Assessing Gut Issues: Short Chain Fatty Acids...Predominant gut bacteria ferment dietary fiber and...
Transcript of Assessing Gut Issues: Short Chain Fatty Acids...Predominant gut bacteria ferment dietary fiber and...
Assessing Gut Issues: Short Chain Fatty Acids
Elizabeth Redmond, PhD, MMSc, RD Chair-Elect Dietitians in Integrative and Functional Medicine DPG Education Specialist, Metametrix Laboratory, Georgia
Short Chain Fatty Acids (SFCA) This session will discuss: 1. What are SCFA ? 2. What do SCFA do? 3. What affects SCFA production? 4. Review of the synergistic relationship of SCFAs and gut bacteria. 5. Possible treatments and case study.
Putrefactive SCFA
Predominant gut bacteria ferment dietary fiber and their monosaccharide components to acetate, propionate, and butyrate, and protein material to valerate, isovalerate and isobutyrate. ∗ C-2 Acetate ∗ C-3 Propionate Saccharolytic (carbohydrate) fermentation SCFA: >90% of SCFA ∗ C-4 Butyrate ∗ C-6 Caproate
∗ iC4 isoButyrate ∗ C-5 Valerate* ∗ iC5 isoValerate Proteolytic (Protein) fermentation SCFA: < 10% of SCFA ∗ iC6 hexanoate
1. What are short chain fatty acids (SCFA)?
An overview of the relationship between transit of food through the human gastrointestinal tract and the digestion of nutrients in the small intestine and
fermentation in the cecum and colon.
Topping D L , Clifton P M Physiol Rev 2001;81:1031-1064
1. What do SCFAs do?
∗ More than 95% of SCFA are produced and absorbed within the colon.
∗ SCFA contribute to normal large bowel
function and prevent pathology through their actions in the lumen and on the colonic musculature and vasculature, and through their metabolism by colonocytes.
Topping, D., Clifton, P. Physiol Rev July 1, 2001 vol. 81 no. 3 1031-1064
Acetate Butyrate Propionate
Immune system Immune system Immune system
Carcinogenesis Carcinogenesis Carcinogenesis
Colonic function Colonic function Colonic function
Adipogenesis Satiety Satiety
Barrier function Neurological effects
Visceral perception Cholesterol metabolism
Insulin sensitivity
Oxidative stress
Journal of AOAC International Vol. 95, No. 1, 2012
Butyrate has been shown to:
Neurogastroenterol Motil (2011) 23, 975–979
∗ Acts as a signal metabolite affecting epithelial cell proliferation, apoptosis, and differentiation.
∗ Affects several inflammatory parameters such as cytokines and myeloperoxidase activity, thus increasing antioxidant capacity.
∗ Provides barrier function: stimulates intestinal mucus production, mucosal repair, and decreases colonic epithelial permeability.
∗ Enhances the growth of lactobacilli and Bifidobacter sp. ∗ Increases mucosal blood flow. ∗ Increases in vitro crypt proliferation. ∗ Clinically can reduce inflammation and diarrhea. ∗ Possible protection against colonic carcinogenesis. ∗ Increases glutathione production.
Acetate has been shown to:
∗ Decreases lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNFα) release from human neutrophils .
∗ Inhibits NF-κB reporter activity in human colon carcinoma cells. ∗ Intravenous administration increases peripheral blood antibody. ∗ Production of natural killer cell activity in cancer patients. ∗ Stimulates proliferation of normal crypt cells. ∗ Enhances ideal motility and increases colonic blood flow. ∗ May have a role in adipogenesis.
Neurogastroenterol Motil (2011) 23, 975–979
• Inhibits proinflammatory eicosanoids, nuclear factor-κB, adhesion molecules, LPS-stimulated TNF-α
• Regulates and inhibits proliferation of activated lymphocytes • Growth arrest and differentiation of human colon cancer cells • Induces colorectal cancer apoptosis • Lowers blood glucose and alters lipid metabolism in healthy human
subjects • Increases satiety - Increases production of leptin • Upregulates peroxisome proliferator activated receptor (PPAR)-
gamma • Activates G protein-coupled receptor and inhibits lipolysis • Intraventricular infusions can impair social behavior and cause brain
abnormalities in rats, similar to those detected in human autism.
Propionate has been shown to:
Neurogastroenterol Motil (2011) 23, 975–979
∗ Acetate has been shown to increase cholesterol synthesis. ∗ Propionate has been shown to inhibit cholesterol synthesis. ∗ Treatments that can decrease the acetate/propionate ratio
have been proposed as a way to reduce serum lipids.
Other clinical uses of SCFA: acetate/propionate ratio
J Clin Gastroenterol. 2006 Mar;40(3):235-43.
Valerate is0butyrate isovalerate
inhibitory effects on cytokine release
strong pungent cheesy or sweaty smell
increase of glutathione (GSH)
proposed that it is the anticonvulsant agent in valerian
induce histone hyperacetylation
major component of the cause of unpleasant foot odor
inhibitory effects on cytokine release
excellent substrate for colonic oxidation, similar to butyrate
Journal of AOAC International Vol. 95, No. 1, 2012
Protein Breakdown
∗ Proteins (from foods , albumin, blood, muscle, secretions) must be broken down to peptides and amino acids before bacteria can metabolize them.
∗ Proteins get broken down by bacterial proteases
and peptidases, and pancreatic endopeptidases. ∗ The end product of the breakdown is SCFA, BCFA
and organic acids.
The breakdown of proteins and peptides by colonic microorganisms.
Metabolism of N-containing substrates in the large gut, and the physiologic significance of the end products.
What affects production of SCFAs? Fecal pH Diet BMI Predominant bacteria Location/Environment Immune Inflammation Race Gender Transit time
Concentration (mmol g dry wt bacteria)
pH 6.8 pH 5.5
Free amino acids
Acetate 10.6 11.7
Propionate 2.8 3.2
Butyrate 1.8 3.2
Valerate 1.9 0.9
ibutyrate 0.5 0.5
ivalerate 2.6 0.9
Total 20.5 20.4
SCFA grown in mixed cultures of intestinal bacteria from amino acids, with a change in pH value.
pH
High-protein, reduced-carbohydrate weight-loss diets promote metabolite profiles likely to be detrimental to colonic health.
M (mmol/L) - -> Total SCFA
acetate propionate butyrate valerate isovalerate isobutyrate
maintenance 108.3 61.97 21.10 16.93 2.07 1.14 1.60
high-protein /moderate-carbohydrate (HPMC)
100.6 55.79 17.41 14.83 2.49 1.85 2.28
high-protein /low-carbohydrate (HPLC)
73.59 39.61 14.71 8.54 1.90 1.62 2.01
P <0.001 <0.001 <0.001 <0.001 <0.083 <0.001 <0.002
Short-chain fatty acids (SCFAs) detected in feces of 17 volunteers given 3 different diets.
Am J Clin Nutr May 2011 vol. 93 no. 5 1062-1072
Diet
0
20
40
60
80
100
120
Maintance HPMC HPLC
*
**= <0.001; *= 0.001; ^=.01
^
Am J Clin Nutr May 2011 vol. 93 no. 5 1062-1072
Level of SCFA in three diet groups
0 20 40 60 80 100
acetate
propionate
butyrate
valerate
isobutyrate
isovalerate
Saccharolytic fermentation
Proteolytic fermentation
HPLC HPMC Maintanance
Am J Clin Nutr May 2011 vol. 93 no. 5 1062-1072 **= <0.001; *= 0.001; ^=.01
**
**
*
*
^
Percent
Percent SCFA for three diet groups
Diet/supplements Effects on SCFAs or their derivatives in inflammatory conditions
Diet with resistant starch (1.53 kg/10 kg of diet)
Improvement of symptoms; epithelial cell proliferation; regeneration of laminin; growth of intestinal bacteria
Diet supplemented with cellobiose (9%)
Reduction of weight loss; diminished tissue edema; attenuation of inflammatory cytokine concentrations
Fiber supplementation (5%)
Reduction in MPO and NO synthase activities; restoration of colonic glutathione levels; diminished TNF- concentrations
Oral butyrate (10 mg/kg)
Improvement of mucosa lesion and attenuation of the inflammatory profile of intestinal mucosa and local lymph nodes in a model of DSS-induced colitis.
Nutrients 2011, 3
Factors affecting protein fermentation
The amount of protein entering the colon depends on the amount of protein and the digestibility of the protein eaten.
∗ Decreased digestibility = increased protein fermentation. ∗ Digestibility of proteins from animal sources exceeds 90%; plant proteins
range from 70–90%. ∗ On a normal mixed diet, the amount of protein has a stronger effect on
the amount reaching the colon.
Mol. Nutr. Food Res. 2012, 56, 184–196; November 1, 2010 vol. 299 no. 5 G1030-G1037
Carbohydrate Gap
Topping D L , Clifton P M Physiol Rev 2001;81:1031-1064: http://physrev.physiology.org/content/81/3/1031.full
o Fiber is comprised principally of polysaccharides and non-starch polysaccharide (NSP). NSP resist digestion by intrinsic human intestinal digestive enzymes completely, their intakes do not account for calculated human SCFA production (the “carbohydrate gap”).
o Some of the deficit may be filled by oligosaccharides (OS), but starch and products of small intestinal starch digestion are thought to contribute the most. This fraction is termed resistant starch (RS).
o A particular problem is that assay procedures are well-established for fiber and/or NSP but not for RS. This means that dietary intakes can be calculated for the former but not the latter, and direct comparison may be difficult. Thus health authorities have been able to make dietary recommendations for fiber but not yet for RS.
Percentage of carbohydrate loss in relation to GI [adapted from Jenkins et al.]
Wong J M W , Jenkins D J A J. Nutr. 2007;137:2539S-2546S; http://lpi.oregonstate.edu/infocenter/phytochemicals/fiber/ http://lpi.oregonstate.edu/infocenter/phytochemicals/fiber/
0
20
40
60
80
100
120
BMI 18-24.9 BMI 25-30 BMI 30+ *
Mean SCFA (mmol/l)
BMI
Obesity (2009) 18, 190–195.
Percent SCFA for three BMI levels
* *
Percent of total SCFA
Obesity (2009) 18, 190–195.
0 20 40 60 80
acetate
butyrate
propionate
valerate
isobutyrate
isovalerate
>30
25-30
18-24.5
Percent SCFA for three BMI levels
Predominant Bacteria
Predominant bacteria, or normal indigenous microflora, have co-evolved with their host, and play a major role in health. They provide:
∗ Colonization resistance against potentially pathogenic organisms ∗ Aid in digestion and absorption ∗ Produce vitamins and SCFAs ∗ Stimulate the GI immune system ∗ Are able to activate innate and adaptive immunity
SCFA Production Acetate Propionate Butyrate Lactate
Bacteroides x x X (D)
Bifidobacteria x X (L)
Lactobacilli x X (D/L)
Clostridia x x x X (L)
Faecalibacteria x X (D)
Fusobacteria x x
Prevotella X
GI tract with bacteria populations shown by region
Anaerobes dominate the gut.
Bacterial Phylumm Bacteroidetes
∗ Bacteroides spp. ∗ Prevotella spp.
Firmicutes ∗ Clostridia spp. ∗ Mycoplasma spp. ∗ Lactobacillus spp.
Proteobacteria ∗ Escherichia coli.
Fusobacteria ∗ Fusobacteria spp.
Actinobacteria ∗ Bifidobacter spp. ∗ Streptomyces spp.
Predominant Bacteria based on diet
0 10 20 30 40
Bacteroides
Lachnospiraceace
Roseburia
F. prausnitzil
HPLC HPMC Maintanance
**
*
** p= <.001; * p< .05 Am J Clin Nutr May 2011 vol. 93 no. 5 1062-1072
Bifidobacter content in RATS fed varying diets
CT – Control diet ; HF – High fat diet
HF-Cell – High fat with non-fermentable fiber
HF-OFS – High fat with fermentable fiber
aberrant crypts per/cm2
J Nutr. 1999 Jul;129(7 Suppl):1483S-7S
Dietary levels of oligofructose and Bifidobacter sp. resulted in a decrease in aberrant crypts in RATS
OF – Oligofructose (inulin)
SBO – Soybean oligosaccharide;
WBO – Wheat bran oligosaccharide
PNAS August 17, 2010 vol. 107 no. 33 14691-14696
Comparative study in children from Europe (EU) and rural Africa (BF)
PNAS August 17, 2010 vol. 107 no. 33 14691-14696
SCFA-producing bacteria could help to prevent establishment of some potentially pathogenic intestinal bacteria. Quantification of SCFAs in fecal samples from BF and EU populations by SPME-GC-MS.
Comparative study in children from Europe (EU) and rural Africa (BF)
51.17%
13.64%
33.92%
1.20%
69.54%
8.30%
20.10%
1.70%
0% 20% 40% 60% 80% 100%
Acetate
Butyrate
Propionate
Valerate
EU BF
PNAS August 17, 2010 vol. 107 no. 33 14691-14696
40.2
31.2
148.6
14.2
66.7
73.9
290
8.4
0 50 100 150 200 250 300
protein
fat
carbohydrate*
fiber
EU
BF
Grams of macronutrients
PNAS August 17, 2010 vol. 107 no. 33 14691-14696
Comparative study in children from Europe (EU) and rural Africa (BF)
Frequency of genes relayed to butyrate, acetate and propionate production in the fecal metagenome of 27 subjects.
Nature, 2012; http://www.nature.com/nature/journal/vnfv/ncurrent/extref/nature11319-s1.pdf
Environment
J. Pediatr Gastroenterol Nutr, Vol. 18, No. 2, 1994.
Fecal Short Chain Fatty Acids in Children with Inflammatory Bowel Disease
White bars= controls; black = severe UC; grey= inactive/mild UC
Immune Reactions
Inflammation
0 50 100 150 200 250
acetate
butyrate
propionate
isobutyratelactate
IBS Healthy
(*P<0.05).
*
*
Open Biochem J. 2010; 4: 53–58.
Amount of SCFAs in each population
Colonic contents of the primary SCFA in African Americans, Caucasian Americans, and Native Africans.
O'Keefe S J D et al. J. Nutr. 2009;139:2044-2048
Race
Case Study
Patient symptoms ∗ belching ∗ flatulence ∗ bloating ∗ abdominal pain ∗ diarrhea ∗ fatigue
∗ Diet history - vegetarian diet - tries to avoid dairy ∗ Symptom questionnaire- meets criteria for IBS ∗ Symptom history ∗ Laboratory assessment of GI function ∗ Do a stool test ∗ Look to see if the patient has vitamin D, B12, or iron
∗ Consider getting these or other fat soluble vitamins ∗ Also consider amino acids
Collect
Resident Micro-biota
Short Chain Fatty Acids
Acetate / Propionate = 48/4.5= 10.66 Average A/P ratio = 3.075 Total cholesterol: 209 HLD: 41 and Lp(a): 75
Percent Short Chain Fatty Acids
12.66
87.27
7.63
92.37
4.76
91.77
7.3
92.7
0 20 40 60 80 100
Proteolytic fermentation
Saccharolytic fermentation
Percent
Case HPLC Maintenance Normal BMI
(Isobutyrate + isovalerate + valerate)
Evaluation of Digestive Markers
Thermogram Results
Treatment options
∗ Use of butyrate ∗ Butyrate functions as the major energy source for colonocytes and modulates
several cellular processes
∗ Changes in dietary habits ∗ Increasing fiber intake of soluble fibers (fermentable) is more effective than
insoluble (non-fermentable), which can increase SCFAs (butyrate). ∗ Decrease total protein intake, or shift to more plant protein. This will result in a
shift from proteolytic to saccharolytic fermentation. ∗ Exclude dairy and casein
∗ Use of prebiotics ∗ Specifically inulin
∗ Product Klaire labs Biotagen ∗ Increase diet sources: artichoke hearts, banana, agave, garlic, onion, wild yam, chicory
Assessing Gut Issues: Short Chain Fatty Acids
Elizabeth Redmond, PhD, MMSc, RD [email protected] Metametrix Laboratory, Georgia Chair-Elect Dietitians in Integrative and Functional Medicine DPG