Bacterial fermentation of complex carbohydrate in the human colon

Hill, M. J.

doi:10.1097/00008469-199510000-00004

Cited by 68 publications

(45 citation statements)

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“…Experimental data have linked dietary composition with colorectal carcinogenesis: a high intake of animal fat provides an increased risk while a high intake of dietary fiber provides a protection against cancer (Potter 1996). Metabolism by colonic bacterial microbiota of dietary fiber generates a high concentration (60-150 mM) of SCFAs, the most representative of that is butyrate (Hill 1995;Jacobs 1987). In fact, different in vivo studies have established the correlation between increased luminal butyrate levels and a decrease in the incidence of colon cancer (McIntyre et al 1993;Medina et al 1998).…”

Section: Discussionmentioning

confidence: 99%

The effects of short-chain fatty acids on colon epithelial proliferation and survival depend on the cellular phenotype

Comalada

Bailón

Haro

et al. 2006

J Cancer Res Clin Oncol

177

125

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Section: Discussionmentioning

confidence: 99%

The effects of short-chain fatty acids on colon epithelial proliferation and survival depend on the cellular phenotype

Comalada

Bailón

Haro

et al. 2006

J Cancer Res Clin Oncol

177

125

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“…This was because there was intense bacterial fermentation of pectin in the colon. Different human intestinal bacteria are known to degrade pectin; these bacteria include Bacteroides strains, eubacteria, clostridia, and Bifidobacteria (15,20,30,41,42). Dekker and Palmer (10) observed that a Bacteroides strain from human feces contained constitutive polysaccharidases, especially polygalacturonic acid-degrading activities.…”

Section: Discussionmentioning

confidence: 99%

Degradation of Pectins with Different Degrees of Esterification by Bacteroides thetaiotaomicron Isolated from Human Gut Flora

Dongowski

Lorenz

Anger

2000

Appl Environ Microbiol

114

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A complete human fecal flora and cultures of defined species obtained from fecal flora were investigated in vitro to determine their ability to ferment the dietary fiber pectin. Bacteroides thetaiotaomicron was tested as a pectin-degrading microorganism alone and in coculture with Escherichia coli. Macromolecular pectins with different degrees of esterification were used as substrates in microbial degradation studies. The levels of oligogalacturonic acids formed in batch cultures were estimated during a 24-or 48-h incubation period by using highperformance thin-layer chromatography and high-performance anion-exchange chromatography. The spectrum and the amount of unsaturated oligogalacturonic acids formed as intermediate products of pectin fermentation changed permanently in the culture media during incubation with the complete fecal flora. After 24 h, no oligogalacturonic acids were detected. The pectin-degrading activities of pure cultures of B. thetaiotaomicron were lower than the pectin-degrading activity of a complete fecal flora. Cocultures of B. thetaiotaomicron and E. coli exhibited intermediate levels of degradation activity. In pure cultures of E. coli no pectin-degrading activity was found. Additionally, the rate of pectin degradation was affected by the degree of esterification of the substrate. Saturated oligogalacturonic acids were not found during pectin fermentation. The disappearance of oligogalacturonic acids in the later stages of fermentation with both the complete fecal flora and B. thetaiotaomicron was accompanied by increased formation of short-chain fatty acids.In human nutrition, pectin is one of the most important sources of dietary fiber. It is present in vegetables and fruits as a component of the plant cell wall. Pectin consists mainly of long linear chains of ␣-1,4-glycoside-linked D-galacturonic acid (homogalacturonan; "smooth" regions) which are partially esterified with methanol. In addition, branched and complex pectic substances are present in the cell wall (rhamnogalacturonans I and II; "hairy" regions) (45). Like other types of dietary fiber, pectin is not depolymerized by endogenous gastrointestinal enzymes during passage through the stomach and the small intestine. A number of physiological effects of pectin or pectin-containing diets have been described; these effects include decreasing serum cholesterol levels (17), increasing fecal excretion of steroids (24), interacting with metal ions (25), and interacting with bile acids in vitro (11). These effects depend on the macromolecular state of pectin.In the colon, pectin is fermented more or less completely by the microflora, as shown previously (8,9,18,28,48). However, there have been only a few studies in which the intermediate steps in pectin degradation by gastrointestinal microorganisms have been examined. On the other hand, the end products of bacterial fermentation of pectin are well known; a spectrum of short-chain fatty acids (SCFA) and different gases (CO 2 , H 2 , H 2 S, CH 4 ) are formed. In some studies it was s...

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“…Furthermore, they might be metabolised by the activity of the intestinal flora [5,6], leading to pH changes in the bowel content and altered formation of metabolites such as short-chain fatty acids or secondary bile acids. The latter components might either inhibit or promote tumour development [7,8,9]. The amounts of bile acids, for instance, are increased by a diet high in fat and cholesterol [10].…”

Section: Epidemiology and Cause Studiesmentioning

confidence: 99%

Colon cancer risk factors from nutrition

Berlau

Glei

Pool‐Zobel

2004

Analytical and Bioanalytical Chemistry

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Nutrition and health are closely connected and malnutrition can seriously endanger health. The consequences are higher risks of developing diseases. Of these, cancers are of special importance. The most frequent nutrition-associated type of cancer is colon cancer. This review summarises the predisposing factors for the development of colon cancer, and molecular mechanisms responsible for sporadic colon cancer. Moreover, it is pointed out that individual genetic predisposition such as polymorphisms of biotransformation systems might affect susceptibility to cancer risk factors. Selected findings of epidemiological research and nutritional habits, foods, and metabolites that could increase cancer risk are discussed. Furthermore, toxicological assessment of food-related risk factors, e.g. heterocyclic amines, and potential protective effects of food ingredients, e.g. the induction of phase II enzymes or removal of already degenerated cells from tissue by apoptosis, inhibition of proliferation, and cell differentiation are discussed. Risks are not necessarily reduced by avoiding certain substances but by healthy and well-balanced nutrition. Knowledge of individual susceptibility will also make it possible to recognise risks and design more specific nutritional recommendations.

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Bacterial fermentation of complex carbohydrate in the human colon

Cited by 68 publications

References 0 publications

The effects of short-chain fatty acids on colon epithelial proliferation and survival depend on the cellular phenotype

The effects of short-chain fatty acids on colon epithelial proliferation and survival depend on the cellular phenotype

Degradation of Pectins with Different Degrees of Esterification by Bacteroides thetaiotaomicron Isolated from Human Gut Flora

Colon cancer risk factors from nutrition

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