broader effects on human health and disease-perhaps importantly as a practical modulation of cancer progression and declining neurocognition.

Berberine inhibits high fat diet-associated colorectal cancer through modulation of the gut microbiota-mediated lysophosphatidylcholine

Dietary fat intake is positively associated with elevated risk of colorectal cancer (CRC). Currently, clinical treatments remian inadequate bacause of the complex pathogenesis of CRC induced by a high-fat diet (HFD). Mechanistically, imbalances in gut microbiota are associated with HFD-associated colorectal tumourigenesis. Therefore, we investigated the anti-tumor activity of berberine (BBR) in modulating the dysregulated gut microbiota and related metabolites by preforming 16S rDNA sequencing and liquid chromatography/mass spectrometry. As expected, BBR treatment significantly decreased the number of colonic polyps, ameliorated gut barrier disruption, and inhibited colon inflammation and related oncogenic pathways in AOM/DSS-induced CRC model mice fed with an HFD. Furthermore, BBR alleviated gut microbiota dysbiosis and increased the abundance of beneficial gut microorganisms, including Akkermansia and Parabacteroides, in HFD-fed CRC mice. In addition, metabolomics analysis demonstrated significantly altered the glycerophospholipid metabolism during the progression of HFD-associated CRC in mice, whereas BBR treatment reverted these changes in glycerophospholipid metabolites, particularly lysophosphatidylcholine (LPC), which was confirmed to promote CRC cell proliferation and ameliorate cell junction impairment. Notably, BBR had no clear anti-tumor effects on HFD-fed CRC model mice with gut microbiota depletion, whereas transplantation of BBR-treated gut microbiota to gut microbiota-depleted CRC mice recapitulated the inhibitory effects of BBR on colorectal tumourigenesis and LPC levels. This study demonstrated that BBR inhibited HFD-associated CRC directly through modulating gut microbiota-regulated LPC levels, thereby providing a promising microbiota-modulating therapeutic strategy for the clinical prevention and treatment of Western diet-associated CRC.

Dietary modulation of gut microbiota in patients with colorectal cancer undergoing surgery: A review

Colorectal cancer (CRC) is the third most frequent malignancy and the second cause of cancer death worldwide. Several factors have been postulated to be involved in CRC pathophysiology, including physical inactivity, unhealthy dietary habits, obesity, and the gut microbiota. Emerging data suggest that the microbiome may play a key role in CRC prognosis and derived complications in patients undergoing colorectal surgery. On the other hand, dietary intervention has been demonstrated to be able to induce significant changes in the gut microbiota and related metabolites in different conditions; therefore, the manipulation of gut microbiota through dietary intervention may constitute a useful approach to improve perioperative dysbiosis and post-surgical outcomes in patients with CRC. In this article, we review the role of the gut microbiota in CRC surgery complications and the potential therapeutic modulation of gut microbiome through nutritional intervention in patients with CRC undergoing surgery.

Effect of gut microbiota in the colorectal cancer and potential target therapy

The symbiotic interaction between gut microbiota and the digestive tract is an important factor in maintaining the intestinal environment balance. Colorectal cancer (CRC) is a complex disease involving the interaction between tumour cells and a large number of microorganisms. The microbiota is involved in the occurrence, development and prognosis of colorectal cancer. Several microbiota species have been studied, such as Fusobacterium nucleatum (F. nucleatum), Enterotoxigenic Bacteroides fragilis (ETBF), Streptococcus bovis (S. bovis), Lactobacillus, and Bifidobacterium. Studies about the interaction between microbiota and CRC were retrieved from Embase, PubMed, Ovid and Web of Science up to 21 Oct 2021. This review expounded on the effect of microbiota on CRC, especially the dysregulation of bacteria and carcinogenicity. The methods of gut microbiota modifications representing novel prognostic markers and innovative therapeutic strategies were also described.

The comet assay for the evaluation of gut content genotoxicity: Use in human studies as an early biomarker of colon cancer risk

This short narrative review describes the use of the comet assay to evaluate the formation of genotoxic compounds in the gut lumen in human studies. The fecal water genotoxicity assay is based on ability of the gut content to induce genotoxicity in a cellular model, employing the aqueous component of the feces (fecal water) as this is supposed to contain most of the reactive species and to convey them to the intestinal epithelium. This non-invasive and low-cost assay has been demonstrated to be associated with colon cancer risk in animal models, and although the final validation against human tumors is lacking, it is widely used as a colo-rectal cancer risk biomarker in human nutritional intervention studies. The contribution given to the field of nutrition and cancer by the FW genotoxicity assay is highlighted, particularly in conjunction with other risk biomarkers, to shed light on the complex relationship among diet, microbiota, individual subject characteristics and the formation of genotoxic compounds in the gut.

Importance of ideal cardiovascular health metrics in the risk of colorectal cancer among people aged 50 years or older: a UK Biobank cohort study

OBJECTIVE

To explore the correlation between the ideal cardiovascular health metrics (ICVHMs) and the incidence of colorectal cancer (CRC) among people aged 50 years or older.

DESIGN

Prospective cohort study.

SETTING

The UK Biobank, a prospective cohort of middle-aged participants recruited between 2006 and 2010.

PARTICIPANTS

The study included 342 226 participants from the UK Biobank aged 50 years or older without prevalent cancer.

EXPOSURE

The ICVHMs consist of four behavioural factors (abstinence from smoking, ideal body mass index (BMI), physical activity at goal and consumption of healthy diet) and three cardiometabolic factors (untreated total cholesterol <200 mg/dL, untreated blood pressure <120/80 mm Hg and untreated fasting plasma glucose <100 mg/dL).

MAIN OUTCOMES

The outcome was ascertained by linkage to cancer and death registries using the International Classification of Diseases, Tenth codes C18-C20.

RESULTS

During a median follow-up time of 8.72 years, 3060 CRC cases were identified. Compared with the reference (participants with ICVHMs ≤2), the multivariable-adjusted HRs for subgroups with 3, 4, 5 and ≥6 ICVHM factors were 0.98 (95% CI 0.85 to 1.12), 0.90 (95% CI 0.77 to 1.02), 0.85 (95% CI 0.71 to 0.98) and 0.69 (95% CI 0.48 to 0.90), respectively. Among the seven ICVHM factors, lower BMI, healthier diet and ideal fasting plasma glucose were significantly associated with lower risk of CRC (HR: 0.86, 95% CI 0.78 to 0.95; HR: 0.92, 95% CI 0.84 to 0.99; HR: 0.90, 95% CI 0.80 to 0.99).

CONCLUSIONS

Adherence to the ICVHMs was associated with a lower risk of CRC among people aged 50 years or older. Among the seven ICVHM factors, BMI, diet and fasting plasma glucose played a more critical role in the prevention of CRC. These findings imply that adherence to ICVHMs should be encouraged to reduce the burden of cardiovascular disease as well as CRC.

Diet-gut microbiota interactions on cardiovascular disease

Cardiovascular diseases (CVD) are a group of disorders of the heart and blood vessels and remain the leading cause of morbidity and mortality worldwide. Over the past decades, accumulating studies indicated that the gut microbiota, an indispensable "invisible organ", plays a vital role in human metabolism and disease states including CVD. Among many endogenous and exogenous factors that can impact gut microbial communities, the dietary nutrients emerge as an essential component of host-microbiota relationships that can be involved in CVD susceptibility. In this review, we summarize the major concepts of dietary modulation of the gut microbiota and the chief principles of the involvement of this microbiota in CVD development. We also discuss the mechanisms of diet-microbiota crosstalk that regulate CVD progression, including endotoxemia, inflammation, gut barrier dysfunction and lipid metabolism dysfunction. In addition, we describe how metabolites produced by the microbiota, including trimethylamine-N-oxide (TMAO), secondary bile acids (BAs), short chain fatty acids (SCFAs) as well as aromatic amino acids (AAAs) derived metabolites play a role in CVD pathogenesis. Finally, we present the potential dietary interventions which interacted with gut microbiota as novel preventive and therapeutic strategies for CVD management.

Emerging Evidence on the Effects of Dietary Factors on the Gut Microbiome in Colorectal Cancer

Dietary factors have important role in modulating the gut microbiome, which in-turn regulates the molecular events in colonic mucosa. The composition and resulting metabolism of the gut microbiome are decisive factors in colorectal cancer (CRC) tumorigenesis. Altered gut microbiome is associated with impaired immune response, and the release of carcinogenic or genotoxic substances which are the major microbiome-induced mechanisms implicated in CRC pathogenesis. Diets low in dietary fibers and phytomolecules as well as high in red meat are important dietary changes which predispose to CRC. Dietary fibers which reach the colon in an undigested form are further metabolized by the gut microbiome into enterocyte friendly metabolites such as short chain fatty acid (SCFA) which provide anti-inflammatory and anti-proliferative effects. Healthy microbiome supported by dietary fibers and phytomolecules could decrease cell proliferation by regulating the epigenetic events which activate proto-oncogenes and oncogenic pathways. Emerging evidence show that predominance of microbes such as Fusobacterium nucleatum can predispose the colonic mucosa to malignant transformation. Dietary and lifestyle modifications have been demonstrated to restrict the growth of potentially harmful opportunistic organisms. Synbiotics can protect the intestinal mucosa by improving immune response and decreasing the production of toxic metabolites, oxidative stress and cell proliferation. In this narrative review, we aim to update the emerging evidence on how diet could modulate the gut microbial composition and revive colonic epithelium. This review highlights the importance of healthy plant-based diet and related supplements in CRC prevention by improving the gut microbiome.

Genotoxic effect of meat consumption: A mini review

In 2015, the International Agency for Research on Cancer classified the consumption of processed meat as carcinogenic to humans (Group 1) and red meat as probably carcinogenic to humans (Group 2A) based on sufficient data from animal models and epidemiological studies. However, research characterising the mechanisms underlying this carcinogenic process in humans are limited, particularly with respect to measures of direct DNA damage. The current review sought to evaluate and summarize the recent literature, published since 2000, regarding the associations of meat consumption and three biomarkers of genotoxicity in humans: DNA strand breaks (measured using the comet assay), DNA adducts, and micronucleus formation. After screening 230 potential articles, 35 were included, and then were classified as experimental or observational in design, the latter of which were further categorized according to their dietary assessment approach. Among the 30 observational studies, 4 of which used two different assays, 3 of 5 comet assay studies, 13 of 20 DNA adduct studies, and 7 of 9 micronucleus studies reported a positive association between meat consumption and DNA damage. Among the 5 experimental studies, 1 of 1 using the comet assay, 3 of 3 measuring DNA adducts and 0 of 1 measuring micronuclei reported significant positive associations with meat consumption. Nevertheless, common limitations among the selected publications included small sample size, and poor methodological reporting of both exposure and outcome measures. Moreover, the vast majority of studies only measured DNA damage in one biological sample using a single assay and we cannot exclude the possibility of publication bias. Ultimately, our review of the literature, published since 2000, revealed a preponderance of studies that support mechanisms of genotoxicity in playing an important role in the meat-cancer association.

Mycotoxin and Gut Microbiota Interactions

The interactions between mycotoxins and gut microbiota were discovered early in animals and explained part of the differences in susceptibility to mycotoxins among species. Isolation of microbes present in the gut responsible for biotransformation of mycotoxins into less toxic metabolites and for binding mycotoxins led to the development of probiotics, enzymes, and cell extracts that are used to prevent mycotoxin toxicity in animals. More recently, bioactivation of mycotoxins into toxic compounds, notably through the hydrolysis of masked mycotoxins, revealed that the health benefits of the effect of the gut microbiota on mycotoxins can vary strongly depending on the mycotoxin and the microbe concerned. Interactions between mycotoxins and gut microbiota can also be observed through the effect of mycotoxins on the gut microbiota. Changes of gut microbiota secondary to mycotoxin exposure may be the consequence of the antimicrobial properties of mycotoxins or the toxic effect of mycotoxins on epithelial and immune cells in the gut, and liberation of antimicrobial peptides by these cells. Whatever the mechanism involved, exposure to mycotoxins leads to changes in the gut microbiota composition at the phylum, genus, and species level. These changes can lead to disruption of the gut barrier function and bacterial translocation. Changes in the gut microbiota composition can also modulate the toxicity of toxic compounds, such as bacterial toxins and of mycotoxins themselves. A last consequence for health of the change in the gut microbiota secondary to exposure to mycotoxins is suspected through variations observed in the amount and composition of the volatile fatty acids and sphingolipids that are normally present in the digesta, and that can contribute to the occurrence of chronic diseases in human. The purpose of this work is to review what is known about mycotoxin and gut microbiota interactions, the mechanisms involved in these interactions, and their practical application, and to identify knowledge gaps and future research needs.

The Microbiome and Cancer: Creating Friendly Neighborhoods and Removing the Foes Within

The human body is colonized by the microbial cells that are estimated to be as abundant as human cells, yet their genome is roughly 100 times the human genome, providing significantly more genetic diversity. The past decade has observed an explosion of interest in examining the existence of microbiota in the human body and understanding its role in various diseases including inflammatory bowel disease, neurologic diseases, cardiovascular disorders, and cancer. Many studies have demonstrated differential community composition between normal tissue and cancerous tissue, paving the way for investigations focused on deciphering the cause-and-effect relationships between specific microbes and initiation and progression of various cancers. Also, evolving are the strategies to alter tumor-associated dysbiosis and move it toward eubiosis with holistic approaches to change the entire neighborhood or to neutralize pathogenic strains. In this review, we discuss important pathogenic bacteria and the underlying mechanisms by which they affect cancer progression. We summarize key microbiota alterations observed in multiple tumor niches, their association with clinical stages, and their potential use in cancer diagnosis and management. Finally, we discuss microbiota-based therapeutic approaches.

The Role of the Gut Microbiome in Colorectal Cancer Development and Therapy Response

Colorectal cancer (CRC) is the third most common cancer worldwide and the leading cause of cancer-related deaths. Recently, several studies have demonstrated that gut microbiota can alter CRC susceptibility and progression by modulating mechanisms such as inflammation and DNA damage, and by producing metabolites involved in tumor progression or suppression. Dysbiosis of gut microbiota has been observed in patients with CRC, with a decrease in commensal bacterial species (butyrate-producing bacteria) and an enrichment of detrimental bacterial populations (pro-inflammatory opportunistic pathogens). CRC is characterized by altered production of bacterial metabolites directly involved in cancer metabolism including short-chain fatty acids and polyamines. Emerging evidence suggests that diet has an important impact on the risk of CRC development. The intake of high-fiber diets and the supplementation of diet with polyunsaturated fatty acids, polyphenols and probiotics, which are known to regulate gut microbiota, could be not only a potential mechanism for the reduction of CRC risk in a primary prevention setting, but may also be important to enhance the response to cancer therapy when used as adjuvant to conventional treatment for CRC. Therefore, a personalized modulation of the pattern of gut microbiome by diet may be a promising approach to prevent the development and progression of CRC and to improve the efficacy of antitumoral therapy.