Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Diet, microbiota and gut health – what five-a-day? Barry Campbell Simms Lecture RCP Regional meeting, York 5th Dec 2016 Gastroenterology Research Unit Cellular & Molecular Physiology, Institute of Translational Medicine [email protected] Diet, microbiota and gut health – what five-a-day? Jon Rhodes Barry Campbell Simms Lecture RCP Regional meeting, York 5th Dec 2016 Gastroenterology Research Unit Cellular & Molecular Physiology, Institute of Translational Medicine [email protected] Diet, microbiota and colonic health – a long history “ A full colon is the root of all suffering” An early advocate of dietary prevention of cancer. ? 1856-1943 Sir William Arbuthnot Lane Promoted whole foods, fruits and vegetables, sunshine and exercise: his plan to foster health and longevity via 3 bowel movements daily. By Photogravure after Elliott & Fry. - [1], CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=33387516 Diet, microbiota and colonic health – a long history “90% of the diseases of civilization are due to improper functioning of the colon…” “…poor diet favors harmful bacteria that can then infect other tissues in the body; that the intestinal flora is changed by the diet of the individual, and is changed for the better…” 1852-1943 Dr John Harvey Kellogg Diet, microbiota and colonic health – a long history 1852-1943 Dr John Harvey Kellogg Diet, microbiota and colonic health – a long history 1852-1943 Dr John Harvey Kellogg Vegetarianism, exercise, a pint of yogurt (half eaten, half as an enema to replace toxic bacteria) for a ‘squeaky clean’ intestine. The importance of our microbiota The Microbiome: Joshua Lederberg argued that microorganisms inhabiting the human body should be included as part of the human genome, because of their influence on human physiology. Lederberg & McCray 2001 Scientist 15: 8 We are only 10% human (more or less) Revised estimates: 3 x 1013 Human cells 3.9 x 1013 Bacteria Approx. 76% Human 10 trillion cells vs. ~100 trillion bugs Sender et al. Plos Biol 2016; doi:10.1371/journal.pbio 10002533 What do we know about our gut microbial community (microbiota)? • Established in the 1st year of life Co-evolves with the immune system • Highly variable between individuals In 154 individuals no single shared abundant species About 160 bacterial species in each faecal sample gene set ~150 times human genome • The range of bacteria appears to be fairly stable with time Turnbaugh & Gordon 2009 J Physiol 587:4153-8 But influenced by diet Turnbaugh et al. 2009. Nature 457:480-4 Qin et al. 2010. Nature 464, 59-65 Bacteria in the normal distal gut % of bacteria 13,000 16S rRNA sequences analysed from healthy young adults and non-IBD controls. Seven major phyla Firmicutes Bacteroidetes >90% Actinobacteria Proteobacteria Fusobacteria Verrucomicrobia, Cyanobacteria Petersen et al. 2008 Cell Host & Microbe 3, 417-27 Inflammation dramatically re-shapes our gut microbiota Inflammation driven dysbiosis % of bacteria % of bacteria 5,405 16S rRNA sequences from patients with CD and UC. Petersen et al. 2008 Cell Host & Microbe 3, 417-27 Reduced microbiota diversity in Crohn’s disease - metagenomic/macroarray approach • fosmid vector approach to construct 2 genomic DNA libraries • 25K clones each, screened for the 16S rRNA gene by DNA hybridisation Manichanh et al. 2006 Gut 55, 205-11 Metagenomics of faecal microbiota also differentiates UC from healthy individuals Qin et al. 2010. Nature 464, 59-65 The importance of the mucus barrier • Colonic mucus is continuous with two layers – inner layer is normally free from bacteria • Small intestinal mucus is discontinuous MUC2 FISH (bacteria) Johansson et al. PNAS 2011; 108, 4659-65 Mucosa-associated bacteria differ from faecal bacteria! includes bacteria that are asaccharolytic (eg some Firmicutes) Or aerobic/ microaerophilic bacteria typically absent from the faeces (eg E. coli) Aldenburg et al. Gastroenterology 2014; 147, 1055-63 Increased ileal mucosa-associated ‘adherent, invasive E. coli’ in CD Look like ‘harmless’ resident strains lacking major pathogenic factors of toxigenic/diarrhoeagenic E. coli Belong mainly to phylogenetic groups B2 and D more commonly associated with ExPEC Darfeuille-Michaud et al. Gastroenterology 1998; 115:1405-13 Darfeuille-Michaud. Int. J. Med. Microbiol. 2002; 292:185-93 Darfeuille-Michaud et al. Gastroenterology 2004;127:412-21 Increased colonic mucosa-associated bacteria were cultured more commonly in CD and colon cancer Pullan et al. Gut 1994; 35:353-9 >53% were E. coli The (paediatric) Crohn’s disease pre-treatment mucosa-associated microbiota Terminal ileum 447 CD patients aged 3 to 17 221 controls (abdo. pain and diarrhoea) Increased include: E. coli, Fusobacteria Reduced include: Faecalibacterium prausnitzii (anti-inflammatory; Protective against ileal Crohn’s relapse) Gevers et al. Cell Host Microbe 2014;15:382-92 Early Crohn’s lesions arise at sites of Peyer's patches or lymphoid follicles TEM Fujimura et al. 1996 Gut 38,724-32 Confocal laser endomicroscopy Krauss et al. 2012. Int. J. Clin. Exp. Path. 5, 411-421 Incidence of CD Number of PP Van Kruiningen et al. 1997 J Clin Gastro 25,470 Long polar fimbriae expressed by Crohn’s E. coli target M cells in the FAE of Peyer’s patches - linking colonization & the presence of early lesions overlying lymphoid follicles Peyer’s patch FISH Cy3-EUB338 Chassaing et al. 2011. J. Clin Invest. 121, 966-75 Dogan et al. 2014. Inflamm Bowel Dis. 20, 1919-32 Crohn’s E. coli replicate within host macrophages and are pro-inflammatory • persisting within mucosal macrophages (human mouse) they promote increased levels of TNF release Double around vesicle coli. and membrane macrophage containing E. Mpofu et al. Gastroenterology 2007; 133 1487-98 Subramanian et al. 2008 AAC 52, 427-34 The mucosal microbiota is also altered in adenoma and colon cancer Mucosa-associated bacteria and colorectal cancer Key increased mucosal bacteria include: Strep. (bovis) gallolyticus Bacteroides fragilis E. coli Fusobacteria nucleatum Enterococcus faecalis Akkermansia mucinophilia Cipe et al. World J Gastro Oncol 2015; 7:233-40 Intracellular E. coli in human colon cancer tissue • Intracellular E. coli (and Bacteriodes) within the colonic mucosa (tumour and histologically normal tissue) in colon cancer • Healthy patient bowel tissue is relatively free from bacteria Alexander Swidsinski Gastroenterology 1998;115: 281-6 Modelling interactions of AIEC in inflammationassociated colorectal carcinogenesis • AOM treated germ-free Il10-/- mice, monoassociated with bacteria to induce colitis Arthur et al. 2012. Science 338: 120-3 Science 2012: 338: 52 • pks associated with decreased tumour burden Concept of colorectal cancer as a bacterial disease 1. Bacteria-epithelial interaction may be crucial by: (i) stimulation of epithelial (Toll-Like) receptors and consequent inhibition of apoptosis (ii) DNA-damaging (genotoxic) effects. 2. This interaction is much more likely once an adenomatous polyp is present 3. E. coli may be particularly important – because they (a) adhere and invade to epithelial cells, (b) tolerate relatively high oxygen environment (microaerophilic) (c) produce genotoxins (pks PAI colibactin) (d) proangiogenic (afa) 4. Adhesin interactions occur with carbohydrate receptors on epithelial cells which may be preventable by dietary polysaccharides Maybe this is how fruit and vegetables protect against colorectal cancer? Diet also shapes the gut microbiota Impact of habitual diet in shaping gut microbiota 16S rRNA gene surveys reveal a clear separation of two child populations from Burkina faso and EU High fruit/ legume fibre diet More Gram +ve saccharolytic spp. High SCFA levels High milk fat/Animal protein diet Low SCFA levels More Gram -ve Proteobacteria De Filippo et al. 2010 PNAS 107, 14691-6 Short-term dietary intervention alters the human gut microbiota and microbial activity. Bacterial 16S ribosomal RNA gene sequencing • Microbial diversity (the difference between each subject’s baseline and dietassociated gut microbiota) changed within 1 day on animal-based diet reaching the colon. David et al. 2014 Nature 505:559-63 Diet, interventions and the gut microbiota Simpson & Campbell 2015. Aliment Pharmacol Ther. 42:158-79 Geographical variation in colorectal cancer incidence WHO 2015 Colon cancer and diet - estimating the size of the risk Colon cancer incidence in <65 year old in Connecticut =10 times that in Nigeria, therefore about 90% of USA colon cancer risk is environmentally determined, largely by diet Doll & Peto. J Natl Cancer Inst. 1981; 66:1191-308 Epidemiology of colon cancer Factors correlated with increased risk: red meat calories alcohol body mass index exercise dietary fibre Abstracted from World Cancer Research Fund/AICR 2016 http://www.wcrf.org/sites/default/files/WCRFI-Matrix-for-all-cancers.pdf Meta-analysis of 21 prospective (cohort) studies shows 14% increased risk for colorectal cancer per 100g red/processed meat per day (8oz = 227g) Chen et al. Plos One 2011: e20456 Fibre and colorectal cancer – not a simple story cereal fibre? 3 studies show protective effect 7 no association 3 increased risk Fruit & vegetables ? 23/28 studies show protective effect Legumes? ….. EPIC Oxford study also shows increased risk for colorectal cancer in vegetarians! Soluble fibre intake and colorectal cancer WCRF, 1997 EPIC 2003; Bingham et al. Lancet 2003; 361:1496-501 Key et al. Am J Clin Nutr 2009; 89; 1620S-6S Diet swap experiment reveals junk food's harm to gut Over 2 weeks - US African American volunteers (n=20) moved to a low-fat, high-fibre diet while 20 volunteers from rural Africa were asked to eat a more Western "junk" food. In rural Africans on diet swap: Inflammation increased. Microbiome and metabolome altered. Increased Fusobacterium spp. (genera associated with CRC) In the African Americans (AA) on diet swap: Increased saccharolytic fermentation and butyrogenesis, Suppressed secondary bile acid synthesis Decrease in Proteobacteria (i.e. potential decrease in CRC risk) O’Keefe SJ et al. Nat Commun. 2015; 6: 6342 Can single dietary components block potentially harmful interactions between bacteria and the gut epithelium ….and thus reduce risk for inflammatory bowel disease and colon cancer? Single dietary constituents may alter host response to bacteria, if not the microbiome % attachment 160 140 NO PLANTAIN 120 PLANTAIN 100 80 60 40 20 • Soluble plantain fibre (non starch polysaccharides) blocks E. coli attachment & invasion to bowel cells 0 HM427 HM545 E. coli strain 14 % invasion 12 NO PLANTAIN 10 PLANTAIN 8 Musa spp. 6 Jon Rhodes 4 2 0 HM427 HM545 E. coli strain Martin et al. 2004 Gastroenterology 127, 80-93 Soluble plant fibres block E. coli translocation across M cells Plantain NSP Not all soluble fibres are equal – Broccoli NSP good Leek and apple NSPs had little effect Roberts et al. 2010 Gut 59:1331-39 Crohn’s E. coli translocation across human ileal Peyer’s patches is blocked by soluble plant fibres Ussing chamber culture to measure bacteria translocation across ex vivo Peyer’s patches Soluble plant fibres block bacteria translocation Contrabiotics’ ‘Contrabiotics’ – a new therapeutic strategy? Roberts et al. 2010 Gut 59:1331-39 Plantain NSP blocks interactions of Salmonella with the intestinal epithelium Roberts et al. J. Nutrit. Biochem. 2013; 24(1): 97-103 Parsons et al. PLoS ONE 2014, 9(2), e87658 control banana pectin High intake of fruit fibre (but not cereal or legumes) protects against Crohn’s (but not UC) Prospective Nurses health study – 170,776 women followed up for 3,317,425 person years 1.4g/d vs. 6.4 g/d fruit fibre Ananthakrishnan et al. 2013 Gastroenterology 145:970-77 Whilst some dietary components block potentially harmful bacteria-epithelial interactions other dietary components may increase them. Permitted food emulsifiers enhance E. coli translocation across the epithelium Ex vivo human ileal tissue mounted in Ussing chambers • Resist digestion • Alter lipid bilayer fluidity at low levels • Mucus in small intestine is discontinuous so relatively exposed to emulsifiers • Acceptable daily intake of 25 mg/kg body wt (FAO/WHO data), 0.01% v/v would represent a persistence of ~7% into terminal ileum in a 60kg human, assuming 1L intestinal contents/day passing to the caecum Roberts et al. Gut 2010; 59, 1331-9 Increasing incidence of Crohn's disease vs. emulsifier consumption Japan Roberts et al. 2013; J. Crohns Colitis 7(4):338-41 Dietary emulsifiers impact mouse gut microbiota promoting colitis and metabolic syndrome (and also CRC) Dietary carboxymethyl cellulose and polysorbate 80 impact on mucus barrier Causing colitis …and metabolic syndrome Effects dependent on altered microbiota; (incl. increased mucolytic bacteria, increased LPS and flagellin) Exacerbated tumour development in mice Chassaing et al. Nature 2015; 519, 92-69 Viennois et al. Cancer Res 2016; epub.; And is lecithin (predominantly phosphatidyl choline) bad too? TMAO=trimethylamine-N-oxide A pro-atherogenic metabolite of choline Lecithin also increases bacterial translocation in Balb/c mice 0.1% v/v in drinking water for 4d Ani et al., in progress, 2016 In patients with Crohn’s disease where bacterial invasion into tissue macrophages/ lymph nodes has already occurred, antibiotics are therapeutic… Could dietary supplements be useful? Vitamin D supports bacterial killing Vitamin D deficiency results in impaired macrophage function and inability to generate defensins TLR2 & TLR4 stimulation lead to VDR expression 1,25(OH)2Vit.D3 bound VDR induces: • immune cell function • NOD2 • Antimicrobial peptides (2 defensins/Cathelicidin) Adams & Hewison 2008. Nat. Clin. Pract. Endocrinol. Metab.; 4, 80-90 Hewison 2010. Endocrinol. Metab. Clin. North Am.; 39: 365 Wang et al. 2010 J Biol Chem; 285: 2227 Vitamin D enhances killing of Crohn’s colonic mucosa-associated E. coli Murine macrophages Human MDM Data for colonic CD isolate HM605 Similar results seen for ‘paradigm’ ileal CD isolate LF82 Flanagan et al. IBD 2015; 21(7):1499-510 Vitamin D deficiency in Crohn’s • • • • Active Crohn's disease is associated with low vitamin D levels 70% of quiescent patients are deficient Crohn’s less common with higher predicted levels Vit D receptor (VDR) polymorphisms associated with Crohn’s Clinical trial: vitamin D3 treatment in Crohn's disease – a randomized double-blind placebo-controlled study. • Vitamin D (1200 IU/day) reduces risk of clinical relapse Jorgensen et al. APT 2010; 32: 377-83 IBD patients (CD & UC) with low vitamin D levels more likely to need surgery If receiving vit. D supplements, they are less likely to require interventions (“health care utilization”) Kabbani et al. Am J Gastro 2016;111:712-9 What is the evidence for “Five A Day” http://www.whatdotheyknow.com/request/five_a_day_evidence_base Susan Davis made this Freedom of Information request to Department of Health The request was partially successful. 23 February 2010 “Dear Department of Health, I am interested in learning more about the evidence base behind the "5 a day" campaign to promote a diet richer in fresh fruit and vegetables. In particular I am interested in finding out how the figure of 5 was arrived at (rather than, say, 4, or 10). Yours faithfully, Susan Davis” Department of Health 24 February 2010 Thank you for your email. Where a reply is appropriate we aim to send one within 20 working days. If your enquiry is about a medical matter, please contact NHS Direct on 0845 4647 or visit [1] NHS Choices, or contact your GP surgery. For the latest on swine flu, please visit [2] the National Pandemic Flu Service (NPFS) or call 0800 1 513 100 . For general health information you may also find it helpful to refer to [3] Directgov, the UK Government's Official information website, or the Department of Health website's [4] Frequently Asked Questions. Basis of “5 a day” Joyce Hughes (2000). The case for increasing the population consumption of fruit and vegetables and the evidence for the effectiveness of interventions. “Internationally an intake of at least five portions (total 400g) of fruit and vegetables per day has become an established “healthy eating” message.” Refers to: Health Education Authority (1997): Eight Guidelines for a Healthy Diet. London: Health Education Authority. (out of print) Based upon levels of fruit and vegetable consumption in Southern Mediterranean countries with low levels of Coronary heart disease. (…..emphasized olive oil) History of “5 a day” “Invented” by Ken Kizer in California, 1980’s "Beginning in the mid and late 1970s, the evidence became quite clear about the role of diet in preventing cancer and heart disease and other conditions." Adopted by USA National Cancer Institute, 1991 Adopted by UK Department of Health, 2003 “5 A day”: What counts? “Potatoes are a vegetable, but they don't count towards your 5 A DAY. That’s because the main nutrient in potatoes is starch. Other vegetables that don’t count towards your 5 A DAY are yams, cassava and plantain: they are also usually eaten as starchy foods. However, other root vegetables such as sweet potatoes, parsnips, swedes and turnips do count toward your 5 A DAY, because they are usually eaten in addition to the starchy food part of the meal.” (“BOGSAT” guidance?) The Mediterranean diet “pyramid” Bach-Faig et al. Pub Health Nutr 2011;14:2274-84 The Mediterranean diet – quantified! Tong et al. BMC Medicine 2016;14:135 PAF – population attributable fraction – preventable mortality by increasing adherence to Mediterranean diet to top third (i.e. 9.1 out of 15 points in “pyramid”) Tong et al. BMC Medicine 2016;14:135 My “5 a day” for (gut) health ‘Mediterranean’ pyramid Tree nuts Red wine (2 glasses) Olives ‘Cancer preventing / contrabiotic’ Broccoli ‘Contrabiotic’ Plantains/green bananas Plus …Aspirin/Vit D supplements And exercise And don’t forget to drink plenty of coffee! Association of Coffee Drinking (4 or more cups/day) with Total and Cause-Specific Mortality Freedman et al. NEJM 2012;366:1891-1904 229,119 men 173,141 women Age 50-71 Followed over 14 years After correction for smoking: ≥ 6 cups coffee/day: Men: 10% decreased deaths Women: 15% decreased deaths Caffeinated = decaffeinated And chocolate! NEJM 2012; 367:1562-1564 Regression coefficient (r) = 0.0791 P<0.0001 r excluding Sweden = 0.0862 0.4kg chocolate/year/person/nobel prize/country “minimally effective chocolate dose = 2kg/year but dose response reveals no apparent ceiling up to highest dose of 11kg/year” And cocoa flavonoids improve cognitive performance in elderly humans and rats With thanks to: Jon Rhodes Looking for the environmental causes of IBD! Crohns Colitis UK CORE Wellcome Trust NIHR MRC BBSRC NWCR Provexis UK Tony Hart Keith Leiper Craig Winstanley Steve Edwards Neil Hall Helen Martin Carol Roberts Melissa Friswell Maelle Prorok-Hamon Yvette Merga Hannah Simpson Bryony Parsons Chiedzo Mpofu Sree Subramanian Paul Flanagan Paul Collins Paul Knight Fei Song Richard Evans Abdullah Alswied Julian Marchesi (Cardiff) Johan Soderholm/Asa Keita (Linkoping, Sweden) Arlette Darfeuille-Michaud (Clermont-Ferrand, France) & Benoit Chassiang (Atlanta, USA) Kenny Simpson & Belgin Dogan (Cornell , USA) Christian Jobin & Janelle Arthur (Chapel Hill NC, USA) Alison Simmons (University of Oxford) Niahm O’Kennedy (Provexis, Aberdeen) Steve Fry (Univ of Edinburgh)