Michael A Conlon

• The Commonwealth Scientific and Industrial Research Organisation

Hypertension, type-2-diabetes (T2D) and obesity are contributory risk factors for the development of metabolic syndrome. Peptides, polyphenols and polysaccharides may inhibit enzymes involved in the disease pathways of this disorder. Peptide hydrolysates (PEP), polyphenol (PP) and polysaccharide (PS) extracts generated from the Australian seaweeds...

This study explored the gut health potential of the green seaweed Ulva rigida (SW-U) and the red seaweed Gracilaria fisheri (SW-G), as well as polysaccharide-enriched extracts (PF-U and PF-G, respectively). The polysaccharide-enriched extracts were not digestible by small intestinal enzymes, but the morphology of samples was changed. After 24 h in...

Diet is known to affect the composition and metabolite production of the human gut microbial community, which in turn is linked with the health and immune status of the host. Whole seaweeds (WH) and their extracts contain prebiotic components such as polysaccharides (PS) and polyphenols (PP). In this study, the Australian seaweeds, Phyllospora como...

(-)-Epigallocatechin gallate (EGCG) and tuna oil (TO) are beneficial bioactive compounds. EGCG, TO or a combination of, delivered by broccoli by-products (BBP), were added to an in vitro anaerobic fermentation system containing human fecal inocula to examine their ability to generate short-chain fatty acids (SCFA), metabolize EGCG and change the gu...

Macroalgae, or seaweeds, are a rich source of components which may exert beneficial effects on the mammalian gut microbiota through the enhancement of bacterial diversity and abundance. An imbalance of gut bacteria has been linked to the development of disorders such as inflammatory bowel disease, immunodeficiency, hypertension, type-2-diabetes, ob...

Oil palm fruit is widely used for edible oils, but the health benefits of other components are relatively unknown. We examined if consuming a polyphenol-rich extract of the fruit, from a vegetation by-product of oil processing, which also contains fibre, has gastro-intestinal benefits in rats on a Western-type diet (WD). The oil palm preparation (O...

In Reply We agree with Dr Benech and colleagues that, in our trial,¹ ideally both donor and autologous FMT should have been processed under anaerobic conditions. Aerobic stool processing results in loss of many beneficial obligate anaerobic organisms such as Faecalibacterium prausnitzii.² However, ours was an investigator-led trial with limited acc...

Importance High-intensity, aerobically prepared fecal microbiota transplantation (FMT) has demonstrated efficacy in treating active ulcerative colitis (UC). FMT protocols involving anaerobic stool processing methods may enhance microbial viability and allow efficacy with a lower treatment intensity. Objective To assess the efficacy of a short dura...

Honeybee caste development is nutritionally regulated by royal jelly (RJ). Major royal jelly protein 1 (MRJP1), the most abundant glycoprotein among soluble royal jelly proteins, plays pivotal roles in honeybee nutrition and larvae development, and exhibits broad pharmacological activities in humans. However, its structure has long remained unknown...

Scope Dietary supplementation with polyphenol‐rich propolis can protect against experimentally‐induced colitis. We examined whether different polyphenol compositions of Chinese propolis (CP) and Brazilian propolis (BP) influences their ability to protect against dextran sulfate sodium (DSS)‐induced colitis in rats. Methods and results HPLC‐DAD/Q‐T...

This article provides a case-study for the simulated industrial-scale production of high-value functional food products from the brown seaweed Ecklonia radiata. Three process scenarios at a batch processing scale of 2000 kg seaweed were assessed for their economic feasibility: Scenario 1: Enzyme-assisted production of a crude seaweed extract; Scena...

This study aimed to understand the prebiotic potential and contribution of four extract fractions from the brown seaweed Ecklonia radiata. Four seaweed fractions were tested for their digestibility and prebiotic effects using an in vitro anaerobic fermentation system containing human faecal inocula. After 24 h fermentation, three seaweed fractions,...

Background Seaweeds are a large and diverse group of photosynthetic macro-algae found across the world's oceans. There is a growing recognition that they are important sources of bioactive compounds with a variety of biological activities that could potentially contribute to functional food and nutraceutical industries. Scope and approach The comp...

We examined the gut health potential of the brown seaweed Ecklonia radiata and its polysaccharides. Rats consumed an AIN-93G-based diet without addition (control) or containing 5% (w/w) of ground dried whole seaweed (WS) or dried powdered polysaccharide fraction (PF) of the seaweed for 1 wk. The PF consisted largely of fucoidan and alginate. PF tre...

Propolis is an important hive product and considered beneficial to health. However, evidence of its potential for improving gut health is still lacking. Here we use rats to examine whether dietary supplementation with propolis could be used as a therapy for ulcerative colitis. Rats were fed with a Western style diet alone (controls) or supplemented...

Background: Faecal microbiota transplantation (FMT) has demonstrated variable efficacy in the treatment of active ulcerative colitis (UC) in three randomised control trials (RCT) to date. Interpretation of FMT RCT evidence is limited by each trial using a different donor stool processing method, placebo control, as well as timing and method of admi...

The human gut contains over 100 trillion bacteria comprising over 1000 bacterial species and in excess of 1 million genes. Recent research suggests that changes in the gut microbial population structure are associated with a wide range of human diseases including both diseases of the gut, such as colorectal cancer, irritable bowel syndrome and infl...

The prebiotic potential of the extracts of a South Australian brown seaweed Ecklonia radiata obtained using different processes was investigated. Six extracts of this seaweed were prepared by enzymatic, acidic, and water extraction processes. The extracts were added to an in vitro anaerobic fermentation system containing human faecal inocula to ass...

Propolis has abundant polyphenolic constituents and is used widely as a health/functional food. Here, we investigated the effects of polyphenol-rich propolis extracts (PPE) on intestinal barrier function in human intestinal epithelial Caco-2 cells, as well as in rats. In Caco-2 cells, PPE increased transepithelial electrical resistance and decrease...

Guest editors Michael Conlon and David Topping introduce this themed collection on foods, the large bowel microbiota and health outcomes.

This study evaluated whether dietary resistant starch (RS) and green tea extract (GTE), which have anti-inflammatory and anti-cancer properties, protect against colitis-associated colorectal cancer (CAC) using a rat model, also investigated potential mechanisms of action of these agents including their effects on the gut microbiota. Rats were fed a...

A possible causal role of the gut microbiota in human obesity is capturing interest. Recent experimental evidence and mechanistic hypotheses suggest that a ‘dysbiotic’ large bowel microbiota, induced mainly by poor diet, increases dietary energy bioavailability and storage in the host. However, research findings in both animals and humans are incon...

Propolis has documented anti-inflammatory properties, although its mechanisms of action are poorly understood. In this study, the anti-inflammatory effects of polyphenol-rich propolis extracts (PPE) from China (CPPE) and Brazil (BPPE) were examined. Oral administration of PPE to lipopolysaccharide (LPS)-challenged mice decreased serum proinflammato...

Background Faecal microbial transplant (FMT) for recurrent Clostridium difficile infection (rCDI) is greatly facilitated by frozen stool banks. However, the effect of frozen storage of stool for greater than 2 months on the viability of stool bacteria is unknown and the efficacy of FMT is not clear.AimTo evaluate the viability of bacteria in stool...

Epidemiological studies have identified increased colorectal cancer (CRC) risk with high red meat (HRM) intakes, whereas dietary fibre intake appears to be protective. In the present study, we examined whether a HRM diet increased rectal O6-methyl-2-deoxyguanosine (O6MeG) adduct levels in healthy human subjects, and whether butyrylated high-amylose...

Orange juice (OJ) flavanones are bioactive polyphenols that are absorbed principally in the large intestine. Ingestion of probiotics has been associated with favourable changes in the colonic microflora. The present study examined the acute and chronic effects of orally administered Bifidobacteria longum R0175 on the colonic microflora and bioavail...

Dietary fiber shortens gut transit time, but data on the effects of fiber components (including resistant starch, RS) on intestinal contractility are limited. We have examined RS effects in male Sprague-Dawley rats fed either a high-amylose maize starch (HAMS) or a wholemeal made from high-amylose wheat (HAW) on ileal and colonic contractility ex v...

There is growing recognition of the role of diet and other environmental factors in modulating the composition and metabolic activity of the human gut microbiota, which in turn can impact health. This narrative review explores the relevant contemporary scientific literature to provide a general perspective of this broad area. Molecular technologies...

Background Rats used in nutritional studies are often kept in wire-based cages to prevent ingestion of bedding and minimise ingestion of faeces. However wire-based cages are criticised because of potential negative animal welfare implications. This study investigated the effects of wire or solid-based cages with corncob bedding on large bowel ferme...

High red meat (HRM) intake is associated with increased colorectal cancer risk, while resistant starch is probably protective. Resistant starch fermentation produces butyrate, which can alter microRNA (miRNA) levels in colorectal cancer cells in vitro; effects of red meat and resistant starch on miRNA expression in vivo were unknown. This study exa...

Objective Colonic fermentation in patients with UC in remission was compared with that in matched healthy subjects on habitual diets and when dietary fibre was increased. Design Fibre intake, faecal output of fibre (measured as non-starch polysaccharide (NSP)), starch, microbiota and fermentation products, and whole gut transit time (WGTT) were ass...

Red meat is considered a risk factor for colorectal cancer (CRC). Heme is considered to promote colonic hyperproliferation and cell damage. Resistant starch (RS) is a food that ferments in the colon with studies demonstrating protective effects against CRC. By utilizing the western diet model of spontaneous CRC, we determined if feeding heme (as he...

Autism spectrum disorder (ASD) is a neurodevelopmental disorder. Many affected individuals also display symptoms of gastrointestinal (GI) disturbance, suggesting GI factors may play an important role in the pathogenesis of ASD and/or related complications. The current review will focus on evidence supporting a role for the GI microbiota and their f...

A recent report indicated that numbers of Sutterella spp. are elevated in gastrointestinal biopsies taken from children with autism spectrum disorder (ASD). We have recently reported changes in the numbers of some bacteria within the stool of ASD children, and now examine whether numbers of Sutterella spp. and some other mucosa-associated bacteria...

High dietary intakes of some protein sources, including soy protein, can increase colonic DNA damage in animals, whereas some carbohydrates attenuate this. We investigated whether inulin and xylo-oligosaccharides (XOS) could be protective against DNA strand breaks by adding them to a human colonic simulator consisting of a proximal vessel (PV) (pH...

Although a genetic component has been identified as a risk factor for developing inflammatory bowel disease, there is evidence that dietary factors also play a role in the development of this disease. The aim of this study was to determine the effects of feeding a red meat diet with and without resistant starch (RS) to mice with dextran sulfate sod...

Butyrate delivery to the large bowel may positively modulate commensal microbiota and enhance immunity. To determine the effects of increasing large bowel butyrate concentration through ingestion of butyrylated high amylose maize starch (HAMSB) on faecal biochemistry and microbiota, and markers of immunity in healthy active individuals. Male and fe...

Synbiotic supplements, which contain multiple functional ingredients, may enhance the immune system more than the use of individual ingredients alone. A double blind active controlled parallel trial over a 21 d exercise training period was conducted to evaluate the effect of Gut Balance™, which contains Lactobacillus paracasei subsp. paracasei (L....

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder where a high frequency of gastrointestinal disturbance (e.g., constipation and diarrhea) is reported. As large bowel fermentation products can have beneficial or detrimental effects on health, these were measured in feces of children with and without ASD to examine whether ther...

Resistant starch (RS), fed as high amylose maize starch (HAMS) or butyrylated HAMS (HAMSB), opposes dietary protein-induced colonocyte DNA damage in rats. In this study, rats were fed Western-type diets moderate in fat (19%) and protein (20%) containing digestible starches [low amylose maize starch (LAMS) or low amylose whole wheat (LAW)] or RS [HA...

Rapid advances in molecular methods that enable culture-independent analysis of the complex bacterial populations is increasing awareness and understanding of the composition and activity of the microbiota in the human gastrointestinal tract, its role in host health and response to changes in diet and lifestyle. In this article we discuss the short...

Population studies show that greater red and processed meat consumption increases colorectal cancer risk, whereas dietary fibre is protective. In rats, resistant starches (a dietary fibre component) oppose colonocyte DNA strand breaks induced by high red meat diets, consistent with epidemiological data. Protection appears to be through SCFA, partic...

Population studies indicate that greater red meat consumption increases colorectal cancer risk while dietary fibre is protective. Previous work in rats showed that diets high in protein, including red meat, increase colonocyte DNA strand breaks and that this effect is attenuated by resistant starches (RS). Telomeres are long hexamer repeats that pr...

Population studies have shown that high red meat intake may increase colorectal cancer risk. Our aim was to examine the effect of different amounts and sources of dietary protein on induction of the promutagenic adduct O(6)-methyl-2-deoxyguanosine (O(6)MeG) in colonocytes, to relate these to markers of large bowel protein fermentation and ascertain...

Gastrointestinal disturbance is frequently reported for individuals with autism. We used quantitative real-time PCR analysis to quantify fecal bacteria that could influence gastrointestinal health in children with and without autism. Lower relative abundances of Bifidobacteria species and the mucolytic bacterium Akkermansia muciniphila were found i...

This study examined the role of degree of polymerization (DP) of inulin-fructans in modulating the interaction between lactic acid bacteria and IgA cecal secretion. Rats were fed a control diet or a diet containing one of the fructans with different DP. Consuming fructans increased the cecal IgA concentrations in the order DP4 > DP8 > DP16. Cecal l...

the Additional material file includes the consort checklist, a more detailed explanation of the analytical approach and the raw values for the cytokines and salivary protein concentrations related to tables 2 through to 6.

Probiotics purportedly reduce symptoms of gastrointestinal and upper respiratory-tract illness by modulating commensal microflora. Preventing and reducing symptoms of respiratory and gastrointestinal illness are the primary reason that dietary supplementation with probiotics are becoming increasingly popular with healthy active individuals. There i...

The dominant genus of sulfate-reducing bacteria (SRB) in humans is Desulfovibrio, and quantitative PCR (QPCR) targeting the 16S rRNA gene is often used in assays. We show that the 16S rRNA gene assay overestimated SRB abundance in feces from 24 adults compared to QPCR assays using primers targeting two genes involved in SRB energy metabolism.

Butyrate and other SCFA produced by bacterial fermentation of resistant starch (RS) or nonstarch polysaccharides (NSP) promote human colonic health. To examine variation in fecal variables, especially butyrate, among individuals and the response to these fibers, a randomized cross-over study was conducted that compared the effects of foods supplyin...

The metabolic end products of the large bowel microbiota contribute significantly to human health. After weaning to solid foods, some of the most important of these are the short chain fatty acids (SCFA) produced by the fermentation of undigested dietary components and endogenous secretions. The main SCFA are acetate, propionate and butyrate which...

Dietary red and processed meats may increase risk of colorectal cancer (CRC), whereas fiber may be protective. Recently, we demonstrated that dietary beef causes greater colonic DNA strand breakage than equivalent levels of chicken in rats and that resistant starch (RS) as 20% high amylose maize starch (HAMS) attenuated the damage. From that study,...

Diet is an important factor in colorectal carcinogenesis; thus, dietary supplements may have a role in colorectal cancer prevention. The objective was to establish the relative luminal, epithelial, and epigenetic consequences of prebiotic, probiotic, and synbiotic dietary supplementation in humans. This was a randomized, double-blind, placebo-contr...

Background: We have examined the relationship between the presence and numbers of methanogenic archaea in the faeces of humans and levels of the short chain fatty acids (SCFAs), especially butyrate, to gain insight into factors that may influence bowel health. In doing so, we have carried out the first cultivation-independent, molecular analysis of...

Non-starch polysaccharides (NSP; major components of dietary fibre) have been rather disappointing in the prevention and management of large bowel inflammatory diseases (IBD) or colorectal cancer (CRC). Resistant starch (RS) is that starch which escapes small intestinal digestion and enters the large bowel. RS contributes to total dietary fibre and...

Recent epidemiological evidence suggests that consumption of diets high in red or processed meats and low in dietary fibre may contribute to the high incidence of colorectal disease in western societies. To increase our understanding of the dietary factors which could contribute to colorectal diseases we have carried out a series of studies using r...

Dietary non-digestible carbohydrates (NDC) play an important role in large-bowel health and one form of NDC, resistant starch (RS), can promote low levels of DNA damage and other markers of colonic health. The objective of the present study was to determine whether the ability of dietary RS or other NDC to influence colonic health, particularly DNA...

Non-starch polysaccharides (NSP; major components of dietary fibre) have been rather disappointing in the prevention and management of large bowel inflammatory diseases (IBD) or colorectal cancer (CRC). Resistant starch (RS) is that starch which escapes small intestinal digestion and enters the large bowel. RS contributes to total dietary fibre and...

To further understand how diets containing high levels of fibre protect against colorectal cancer, we examined the effects of diets high in nonstarch polysaccharides (NSP) or high in NSP plus resistant starch (RS) on the composition of the faecal microbial community in 46 healthy adults in a randomized crossover intervention study. Changes in bacte...

Human population studies show that dietary red and processed, but not white, meats are associated with increased risk of colorectal cancer but dietary fibre appears to be protective. We examined whether dietary cooked red or white meat had differential effects on colonic DNA damage in rats and if resistant starch (RS), a dietary fibre component, pr...

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Feeding higher levels of dietary animal protein (as casein or red meat) increases colonic DNA damage and thins the colonic mucus barrier in rats. Feeding resistant starch (RS) reverses these changes and increases large bowel SCFA. The present study examined whether high dietary dairy (casein or whey) or plant (soya) proteins had similar adverse eff...

Previous studies have shown increased levels of colonocyte DNA damage (as measured by the comet assay) and thinning of the colonic mucus layer in rats fed higher dietary protein as casein or red meat with highly digestible starch. Feeding resistant starch (RS) as high amylose maize starch (HAMS) opposed these changes. However, the dietary level of...

Background : We have examined the relationship between the presence and numbers of methanogenic archaea in the faeces of humans and levels of the short chain fatty acids (SCFAs), especially butyrate, to gain insight into factors that may influence bowel health. In doing so, we have carried out the first cultivation-independent, molecular analysis o...

In a previous study we have shown that high levels of dietary protein (as casein) result in increased levels of colonic DNA damage, measured by the comet assay, and thinning of the colonic mucus layer in rats when dietary resistant starch (RS) is negligible. Feeding RS abolishes these effects. This study aimed to establish whether a diet high in pr...

We have shown independently that dietary fiber and n-3 fatty acids can affect gut function. This study investigated the interactive effects of resistant starch (RS) (as high amylose maize starch [HAMS]) and tuna fish oil on ileal contractility. Four-week-old male Sprague Dawley rats were fed 4 diets that contained 100 g/kg fat as sunflower oil or t...

A previous study using rats demonstrated that high levels of dietary casein resulted in increased levels of colonic DNA damage and a reduced thickness of the colonic mucus barrier in the absence of resistant starch. This study aimed to establish whether a diet high in a different form of dairy protein, whey protein, would cause a similar increase i...

Epidemiologic studies suggest that dietary complex carbohydrates are protective against colorectal cancer but dietary protein may increase risk. However, experimental data to support these relationships are scant. We have shown in rats that consumption of a high-protein (25% casein) diet for 4 wk resulted in a twofold increase in damage to colonocy...

Background - Diet has a major influence on the development of degenerative diseases of the large bowel and non-digestible carbohydrates appear to protect against colorectal cancer whereas energy, fat and protein are risk factors. Recently, low carbohydrate, high protein diets have become popular as a means of weight loss. However, the long-term eff...

Background - Dietary fibre and resistant starch (RS) appear to promote the health of the large bowel through faecal bulking and increased fermentation. The influence of other dietary factors, such as polyunsaturated fatty acids (PUFA), on the effectiveness of these components is unclear. Objective - To examine whether a rich source of (n-3) PUFA (f...

Whey‐derived growth factor extract (WGFE) and the acid‐activated form (WGFE‐a) were tested for their ability to influence the migration of cells from chicken flexor tendon biopsies into fibrin clots. When added to the medium surrounding clots, both extracts significantly inhibited migration relative to controls ( P < 0.05) in a dose‐dependent manne...

To determine if a single injection of insulin-like growth factor-I (IGF-I) can affect muscle protein synthesis in chickens, 7-d-old male Single Comb White Leghorn chicks were injected s.c. with physiological saline (control) or 35 microg of recombinant human IGF-I. After 2 h 30 min, or 6, 12, or 24 h the chicks were injected with 3H-phenylalanine a...

The relationship between nutritional status and insulin-like growth factor binding protein-2 (IGFBP-2) gene expression in chickens was studied. Chickens (6 wk old) were food deprived for 2 d and then refed. IGFBP-2 mRNA in the brain was significantly decreased by food deprivation and levels did not increase when birds were refed for 24 h. Gizzard a...