digestive health, gut microbiota and fermented foods: what ...€¦ · learning objectives...

December 6, 2018

Presenter:

Joanne Slavin, PhD, RDProfessor Department of Food Science and Nutrition

University of Minnesota

Moderator:James M. Rippe, MD – Leading cardiologist, Founder and Director;

Rippe Lifestyle Institute

Approved for 1 CPE (Level 2) by the Commission on Dietetic Registration, credentialing agency for the Academy of Nutrition and Dietetics.

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Digestive Health, Gut Microbiota and Fermented Foods: what does the science say?

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Today’s Faculty

Joanne Slavin, PhD, RDProfessor Department of Food Science and NutritionUniversity of Minnesota

Moderator:James M. Rippe, MD – Leading cardiologist.Founder and Director, Rippe Lifestyle Institute

Learning Objectives Participants will understand accepted measures for digestive health Participants will appreciate the challenges to measuring effects of

dietary fiber, prebiotics, probiotics, and FODMAPs on digestive health

Participants will learn about processing methods to improve digestive health with food, such as fermentation practices including sourdough

Participants will be able to apply clinically relevant strategies that may help their clients make dietary changes that are associated with gut health.

NUTRI-BITES®

Webinar SeriesDigestive Health, Gut Microbiota and Fermented Foods: what does the science say?

Joanne Slavin Professor

University of MinnesotaDecember 6, 2018

Digestive health, gut microbiota, and fermented foods:  What does the science say? 

Competing interests

Dr. Slavin thanks the following organizations for providing research funds for her laboratory the past 5 years.  American Pulse Association, ILSI‐NA, MNDrive Global Food Ventures, United States Department of Agriculture, the Mushroom Council, GSK, Pepsico, Coca‐Cola, Danone, Welch’s, Nestle Health Sciences, DSM, Nexira, and Taiyo.  

These research projects are in the areas of dietary fiber, whole grains, legumes, FODMAPS, nutrient losses in deep winter greenhouses, mushrooms, digestive health, protein needs, carbohydrate needs, and snacking.  

She serves on the scientific advisory board for Tate and Lyle and Atkins Nutritionals.  

She owns a 1/3 share of the Slavin Sisters Farm LLC, a 119 acre farm in Walworth, WI that is currently rented.  

What is digestive health?• Absence of digestive disease• Normal bowel function – subjective • Regular bowel movements

– Between 3/day and 3/week normal• Stool weight above 200 g/day considered diarrhea, but many vegetarians have stool weights of 300 g/day and greater

• Absence of symptoms – bloating, gas, noises, pain• Quality of life suffers greatly when gut health is compromised

What reaches the large intestine?

• Normal subjects:– Undigested carbohydrates (fiber, oligosaccharides, lactulose)

– 5% of ingested fat– 8% of ingested protein– Unabsorbed minerals, vitamins– Unabsorbed phytochemicals 

2 days in the gut =

• Absorption of water, electrolytes• Bacterial breakdown of carbohydrates, protein, phytochemicals (phytoestrogens, phenolic compounds)

• Production and absorption of short chain fatty acids, other bacterial metabolites

• Feces are 75% water, undigested fiber, bacteria, other unabsorbed nutrients

Limitations to fecal samples

• Not practical in epidemiological studies• No accepted standard

– Stool weight (grams/day)– Stool chemistry– Microflora – methods, what is best– Stool frequency (easy to collect)– Quality of life (used in IBS trials)

Non‐dietary factors that affect laxation

• Stress• Exercise (Oettle. Gut 1991;32:941)• Smoking• Coffee drinking• Drugs (laxatives) (Lembo A, Camilleri M. New Eng J Med 2003;349:1360)

• Personality (Tucker et al. Gastroenterology1981;81:879)

Fiber agreement• Marker of a healthy diet 

– whole grains, fruits, vegetables, legumes• Concept 

– carbohydrates and lignin that escape digestion in the upper GI tract but may be fermented in the gut

• Nutrient– according to 2002 Dietary Reference Intakes (DRIs)

• Regulated– On the Nutrition Facts panel – 25 g current Daily Value (DV) , proposed to increase to 28 g DV

• Health claims– oat bran, barley bran, and psyllium and CVD in US

Fiber:  Effects throughout the GI tractIncreased chewing and more saliva production

Increased gastric distention and delayed emptyingDelayed nutrient

absorption, blunted glucose and insulin response

Change in gut hormones (GLP-1, PYY, ghrelin) Fermentation: SCFAs,

microbiota changes, pH

Fiber in the human gut

• Fibers (pectin, inulin) can be extensively fermented (> 90%) or poorly fermented (purified cellulose, <10%)

• Even fibers that are extensively fermented can increase fecal biomass since bacterial mass increases and that also binds water

• Feces are about 75% water so surviving fiber or bacteria will increase fecal weight

Fiber and laxation• Different fibers have different effects on stool weight, but a 

properly powered study will show differences in stool weight with fiber intake

• Stool frequency generally does not change if frequency is already normal (1/day)

• If transit time is normal (2 days, 48 hours), additional fiber will not change transit time (Marlett et al. Am J Clin Nutr2000;72:784‐789).

• Fiber intakes will normalize transit times to 2 – 4 days (Harvey et al. Lancet 1973;1:1278‐1280).

Average increase in fecal weight per gram fiber fed

• Wheat bran 4.9‐5.4 g/g fiber* • Oats 3.4‐4.5 g/g fiber* • Legumes 2.2 g/g fiber fed*• Pectin/novel fibers 1.2 g/g fiber fed*• Inulin 1.0 g/g fiber fed

– Slavin & Feirtag. Food Funct 2011;2:72‐77

*Cummings JH. 1993. CRC Handbook of Dietary Fiber in Human Nutrition

Summary of tolerance data(Grabitske & Slavin, 2009)

• Dietary fiber – up to 80 g/d in vegetarians – no UL• Resistant starch – 80 g• Fructo‐oligosaccharides – 10‐15 g – diarrhea at 40 g• FODMAP – fermentable oligo, di and mono‐saccharides and polyols– Most of published studies from Australia – interest with low gluten and IBS patients

FODMAPsAcronym that stands for 

Fermentable Oligo‐, Di‐, and Monosaccharides, And Polyols (FODMAP)

Term coined in 2005 by Australian researchers who theorize that foods containing these carbohydrates worsen symptoms of digestive disorders:  Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Disease (IBD)

* Gibson PR, Shepherd SJ. Aliment Pharmacol Ther 2005; 21: 1399 ‐ 1409

Fermentation by microflora

• Some evidence suggests fiber fermentation provides physiological benefit such as– Increased mineral absorption– Stimulation of beneficial microbes (prebiotic)– Decrease survival of pathogenic bacteria through reduction in pH

– Providing nourishment to colonocytes (SCFAs, butyrate) for increased cell growth & maintenance

(2017 ISAPP Consensus Statement, 2017)

Prebiotic: a substance that is selectively utilized by host microorganisms conferring a health benefit 

Probiotics

WHO Definition: Livemicroorganisms that when administered in adequate amounts confer a health benefit on the host

• Probiotics are live microbes that can be formulated into many different products, such as food, drugs, or dietary supplements. 

• Examples:– Lactobacillus– Bifidobacterium– Saccharomyces cerevisiae (yeast)– E. coli– Bacillus 

Microbial Probiotic Species

Fermented Foods & Beverages

• Typically do not contain live cultures due to heat treatment, filtration or food processing to improve shelf life – hence, not true probiotics:• Sourdough bread• Fermented meat• Sauerkraut• Wine & beer• Vinegar

• Acidophilus milk• Sour cream• Cottage cheese with active culture• Miso (fermented soybean paste)• Tempeh (fermented soybean)

Other Fermented Food Sources

• Fermented dairy products– Some yogurts– Some natural cheese– Buttermilk– Kefir

• Cultures may or may not be considered probiotic, depending on bacteria levels when eaten & whether bacteria have been shown to confer health benefits.

Live & Active Cultures

ProbioticsKnown:1. Some probiotics are helpful‐ preventing diarrhea caused by infections and 

antibiotics,  and improving symptoms of irritable bowel syndrome2. The U.S. Food and Drug Administration has not approved any probiotics 

for preventing or treating any health problem3. If people are generally healthy, probiotics have a good safety record. 

However, there have been reports linking probiotics to severe health effects, such as dangerous infections, in people with weakened immune systems

Unknown:1. Which probiotics are helpful and which are not‐ not all probiotics have 

the same effect, effects are likely strain specific2. How much of the probiotic people should take3. Who would most likely benefit from taking probiotics

The Human Microbiome

• We are a composite of species: eukaryotic, bacterial, viral ‐ up to 10x more microbial cells than human

• Gut Microbiota = microbes in our GI tract, ~100 trillion organisms

• Microbiome= their collective genome, >100 times as many genes as human genome

• Produce additional energy otherwise inaccessible to the host• short chain fatty acids

• Produce vitamins in colon• Biotin. Vitamin K

• Metabolize carcinogens• Provide ability to harvest nutrients

• Enhance calcium absorption• Prevent colonization by pathogens• Assist in the development of a mature immune 

system

What microbes do in the body

(Ley at al. Nature, 2006)

Microbiome RevolutionGut Microbes Associated with Obesity 

12 Unrelated obese subjects on fat or carbohydrate restricted diet

Monitored for one year

Increase in Bacteroidetes correlates with change in weight

360 B.C.

Kostic et al. Genes and Development 27:701‐718, 2013

Dominguez‐Bello M et al. Gastronenterology 14:1713‐1719, 2011

Microbiota changes over the life span

Diet may change gut microbial profiles in humans

Arora and Backhed, J. Int. Med., 280:339, 2016

Evidence From:Observational studies• Globally distinct populations• Long‐term food pattern consumption‐ Enterotypes

Short‐term dietary interventions• Low‐ versus high‐fiber diets• Animal versus plant food sources• Macronutrient ratios

Global Population Differences:  Children in Rural Africa (BF)  versus Urban Europe (EU)

Different dietary intake results in differences in gut bacteria:

A:  Burkina Faso, Africa Dietary intake, ages 1‐6

672.2‐996.1 kcal/day Protein: 30.9‐40.2 g Fat: 18.9‐31.2 g Carbohydrate: 102.6‐148.6 g

B:  European Union, Italy Dietary intake, ages 1‐6

1068.7‐1512.7 kcal/day Protein: 41.9‐66.7 g Fat: 56.1‐73.9 g Carbohydrate: 190.0‐290.0 g

De Filippo et al. Proc Natl Acad Sci USA, 107:14691‐14696, 2010

Dietary components that alter gut bacteria

• Most of the human published studies:– Dietary fiber

• Fermentation not accepted as physiological benefit in new FDA fiber definition; fermentation is accepted in Canada

– Prebiotics • oligosaccharides

– Probiotics• Fermented foods, yogurt, sauerkraut, kefir, sourdough 

Dietary components altered by the gut bacteria• Fermentable carbohydrates• Proteins• Vitamin synthesis• Bile acids• Phytochemicals/polyphenols

– Phenolic acids, flavonoids, stilbenes, lignans, secoiridoids

• Rowland et al (2017) Eur J Nutr (09/04/17 online)

Dietary Fiber and Bacterial Diversity

Martens E. Nature 529:158‐159, 2016Sonnenburg, E. et al. Nature 529: 212‐215, 2016

Josephs‐Spaulding et al. Appl Microbiol Biotechnol ePub April 22, 2016

1. Organisms living on and within food may be either friends or foes to the consumer.

2. The human microbiome may decrease in diversity due to exposure to antibiotics, the consumption of a high‐fat and high‐sugar diet and decreased consumption of dietary fiber

3. Decreased diversity can increase susceptibility to invasive food‐borne pathogens such as Clostridium, Staphylococcus aureus, Escherichia coli and Listeria monocytogenes

4. These organisms have greater potential to colonize and outcompete the host‐associated community during dysbiosis

5. Some bacteria that are normal constituents of the microbiome and are sold as probiotics may become pathogenic such as Escherichia coli 

Recent findings from American Gut Project

• Diversity of microbes in the gut is much more vast than originally thought

• Migration from a non‐westernized nation to the US is associated with a loss of gut microbiome diversity

• Subjects who ate more than 30 types of plant foods weekly had more diversity than subjects who ate only 10 types of plant foods

• Diversity has not been linked to a health outcome

Conclusions• The microbiome is integral to human physiology, maintenance of 

health and development of disease.• Dietary fiber is known to alter gut health, including changes in the 

microbiota• Fermented foods and probiotics can also alter gut health• Gut health is difficult to measure; besides stool chemistry measure, 

subjective measures of digestive comfort important to consumers• Many developing links between changes in the microbiota and 

health outcomes, but no accepted “healthy” microbiota

Recommendations to Clients• Most evidence resides with increasing dietary fiber from a diverse set of foods– Typical fiber intakes need to be doubled– Too much fermentation can lead to digestive distress ‐ FODMAPs

• Emerging evidence on effect of dietary components on gut health and microbiome– A variety of plant foods increase diversity of microbiota

Questions?

Participants will understand accepted measures for digestive health Participants will appreciate the challenges to measuring effects of

dietary fiber, prebiotics, probiotics, and FODMAPs on digestive health

Participants will learn about processing methods to improve digestive health with food, such as fermentation practices including sourdough

Participants will be able to apply clinically relevant strategies that may help their clients make dietary changes that are associated with gut health.

NUTRI-BITES®

Webinar SeriesDigestive Health, Gut Microbiota and Fermented Foods: what does the science say?

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Ohio State University

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Digestive Health, Gut Microbiota and Fermented Foods: what does the science say?