“…It has repeatedly been demonstrated that dietary fibre is effective in reducing transit time through the gut and in increasing stool bulk (Burkitt et al, 1972;Cummings et al, 1992). In the present study the total average intake of dietary fibre between the dietary groups varied between 35.5 and 42.0 g dietary fibre/day (results not shown), but no significant differences were found between the dietary groups with respect to mean transit time.…”
Objective: The aim of this study was to measure the apparent digestibility of fat and the transit time upon addition of whole sunflower seeds (SU) or flaxseeds (FL) to rye breads consumed as part of a whole diet. Method: In a randomized crossover study, gross intake and faecal excretion of fat and energy were measured in 11 young healthy men aged 24.672.7 years. During each 7 days intervention periods, the subjects received a basal diet plus 300 g of one of four rye breads: (1) rye bread; (2) rye bread with SU; (3) rye bread with FL; (4) low extraction rate rye bread with SU and FL. Fat binding properties of rye breads (1) and (3) were determined by in vitro digestion. Results: Addition of whole SU or FL to breads increased daily gross intake of fat and energy (Po0.001). The amounts of apparently digested fat (g/day) and energy were lowered when subjects consumed the SU or FL rye bread (Po0.001). The effect on energy digestibility of FL was more pronounced than that of SU. The in vitro fat digestibility of rye breads and whole diets show fat-binding properties of FL when compared to the rye bread diet (Po0.05). Conclusions: Enrichment of bread with whole FL does not appear to result in increased fat and energy intake when added to breads, but the results rather indicate an impairment of nutrient utilization.
“…It has repeatedly been demonstrated that dietary fibre is effective in reducing transit time through the gut and in increasing stool bulk (Burkitt et al, 1972;Cummings et al, 1992). In the present study the total average intake of dietary fibre between the dietary groups varied between 35.5 and 42.0 g dietary fibre/day (results not shown), but no significant differences were found between the dietary groups with respect to mean transit time.…”
Objective: The aim of this study was to measure the apparent digestibility of fat and the transit time upon addition of whole sunflower seeds (SU) or flaxseeds (FL) to rye breads consumed as part of a whole diet. Method: In a randomized crossover study, gross intake and faecal excretion of fat and energy were measured in 11 young healthy men aged 24.672.7 years. During each 7 days intervention periods, the subjects received a basal diet plus 300 g of one of four rye breads: (1) rye bread; (2) rye bread with SU; (3) rye bread with FL; (4) low extraction rate rye bread with SU and FL. Fat binding properties of rye breads (1) and (3) were determined by in vitro digestion. Results: Addition of whole SU or FL to breads increased daily gross intake of fat and energy (Po0.001). The amounts of apparently digested fat (g/day) and energy were lowered when subjects consumed the SU or FL rye bread (Po0.001). The effect on energy digestibility of FL was more pronounced than that of SU. The in vitro fat digestibility of rye breads and whole diets show fat-binding properties of FL when compared to the rye bread diet (Po0.05). Conclusions: Enrichment of bread with whole FL does not appear to result in increased fat and energy intake when added to breads, but the results rather indicate an impairment of nutrient utilization.
“…The dilution rate interval was chosen to support the realistic growth rates of luminal bacteria in the colon. Specific growth rate of the bacteria was calculated based on the colonic transit time of digesta in people consuming the Western diet, which varies from 40 to 140 h (median 60–70 h) [25–27], and the estimated amount of bacteria, that increases from 10 8 in proximal colon to 10 11 cfu/g in feces [28]. Considering both the period the bacteria have for degradation of the dietary fibers and the coinciding increase of the bacterial biomass in colon, the specific growth rate of the bacteria decrease from 0.3 down to 0.02 1/h.10.1080/16512235.2018.1549922-F0001Figure 1.Experimental scheme of the De-stat cultivations.…”
Background: Nutrient and energy metabolism in human colon depends on bacterial growth rate that is determined by the colonic transit rate.Objective: A novel approach, De-stat culture was used to distinguish the fast and slow growing sub-populations from fecal microbiota.Design: The enrichment and metabolism of bacteria from pooled fecal cultures of children was studied at dilution rates D = 0.2–0.0 1/h in mucin-supplemented media containing either arabinogalactan or apple pectin.Results: The study revealed clear differentiation of the fecal microbiota at higher (above 0.1 1/h) and lower (below 0.1 1/h) dilution rates, along with metabolic changes. Similarity of the fast and slow growing bacteria was observed in two different fecal pools and on both substrates, suggesting the dilution rate as the main triggering parameter for selection of bacteria. At high dilution rates, the species Collinsella aerofaciens, Dorea longicatena, Escherichia coli, Lachnoclostridium torques, and different Bacteroides (B. caccae, B. fragilis, B. ovatus, B. thetaiotaomicron, B. vulgatus) were dominant in both media variants. At low dilution rates, Akkermansia muciniphila, Eisenbergiella tayi, Negativicoccus succinivorans, and a group of Ruminococcaceae became dominant in both media and in both fecal pools. This change in bacterial population accompanied by the increased production of propionic and butyric acids as well as higher consumption of alanine and branched chain amino acids at low dilution rates.Conclusions: The study suggests that specific growth rate has important effect on the dynamics of colon microbiota. Manipulation of the proportions of fast and slow growing gut bacteria through modulation of the transit rate could be a target in human nutrition studies. The De-stat study would enable to predict changes in microbiota composition associated with the decrease or increase of the colonic transit rate.
“…The importance of indigestible carbohydrates in the aetiology of bowel disease became apparent with the pioneering work of Burkitt and colleagues (Burkitt et al, 1972). These researchers compared faecal weight and transit times of individuals in Africa consuming an unre®ned diet, with those in the United Kingdom consuming re®ned diets (Burkitt et al, 1972).…”
Section: Introductionmentioning
confidence: 99%
“…These researchers compared faecal weight and transit times of individuals in Africa consuming an unre®ned diet, with those in the United Kingdom consuming re®ned diets (Burkitt et al, 1972). They concluded that a de®ciency in dietary ®bre may have an important role in the development of certain diseases of the large bowel evident in Western countries including appendicitis, constipation, diverticulosis and colon cancer (Burkitt et al, 1972).…”
Section: Introductionmentioning
confidence: 99%
“…For example bacterial fermentation of carbohydrate (NSP and RS) increases faecal weight via increased bacterial mass (Stephen & Cummings, 1979;Phillips et al, 1995). Increased faecal bulk will also dilute the concentration of potential carcinogens, while the rapid transit through the colon reduces the contact time of carcinogens with the colonic epithelium (Burkitt et al, 1972).…”
Objectives: This study investigated, on 53 Australians consuming a typical Western diet, the relationship between dietary intake, faecal excretion of carbohydrate and changes in faecal markers believed to be relevant to colon cancer risk, for example faecal output, transit time and concentrations of phenols, ammonia and butyrate. Design: Fifty-three subjects consuming their usual diet were asked to record and weigh all food consumed for a seven day period, and to collect faeces for three days during this period. Setting: Geelong, Victoria, Australia. Subjects: All volunteers were either staff and students of the university, or associates of the authors. Interventions: None. Results: Volunteers had the following dietary intakes of carbohydrate (g/d; mean AE s.d.); starch 131 AE 41 (including resistant starch (RS), 5 AE 2), sugar 108 AE 37 and non-starch polysaccharides (NSP) 14 AE 7. Daily faecal output was 127 AE 70 g and transit time 47 AE 19 h. Analysis of faecal samples found 0.8 AE 1.2 g RS and 5.6 AE 3.6 g NSP were excreted daily. Dietary starch intake was the only dietary carbohydrate to show a signi®cant relationship with the concentration (mmol/L) of butyrate excreted in faeces (r 0.34, P`0.05). Dietary intake of RS was associated with higher concentrations of faecal ammonia (r 0.34, P`0.05), but this association was reversed when RS was combined with NSP in the diet (r 0.07, NS). In contrast to dietary intake, the faecal excretion of RS was negatively related to faecal ammonia concentration (r 7 0.40, P`0.01) and positively related to faecal output (r 0.64, P`0.01). Individuals who consumed more NSP in their diet (19 AE 7 g/d) excreted more than 150 g faeces per day and had higher quantities of faecal-RS and -NSP; faster transit times; higher concentrations of short chain fatty acids and lower concentrations of potentially harmful ammonia and phenols. Conclusions: The combination of RS and NSP in the colon may be required to achieve an optimal luminal environment conducive to`colonic health'. The results also support the suggestion that faecal output (`or b 150 g/d) may provide a useful index of colon cancer risk. High faecal outputs are achieved through higher intakes of NSP (the major component of dietary ®bre). Sponsorship: This work was supported by a scholarship to A. Birkett from the Australian Postgraduate Research Council.
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