The metabolic consequences of slow colonic transit

Exercise-induced microbial changes in preventing type 2 diabetes

The metabolic benefits associated with long-term physical activity are well appreciated and growing evidence suggests that it involves the gut microbiota. Here we re-evaluated the link between exercise-induced microbial changes and those associated with prediabetes and diabetes. We found that the relative abundances of substantial amounts of diabetes-associated metagenomic species associated negatively with physical fitness in a Chinese athlete students cohort. We additionally showed that those microbial changes correlated more with handgrip strength, a simple but valuable biomarker suggestive of the diabetes states, than maximum oxygen intake, one of the key surrogates for endurance training. Moreover, the causal relationships among exercise, risks for diabetes, and gut microbiota were explored based on mediation analysis. We propose that the protective roles of exercise against type 2 diabetes are mediated, at least partly, by the gut microbiota.

Advancing human gut microbiota research by considering gut transit time

Accumulating evidence indicates that gut transit time is a key factor in shaping the gut microbiota composition and activity, which are linked to human health. Both population-wide and small-scale studies have identified transit time as a top covariate contributing to the large interindividual variation in the faecal microbiota composition. Despite this, transit time is still rarely being considered in the field of the human gut microbiome. Here, we review the latest research describing how and why whole gut and segmental transit times vary substantially between and within individuals, and how variations in gut transit time impact the gut microbiota composition, diversity and metabolism. Furthermore, we discuss the mechanisms by which the gut microbiota may causally affect gut motility. We argue that by taking into account the interindividual and intraindividual differences in gut transit time, we can advance our understanding of diet-microbiota interactions and disease-related microbiome signatures, since these may often be confounded by transient or persistent alterations in transit time. Altogether, a better understanding of the complex, bidirectional interactions between the gut microbiota and transit time is required to better understand gut microbiome variations in health and disease.

A RETROSPECTIVE REVIEW OF POST-METAMORPHIC MOUNTAIN CHICKEN FROG (LEPTODACTYLUS FALLAX) NECROPSY FINDINGS FROM EUROPEAN ZOOLOGICAL COLLECTIONS, 1998 TO 2018

The mountain chicken frog (Leptodactylus fallax) is the largest endemic amphibian species in the Western Hemisphere. Since 1998, this critically endangered species has been maintained as a European Endangered Species Programme, but low breeding success and a high mortality rate threaten the sustainability of the captive frog population. In the current study, we analyzed gross and histopathologic postmortem information from 212 mountain chicken frogs that died in European zoological collections from 1998 to 2018. Thin body condition was the most commonly reported finding across all submissions, observed in 125 frogs. The gastrointestinal and urinary systems were reported to have the highest prevalence of pathologic findings on gross and histopathologic examination. Inflammatory disease was the most frequent diagnosis after histopathologic examination of relevant tissues, with intestinal inflammatory disease (n = 76) followed by tubulointerstitial nephritis (n = 26) being the most commonly reported. Neoplasia was reported in 42 of 212 (19.8%) frogs, all of which were adults. A defined cause of death, or reason for euthanasia, was proposed for 164 of 212 (77.4%) frogs, with inflammatory diseases processes (74 of 212; 34.9%) most commonly implicated. Intestinal adenocarcinoma, seemingly restricted to the colon, caused the deaths of 31 adult frogs. Further investigations to determine factors contributing to the high incidence of inflammatory disease processes and neoplasia are advocated to improve the health and sustainability of the captive mountain chicken frog population.

Characteristics of fecal metabolic profiles in patients with irritable bowel syndrome with predominant diarrhea investigated using 1 H-NMR coupled with multivariate statistical analysis

BACKGROUND

Gut microbiota are known to be closely related to irritable bowel syndrome (IBS). However, not much is known about characteristic fecal metabolic profiles of IBS. We aimed to characterize fecal metabolites in patients with IBS with predominant diarrhea (IBS-D) using ¹ H-nuclear magnetic resonance (¹ H-NMR) spectroscopy.

METHODS

In this study, we enrolled 29 patients diagnosed with IBS-D according to the Rome IV criteria, 22 healthy controls (HC) and 11 HC administered laxatives (HC-L) in the age group of 20-69 year. The usual diet of the patients and HC was maintained, their fecal samples were collected and investigated by NMR-based global metabolic profiling coupled with multivariate statistical analysis.

RESULTS

We detected 55 metabolites in ¹ H-NMR spectra of fecal samples: four amines, 16 amino acids, six fatty acids, eight organic acids, three sugars, and 18 other compounds. Orthogonal partial least square-discriminant analysis derived score plots showed clear separation between the IBS-D group and the HC and HC-L groups. Among the 55 metabolites identified, we found five disease-relevant potential biomarkers distinguishing the IBS-D from the HC, namely, cadaverine, putrescine, threonine, tryptophan, and phenylalanine.

CONCLUSIONS

The patients with IBS-D were clearly differentiated from the HC and HC-L by fecal metabolite analysis using ¹ H-NMR spectroscopy, and five fecal metabolites characteristic of IBS-D were found. The findings of this study could be used to develop alternative and complementary diagnostic methods and as a source of fundamental information for developing novel therapies for IBS-D.

Higher Atazanavir Plasma Exposure in Rats is Associated with Gut Microbiota Changes Induced by Cotrimoxazole

BACKGROUND

Cotrimoxazole (TMP-SMX) is concomitantly used as a primary prophylaxis of opportunistic infections with antiretroviral agents, such as Atazanavir (ATV). Results from an ex vivo study showed changes in intestinal absorption of ATV when rats were pretreated with TMP-SMX. The objective of this in vivo study is to determine the effect of TMP-SMX on the pharmacokinetics of ATV in rats. We also studied changes in gut microbiota induced by TMP-SMX.

METHODS

We used the non-compartment analysis to compare the pharmacokinetics of ATV in a parallel group of rats treated with a low or therapeutic dose of TMP-SMX for nine days to untreated control rats. Gut microbiota was characterized using qPCR and High Throughput Sequencing of 16S rDNA.

RESULTS

Rats treated with TMP-SMX showed a much broader exposure to ATV compared to the control group (AUC0-8h (ng.mL-1.h), 25975.9±4048.7 versus 2587.6±546.9, p=0.001). The main observation regarding the gut microbiota was a lower proportion of enterobacteria related to the administration of TMP-SMX. Moreover, the Total Gastrointestinal Transit Time (TGTT) was longer in the TMP-SMX treated group.

CONCLUSION

Concomitant administration of TMP-SMX and ATV significantly increased ATV exposure in rats. This increase could be the result of a prolonged TGTT leading to an increase in the intestinal residence time of ATV favoring its absorption. Gut microbiota changes induced by TMP-SMX could be at the origin of this prolonged TGTT. If demonstrated in humans, this potential interaction could be accompanied by an increase in the adverse effects of ATV.

An epidemiologic perspective on the stem cell hypothesis in human carcinogenesis

BACKGROUND

Tomasetti and Vogelstein have hypothesized that the patterns of cancer incidence in various cells and tissues are highly correlated with the estimated lifetime number of stem cell divisions. The authors reviewed the risks in tissues of 17 types of cancer from the United States and 69 additional countries. Positive correlations were observed consistently between the tissue - specific cancer incidence and the estimated lifetime number of stem cell divisions. The authors concluded that approximately two-thirds of global cancer incidence may be attributed to random DNA replication errors.

METHODS

An epidemiologic perspective is presented that may serve as a counterpoint in interpreting organ-specific cancer risks. The unifying nature of the Tomasetti/Vogelstein hypothesis must be viewed in the context of diverse and contrasting global trends and patterns of types and "causes" of cancers that are closely linked with economic development and cultural lifestyle practices. The presentation is organized by reviewing the global burden of cancer; concepts of causal inferences and counterfactual assumptions; multifactorial causes of hepatocellular carcinoma and a hierarchy of causes that varies internationally; tobacco carcinogenesis and the multiplex associations with 19 cancer sites and tissues; profile in contrasts in transit through the small and large intestine.

OBSERVATIONS AND CONCLUSIONS

It is readily recognized that DNA replication errors and number of stem cell divisions may vary in individuals and populations due to external environmental genotoxic chemicals and biologic agents, and internal hormonal and metabolic factors. There is a striking contrast in the risk of adenocarcinoma in the small intestine with that in the large intestine. Tomasetti and Vogelstein indicated that the cumulative number of divisions of stem cells over a lifetime in normal epithelial mucosal cells from colorectal cancer patients was 4 time greater than in the epithelial tissue from patients with adenocarcinoma of the small intestine. Their conclusion would suggest a "seed" and "soil" interaction rather than exclusively the independence of either component. Namely, that the contrasting physiological, biochemical, microbial and immunological features in the lumen and on the mucosal surface of the large intestine, in contrast to that in the small intestine, would foster molecular genetic and epigenetic events that are advantageous to neoplasia in the large intestine.

Indoxyl sulphate and kidney disease: Causes, consequences and interventions

In the last decade, chronic kidney disease (CKD), defined as reduced renal function (glomerular filtration rate (GFR) < 60 mL/min per 1.73 m(2) ) and/or evidence of kidney damage (typically manifested as albuminuria) for at least 3 months, has become one of the fastest-growing public health concerns worldwide. CKD is characterized by reduced clearance and increased serum accumulation of metabolic waste products (uremic retention solutes). At least 152 uremic retention solutes have been reported. This review focuses on indoxyl sulphate (IS), a protein-bound, tryptophan-derived metabolite that is generated by intestinal micro-organisms (microbiota). Animal studies have demonstrated an association between IS accumulation and increased fibrosis, and oxidative stress. This has been mirrored by in vitro studies, many of which report cytotoxic effects in kidney proximal tubular cells following IS exposure. Clinical studies have associated IS accumulation with deleterious effects, such as kidney functional decline and adverse cardiovascular events, although causality has not been conclusively established. The aims of this review are to: (i) establish factors associated with increased serum accumulation of IS; (ii) report effects of IS accumulation in clinical studies; (iii) critique the reported effects of IS in the kidney, when administered both in vivo and in vitro; and (iv) summarize both established and hypothetical therapeutic options for reducing serum IS or antagonizing its reported downstream effects in the kidney.

Production and cytomolecular identification of new wheat-perennial rye (Secale cereanum) disomic addition lines with yellow rust resistance (6R) and increased arabinoxylan and protein content (1R, 4R, 6R)

Wheat-Secale cereanum addition lines with yellow rust resistance (6R) and increased arabinoxylan content (1R, 4R, 6R) have been selected and identified in order to increase biodiversity of wheat. Perennial rye (Secale cereanum, 2n = 2x = 14, RR) cultivar Kriszta has a large gene pool that can be exploited in wheat breeding. It has high protein and dietary fibre content, carries several resistance genes, tolerant to frost and drought, and adapts well to disadvantageous soil and weather conditions. In order to incorporate agronomically useful features from this perennial rye into cultivated wheat, backcross progenies derived from a cross between the wheat line Mv9kr1 and perennial rye 'Kriszta' have been produced, and addition lines disomic for 1R, 4R and 6R chromosomes have been selected using GISH, FISH and SSR markers. Quality measurements showed that addition of 'Kriszta' chromosomes 4R and 6R to the wheat genome had increased the total protein content. The 4R addition line contained slightly, while 1R and 6R additions significantly higher amount of arabinoxylan than the parental wheat line. Besides this, the 6R addition line appeared to be resistant to yellow rust in highly infected nurseries, consequently it may carry a new effective gene different from that harboured in the 1RS.1BL translocation for resistance to this disease.

Stool consistency is strongly associated with gut microbiota richness and composition, enterotypes and bacterial growth rates

OBJECTIVE

The assessment of potentially confounding factors affecting colon microbiota composition is essential to the identification of robust microbiome based disease markers. Here, we investigate the link between gut microbiota variation and stool consistency using Bristol Stool Scale classification, which reflects faecal water content and activity, and is considered a proxy for intestinal colon transit time.

DESIGN

Through 16S rDNA Illumina profiling of faecal samples of 53 healthy women, we evaluated associations between microbiome richness, Bacteroidetes:Firmicutes ratio, enterotypes, and genus abundance with self-reported, Bristol Stool Scale-based stool consistency. Each sample's microbiota growth potential was calculated to test whether transit time acts as a selective force on gut bacterial growth rates.

RESULTS

Stool consistency strongly correlates with all known major microbiome markers. It is negatively correlated with species richness, positively associated to the Bacteroidetes:Firmicutes ratio, and linked to Akkermansia and Methanobrevibacter abundance. Enterotypes are distinctly distributed over the BSS-scores. Based on the correlations between microbiota growth potential and stool consistency scores within both enterotypes, we hypothesise that accelerated transit contributes to colon ecosystem differentiation. While shorter transit times can be linked to increased abundance of fast growing species in Ruminococcaceae-Bacteroides samples, hinting to a washout avoidance strategy of faster replication, this trend is absent in Prevotella-enterotyped individuals. Within this enterotype adherence to host tissue therefore appears to be a more likely bacterial strategy to cope with washout.

CONCLUSIONS

The strength of the associations between stool consistency and species richness, enterotypes and community composition emphasises the crucial importance of stool consistency assessment in gut metagenome-wide association studies.

Galacto-oligosaccharides and Colorectal Cancer: Feeding our Intestinal Probiome

Prebiotics are ingredients selectively fermented by the intestinal microbiota that promote changes in the microbial community structure and/or their metabolism, conferring health benefits to the host. Studies show that β (1-4) galacto-oligosaccharides [β (1-4) GOS], lactulose and fructo-oligosaccharides increase intestinal concentration of lactate and short chain fatty acids, and stool frequency and weight, and they decrease fecal concentration of secondary bile acids, fecal pH, and nitroreductase and β-glucuronidase activities suggesting a clear role in colorectal cancer (CRC) prevention. This review summarizes research on prebiotics bioassimilation, specifically β (1-4) GOS, and their potential role in CRC. We also evaluate research that show that the impact of prebiotics on host physiology can be direct or through modulation of the gut intestinal microbiome, specifically the probiome (autochtonous beneficial bacteria), we present studies on a potential role in CRC progression to finally describe the current state of β (1-4) GOS generation for industrial production.

Effect of the consumption of a cheese enriched with probiotic organisms (Bifidobacterium lactis bi-07) in improving symptoms of constipation

CONTEXT

Constipation is a very common symptom in the general population. One way of non-pharmacological treatment of constipation is through the addition of probiotics to food.

OBJECTIVES

The aim of this study was to evaluate de effect of the consumption of a fresh cheese, enriched with Bifidobacterium lactis Bi-07 on the symptoms of constipated women.

METHODS

A randomized controlled trial, carried out in the Basic Health Units of Guaporé's City - RS/Brazil, between January and May 2012, with 30 constipated women. The patients were randomized into two groups whom received, for 30 days, 30 g of fresh cheese enriched with Bifidobacterium lactis Bi-07 (n = 15) or regular fresh cheese (n = 15). Constipation symptoms were evaluated according to ROMA III Consensus, before and after the nutritional intervention. Also, data of clinical and anthropometric characteristics of the individuals were collected. Accepted level of significance 5% (P≤0,05).

RESULTS

The medium age of the studied population was 37,5±14,4 years in the intervention group and 40,8±12,8 years in the control group. After 30 days we observed that the ingestion of fresh cheese enriched with Bifidobacterium lactis Bi-07 promoted benefic effects on the symptoms of strength to evacuate.

CONCLUSION

The consumption of 30g/day of a fresh cheese enriched with Bifidobacterium lactis Bi-07 has beneficial effects on constipation symptoms.

Nutritional properties of einkorn wheat (Triticum monococcum L.)

The hulled wheat einkorn (Triticum monococcum L. ssp. monococcum), a staple food of early farmers for many thousand years, today is cropped only in small areas of the Mediterranean region and continental Europe. Increasing attention to the nutritional quality of foods has fostered renewed interest in this low-impact crop. The reappraisal of einkorn quality evidenced that this ancient wheat has some dietary advantages over polyploid wheats. Einkorn wholemeal is poor in dietary fibre but rich in proteins, lipids (mostly unsaturated fatty acids), fructans and trace elements (including zinc and iron). The good concentration of several antioxidant compounds (carotenoids, tocols, conjugated polyphenols, alkylresorcinols and phytosterols) and low β-amylase and lipoxygenase activities (which limit antioxidant degradation during food processing) contribute to the excellent nutritional properties of its flour, superior to those of other wheats. Conversely, einkorn has relatively low bound polyphenol content and high polyphenol oxidase activity. In spite of eliciting weaker toxic reactions than other Triticum species, einkorn is not suitable for coeliacs. Current trends towards the consumption of functional foods suggest that this cereal may still play a significant role in human consumption, especially in the development of new or special foods with superior nutritional quality.

Cereal-based gluten-free food: how to reconcile nutritional and technological properties of wheat proteins with safety for celiac disease patients

The gluten-free diet is, to date, the only efficacious treatment for patients with Celiac Disease. In recent years, the impressive rise of Celiac Disease incidence, dramatically prompted changes in the dietary habit of an increasingly large population, with a rise in demand of gluten-free products. The formulation of gluten-free bakery products presents a formidable challenge to cereal technologists. As wheat gluten contributes to the formation of a strong protein network, that confers visco-elasticity to the dough and allows the wheat flour to be processed into a wide range of products, the preparation of cereal-based gluten-free products is a somehow difficult process. This review focuses on nutritional and technological quality of products made with gluten-free cereals available on the market. The possibility of using flour from naturally low toxic ancient wheat species or detoxified wheat for the diet of celiacs is also discussed.

Inverse association of colorectal cancer prevalence to serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in a large Appalachian population

Background

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent environmental contaminants that affect metabolic regulation, inflammation, and other factors implicated in the development and progression of colorectal cancer (CRC). However, the link between these compounds and CRC remains unknown. In this cross-sectional study, we investigated the association of CRC diagnosis to PFOA and PFOS blood levels in a large Appalachian population.

Methods

Participants were 47,359 adults ≥ 21 years of age and residing in six PFOA-contaminated water districts in the mid-Ohio Valley (N = 47,151 cancer-free adults, 208 cases of primary CRC). All participants completed a comprehensive health survey between 2005 and 2006; serum levels of PFOA, PFOS, and a range of other blood markers were also measured. Medical history was assessed via self report and cancer diagnosis confirmed via chart review.

Results

CRC showed a strong inverse, dose–response association with PFOS serum levels (odds ratio (OR) adjusted for potential confounders = 0.2, 95% confidence interval (CI) 0.2,0.3) for highest vs. lowest quartile of PFOS, P-trend < 0.00001) and a significant, but more modest inverse association with PFOA (adjusted OR = 0.6 (CI 0.4, 0.9) for highest vs. lowest quartile, P-trend = 0.001). These inverse associations were stronger in those diagnosed within the previous 6 years and resident in the same water district for a minimum of 10–15 years preceding assessment. The relationship between PFOA and CRC was also more pronounced in men and leaner adults, and showed a stronger linear trend at lower exposure levels.

Conclusions

In this large cross-sectional study, we found a strong, inverse association between PFOS and likelihood of CRC diagnosis and a significant, although more modest inverse association between PFOA and CRC. If confirmed in prospective investigations, these findings may aid in identifying new strategies for CRC prevention and treatment and inform future studies regarding mechanisms underlying CRC pathogenesis.

Incidence of gall stone formation in acromegalic patients on octreotide therapy

OBJECTIVE

Octreotide, a long-acting synthetic somatostatin analog, has been widely used for ac-romegalic patients. Gastrointestinal (GI) side effects and gall stones are predominant side effects. We report incidence of gall stones in our cohort of acromegalic patients treated with octreotide therapy.

DESIGN

Retrospective case observational study.

SETTING

Endocrinology Unit, Dr. Ram Manohar Lohia, Hospital, New Delhi.

MATERIALS AND METHODS

Patients of acromegaly on primary or secondary octreotide therapy.

INTERVENTION

Patients were enquired regarding complaints related to the GI system and their medical records were reviewed. Ultrasound films at various intervals while on octerotide therapy were evaluated by the radiologist for presence of sludge and development of gall stones.

RESULTS

Of seven patients, five developed gallstones and sludge was seen in three patients at intervals ranging from 11 to 36 months postoctreotide initiation.

CONCLUSION

A high incidence of gall stone formation in the present study as compared to the West was noted, the reasons for which are not clear.

Dose-response effect of Bifidobacterium lactis HN019 on whole gut transit time and functional gastrointestinal symptoms in adults

OBJECTIVE

To assess the impact of Bifidobacterium lactis HN019 supplementation on whole gut transit time (WGTT) and frequency of functional gastrointestinal (GI) symptoms in adults.

MATERIAL AND METHODS

We randomized 100 subjects (mean age: 44 years; 64% female) with functional GI symptoms to consume a proprietary probiotic strain, B. lactis HN019 (Fonterra Research Centre, Palmerston North, New Zealand), at daily doses of 17.2 billion colony forming units (CFU) (high dose; n = 33), 1.8 billion CFU (low dose; n = 33), or placebo (n = 34) for 14 days. The primary endpoint of WGTT was assessed by X-ray on days 0 and 14 and was preceded by consumption of radiopaque markers once a day for 6 days. The secondary endpoint of functional GI symptom frequency was recorded with a subject-reported numeric (1-100) scale before and after supplementation.

RESULTS

Decreases in mean WGTT over the 14-day study period were statistically significant in the high dose group (49 ± 30 to 21 ± 32 h, p < 0.001) and the low dose group (60 ± 33 to 41 ± 39 h, p = 0.01), but not in the placebo group (43 ± 31 to 44 ± 33 h). Time to excretion of all ingested markers was significantly shorter in the treatment groups versus placebo. Of the nine functional GI symptoms investigated, eight significantly decreased in frequency in the high dose group and seven decreased with low dose, while two decreased in the placebo group. No adverse events were reported in any group.

CONCLUSIONS

Daily B. lactis HN019 supplementation is well tolerated, decreases WGTT in a dose-dependent manner, and reduces the frequency of functional GI symptoms in adults.

Environment and genotype effects on the content of dietary fiber and its components in wheat in the HEALTHGRAIN diversity screen

Within the HEALTHGRAIN diversity screen, the variability of the contents of dietary fiber (DF) and components thereof was studied in wheat. Furthermore, the contribution of genotype and environment to this variability was estimated. The levels of total DF (TDF), total nonstarch polysaccharide (TOTNSP), water-extractable nonstarch polysaccharide (WENSP), total arabinoxylan (TOTAX), lignin, and beta-glucan in whole meal, flour, and/or bran varied approximately 1.8-fold. The highest variability was observed for the water-extractable arabinoxylan (WEAX) level in flour and bran (approximately 3.7-fold). Genotype and environment contributed to a similar extent to the variability in TDF, TOTNSP, and TOTAX content in wheat. The observed relatively high impact of genotype-environment interaction suggests that the levels of these constituents are weak breeding parameters. The WENSP level is a more stable parameter as the effect of the interaction term was much less than the impact of genotype. For TOTAX and WEAX in flour, WEAX in bran, beta-glucan in whole meal, and extract viscosity, wheat genotype determined approximately 50% or higher of the variation observed, whereas the impact of the genotype-environment interaction was relatively low. These findings suggest that the health-related and technological functionality of wheat can be directed to a certain extent by selection of appropriate wheat varieties.

Temporal and spatial changes in cell wall composition in developing grains of wheat cv. Hereward

A combination of enzyme mapping, FT-IR microscopy and NMR spectroscopy was used to study temporal and spatial aspects of endosperm cell wall synthesis and deposition in developing grain of bread wheat cv. Hereward. This confirmed previous reports that changes in the proportions of the two major groups of cell wall polysaccharides occur, with beta-glucan accumulating earlier in development than arabinoxylan. Changes in the structure of the arabinoxylan occurred, with decreased proportions of disubstituted xylose residues and increased proportions of monosubstituted xylose residues. These are likely to result, at least in part, from arabinoxylan restructuring catalysed by enzymes such as arabinoxylan arabinofurano hydrolase and lead to changes in cell wall mechanical properties which may be required to withstand stresses during grain maturation and desiccation.

Constipation is relieved more by rye bread than wheat bread or laxatives without increased adverse gastrointestinal effects

Rye bread and lactobacilli modify the colonic environment and have the potential to relieve constipation and could be a safe and convenient alternative to laxatives. The effects of rye bread and cultured buttermilk with Lactobacillus rhamnosus GG (LGG) on bowel function and colon metabolism were investigated and compared with laxatives in 51 constipated adults. They were randomized to receive whole-grain rye bread (minimum 240 g/d), LGG (2 x 10(10) colony-forming units/d), whole-grain rye bread (minimum 240 g/d) + LGG (2 x 10(10) colony-forming units/d), white wheat bread (maximum 192 g/d), or laxatives (as usual for a participant) for 3 wk. Participants recorded their dietary habits, bowel function, and gastrointestinal symptoms. Fecal weight, pH, SCFA and bacterial enzyme activities, total intestinal transit time (TITT), and breath hydrogen were determined. Rye bread, compared with white wheat bread, shortened TITT by 23% (P = 0.040), increased weekly defecations by 1.4 (P = 0.014), softened feces [odds ratio (OR) 3.98; P = 0.037], eased defecation (OR 5.08; P = 0.018), increased fecal acetic acid and butyric acid contents by 24% (P = 0.044) and 63% (P <0.001), respectively, and reduced fecal beta-glucuronidase activity by 23% (P = 0.014). Compared with laxatives, rye bread reduced TITT by 41% (P = 0.006), fecal beta-glucuronidase activity by 38% (P = 0.033), and fecal pH by 0.31 units (P = 0.006). LGG did not relieve constipation or significantly affect colonic metabolism. Gastrointestinal adverse effects did not significantly differ among the study groups. In conclusion, rye bread relieves mild constipation and improves colonic metabolism compared with white wheat bread and commonly used laxatives without increasing gastrointestinal adverse effects.

The epidemiology and pathogenesis of neoplasia in the small intestine

PURPOSE

The mucosa of the small intestine encompasses about 90% of the luminal surface area of the digestive system, but only 2% of the total annual gastrointestinal cancer incidence in the United States.

METHODS

The remarkable contrast in age-standardized cancer incidence between the small and large intestine has been reviewed with respect to the cell type patterns, demographic features, and molecular characteristics of neoplasms.

RESULTS

Particularly noteworthy is the predominance of adenocarcinoma in the colon, which exceeds 98% of the total incidence by cell type, in contrast to that of 30% to 40% in the small intestine, resulting in an age-standardized ratio of rates exceeding 50-fold. The prevalence of adenomas and carcinomas is most prominent in the duodenum and proximal jejunum. The positive correlation in global incidence rates of small and large intestinal neoplasms and the reciprocal increases in risk of second primary adenocarcinomas suggest that there are common environmental risk factors. The pathophysiology of Crohn inflammatory bowel disease and the elevated risk of adenocarcinoma demonstrate the significance of the impaired integrity of the mucosal barrier and of aberrant immune responses to luminal indigenous and potentially pathogenic microorganisms.

CONCLUSION

In advancing a putative mechanism for the contrasting mucosal susceptibilities of the small and large intestine, substantial differences are underscored in the diverse taxonomy, concentration and metabolic activity of anaerobic organisms, rate of intestinal transit, changing pH, and the enterohepatic recycling and metabolism of bile acids. Experimental and epidemiologic studies are cited that suggest that the changing microecology, particularly in the colon, is associated with enhanced metabolic activation of ingested and endogenously formed procarcinogenic substrates.

Wheat

Wheat is the dominant crop in temperate countries being used for human food and livestock feed. Its success depends partly on its adaptability and high yield potential but also on the gluten protein fraction which confers the viscoelastic properties that allow dough to be processed into bread, pasta, noodles, and other food products. Wheat also contributes essential amino acids, minerals, and vitamins, and beneficial phytochemicals and dietary fibre components to the human diet, and these are particularly enriched in whole-grain products. However, wheat products are also known or suggested to be responsible for a number of adverse reactions in humans, including intolerances (notably coeliac disease) and allergies (respiratory and food). Current and future concerns include sustaining wheat production and quality with reduced inputs of agrochemicals and developing lines with enhanced quality for specific end-uses, notably for biofuels and human nutrition.

A prospective study of bowel motility and related factors on breast cancer risk

BACKGROUND

Estrogen is an established risk factor for breast cancer. Greater bowel motility has been associated with increased estrogen excretion and lower serum estrogen levels, suggesting that it may influence breast cancer risk. However, only one other epidemiologic study thus far, to our knowledge, has examined the relation between bowel motility and breast cancer risk.

METHODS

We prospectively examined whether bowel motility, measured by self-reported frequency of bowel movements, and related factors (constipation, laxative use, water consumption, and dietary fiber intake) were associated with incidence of breast cancer among 28,586 postmenopausal women, ages 50 to 76 years, in the Vitamins and Lifestyle study. Cox proportional hazards models were used to estimate multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI). From 2000 to 2005, 507 incident invasive breast cancers among the cohort were identified.

RESULTS

Women with very frequent (> or =3/d) bowel movements had a 46% decreased risk compared with 1/d women (RR, 0.54; 95% CI, 0.31-0.92), but the test for linear trend was not significant (P(trend) = 0.41). Constipation was nonsignificantly associated with increased risk (RR, 1.30 for > or =1/wk versus <1/y; 95% CI, 0.87-1.95). No statistically significant associations were observed for the other study exposures: 10-year chemical laxative use, 10-year use of fiber laxatives, water consumption, and dietary fiber intake.

CONCLUSION

This study adds limited support to the hypothesis that increased bowel motility lowers breast cancer risk.

Variation in the content of dietary fiber and components thereof in wheats in the HEALTHGRAIN Diversity Screen

Within the HEALTHGRAIN diversity screening program, the variation in the content of dietary fiber and components thereof in different types of wheat was studied. The wheat types were winter (131 varieties) and spring (20 varieties) wheats (both Triticum aestivum L., also referred to as common wheats), durum wheat (Triticum durum Desf., 10 varieties), spelt wheat (Triticum spelta L., 5 varieties), einkorn wheat (T. monococcum L., 5 varieties), and emmer wheat (Triticum dicoccum Schubler, 5 varieties). Common wheats contained, on average, the highest level of dietary fiber [11.5-18.3% of dry matter (dm)], whereas einkorn and emmer wheats contained the lowest level (7.2-12.8% of dm). Intermediate levels were measured in durum and spelt wheats (10.7-15.5% of dm). Also, on the basis of the arabinoxylan levels in bran, the different wheat types could be divided this way, with ranges of 12.7-22.1% of dm for common wheats, 6.1-14.4% of dm for einkorn and emmer wheats, and 10.9-13.9% of dm for durum and spelt wheats. On average, bran arabinoxylan made up ca. 29% of the total dietary fiber content of wheat. In contrast to what was the case for bran, the arabinoxylan levels in flour were comparable between the different types of wheat. For wheat, in general, they varied between 1.35 and 2.75% of dm. Einkorn, emmer, and durum wheats contained about half the level of mixed-linkage beta-glucan (0.25-0.45% of dm) present in winter, spring, and spelt wheats (0.50-0.95% of dm). All wheat types had Klason lignin, the levels of which varied from 1.40 to 3.25% of dm. The arabinoxylan contents in bran and the dietary fiber contents in wholemeal were inversely and positively related with bran yield, respectively. Aqueous wholemeal extract viscosity, a measure for the level of soluble dietary fiber, was determined to large extent by the level of water-extractable arabinoxylan. In conclusion, the present study revealed substantial variation in the contents of dietary fiber and constituents thereof between different wheat types and varieties.

The HEALTHGRAIN Cereal Diversity Screen: concept, results, and prospects

One hundred and fifty bread wheat lines and 50 other lines of small-grain cereals (spelt, durum wheat, Triticum monococcum, Triticum dicoccum, oats, rye, and barley) were selected for diversity in their geographical origin, age, and characteristics. They were grown on a single site in Hungary in 2004-2005, harvested, milled, and analyzed for a range of phytochemicals (tocols, sterols, phenolic acids, folates, alkylresorcinols) and fiber components that are considered to have health benefits. Detailed analyses of these components in the different species are reported in a series of accompanying papers. The present paper discusses the comparative levels of the bioactive components in the different species, showing differences in both ranges and mean amounts. Furthermore, detailed comparisons of the bread wheat lines show that it is possible to identify lines in which high levels of phytochemicals and dietary fiber components are combined with good yield and processing quality. This means that commercially competitive lines with high levels of bioactive components are a realistic goal for plant breeders.

Association between farnesoid X receptor expression and cell proliferation in estrogen receptor-positive luminal-like breast cancer from postmenopausal patients

The farnesoid X receptor (FXR, NR1H4), a member of the nuclear receptor superfamily of ligand-dependent transcription factors, is normally produced in the liver and the gastrointestinal tract, where it acts as a bile acid sensor. It has been recently detected in breast cancer cell lines and tissue specimens. The expression of FXR was scored (0-8) by immunohistochemistry on 204 breast cancer samples and correlated with established cancer biomarkers. Moreover, the effect of the FXR activator chenodeoxycholic acid (CDCA) was determined on cell proliferation and estrogen receptor regulation/activation in breast cancer cell lines. FXR was detected in 82.4% of samples with a high median expression score of 5. FXR expression significantly correlated with estrogen receptor (ER) expression (P = 0.009) and luminal-like markers. In ER-positive tumors, FXR expression was significantly correlated with the proliferation marker Ki-67 (P < 0.001) and the nodal status (P = 0.028), but only so in postmenopausal women, suggesting that lack of estrogens may disclose the association between FXR and cell proliferation. In vitro experiments confirmed clinical data since CDCA stimulated the proliferation of ER-positive cells only in steroid-free medium, a stimulation inhibited upon siRNA-silencing of FXR expression as well as ER blockade by antiestrogens. Moreover, co-immunoprecipitation experiments revealed that CDCA activated-FXR interacted with ER. These results suggest that ER-positive breast tumors could be stimulated to proliferate via a crosstalk between FXR and ER, particularly in a state of estrogen deprivation (menopause, aromatase inhibitors).

Increased cholinergic contractions of jejunal smooth muscle caused by a high cholesterol diet are prevented by the 5-HT4 agonist--tegaserod

Background

Excess cholesterol in bile and in blood is a major risk factor for the respective development of gallbladder disease and atherosclerosis. This lipid in excess negatively impacts the functioning of other smooth muscles, including the intestine. Serotonin is an important mediator of the contractile responses of the small intestine. Drugs targeting the serotonin receptor are used as prokinetic agents to manage intestinal motor disorders, in particular irritable bowel syndrome. Thus, tegaserod, acting on 5-HT₄ receptor, ideally should obviate detrimental effects of excessive cholesterol on gastrointestinal smooth muscle. In this study we examined the effect of tegaserod on cholesterol-induced changes in the contractile responses of intestinal smooth muscle.

Methods

The effects of a high cholesterol (1%) diet on the in vitro contractile responses of jejunal longitudinal smooth muscle from Richardson ground squirrels to the cholinergic agonist carbachol were examined in the presence or absence of tetrodrodotoxin (TTX). Two groups of animals, fed either low (0.03%) or high cholesterol rat chow diet, were further divided into two subgroups and treated for 28 days with either vehicle or tegaserod.

Results

The high cholesterol diet increased, by nearly 2-fold, contractions of the jejunal longitudinal smooth muscle elicited by carbachol. These cholinergic contractions were mediated by muscarinic receptors since they were blocked by scopolamine, a muscarinic receptor antagonist, but not by the nicotinic receptor antagonist, hexamethonium. Tegaserod treatment, which did not affect cholinergic contractions of tissues from low cholesterol fed animals, abrogated the increase caused by the high cholesterol diet. With low cholesterol diet TTX enhanced carbachol-evoked contractions, whereas this action potential blocker did not affect the augmented cholinergic contractions seen with tissues from animals on the high cholesterol diet. Tegaserod-treatment removed the effects of a high cholesterol diet on neuronal muscarinic receptors, as the potentiating effect of TTX on carbachol-elicited contractions was maintained in these animals.

Conclusion

A high cholesterol diet causes significant changes to cholinergic neurotransmission in the enteric nerves of the jejunum. The mechanisms by which these effects of cholesterol are reversed by tegaserod are unknown, but relate to removal of an inhibitory effect of cholesterol on enteric nerves.

Dietary fish oil increases acetylcholine- and eicosanoid-induced contractility of isolated rat ileum

The long-chain (n-3) polyunsaturated fatty acids (PUFA) have been reported to exhibit health benefits and healing properties for the gastrointestinal tract. The aim of this study was to investigate the effects of dietary fish oil supplementation on the in vitro contractility of gut tissue. Rats (9 wk old) were fed synthetic diets supplemented with 170 g/kg Sunola oil (SO; 850 g/kg as oleic acid [18:1(n-9)]) or with 100 g/kg of the SO replaced by saturated animal fat (SF) or fish oil (FO) for 4 wk. In the colon, there was no difference in the sensitivity (50% effective concentration) or the maximal contraction among the three dietary groups induced by acetylcholine or 8-iso-prostaglandin (PG)E(2) with the rat colon being relatively insensitive to the thromboxane mimetic U-46619. However, in the ileum, the FO group had greater maximal contractions induced by acetylcholine and 8-iso-PGE(2) compared with the SO and SF groups (P < 0.05), and greater maximal contractions induced by PGE(2), PGF(2alpha) and U-46619 compared with the SF group (P < 0.05). FO feeding increased the incorporation of (n-3) PUFA (eicosapentaenoic [20:5(n-3)], docosapentaenoic [22:5(n-3)] and docosahexaenoic acids [22:6(n-3) primarily at the expense of (n-6) PUFA (linoleic [18:2(n-6)] and arachidonic acids [20:4(n-6)]) in the ileum and colon phospholipid fatty acids (P < 0.05). The FO group had a lower cecal digesta pH (P < 0.001) and a greater butyrate concentration than the SF group (P < 0.05). These results suggest that dietary (n-3) PUFA may modulate the contractility of the small intestine.

Plasma deoxycholic acid concentration is elevated in postmenopausal women with newly diagnosed breast cancer

OBJECTIVE

High concentrations of plasma deoxycholic acid (DCA) are found in human breast cyst fluid and it has been hypothesised that this may be related to risk of breast cancer. The aim of this pilot study was to ascertain whether plasma bile acid concentrations were greater in women with breast cancer.

DESIGN

A case-control study comparing postmenopausal women with breast cancer with healthy controls was conducted.

SUBJECTS

Twenty Caucasian postmenopausal breast cancer patients were recruited at the time of diagnosis together with 20 healthy controls matched for age and body mass index. Exclusion criteria included any treatment for breast cancer, use of hormone replacement therapy in the last 12 months, diabetes mellitus, a history of liver or gall bladder disease or abnormal liver function.

MEASUREMENTS

Fasting plasma bile acid concentrations were determined by gas-liquid chromatography/mass spectrometry.

RESULTS

The mean plasma DCA concentration was 52% higher (P=0.012) in patients with breast cancer compared with controls.

CONCLUSION

These results support the hypothesis that DCA may be involved in the aetiology of breast cancer.

Bifidobacterium animalis strain DN-173 010 shortens the colonic transit time in healthy women: a double-blind, randomized, controlled study

BACKGROUND

A previous study has suggested that Bifidobacterium animalis DN-173 010 shortens the colonic transit time in women.

AIM

To confirm this effect and to determine whether modifications of the faecal bacterial mass and/or faecal secondary bile salts may be the explanation.

METHODS

A double-blind, cross-over study was performed. Thirty-six healthy women were studied in four consecutive 10-day periods. During periods 2 and 4, they ingested three 125 g cups per day of a fermented milk which was either a product containing B. animalis DN-173 010 or a control without bifidobacteria. Periods 1 and 3 were run-in and washout periods, respectively. The total and segmental colonic transit times were assessed using a pellet method. In 12 subjects, all stools were collected and analysed for pH, faecal weight, bacterial mass and bile acids.

RESULTS

The total and sigmoid transit times were significantly shorter during dosing with B. animalis compared to the control period. The other transit times, faecal weight, pH, bacterial mass and bile acids were not significantly affected.

CONCLUSIONS

B. animalis DN-173 010 shortens the colonic transit time in healthy women. This effect is not explained by modifications of the faecal bacterial mass or secondary bile acids.

Acute effects of dietary fat composition on postprandial plasma bile acid and cholecystokinin concentrations in healthy premenopausal women

Bile acids derived from intestinal bacterial metabolism and transported to the breast in plasma may influence risk of breast cancer. The purpose of the present study was to test the hypothesis that fatty acid chain length and degree of unsaturation differ with regard to their influence on the postprandial release of cholecystokinin (CCK) and the subsequent increase in plasma bile acid concentrations that occur following a meal. A randomized crossover design was used to compare five high-fat test meals (50 g fat) with a low-fat test meal (15 g) on plasma bile acid and CCK concentrations in eighteen healthy premenopausal women. The high-fat meals were enriched in oleate or palmitate, or linoleate or medium-chain triacylglycerols (MCT) or a blend of oleate and long-chain n-3 fatty acids. The postprandial increase in plasma CCK concentration was lower on the MCT meal compared with all meals and was greater following the linoleate compared with the low-fat meal. Plasma bile acid concentrations increased 2-3-fold postprandially but the increase was lower following the MCT meal compared with the other meals and was greater on the linoleate meal compared with the low-fat meal. The postprandial increases in plasma chenodeoxycholic acid concentration showed a trend to rise with increasing unsaturation of the test meal. In conclusion, meals rich in linoleate are a potent stimulus for CCK release and lead to prolonged elevations of plasma bile acids and meals containing MCT inhibit CCK release and the subsequent increase in plasma bile acid concentrations.

Review article: epidemiology of gall-bladder disease--role of intestinal transit

Recent epidemiological studies have suggested that hyperinsulinaemia may be a central factor in the pathogenesis of cholesterol gallstones, explaining a probable link with physical inactivity as well as abdominal adiposity. There is also increasing evidence for the hypothesis that enrichment of bile with DCA. 'the colonic bile acid', leads to enrichment of bile with cholesterol. Biliary DCA can be raised and lowered by slowing down and speeding up colonic transit, respectively. Slow transit is characteristic of non-obese British women with gallstones and of non-obese peasants in a gallstone-prone mountain community. High biliary DCA predicts recurrence of gallstones and so does laxative usage, a pointer to constipation and therefore to slow transit. In some studies, at least, a high fibre intake is protective against gallstones. Much else besides fibre influences colonic function. Future studies of gallstone aetiology should include measurements of colonic function. Measures that speed up colonic transit should be tested for their ability to prevent gallstone formation in high-risk individuals.