Biomedical subjects

M Champ

Publications and source records attributed to M Champ.

At least 19 recordsLinked to original sources

PubMed2001

Only fibres promoting a stable butyrate producing colonic ecosystem decrease the rate of aberrant crypt foci in rats.

BACKGROUND: Dietary fibres have been proposed as protective agents against colon cancer but results of both epidemiological and experimental studies are inconclusive. AIMS: Hypothesising that protection against colon cancer may be restricted to butyrate producing fibres, we investigated the factors needed for long term stable butyrate production and its relation to susceptibility to colon cancer. METHODS: A two part randomised blinded study in rats, mimicking a prospective study in humans, was performed using a low fibre control diet (CD) and three high fibre diets: starch free wheat bran (WB), type III resistant starch (RS), and short chain fructo-oligosaccharides (FOS). Using a randomised block design, 96 inbred rats were fed for two, 16, 30, or 44 days to determine the period of adaptation to the diets, fermentation profiles, and effects on the colon, including mucosal proliferation on day 44. Subsequently, 36 rats fed the same diets for 44 days were injected with azoxymethane and checked for aberrant crypt foci 30 days later. RESULTS: After fermentation had stabilised (44 days), only RS and FOS produced large amounts of butyrate, with a trophic effect in the large intestine. No difference in mucosal proliferation between the diets was noted at this time. In the subsequent experiment one month later, fewer aberrant crypt foci were present in rats fed high butyrate producing diets (RS, p=0.022; FOS, p=0.043). CONCLUSION: A stable butyrate producing colonic ecosystem related to selected fibres appears to be less conducive to colon carcinogenesis.

Animals↗

PubMed2000

Bioavailability of starch and postprandial changes in splanchnic glucose metabolism in pigs.

Changes in splanchnic metabolism in pigs were assessed after meals containing slowly or rapidly digested starch. The pigs were fed a mixed meal containing a "slow" native (n = 5) or a "rapid" pregelatinized (n = 5) cornstarch naturally enriched with [(13)C]glucose. Absorption of [(13)C]glucose was monitored by the arteriovenous difference technique, and infusion of D-[6, 6-(2)H(2)]glucose in the jugular vein was used to calculate the systemic appearance of [(13)C]glucose. Arteriovenous balance data obtained during a 12-h study period showed that the fraction of ingested glucose equivalent appearing as glucose in the portal vein was 49.7 +/- 7.2% for the slow starch and 48.2 +/- 7.5% for the rapid starch (P = 0.86). These values, corrected for the gut extraction of circulating [(13)C]glucose, became 66.4 +/- 5.6 and 65. 3 +/- 5.6%, respectively (P = 0.35). Isotope dilution data indicated that systemic appearance of exogenous [(13)C]glucose represented 62. 9 +/- 7.6 and 67.4 +/- 3.0% of the oral load for slow and rapid starch, respectively (P = 0.68). Arterial glucose utilization by the gut increased from 7.3 +/- 0.9 micromol x kg(-1) x min(-1) before the meal to 8.5 +/- 1.6 micromol x kg(-1) x min(-1) during absorption, independently of the nature of the starch. Thus splanchnic glucose metabolism was unaffected by the nature of starch ingested.

Animals↗

PubMed1999

Bioavailability of starch in bread rich in amylose: metabolic responses in healthy subjects and starch structure.

OBJECTIVE: This study investigated whether postprandial metabolic responses to bread could be lowered by substituting high amylose maize starch for a part of the flour. DESIGN AND SUBJECTS: Eight healthy subjects consumed test meals of equivalent nutritional composition based on white wheat bread, bread rich in amylose (HAWB) and spaghetti as a breakfast meal. Blood samples were collected to measure insulin and glucose concentration during two hours after consumption. The degree of starch crystallinity was investigated by X-ray diffraction and DSC analysis. RESULTS: HAWB produced low glycaemic (60 +/- 18) and insulinaemic (57 +/- 20) indexes similar to those of spaghetti (83 +/- 46, 61 +/- 16). In vitro amylase hydrolysis of the three foods showed that high amylose content in HAWB significantly lowered starch degradation in bread without affecting hydrolysis kinetics. Addition of amylose in dough increased the resistant starch content of HAWB (14% of dry matter). The resistant starch fraction was mainly composed of crystalline amylose (B-type X-ray diffraction pattern, melting temperature 105 degrees C) attributable to native high amylose maize starch incompletely gelatinised during bread-cooking. CONCLUSIONS: Bread produced by the substitution of high amylose maize starch for a part of wheat flour showed a low glycaemic index. Resistant starch in HAWB corresponded to native crystalline amylose not gelatinised during normal bread-processing conditions.

Adult↗

PubMed1998

Effect of resistant starch and/or fat-soluble vitamins A and E on the initiation stage of aberrant crypts in rat colon.

This study reports the modulating effects of resistant starch (RS) and the fat-soluble vitamins A or E, alone or in combination, on initiation of preneoplastic lesions in rat colon aberrant crypt foci (ACF) induced by 1,2-dimethylhy-drazine. One group of male Sprague-Dawley rats was fed a basic diet and five groups were fed experimental diets supplemented with 25% RS, 200 IU vitamin A, 5 IU vitamin E, 25% RS + 200 IU vitamin A, or 25% RS + 5 IU vitamin E for four weeks. After induction by 1,2-dimethylhydrazine, all the animals were fed basic diets for four more weeks before sacrifice. Compared with the basic diet, only the vitamin A-supplemented diet significantly reduced the incidence of ACF. The vitamins incorporated in the animals' diets increased the vitamin concentrations in hepatic and colonic cells compared with the animals fed the basic diet. The preventive effect of vitamin A seems to be due to a direct effect on colonic epithelial cells. The three diets supplemented with RS significantly decreased cecal pH and bacterial beta-glucuronidase activity and increased cecal weight and fecal output. The retrograde high-amylose maize, type 3, used in this study does not significantly decrease ACF. This RS has an effect on the colon similar to that of nonstarch polysaccharides. Neither biochemistry nor four weeks of dietary supplementation is likely sufficient for adaptation of the rat colonic flora.

1,2-Dimethylhydrazine↗

PubMed1998

Whole-body, peripheral and intestinal endogenous acetate turnover in dogs using stable isotopes.

Acetate metabolism supplies about 10% of energy requirements in food-deprived nonruminant animals. This study used a stable isotope dilution method to investigate the fate of acetate in 24-h food-deprived dogs free of colonic fermentation. Three dogs received intravenous bolus injections of 40 or 70 micromol/kg of [1-13C] acetate, and carotid blood was then sampled during a 15-min period to estimate the acetate distribution volume. Ten dogs received intravenous [1-13C] acetate infusions of 1.05 +/- 0.02 or 2.10 +/- 0. 10 micromol/(kg.min) for 120 or 200 min after a prime of 200 or 70 micromol/kg, respectively. Cephalic venous and carotid arterial blood were sampled for all dogs, and portal blood for five. Acetate distribution volume was 0.27 +/- 0.16 L/kg (mean +/- SEM). The concentrations of acetate in arterial (144 +/- 17 micromol/L), venous (155 +/- 20 micromol/L) and portal plasma (131 +/- 16 micromol/L) were not significantly different during infusion, whereas isotopic enrichments [mole percent excess (MPE): labeled acetate/all acetate molecules] in portal (1.2 +/- 0.2 MPE) and venous plasma (1.7 +/- 0.3 and 2.6 +/- 0.7 MPE) were lower than in arterial plasma for both infusion rates (4.9 +/- 0.6 and 7.6 +/- 0.8 MPE, respectively, P < 0.005). Whole-body acetate turnover was 24.4 +/- 2.4 micromol/(kg.min). Fractional acetate extractions for forelimb and intestine were 62 +/- 7 and 72 +/- 6%, respectively, and the production for each organ was 0.3 and 1.1 micromol/(kg.min) respectively, similar to that of utilization (P > 0.05). It is concluded that the forelimb and intestine produce and utilize acetate as an energy source in 24-h food-deprived dogs free of colonic fermentation.

Acetates↗

PubMed1998

Dietary amylose-amylopectin starch content affects glucose and lipid metabolism in adipocytes of normal and diabetic rats.

The aim of this study was to evaluate the effects of the chronic consumption of two starches, characterized by different glycemic indices and amylose-amylopectin content, on glucose metabolism in rat epididymal adipocytes. The two chosen starches were from mung bean (32% amylose) and cornstarch (0.5% amylose). The alpha-amylase digestibility was higher for the waxy cornstarch than that of the mung bean starch (60 +/- 4 vs. 45 +/- 3%, mean +/- SEM, respectively). The glycemic index of the waxy cornstarch diet (575 g starch /kg diet) was higher than that of the mung bean starch diet (107 +/- 7 vs. 67 +/- 5%, P < 0.01) when measured in vivo in two groups of normal rats (n = 9). In a subsequent study, normal and diabetic (streptozotocin-injected on d 2 of life) male Sprague-Dawley rats (18 per group) consumed a diet containing 575 g starch/kg diet as either waxy cornstarch or mung bean starch. After 3 wk, food intake, epididymal fat pad weights, and plasma glucose, insulin and triglyceride concentrations did not differ between diet groups. Adipocyte diameter was smaller in rats that consumed mung bean starch compared with those that consumed the waxy cornstarch diet (P < 0.01). The mung bean diet increased maximal insulin-stimulated 14C-glucose oxidation (% of basal values, P < 0. 05). In contrast, incorporation of 14C-glucose into total lipids was significantly lower in rats that consumed the mung bean diet (P < 0. 05). We conclude that in both normal and diabetic rats, the chronic replacement of a high glycemic index starch by a low glycemic index one in a mixed diet increases insulin-stimulated glucose oxidation, decreases glucose incorporation into total lipids and decreases epididymal adipocyte diameter. Thus, the type of starch mixed into the diet has important metabolic consequences at the cellular level in both normal and diabetic rats.

Adipocytes↗

PubMed1998

Digestion of carbohydrate from white beans (Phaseolus vulgaris L.) in healthy humans.

Resistant starch (RS) is thought to be present in large amounts in legume seeds; however, it has never been quantified in healthy humans. RS from cooked (atmospheric pressure) white beans was quantified in humans and pigs, and characterized to explain its low digestibility. Six human volunteers were intubated to collect ileal digesta after an experimental meal composed of orange juice, butter and 167 g beans (dry matter basis). The reliability of the intubation method was examined in a pig study in which it was compared with another collection method, ileal cannulation. Chemical analyses, microscopy and size exclusion chromatography were performed on human and pig digesta. The pig study showed that the intubation method may underestimate the quantity of RS. However, no chemical/physical difference was observed between the RS collected by the two techniques. In the human study, 16.5 +/- 1.3% (11.3 g) of the ingested starch was recovered as RS. The microscopy of the digesta showed that part of the RS was enclosed in the cell walls. Although the RS was composed mainly of alpha-glucan molecules with a degree of polymerization (DP) 40 to 60, oligosaccharides and large molecules of DP > 400 were also present. Retrogradation was not found to be the main factor responsible for starch malabsorption. We conclude that white beans may contain a large amount of RS formed mainly by partially degraded molecules protected by the cell walls during their transit through the gut.

Adult↗

PubMed1997

Short-chain fructo-oligosaccharides reduce the occurrence of colon tumors and develop gut-associated lymphoid tissue in Min mice.

C57BL/6J-Min/+ mice, which are heterozygous for a non-sense mutation in the Apc gene, provide a model for both familial adenomatous polyposis and sporadic colon cancers. In our study, gut tumors and small intestine lymphoid nodules were counted in Min mice fed fiber-enriched diets for 6 weeks. Neither starch-free wheat bran nor resistant starch modified the number of tumors. However, short-chain fructo-oligosaccharides dramatically reduced the incidence of colon tumors and concomitantly developed gut-associated lymphoid tissue. Our experiment shows that short-chain fructo-oligosaccharides counteract advanced stages of colon carcinogenesis, possibly via stimulation of antitumoral immunity by modulation of the colonic ecosystem.

Animals↗

PubMed1997

Effects of resistant starch- and vitamin A-supplemented diets on the promotion of precursor lesions of colon cancer in rats.

We have evaluated the potential protective effect of resistant starch (RS)- and vitamin A-supplemented diets on the promotion of preneoplasic lesions of rat colon, aberrant crypt foci (ACF), induced by 1,2-dimethylhydrazine dihydrochloride (DMH). We have tried to show whether the association of these two dietary constituents in the same diet could have synergistic effects. RS, vitamin A, and RS+ vitamin A were incorporated into the rat diets. Experimental diets were given one week after DMH injection and maintained for 12 weeks until the animals were sacrificed. The total number of ACF decreased with the three experimental diets. For RS- and RS + vitamin A-supplemented diets, this decrease is primarily due to a decrease in small ACF. For the vitamin A-supplemented diet, small and large ACF have a tendency to decrease. The effects of the diets on parameters influencing colon carcinogenesis were also studied. Only RS- and RS + vitamin A-supplemented diets have modified cecal pH, fecal and cecal butyrate contents, fecal excretion, cecal weight, and colon length. Vitamin A has been observed in colonic epithelial cells of rats receiving vitamin A- and RS+ vitamin A-supplemented diets. The association between RS and vitamin A shows neither a cumulative nor a synergistic protective effect.

Animals↗

PubMed1997

Metabolic effects of digestible and partially indigestible cornstarch: a study in the absorptive and postabsorptive periods in healthy humans.

To compare the effects of digestible (pregelatinized) and partially indigestible (retrograded) cornstarches on some metabolic indexes, we studied eight healthy volunteers during two periods separated by 1 wk. In each period, fasting volunteers consumed at 0800 the test meal containing either the digestible or partially indigestible cornstarch; blood and breath were sampled in the absorptive period for 8 h. To study its late effects, the same test meal as that served at 0800 was given again at 2200, and blood and breath were sampled for 3 h in the postabsorptive period the next morning, i.e., 10 h after ingestion of the test meal. In the absorptive period, blood glucose and insulin were significantly higher after ingestion of digestible cornstarch than after partially indigestible cornstarch. In the postabsorptive period concentrations of blood glucose, insulin, and fatty acids were not significantly different, whereas concentrations of blood acetate, breath hydrogen, methane, and 13CO2, and the respiratory quotient and satiety were significantly higher (P < 0.05) and concentrations of blood glycerol significantly lower (P < 0.05) after ingestion of partially indigestible cornstarch than after digestible cornstarch. We conclude that in healthy humans, digestion of partially indigestible cornstarch is slow in the small intestine and its colonic fermentation continues 10-13 h after its ingestion. Compared with pregelatinized cornstarch, the shift in starch digestion induced by retrogradation leads to a reduction in glycemic and insulinemic responses in the absorptive period and in lipolysis in the postabsorptive.

Adolescent↗

PubMed1996

Effects of long-term low-glycaemic index starchy food on plasma glucose and lipid concentrations and adipose tissue cellularity in normal and diabetic rats.

The present study aimed to assess the metabolic consequences of the chronic ingestion of two starches giving different postprandial glycaemic responses in normal and diabetic rats. The two starches chosen were mung-bean (Phaseolus aureus) starch (97% pure starch) and wheat starch presented as ground French toast. First, we studied the characteristics of these two starches. In vitro the alpha-amylase (EC 3.2.1.1) digestibilities of these starches were 40 (SE 3) and 62 (SE 4)% respectively at 30 min, whereas the contents of resistant starch were 77 (SE 4) and 22 (SE 4) g/kg respectively. In vivo the mung-bean starch produced lower postprandial glycaemic responses than the wheat starch (areas under the curve were: 91 (SE 28) and 208 (SE 33) mmol.min/l, P < 0.05) in normal rats (n 8). We then submitted twenty-eight normal and twenty-eight diabetic (neonatal streptozotocin on second day of birth) male Sprague-Dawley rats (6 weeks old) to a diet containing 570 g starch/kg as either mung-bean starch or wheat starch (n 14 rats/group). After 5 weeks on the diets food intakes and body weights were identical in each group. Liver and kidney weights were comparable when expressed as relative weight. The mung-bean-starch diet slightly decreased epididymal fat-pad weight (P < 0.14, ANOVA) and led to a marked decrease in adipocyte volume (P < 0.05). Plasma triacylglycerol and phospholipid concentrations were lower after the mung-bean-starch diet than after the wheat-starch diet in both normal and diabetic rats, whereas free fatty acid concentrations were lower only in normal rats. Similarly, non-fasting plasma glucose concentrations decreased (P < 0.05) in normal rats fed on mung-bean starch but not in diabetic ones (P < 0.14). Insulin levels tended to be lower, but not significantly, after mung-bean-starch feeding than after wheat starch. We conclude that the replacement of 570 g wheat starch/kg diet with mung-bean starch for 5 weeks resulted in (1) lowered non-fasting plasma glucose and free fatty acid levels in normal but not in diabetic rats, (2) a reduction in plasma triacylglycerol concentration and adipocyte volume in both normal and diabetic rats. Thus, the type of starch mixed into the diet may have important metabolic consequences in normal and diabetic rats.

Adipocytes↗

PubMed1996

Kinetic aspects of acetate metabolism in healthy humans using [1-13C] acetate.

Acetate metabolism in humans is not well known. Kinetic aspects of acetate were investigated in the postabsorptive state on healthy subjects. In a first study, six subjects were infused with a primed constant infusion of [1-13C]acetate for 3 h and a prime of NaH13CO3. No difference was found between arterialized and venous tracer enrichments from the arm, although arterialized acetate concentrations were higher (74 +/- 12 vs. 59 +/- 14 mumol/l, P < 0.05), suggesting that the hand muscles used but did not produce acetate in the postabsorptive state. Total body flux of acetate was 8.4 +/- 0.6 mumol.kg-1.min-1, of which 69 +/- 5% was oxidized. Acetate contributed to 6.5 +/- 0.4% of the basal energy expenditure. In a second study, five volunteers were submitted to a gastric infusion for 3 h followed by an intravenous infusion of [1-13C]acetate for 3 h. Higher fluxes were observed with the tracer gastric infusion, and the first-pass removal of acetate within the splanchnic bed was 60 +/- 7%. Acetate contributes significantly to the energy supply of the body. It is mainly used by the liver when produced in the gut.

Acetates↗

PubMed1995

Distribution of 239,240Pu and 238Pu concentrations in sediments from the Ob and Yenisey Rivers and the Kara Sea.

The major sources of plutonium isotopes in the environment are from nuclear weapons testing via global and close-in (debris) fallout, nuclear fuel reprocessing and fabrication plant effluents. Measurements of differences in the Pu isotopic ratios (239Pu/240Pu, 238Pu/239,240Pu and 241Pu/239,240Pu) have yielded information not only on the time horizons for sedimentary deposits but also on the sources of Pu. We have measured 238Pu, 239,240Pu and 137Cs concentrations in the surficial sediments of the Ob and Yenisey Rivers (Russia) and the Kara Sea. The downcore variations of 238Pu and 239,240Pu concentrations have also been measured in some sediment cores. A comparison of the sediment core inventories of 239,240Pu along with the 238Pu/239,240Pu activity ratios with those expected from global fallout at the study sites allows us to estimate the relative amounts of reactor-derived 238Pu and 239,240Pu from the dumped reactor sites in the study area. In surficial sediment samples, the 239,240Pu concentrations vary between 9.4 and 627 mBq kg-1, with a mean of 250 mBq kg-1. The 238Pu/239,240Pu activity ratios vary between 0.009 and 0.065 with an average value of 0.034 +/- 0.003. This range can be compared to the average 238Pu/239,240Pu activity ratio of 0.030 for the year 1993 from nuclear weapons testing and SNAP fallout obtained from soil studies, indicating very little additional sources of 238Pu to the sediments in the study area. In sediment cores, the maximum depths at which 239,240Pu was detected varied between 6 and 12 cm. These depths yield average apparent sedimentation rates in the coastal Kara Sea between 1.5 and 3.0 mm yr-1 (assuming Pu input since 1952, and no sediment mixing).

Arctic Regions↗

PubMed1995

Effect of acetate and propionate on fasting hepatic glucose production in humans.

OBJECTIVE: Short chain fatty acids (SCFA, e.g. acetate and propionate) produced from bacterial colonic fermentation may be involved in the improvement of fasting glucose concentration observed with high dietary fibre diets. Because fasting blood glucose is related to hepatic glucose production, we have tested the effect of propionate and acetate on hepatic glucose production. SETTING: The study was carried out in the Clinical Research Center for Human Nutrition. SUBJECTS: Six healthy young volunteers. INTERVENTIONS: The subjects received, in a random order: acetate (12 mmol/h), or propionate (4 mmol/h), or acetate+propionate (12 mmol/h + 4 mmol/h), or an isotonic sodium salt solution (saline) in 3 h gastric infusions. Blood glucose and plasma insulin was monitored. Hepatic glucose production was measured with an isotopic method using [6,6-2H2] glucose. RESULTS: No changes were observed in blood glucose, plasma insulin concentrations or hepatic glucose production with any of the infused solutions. An increase in free fatty acid (FFA) plasma concentration related to the fasting state was observed with the saline solution, but not with the SCFA infusions (P < 0.05). There was also an increase in beta-hydroxybutyrate concentration with the saline and the acetate solutions, but not with the propionate or acetate+propionate solutions. CONCLUSIONS: SCFA, administered at a rate calculated on the basis of a continuous daily fermentation of 30 g dietary fibres, do not change hepatic glucose production or fasting blood glucose. Propionate and acetate decrease plasma FFA, and further studies are needed to explore this effect on glucose tolerance and insulin sensitivity.

Acetates↗

PubMed1995

Banana starch breakdown in the human small intestine studied by electron microscopy.

OBJECTIVE: To determine the origin of the poor digestibility of banana starch granules in the human small intestine. DESIGN: The subjects received the same experimental meal. SETTING: Nutrition Research Unit, Laënnec Hospital, CHU, Nantes. SUBJECTS: Six healthy young subjects. INTERVENTIONS: The digestion of raw green banana flour in the upper part of the gut was studied by the intubation technique. After ingestion of 30 g banana flour mixed with a complex meal, ileal samples were continuously collected during 14 h. In order to determine the structural nature of this resistant starch, the dried ileal samples were observed with scanning and transmission electron microscopy. Transmission electron microscopy was performed after treatment with periodic acid-thiosemicarbazide-silver nitrate. RESULTS: Banana starch proved very resistant to in vivo amylase hydrolysis since 84% of the starch ingested reached the terminal ileum. The microscopic observations showed that raw banana flour contained irregularly shaped dense starch granules with smooth surfaces. After their passage through the small intestine, starch granules appeared exocorroded, with porous surfaces, and some exhibited several irregular pits, crevices or holes by which the enzymes had penetrated and hydrolysed the inner part. Cell walls closely associated with starch granules could have hindered enzyme access to starch. CONCLUSIONS: Encapsulation could be partly responsible for the low digestibility of starch in banana flour, together with the intrinsic resistance of banana starch granules.

Digestion↗

PubMed1995

Digestion of raw banana starch in the small intestine of healthy humans: structural features of resistant starch.

The digestion of freeze-dried green banana flour in the upper gut was studied by an intubation technique in six healthy subjects over a 14 h period. Of alpha-glucans ingested, 83.7% reached the terminal ileum but were almost totally fermented in the colon. Structural study of the resistant fraction showed that a small part of the alpha-glucans which escaped digestion in the small intestine was composed of oligosaccharides from starch hydrolysis, whereas the rest was insoluble starch in granule form with physical characteristics similar to those of raw banana starch. Passage through the small intestine altered granule structure by increasing susceptibility to further alpha-amylase hydrolysis. Compared with resistant starch values in vivo, those obtained with the in vitro methods tested were inadequate to estimate the whole fraction of starch reaching the terminal ileum.

Adult↗

PubMed1995

[Rapid assay of plasma acetate by gas chromatography: evaluation and comparison with two other methods].

Human plasma acetate is derived from colonic fermentation of fiber and endogenous metabolism of dextrose and fatty acids. Acetate may have regulatory functions in hepatic carbohydrate metabolism. Intake of dietary fiber is associated with several beneficial effects on carbohydrates and lipids metabolisms. To study theses effects a valid and automated method for routine analysis of acetate in plasma is necessary. After oral administration of lactulose to healthy human volunteers, the concentration of plasma acetate was measured by head space gas chromatography (HS-GC), vacuum distillation gas chromatography (VD-GC) and enzymatic spectrometric method (ES). The method HS-GC was linear to 0.5 mmol.l-1 (n = 5, r = 0.998), the detection limit is 0.005 mmol.l-1. Within-day variation (CV) was 3.60% and day-to-day variation was 4.5% (0.1 mmol.l-1). The coefficients of correlation between CG-ET/CG-DsV and CG-ET/E-M are 0.903 (p = 0.0001) and 0.54 (p = 0.006) respectively, the mean square errors are respectively 0.118 and 0.138 mmol.l-1. The variation curves of plasma acetate measured by GC versus time show peak concentration of 0.323 to 0.380 mmol.l-1 at 120 min.

Acetates↗

PubMed1994

Measurement of whole body acetate turnover in healthy subjects with stable isotopes.

Colonic fermentation of dietary fibres produces short-chain fatty acids (e.g. acetate, propionate). Measurements of whole body acetate turnover was used in order to estimate the production of colonic short-chain fatty acids in human subjects. However, higher flux rates for acetate have been reported in human studies with stable isotopes as compared to radioactive tracers. The reasons for this discrepancy are unclear. In this study, the stable isotope (1-13C)acetate was used and a method was developed to measure its enrichment in plasma. Variations between and within assays were less than 5%. The standard curve was linear from 0.5% to 10% enrichment. When this tracer was infused for 160 min in six healthy volunteers, acetate turnover was found to be 7.5 +/- 1 mumol kg-1 min-1, which is similar to data reported with radioactive tracers. We assumed that the higher flux rate previously observed with stable isotope tracers was related to differences in the physiological status of the subjects involved in these studies.

Acetates↗