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Irritable Bowel Syndrome Is Not Associated with an Increased Risk of Polyps and Colorectal Cancer: A Systematic Review and Meta-Analysis.
Vichos, T, Rezaie, A, Vichos, P, Cash, B, Pimentel, M
Digestive diseases and sciences. 2023;68(6):2585-2596
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Colorectal cancer (CRC) is one of the most common cancers and adenomatous colorectal polyps (CRP) are a risk factor for developing CRC. The potential role of functional disturbances seen in irritable bowel syndrome (IBS) for the development of CRC are not yet clear. The aim of this systematic review and meta-analysis was to evaluate the occurrence of CRC and CRP in IBS patients. 14 cohort studies with a total of 654,764 IBS patients and 2,277,195 controls and six cross-sectional studies with 26,641 IBS patients and 87,803 controls were included in the review. Based on the pooled data from 5 cross-sectional studies, IBS patients had a significantly lower occurrence of CRP (by 71%). CRC risk was also reduced but this did not reach statistical significance. Only four of the 14 cohort studies were included in the meta-analysis and, again, CRC risk was lower in IBS patients but this was not statistically significant.
Abstract
OBJECTIVES Colorectal cancer (CRC) is the third most common malignancy in the US. Several factors are associated with increased/decreased CRC risk and often linked to adenomatous colorectal polyps (CRP). Recent studies suggest a lower risk of neoplastic lesions among irritable bowel syndrome (IBS) patients. We aimed to systematically assess the occurrence of CRC and CRP in IBS patients. METHODS Searches of the Medline, Cochrane, and EMBASE databases were performed, blindly and independently, by two investigators. Studies of CRC or CRP incidence in IBS patients (diagnosed by Rome or other symptom-based criteria) were eligible for inclusion. CRC and CRP effect estimates were pooled in meta-analyses using random models. RESULTS Of 4941 non-duplicate studies, 14 were included, comprising 654,764 IBS patients and 2,277,195 controls in 8 cohort studies, and 26,641 IBS patients and 87,803 controls in 6 cross-sectional studies. Pooled analysis revealed a significantly decreased prevalence of CRP in IBS subjects vs. controls, with a pooled odds ratio (OR) of 0.29 (95% CI (0.15, 0.54)). There was significant heterogeneity between studies (I2 = 96%, p < 0.01). This finding persisted when studies which did not report pre-cancerous polyps separately were excluded (OR 0.23, 95% CI (0.15, 0.35), I2 = 85%, p < 0.01). CRC prevalence was lower in IBS subjects, but this did not reach statistical significance (OR 0.40, 95% CI (0.09, 1.77]). CONCLUSION Our analyses reveal a decreased incidence of colorectal polyps in IBS, although CRC did not reach significance. Mechanistic studies with detailed genotypic analysis and clinical phenotyping are needed to better elucidate the potentially protective effect of IBS on CRC development.
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Disturbances of Vaginal Microbiome Composition in Human Papillomavirus Infection and Cervical Carcinogenesis: A Qualitative Systematic Review.
Wu, M, Li, H, Yu, H, Yan, Y, Wang, C, Teng, F, Fan, A, Xue, F
Frontiers in oncology. 2022;12:941741
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Cervical cancer remains the fourth most prevalent cancer in women worldwide. The infection of certain strains of human papillomavirus (HPV)) are thought to have an important causative role in the development of cervical cancer. But since a vast majority of HPV infections clear naturally within a few months, this indicates other factors at play determine the progression of the disease and its cancerous developments. Recent findings indicate that there may be a close link between disruptions of the vaginal microbiome and HPV infection, cervical lesions, cervical cancer and other gynaecological diseases. However, the evidence thus far is quite varied. Hence this systematic review sought to gather the current evidence and integrate it to create up-to-date knowledge. Included were the 22 studies relating to vaginal microbiota, and women with HPV-associated cervical diseases. The studies were conducted in various countries around the world and contained a mixture of case-controlled, cross-sectional and longitudinal studies. The authors acknowledge the challenges of summarising the findings due to differences in how the studies have been conducted. The results of the review showed that vaginal disturbances in HPV infections and related cervical diseases, seem to manifest in decreases in Lactobacilli, and increases in aerobic and anaerobic bacteria. Lactobacillus iners seemed to have either protective or pathogenic effects. They also noted that there are geographical and ethnic differences and patterns, which made the consolidation of results more challenging. For future research, the authors deemed the role of the Lactobacillus family of particular interest.
Abstract
BACKGROUND Emerging evidence has demonstrated a close association between perturbations in vaginal microbiota composition in women and human papillomavirus (HPV) infection, cervical lesions, and cervical cancer (Ca); however, these findings are highly heterogeneous and inconclusive. AIM: To perform a comprehensive systematic review of the global disturbance in the vaginal microbiota, specifically in women with HPV-associated cervical diseases, and to further conduct within- and across-disease comparisons. METHOD Twenty-two records were identified in a systematic literature search of PubMed, Web of Science, and Embase up to February 28, 2022. We extracted microbial changes at the community (alpha and beta diversity) and taxonomic (relative abundance) levels. Within- and across-disease findings on the relative abundance of taxonomic assignments were qualitatively synthesized. RESULTS Generally, significantly higher alpha diversity was observed for HPV infection, cervical lesions, and/or cancer patients than in controls, and significant differences within beta diversity were observed for the overall microbial composition across samples. In within-disease comparisons, the genera Gardnerella, Megasphaera, Prevotella, Peptostreptococcus, and Streptococcus showed the greatest abundances with HPV infection; Sneathia and Atopobium showed inconsistent abundance with HPV infection, and Staphylococcus was observed in Ca. Across diseases, we find increased levels of Streptococcus and varying levels of Gardnerella were shared across HPV infections, high-grade squamous intraepithelial lesions, and Ca, whereas Lactobacillus iners varied depending on the HPV-related disease subtype. CONCLUSIONS This systematic review reports that vaginal microbiome disturbances are correlated to the depletion of Lactobacillus, enrichment of anaerobes, and increased abundance of aerobic bacteria in HPV infection and related cervical diseases. Moreover, L. iners may exert either protective or pathogenic effects on different HPV-related diseases.
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The Human Vulvar Microbiome: A Systematic Review.
Pagan, L, Ederveen, RAM, Huisman, BW, Schoones, JW, Zwittink, RD, Schuren, FHJ, Rissmann, R, Piek, JMJ, van Poelgeest, MIE
Microorganisms. 2021;9(12)
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Vaginal microbiome composition and its link with cancer is an emerging area in research. Imbalances in the vaginal microbiome could initiate carcinogenesis by altering immunity and metabolism and accelerating inflammation. This systematic review included ten studies and assessed the vulvar microbiome in premalignant vulvar disease and healthy vulvar skin. The healthy vulvar skin showed several bacterial taxa of Lactobacillus, Corynebacterium, Staphylococcus and Prevotella of intestinal, cutaneous and vaginal origin. L. crispatus and L. iners were dominant on the vulva of most healthy women. L. gasseri dominance was non-significantly associated with vestibulodynia. Menstruation did not alter the bacterial composition. Premenarchial Lichen sclerosus may have an association with microbial dysbiosis. Further robust studies are required to identify the vaginal microbial composition due to the high heterogeneity of the studies included, small sample size and methodological limitations. Healthcare professionals can utilise the data from this study to better understand how the vulvar microbiome influences disease aetiology and its importance as a target for therapy.
Abstract
The link between cancer and the microbiome is a fast-moving field in research. There is little knowledge on the microbiome in ((pre)malignant) conditions of the vulvar skin. This systematic review aims to provide an overview of the literature regarding the microbiome composition of the healthy vulvar skin and in (pre)malignant vulvar disease. This study was performed according to the PRISMA guidelines. A comprehensive, electronic search strategy was used to identify original research articles (updated September 2021). The inclusion criteria were articles using culture-independent methods for microbiome profiling of the vulvar region. Ten articles were included. The bacterial composition of the vulva consists of several genera including Lactobacillus, Corynebacterium, Staphylococcus and Prevotella, suggesting that the vulvar microbiome composition shows similarities with the corresponding vaginal milieu. However, the vulvar microbiome generally displayed higher diversity with commensals of cutaneous and fecal origin. This is the first systematic review that investigates the relationship between microbiome and vulvar (pre)malignant disease. There are limited data and the level of evidence is low with limitations in study size, population diversity and methodology. Nevertheless, the vulvar microbiome represents a promising field for exploring potential links for disease etiology and targets for therapy.
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Yogurt, cultured fermented milk, and health: a systematic review.
Savaiano, DA, Hutkins, RW
Nutrition reviews. 2021;79(5):599-614
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Many fermented foods are associated with health benefits, including fermented dairy products. Whereby diary itself is part of many nutritional guidelines, the guidances rarely distinguish between dairy and fermented dairy. This qualitative, systematic review sought to capture how consumption of fermented milk products influences health. The review included 108 studies, with over 70% reporting beneficial health outcomes. A small number of studies reported insignificant or neutral results and four unfavourable ones. The aspects of health that were considered included lactose digestion and tolerance, gut health and disease, diarrhoea and constipation, irritable bowel syndrome, cardiovascular health and disease, hypertension, blood lipids, cancer risk, colorectal/breast/prostate cancer, weight and body composition, diabetes risk and metabolic syndrome and bone health. The authors concluded that eating fermented dairy products aided lactose digestion and showed a consistent link with reduced risk of breast and colorectal cancer, type 2 diabetes, and improved weight maintenance, cardiovascular, bone, and gastrointestinal health. As dairy appears to increase the risk for prostate cancer, fermented dairy seems to be no different here to unfermented dairy at increasing the risk. Some potential mechanisms are proposed in the discussion section, how fermented dairy may elicit its health benefits. Given the predominant health benefits of fermented dairy, the authors encouraged to include fermented dairy into national nutrition guidelines and stress distinction between dairy and fermented dairy products. This review captures current evidence of the widespread health benefits of fermented dairy consumption worthwhile considering in clinical practice. In the absence of more clear findings in relation to prostate cancer and prevention, a cautious approach to dairy and fermented dairy consumption may be warranted.
Abstract
Consumption of yogurt and other fermented products is associated with improved health outcomes. Although dairy consumption is included in most dietary guidelines, there have been few specific recommendations for yogurt and cultured dairy products. A qualitative systematic review was conducted to determine the effect of consumption of fermented milk products on gastrointestinal and cardiovascular health, cancer risk, weight management, diabetes and metabolic health, and bone density using PRISMA guidelines. English language papers in PubMed were searched, with no date restrictions. In total, 1057 abstracts were screened, of which 602 were excluded owing to lack of appropriate controls, potential biases, and experimental design issues. The remaining 455 papers were independently reviewed by both authors and 108 studies were included in the final review. The authors met regularly to concur, through consensus, on relevance, methods, findings, quality, and conclusions. The included studies were published between 1979 and 2017. From the 108 included studies, 76 reported a favorable outcome of fermented milks on health and 67 of these were considered to be positive or neutral quality according to the Academy of Nutrition and Dietetics' Quality Criteria Checklist. Of the 32 remaining studies, the study outcomes were either not significant (28) or unfavorable (4), and most studies (18) were of neutral quality. A causal relationship exists between lactose digestion and tolerance and yogurt consumption, and consistent associations exist between fermented milk consumption and reduced risk of breast and colorectal cancer and type 2 diabetes, improved weight maintenance, and improved cardiovascular, bone, and gastrointestinal health. Further, an association exists between prostate cancer occurrence and dairy product consumption in general, with no difference between fermented and unfermented products. This article argues that yogurt and other fermented milk products provide favorable health outcomes beyond the milk from which these products are made and that consumption of these products should be encouraged as part of national dietary guidelines. Systematic review registration: PROSPERO registration no. CRD42017068953.
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Salmonella Infection in Chronic Inflammation and Gastrointestinal Cancer.
Zha, L, Garrett, S, Sun, J
Diseases (Basel, Switzerland). 2019;7(1)
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Salmonella is a group of bacteria that is normally associated with food poisoning. In 2% to 5% of people with Salmonella food poisoning, the bacteria remain in the body, leading to long-term infection, which has been linked to various health problems. This literature review looked at the link between Salmonella infection and the development of diseases such as inflammatory bowel disease (IBD), gall bladder cancer and colon cancer. The authors describe how long-term Salmonella infection plays a role in several biological processes, such as stem cell maintenance, host cell transformation, and gut dysbiosis. Leaky gut, dysbiosis and inflammation are induced by the bacteria and contribute to the development of cancer. The authors conclude that more studies are needed to further understand the relationship between Salmonella infections and the risk of colon cancer.
Abstract
Salmonella not only causes acute infections, but can also cause patients to become chronic "asymptomatic" carriers. Salmonella has been verified as a pathogenic factor that contributes to chronic inflammation and carcinogenesis. This review summarizes the acute and chronic Salmonella infection and describes the current research progress of Salmonella infection contributing to inflammatory bowel disease and cancer. Furthermore, this review explores the underlying biological mechanism of the host signaling pathways manipulated by Salmonella effector molecules. Using experimental animal models, researchers have shown that Salmonella infection is related to host biological processes, such as host cell transformation, stem cell maintenance, and changes of the gut microbiota (dysbiosis). Finally, this review discusses the current challenges and future directions in studying Salmonella infection and its association with human diseases.
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Coffee Consumption and Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis of Prospective Studies.
Sartini, M, Bragazzi, NL, Spagnolo, AM, Schinca, E, Ottria, G, Dupont, C, Cristina, ML
Nutrients. 2019;11(3)
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Coffee is the second most widely consumed drink worldwide, after water. It contains many active compounds that affect the health and functioning of the digestive tract. Previous population studies on the relationship between coffee consumption and cancer prevention have had mixed results. The aim of this systematic review and meta-analysis was to provide an up to date summary of the relationship between coffee consumption and the risk of colorectal cancer. The authors looked at 26 prospective studies. When results from the 26 studies were pooled, no significant relationship between coffee consumption and colorectal cancer was found. The researchers then looked at the results by ethnicity and found a protective effect for coffee on colorectal cancer in people from the US. For colon cancer, coffee was protective in men and women combined and in men alone, regardless of ethnicity. When the results were separated according to ethnicity, a significant protective effect was noted in European men and in Asian women. There was no association between coffee consumption and rectal cancer. Decaffeinated coffee demonstrated a protective effect against colorectal cancer in both men and women. The authors concluded that ethnicity could explain the mixed results of previous studies. Further research is needed into the relationship between a person’s genetic make-up and the risk of colorectal cancer associated with coffee.
Abstract
Coffee is a blend of compounds related to gastrointestinal physiology. Given its popularity and the epidemiology of colorectal cancer, the impact of this beverage on public health could be considerable. Our aim was to provide an updated synthesis of the relationship between coffee consumption and the risk of colorectal cancer. We conducted a systematic review and meta-analysis of 26 prospective studies. Regarding colorectal cancer, no significant relationship was detected. Stratifying for ethnicity, a protective effect emerged in US subjects. Concerning colon cancer, coffee proved to exert a protective effect in men and women combined and in men alone. Stratifying for ethnicity, a significant protective effect was noted in European men only and in Asian women only. Concerning rectal cancer, no association was found. Decaffeinated coffee exhibited a protective effect against colorectal cancer in men and women combined. Studies were appraised for their quality by means of the Newcastle-Ottawa Quality Assessment Scale for Cohort studies. Only one study proved to be of low quality. Ethnicity could explain the heterogeneity of the studies. However, little is known about the relationship between the genetic make-up and the risk of colorectal cancer associated with coffee. Further research is warranted.
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The Effect of Nutrition Intervention with Oral Nutritional Supplements on Pancreatic and Bile Duct Cancer Patients Undergoing Chemotherapy.
Kim, SH, Lee, SM, Jeung, HC, Lee, IJ, Park, JS, Song, M, Lee, DK, Lee, SM
Nutrients. 2019;11(5)
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Despite the advantages of chemotherapy, it can cause cancer-related malnutrition leading to both reduced quality of life and reduced survival rate. Oral nutritional supplements (ONSs) provide balanced nutrients, calories, and protein to complement insufficient oral intake, and ONS provision during treatment may improve nutritional status. The aim of this study was to investigate the impact of ONS on nutritional status in patients undergoing chemotherapy for pancreatic and bile duct cancer. Patients were randomly allocated to the ONS group (15) and non-ONS group (19) and dietary intake and body weight were assessed at weeks 1, 2, 4 and 8. Body composition and quality of life was assessed at baseline and week 8. This study found the supply of ONS helped promote health by increasing body fat mass, improving quality of life and decreasing fatigue symptoms in pancreatic and bile duct cancer patients. These results were more pronounced in patients in the first cycle of chemotherapy. Based on these results, the authors conclude ONS may improve nutritional status by increasing fat mass and/or maintaining the body composition of patients undergoing chemotherapy.
Abstract
Chemotherapy may negatively affect nutritional status and quality of life (QOL) in pancreatic cancer patients. Our aim was to investigate the beneficial effects of oral nutrition supplements (ONS) on pancreatic and bile duct cancer patients undergoing chemotherapy. Among patients with progressive pancreatic and bile duct cancer receiving chemotherapy, the ONS group (n = 15) received two packs of ONS daily for 8 weeks while the non-ONS group (n = 19) did not. Anthropometric measures, dietary intake, nutritional status, and quality of life were assessed. ONS significantly increased daily intakes of energy, carbohydrates, proteins, and lipids at 8 weeks compared to the baseline. After 8 weeks, fat mass significantly increased in the ONS group. For patients in their first cycle of chemotherapy, body weight, fat-free mass, skeletal muscle mass, body cell mass, and fat mass increased in the ONS group but decreased in the non-ONS group. Fat mass increased in second or higher cycle only in the ONS group. Patient-generated subjective global assessments (PG-SGA) and fatigue scores in the Quality of Life Questionnaire Core 30 (QLQ-C30) improved in the ONS group. ONS might improve nutritional status by increasing fat mass and/or maintaining the body composition of pancreatic and bile duct cancer patients with chemotherapy, especially those in the first cycle, and alleviate fatigue symptoms.
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Dietary patterns and Helicobacter pylori infection in a group of Chinese adults ages between 45 and 59 years old: An observational study.
Shu, L, Zheng, PF, Zhang, XY, Feng, YL
Medicine. 2019;98(2):e14113
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Research has shown that diet plays an important role in the development of Helicobacter pylori (H pylori) infection, a major cause of many digestive diseases. The aim of this cross-sectional study was to examine the relationship between dietary patterns and H pylori infection in a Chinese population aged 45-59. Dietary patterns among 3014 adults were assessed through a food frequency questionnaire and diet patterns were categorised as either health-conscious, Western, grains-vegetables and high salt. A breath test was used to diagnose H pylori infection and the prevalence among the entire test population was 27.5%. This study found that among this population, the grains-vegetables pattern was associated with a decreased risk of H pylori infection whereas the high salt pattern was associated with an increased risk. The authors suggest these findings be confirmed through further prospective studies and include a wider cohort that is more indicative of the general population.
Abstract
Limited studies have reported the association between dietary patterns and the risk of Helicobacter pylori (H pylori) infection. The purpose of this study was to evaluate the relationship between dietary patterns and H pylori infection in a Chinese population ages from 45 to 59 years. We performed a cross-sectional examination of the associations between dietary patterns and H pylori infection in 3014 Chinese adults ages between 45 and 59 years from Hangzhou city, Zhejiang province, China. Dietary intake was assessed through a semi-quantitative food frequency questionnaire (FFQ). H pylori infection was diagnosed using the C-urea breath test. Multivariable logistic regression analyses were used to determine the associations between dietary patterns and the risk of H pylori infection. The prevalence of H pylori infection was 27.5%. Four major dietary patterns were identified by means of factor analysis: health-conscious, Western, grains-vegetables and high-salt patterns. After adjustment for the potential confounders, participants in the highest quartile of the "grains-vegetables" pattern scores had a lower odds ratio (OR) for H pylori infection (OR = 0.82; 95% confidence interval [CI]: 0.732-0.973; P = .04) than did those in the lowest quartile. Compared with those in the lowest quartile, participants in the highest quartile of the "high-salt" pattern scores had a greater OR for H pylori infection (OR = 1.13; 95%CI: 1.004-1.139; P = .048). Besides, no significant associations were found between the "health-conscious" and "Western" dietary patterns and the risk of H pylori infection.Our findings demonstrate that the "grains-vegetables" pattern is associated with a decreased risk, while "high-salt" pattern is associated with an increased risk of H pylori infection.
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Associations between Dietary Patterns and Bile Acids-Results from a Cross-Sectional Study in Vegans and Omnivores.
Trefflich, I, Marschall, HU, Giuseppe, RD, Ståhlman, M, Michalsen, A, Lampen, A, Abraham, K, Weikert, C
Nutrients. 2019;12(1)
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Colorectal cancer is associated with higher intakes of meat and lower consumption of fibre. Fibre may alter cholesterol and bile acid production and high bile acids may cause changes in the cells of the colon. Vegan diets high in fibre and low in fat may affect bile acid production and this observational study of 72 people aimed to compare bile acids in the faeces and blood of vegans and omnivores. The results showed that vegans had higher fibre and lower fat intakes, compared to omnivores, and although bile acids in the faeces were lower in vegans, blood levels were higher. Fat intake was associated with increased bile acids in the faeces whereas fibre intake was associated with lower levels. Coffee, fish, margarine, fried potatoes, bread, and processed meat were all associated with increased bile acids in the faeces and muesli was associated with lower levels. It was concluded that high fibre, low-fat intakes characteristic of vegan diets, are associated with lower bile acids in the faeces and this could impact colorectal cancer incidence. This study could be used by healthcare professionals to recommend a vegan diet high in fibre and low in saturated fat to individuals with colorectal cancer or those who are at an increased risk.
Abstract
Bile acids play an active role in fat metabolism and, in high-fat diets, elevated concentrations of fecal bile acids may be related to an increased risk of colorectal cancer. This study investigated concentrations of fecal and serum bile acids in 36 vegans and 36 omnivores. The reduced rank regression was used to identify dietary patterns associated with fecal bile acids. Dietary patterns were derived with secondary and conjugated fecal bile acids as response variables and 53 food groups as predictors. Vegans had higher fiber (p < 0.01) and lower fat (p = 0.0024) intake than omnivores. In serum, primary and glycine-conjugated bile acids were higher in vegans than in omnivores (p ≤ 0.01). All fecal bile acids were significantly lower in vegans compared to omnivores (p < 0.01). Processed meat, fried potatoes, fish, margarine, and coffee contributed most positively, whereas muesli most negatively to a dietary pattern that was directly associated with all fecal bile acids. According to the pattern, fat intake was positively and fiber intake was inversely correlated with bile acids. The findings contribute to the evidence that, in particular, animal products and fat may play a part in higher levels of fecal bile acids.
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Gut dysbiosis: a potential link between increased cancer risk in ageing and inflammaging.
Biragyn, A, Ferrucci, L
The Lancet. Oncology. 2018;19(6):e295-e304
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This study looks at the important role our gut bacterial and commensal microbes play in supporting immunity and potentially reducing the risk of cancer from aging. Cancer risk increases as we age and is one of the main causes of reduced life expectancy. Our gut microbiome changes continually in response to diet, lifestyle, infection, and activation of immune responses. Gut dysbiosis is characterised by a shift towards proinflammatory commensals and a reduction of beneficial microbes, which can cause impairment and leakiness of the intestinal barrier. This is thought to trigger inflammaging or rather aging in a state of continual inflammation, where the immune system is in a heightened state of activation, and the body essentially creates an environment conducive to cancer. The gut is populated by trillions of species of bacteria which work together with our immune cells. As we age the diversity and density of these beneficial bacteria reduce. Therapies which support the balance of our commensal bacteria may prove effective at reducing rates of cancer in the elderly.
Abstract
Cancer incidence substantially increases with ageing in both men and women, although the reason for this increase is unknown. In this Series paper, we propose that age-associated changes in gut commensal microbes, otherwise known as the microbiota, facilitate cancer development and growth by compromising immune fitness. Ageing is associated with a reduction in the beneficial commensal microbes, which control the expansion of pathogenic commensals and maintain the integrity of the intestinal barrier through the production of mucus and lipid metabolites, such as short-chain fatty acids. Expansion of gut dysbiosis and leakage of microbial products contributes to the chronic proinflammatory state (inflammaging), which negatively affects the immune system and impairs the removal of mutant and senescent cells, thereby enabling tumour outgrowth. Studies in animal models and the importance of commensals in cancer immunotherapy suggest that this status can be reversible. Thus, interventions that alter the composition of the gut microbiota might reduce inflammaging and rejuvenate immune functions to provide anticancer benefits in frail elderly people.