Yogurt consumption and colorectal polyps

Yogurt Prevents Colorectal Tumorigenesis in ApcMin/+ Mice

SCOPE

Yogurt consumption is related to a decreased risk of colorectal cancer (CRC), but whether such association is causal remains unclear. Patients with familial adenomatous polyposis (FAP) are at increased risk of CRC development. Here, the study investigates the efficacy of yogurt for intestinal polyposis chemoprevention in ApcMin/+ mice, a preclinical model for human FAP.

METHODS AND RESULTS

A 10-week yogurt supplementation (15 g kg-1) in ApcMin/+ mice significantly reduces the intestinal polyp number (6.50 ± 0.97 versus 1.80 ± 0.49; p < 0.001) compared to controls. 16S rRNA gene-based microbiota analysis suggests that yogurt supplementation may greatly modulate the gut microbiome composition, especially in the relative abundance of Lactobacillus and Bifidobacterium. Importantly, the fecal concentration of d-lactate (d-Lac, 0.39 ± 0.04 µmol g-1 versus 8.14 ± 0.62 µmol g-1; p < 0.001) is boosted by yogurt, while oral administration with d-Lac (125 or 250 mg kg-1) reduces the polyp number by 71.43% or 77.14% (p < 0.001), respectively. The study also observes that d-Lac does not affect cell viability and anchorage-independence in CRC cells, but it greatly suppresses epidermal growth factor (EGF) or 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell transformation in preneoplastic cells. Mechanistically, it demonstrates that d-Lac may attenuate epithelial cell transformation by targeting PI3K/AKT/β-catenin axis.

CONCLUSION

Yogurt protects against intestinal polyposis in ApcMin/+ mice, and d-Lac may partially account for the chemopreventive effects above.

Yogurt Prevents Colitis-Associated Colorectal Cancer in Mice

SCOPE

Epidemiological studies indicate an inverse correlation between yogurt consumption and colorectal cancer (CRC), but whether there is a cause-and-effect relationship has not yet been validated. This study aims to investigate the effects and possible mechanisms of yogurt on colitis-associated colorectal cancer (CAC) in mice.

METHODS AND RESULTS

Experimental CAC is induced by azoxymethane (AOM, 10 mg kg-1 , ip) followed by three cycles of dextran sulfate sodium (DSS, 3%) treatment. Colitis is induced by adding DSS (3%) in drinking water for 5 days. Primary mouse macrophages are isolated for mechanistic studies. Data clearly show that yogurt (15 g kg-1 body weight) significantly reduces the multiplicity of colonic neoplasms by 38.83% in mice. Yogurt protects mice from colitis dependent on lactate receptor GPR81. The deficiency of Gpr81 exacerbates colitis and CAC in mice. Further investigation reveals that GPR81 may be dispensable for gut barrier function but essential for colonic mucosal repair. d-lactate in yogurt can activate GPR81 to suppress proinflammatory macrophage polarization, thereby facilitating inflammatory resolution after colonic injury and consequently suppressing CAC progression.

CONCLUSION

Yogurt effectively protects against colitis-associated colorectal tumorigenesis in mice, and this study provides a rationale for introducing yogurt supplementation to patients with chronic inflammatory bowel diseases.

Targeting beta-catenin signaling for prevention of colorectal cancer - Nutraceutical, drug, and dietary options

Progressive up-regulation of β-catenin signaling is very common in the transformation of colorectal epithelium to colorectal cancer (CRC). Practical measures for opposing such signaling hence have potential for preventing or slowing such transformation. cAMP/PKA activity in colon epithelium, as stimulated by COX-2-generated prostaglandins and β2-adrenergic signaling, boosts β-catenin activity, whereas cGMP/PKG signaling has the opposite effect. Bacterial generation of short-chain fatty acids (as supported by unrefined high-carbohydrate diets, berberine, and probiotics), dietary calcium, daily aspirin, antioxidants opposing cox-2 induction, and nicotine avoidance, can suppress cAMP production in colonic epithelium, whereas cGMP can be boosted via linaclotides, PDE5 inhibitors such as sildenafil or icariin, and likely high-dose biotin. Selective activation of estrogen receptor-β by soy isoflavones, support of adequate vitamin D receptor activity with UV exposure or supplemental vitamin D, and inhibition of CK2 activity with flavanols such as quercetin, can also oppose β-catenin signaling in colorectal epithelium. Secondary bile acids, the colonic production of which can be diminished by low-fat diets and berberine, can up-regulate β-catenin activity by down-regulating farnesoid X receptor expression. Stimulation of PI3K/Akt via insulin, IGF-I, TLR4, and EGFR receptors boosts β-catenin levels via inhibition of glycogen synthase-3β; plant-based diets can down-regulate insulin and IGF-I levels, exercise training and leanness can keep insulin low, anthocyanins and their key metabolite ferulic acid have potential for opposing TLR4 signaling, and silibinin is a direct antagonist for EGFR. Partially hydrolyzed phytate can oppose growth factor-mediated down-regulation of β-catenin by inhibiting Akt activation. Multifactorial strategies for safely opposing β-catenin signaling can be complemented with measures that diminish colonic mutagenesis and DNA hypomethylation - such as avoidance of heme-rich meat and charred or processed meats, consumption of phase II-inductive foods and nutraceuticals (e.g., Crucifera), and assurance of adequate folate status.

Association of egg consumption with colorectal polyp prevalence: findings from the Lanxi Pre-Colorectal Cancer Cohort (LP3C) in China

Eggs contain high-quality protein, lavish vitamins and other bioactive nutrients but are rich in cholesterol. Our study is designed to assess the association of egg intake with polyp prevalence. A total of 7068 participants at a high risk of CRC from the Lanxi Pre-Colorectal Cancer Cohort Study (LP3C) were recruited. A food frequency questionnaire (FFQ) was utilized to obtain dietary data through a face-to-face interview. Cases of colorectal polyps were identified by electronic colonoscopy. The logistic regression model was exploited to achieve odds ratios (ORs) and 95% confidence intervals (CIs). Overall 2064 cases of colorectal polyps were identified in the 2018-2019 survey of LP3C. A positive association of egg consumption with colorectal polyp prevalence was found after the multivariable adjustment [OR_{Q4 vs. Q1} (95% CI): 1.23 (1.05-1.44); P_trend = 0.01]. However, a positive relationship disappeared after further adjustment for dietary cholesterol (P_trend = 0.37), which explained that the harmful role of eggs could be ascribed to the high content of dietary cholesterol. Besides, a positive trend was found between dietary cholesterol and polyp prevalence [OR (95% CI): 1.21 (0.99-1.47); P_trend = 0.04]. Furthermore, replacing 1 egg (50 g d^-1) with an equal amount of total dairy products was related to 11% lower colorectal polyp prevalence [OR (95% CI): 0.89 (0.80-0.99); P = 0.03]. In summary, higher egg consumption was correlated with a higher polyp prevalence among the Chinese population at a high risk of CRC, which was ascribed to the high content of dietary cholesterol in eggs. Besides, individuals with the highest dietary cholesterol tended to have a higher polyp prevalence. Reducing the consumption of eggs and replacing eggs with total dairy products as alternative protein sources may prevent the occurrence of polyps in China.

The Impact of Prebiotic, Probiotic, and Synbiotic Supplements and Yogurt Consumption on the Risk of Colorectal Neoplasia among Adults: A Systematic Review

Prebiotic and probiotic supplementation and yogurt consumption (a probiotic food) alter gut microbial diversity, which may influence colorectal carcinogenesis. This systematic review evaluates the existing literature on the effect of these nutritional supplements and yogurt consumption on colorectal neoplasia incidence among adults. We systematically identified ten randomized controlled trials and observational studies in adults age ≥ 18 without baseline gastrointestinal disease. Prebiotics included inulin, fructooligosaccharides, galactooligosaccharides, xylooligosaccharides, isomaltooligosaccharides, and β-glucans. Probiotics included bacterial strains of Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, Bacillus, Pediococcus, Leuconostoc, and Escherichia coli. Synbiotic supplements, a mixture of both prebiotic and probiotic supplements, and yogurt, a commonly consumed dietary source of live microbes, were also included. We defined colorectal neoplasia as colorectal adenomas, sessile serrated polyps, and colorectal cancer (CRC). Overall, findings suggest a moderate decrease in risk of adenoma and CRC for high levels of yogurt consumption compared to low or no consumption. Prebiotic supplementation was not associated with colorectal neoplasia risk. There was some evidence that probiotic supplementation may be associated with lower risk of adenomas but not with CRC incidence. Higher yogurt consumption may be associated with lower incidence of colorectal neoplasia. We found little evidence to suggest that prebiotic or probiotic supplements are associated with significant decreases in CRC occurrence.

Gut microbiota: Role and Association with Tumorigenesis in Different Malignancies

The microbiota has been associated with different cancer and may vary from patient to patient. A specific microbial strain can alter the progression of cancer and therapeutic outcome in response to anti-cancer therapy. The variations in microbiota contributed due to the individual microbiome of the microorganism are responsible for diverse clinical outcomes. The expansion of microbiota subpopulation during dysbiosis can lead to toxin production, inducing inflammation and cancer. The microbiota can be a dual-edged sword because it can be tumor-suppressive or oncogenic in the case of the gut. The transition of cancer cells from early to late-stage also impacts the composition of the microbiota, and this alteration could change the behavior of cancer. Multi-omics platforms derived data from an individual's multi-dimensional data (DNA, mRNA, microRNA, protein, metabolite, microbiota, and microbiome), i.e., individualome, to exploit it for personalized tailored treatment for different cancers in a precise manner. A number of studies suggest the importance of microbiota and its add-in suitability to existing treatment options for different malignancies. Furthermore, in vitro, and in vivo studies and cancer clinical trials suggest that probiotics have driven modulation of gut microbiota and other sites discourage the aggressive behavior and progression of different cancers.

De- "bug"-ing the microbiome in lung cancer

The identification of microbes enriched in the healthy lung has led to the compelling discovery that microbes may contribute to lung cancer pathogenesis. Here, we review the recent literature showing microbial associations with lung cancer as well as the functional features that have been identified in human and murine studies. Most biomarker data remain limited due to variable findings. However, multiple studies have found that lung tumors or ipsilateral airway samples have decreased α diversity compared to normal tissue. Specific genera, such as Veillonella and Streptococcus, were also found in association with lung tumors using multiple sampling methodologies. These microbes, which are generally found in the upper respiratory track, are associated with an IL-17 signature in the lung, potentially resulting in a pro-tumorigenic environment. Studies detailing these immune mechanisms are limited, and further investigation is necessary to delineate how these bacteria, their metabolites, and potentially tumor-associated neoantigens modulate the immune response in cancer.

Adult-Attained Height and Colorectal Cancer Risk: A Cohort Study, Systematic Review, and Meta-Analysis

BACKGROUND

The influence of anthropometric characteristics on colorectal neoplasia biology is unclear. We conducted a systematic review and meta-analysis to determine if adult-attained height is independently associated with the risk of colorectal cancer or adenoma.

METHODS

We searched MEDLINE, EMBASE, the Cochrane Library, and Web of Science from inception to August 2020 for studies on the association between adult-attained height and colorectal cancer or adenoma. The original data from the Johns Hopkins (Baltimore, MD) Colon Biofilm study was also included. The overall HR/OR of colorectal cancer/adenoma with increased height was estimated using random-effects meta-analysis.

RESULTS

We included 47 observational studies involving 280,644 colorectal cancer and 14,139 colorectal adenoma cases. Thirty-three studies reported data for colorectal cancer incidence per 10-cm increase in height; 19 yielded an HR of 1.14 [95% confidence interval (CI), 1.11-1.17; P < 0.001), and 14 engendered an OR of 1.09 (95% CI, 1.05-1.13; P < 0.001). Twenty-six studies compared colorectal cancer incidence between individuals within the highest versus the lowest height percentile; 19 indicated an HR of 1.24 (95% CI, 1.19-1.30; P < 0.001), and seven resulting in an OR of 1.07 (95% CI, 0.92-1.25; P = 0.39). Four studies reported data for assessing colorectal adenoma incidence per 10-cm increase in height, showing an overall OR of 1.06 (95% CI, 1.00-1.12; P = 0.03).

CONCLUSIONS

Greater adult attained height is associated with an increased risk of colorectal cancer and adenoma.

IMPACT

Height should be considered as a risk factor for colorectal cancer screening.

Dairy Consumption and Risk of Conventional and Serrated Precursors of Colorectal Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Objective

The consumption of dairy is associated with decreased risk of colorectal cancer (CRC), but few studies have assessed the relationship between dairy consumption and precursors of CRC. Therefore, we performed the first meta-analysis to further evaluate this association.

Methods

PubMed, Embase, Scopus, and Web of Science databases were searched through July 2020 for observational studies. Study-specific risk estimates for the highest versus lowest category were pooled using the random-effects and fixed-effects model. The methodological quality of included studies was assessed using the ROBINS-I Scale.

Results

A total of 12 studies were included (3 cohort studies and 9 case-control studies). Compared with the lowest level consumption, fermented dairy products had a decreased risk of precursors of CRC in both cohort (RR = 0.92 95% CI: 0.87–0.97) and case-control studies (RR = 0.98 95% CI: 0.96–0.99). Total dairy (RR = 0.80 95% CI: 0.68–0.96) and cheese (RR = 0.96 95% CI: 0.93–0.99) consumption was inversely associated with the risk in case-control studies whereas yogurt consumption was inversely associated with the risk in cohort studies (RR = 0.91 95%CI: 0.86–0.96). No significant associations were found for consumption of total milk and non/low-fat milk. For dose-response analyses, evidence of linear association was found in total dairy and yogurt consumption. The risk decreased by 12% for an increment of 200 g/d total dairy consumption (RR = 0.88 95% CI: 0.81–0.95) and decreased by 8% for an increment of 50 g/d yogurt consumption (RR = 0.92 95% CI: 0.85–0.99).

Conclusions

Fermented dairy products, specifically yogurt and cheese, were significantly associated with decreased risk of conventional and serrated precursors of colorectal cancer.

Calcium and dairy products in the chemoprevention of colorectal adenomas: a systematic review and meta-analysis

The risk of transition to colorectal cancer (CRC) in advanced colorectal adenomas (ACAs) is about 2.5 times higher than the non-advanced ones. This systematic review and meta-analysis was performed to determine the effect of calcium and dairy products on the incidence of CAs and ACAs. Six databases were systematically searched and 37 relevant clinical trials and observational studies involving over 10,964 cases were selected for inclusion. The results showed that calcium consumption reduced the risk of CAs incidence by 8% (RR: 0.92; 95% CI: 0.89-0.96), and calcium intake as a food and dairy product reduced it about 21% (RR: 0.79; 95% CI: 0.72-0.86), and 12% (RR: 0.88; 95% CI: 0.78-0.98), respectively. However, calcium supplementation did not show a significant effect on CAs incidence (RR: 0.97; 95% CI: 0.89-1.05). Results also revealed that total calcium intake markedly reduced the risk of ACAs (RR: 0.79; 95% CI: 0.73-0.85) and the risk of recurrence of adenomas about 12% (RR: 0.88; 95% CI: 0.84-0.93). Our results suggest that natural sources of calcium such as dairy products and foods may have more effective role than supplementary calcium in terms of reducing the risk of incidence and recurrence of colorectal adenomas and advanced adenomas.

Postbiotics, Metabolic Signaling, and Cancer

Postbiotics are health-promoting microbial metabolites delivered as a functional food or a food supplement. They either directly influence signaling pathways of the body or indirectly manipulate metabolism and the composition of intestinal microflora. Cancer is the second leading cause of death worldwide and even though the prognosis of patients is improving, it is still poor in the substantial part of the cases. The preventable nature of cancer and the importance of a complex multi-level approach in anticancer therapy motivate the search for novel avenues of establishing the anticancer environment in the human body. This review summarizes the principal findings demonstrating the usefulness of both natural and synthetic sources of postbotics in the prevention and therapy of cancer. Specifically, the effects of crude cell-free supernatants, the short-chain fatty acid butyrate, lactic acid, hydrogen sulfide, and β-glucans are described. Contradictory roles of postbiotics in healthy and tumor tissues are highlighted. In conclusion, the application of postbiotics is an efficient complementary strategy to combat cancer.