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Biomedical subjects

F Bornet

Publications and source records attributed to F Bornet.

At least 19 recordsLinked to original sources
PubMed2003

A digestive tolerance study of maltitol after occasional and regular consumption in healthy humans.

AIM: We aimed to evaluate the gastro-intestinal tolerance to an indigestible bulking sweetener containing sugar alcohol using a double-blind random cross-over study. METHOD: In order to simulate their usual pattern of consumption, 12 healthy volunteers ingested maltitol or sucrose throughout the day, either occasionally (once a week for each sugar, first period) or regularly (every day for two 9 day periods, second period). In both patterns of consumption, daily sugar doses were increased until diarrhea and/or a grade 3 (ie severe) digestive symptom occurred, at which the dose level was defined as the threshold dose (TD). RESULTS: In the first period (occasional consumption), the mean TD was 92+/-6 g with maltitol and 106+/-4 g with sucrose (P=0.059). The mean intensity of digestive symptoms was 1.1 and 1.3, respectively (P=NS). Diarrhea appeared in six and one subjects respectively (P=0.035). In the second period (regular consumption), the mean TD was 93+/-9 g with maltitol and 113+/-7 g with sucrose (P=0.008). The mean intensity of digestive symptoms was 1.7 and 1.2, respectively (P=NS). However, diarrhea appeared in eight and three subjects, respectively (P=0.04). Maltitol and sucrose TDs between the two periods were not different. CONCLUSIONS: Under our experimental conditions, in comparison to sucrose: (a) occasional or regular consumption of maltitol is not associated with severe digestive symptoms; (b) in both patterns of maltitol consumption, diarrhea frequency is higher, but it appeared only for very high doses of maltitol, much greater than those currently used; (c) maltitol does not lead to intestinal flora adaptation after a 9 day period of consumption.

Abdominal Pain↗
PubMed2001

Cytokine mRNA expression in mouse colon: IL-15 mRNA is overexpressed and is highly sensitive to a fibre-like dietary component (short-chain fructo-oligosaccharides) in an Apc gene manner.

On the basis of studies using the Min mouse model of colon carcinogenesis, we have recently proposed that a fibre-like food (short-chain fructo-oligosaccharides, sc-FOS) fermented in the colon may stimulate a mechanism of cancer immunosurveillance. In the present paper, we have investigated the expression of cytokines as potential effector molecules. Interleukin (IL-)4, IL-5, IL-13, IL-15 and interferon (INF)-gamma mRNAs were detected by a multi-probe ribonuclease protection assay in C57BL/6J and Min mouse colons. IL-15 mRNA expression was significantly amplified (P=0.01) by the sc-FOS-enriched diet in the colon of Min mice.

Animals↗
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↗
PubMed2001

Five-week intake of short-chain fructo-oligosaccharides increases intestinal absorption and status of magnesium in postmenopausal women.

Fermentable carbohydrates have been shown to be nondigestible by human enzymes in the small intestine but are fermented extensively in the large bowel to short-chain fatty acids (SCFAs), which can increase mineral absorption. It has been shown that feeding such carbohydrates including short-chain fructo-oligosaccharides (sc-FOSs) increases intestinal magnesium (Mg) absorption in animals, but their beneficial impact on Mg absorption in humans still remains to be established. Therefore, this work aimed to investigate the effect of moderate daily doses of sc-FOSs (10 g/day) on the intestinal absorption and status of Mg in postmenopausal women without hormone replacement therapy (HRT). Eleven healthy postmenopausal women aged 59 +/- 6 years (mean +/- SD) received for 5 weeks sc-FOS or sucrose (placebo) treatments according to a randomized, double-blind, crossover design separated by a washout period of at least 3 weeks. Subjects ingested 87.5 mg of stable isotope 25Mg together with a fecal marker. Subsequently, feces were collected for 5-7 days. An inductively coupled plasma mass spectrometer (ICP/MS) was used for 25Mg stable isotope measurements in feces, urine, and blood. Mg levels were assessed also at the beginning and at the end of each treatment in plasma, erythrocytes, and urine. These measurements allowed for the determination of net intestinal Mg absorption and Mg status. The results show that the addition of 10 g sc-FOS to the diet increased Mg absorption by 12.3%, from 30.2 +/- 5.0% (placebo treatment) to 33.9 +/- 7.2% (sc-FOS treatment; mean +/- SD; p < 0.02). This increase in intestinal Mg absorption was accompanied by an increase in plasma 25Mg level and led to a higher urinary 25Mg excretion. This is the first time that such an effect is shown in humans. The overall conclusion of this work is that the ingestion of moderate doses of sc-FOS did improve intestinal Mg absorption and status in postmenopausal women. Because of the important role of Mg in many cellular functions, such Mg absorption improvement may be particularly interesting when the dietary intake of Mg is limited.

Aged↗
PubMed2000

Olive oil phenolics are dose-dependently absorbed in humans.

Olive oil phenolic constituents have been shown, in vitro, to be endowed with potent biological activities including, but not limited to, an antioxidant action. To date, there is no information on the absorption and disposition of such compounds in humans. We report that olive oil phenolics, namely tyrosol and hydroxytyrosol, are dose-dependently absorbed in humans after ingestion and that they are excreted in the urine as glucuronide conjugates. Furthermore, an increase in the dose of phenolics administered increased the proportion of conjugation with glucuronide.

Adult↗
PubMed2000

Relationships between transit time in man and in vitro fermentation of dietary fiber by fecal bacteria.

OBJECTIVE: To assess the effects of drug-induced changes in mean transit time (MTT) on the activity of human fecal flora in vitro. METHODS: The activity of fecal flora was estimated by the ability of a fecal inoculum to ferment a substrate (beet fiber) in vitro in a batch system for 24 h. The inoculum was collected from 8 healthy volunteers studied during three 3-week randomized periods, who received a controlled diet alone (control period) or the same diet with either cisapride or loperamide. Cisapride and loperamide were adjusted in order to halve and double MTT measured during the control period. At the end of each period, the percentage disappearance of the initial added substrate and the concentration and the profile of short-chain fatty acids (SCFAs), were determined. RESULTS: In the control period, the pH of the inoculum and SCFA concentration were inversely related to MTT (P=0.0001). Individual SCFA production was also significantly related to MTT (P<0.01). Cisapride-reduced transit time was associated with a significant rise in the concentrations of total SCFAs (P<0.05), propionic and butyric acids (P<0.05) and the percentage substrate disappearance (P<0.05). Inverse relations were observed during the loperamide period. Moreover, MTT was inversely related to the percentage substrate disappearance (P<0.001), SCFA production (P<0.001) and butyrate production (P<0.0005). CONCLUSION: Changes in MTT alter bacterial activity and modify the bacterial pathways affecting the proportion of individual SCFAs. European Journal of Clinical Nutrition (2000) 54, 603-609

Adult↗
PubMed2000

Cholesterol crystallization in gall-bladder bile of pigs given cholesterol-beta-cyclodextrin-enriched diets with either casein or soyabean concentrate as protein sources.

Cholesterol precipitation from supersaturated bile is the earliest and determinant step in the formation of cholesterol gallstones, which is thought to be diet-dependent. Bile composition, appearance and growth of cholesterol crystals were studied in fresh gall-bladder biles from pigs adapted to four different protein-containing diets over 3 weeks: 160 g dietary protein/kg as casein (C16; n 6), or as soyabean-protein concentrate (S16; n 6), or a mixture of both protein sources (casein-soyabean protein, 70:30, w/w) (CS16; n 6), or 320 g of the mixed protein/kg (CS32; n 6). Moreover, all four diets contained 3 g cholesterol/kg and 50 g beta-cyclodextrin/kg as modifiers of bile composition towards cholesterol pro-crystallization. Cholesterol precipitation was most active after the high-protein diet, CS32, and the casein diet, C16, and lowest after the soyabean-protein diet, S16. It was intermediate after the mixed diet, CS16, but still much lower than in the former two groups. These diet-induced variations were suggested to be mediated through modifications in the biliary profile of bile acids, whereas all other biliary constituents studied were essentially unchanged. The fasting level of plasma cholesterol was lowest in both 160 g protein/kg diets containing soyabean protein (S16 and CS16), highest for the high-protein diet CS32, and intermediate for the C16 diet. These results should encourage clinical studies on the effect of soyabean protein, or other vegetable proteins, for primary or recurrence prevention of cholelithiasis at its earliest stage.

Animals↗
PubMed1999

T cell status influences colon tumor occurrence in min mice fed short chain fructo-oligosaccharides as a diet supplement.

We have previously shown that addition of short chain fructo-oligosaccharides (indigestible carbohydrates) to food prevented colon tumors in C57BL/6-Apc(Min/+) mice, a model for human colon cancer. As gut-associated lymphoid tissue was concomitantly developed, we suggested that the immune response generated by this food may interfere with carcinogenesis due to involvement of mucosal cells in the regulation of tissue homeostasis. In the present experiment, we tested whether T cell status may influence colon tumor formation in Min mice fed a food supplement of short chain fructo-oligosaccharides. Min mice depleted of CD4(+) and CD8(+) lymphocytes developed twice as many tumors as immunocompetent mice (0.8 as compared with 0.4, the mean number in 7-week-old Min mice when food supplementation began; P = 0.02). It is concluded that food supplementation with a substrate (a known prebiotic) fermented in the colon may stimulate a mechanism of immunosurveillance that would otherwise remain inefficient.

Animals↗
PubMed1999

Short-chain fructo-oligosaccharide administration dose-dependently increases fecal bifidobacteria in healthy humans.

Short-chain fructo-oligosaccharides (SC-FOS) are a mixture of oligosaccharides consisting of glucose linked to fructose units (Gfn; n = </= 4), which are not digested in the human small intestine but are fermented in the colon where they specifically promote the growth of bifidobacteria. In healthy volunteers, we assessed the tolerance and the threshold dose of SC-FOS that significantly increased fecal bifidobacteria counts and the possibility of a dose-response relationship. Randomly divided into five groups and eating their usual diets, healthy volunteers (40: 18 males, 22 females) ingested in two oral doses for 7 d a powder mixture containing (g SC-FOS/d): 0, G0; 2.5, G2.5; 5, G5; 10, G10; 20, G20. Stools were collected before (d1) and at the end (d8) of sugar consumption, and tolerance was evaluated using a daily chart. Total anaerobe counts were not affected by SC-FOS ingestion. Bifidobacteria counts at d8 were greater in groups G10 and G20 than in G0 and G2.5 (P < 0.05). Fecal pH did not differ among groups. A significant correlation between the dose of SC-FOS ingested and the fecal bifidobacteria counts was observed at d8 (r = 0.53; P < 0.01). Excess flatus was significantly more frequent in subjects consuming G20 than in those consuming G0, G2.5 or G5 (P < 0.05), and more intense in G20 than in G0 and G5 groups (P < 0.05). In conclusion, the optimal and well-tolerated dose of SC-FOS that significantly increased fecal bifidobacteria in healthy volunteers consuming their usual diet is 10 g/d.

Adolescent↗
PubMed1998

Plasma leptin and hunger ratings in healthy humans.

Leptin, the ob gene product, is considered as a signal involved in the regulation of energy stores through centrally mediated effects on ingestive behavior and metabolism. To investigate the relationships between appetite-related sensations and circulating leptin in humans, 12 healthy male volunteers were served two test lunches (1200 kcal, 38% carbohydrate, 50% fat, 12% protein) with comparable palatability but resulting in different postprandial hunger ratings, and plasma leptin concentrations were monitored during 8 h after meal ingestion. Whereas postprandial hunger ratings (assessed by visual analog scales) and plasma insulin patterns differed significantly between meals, no significant difference in postprandial plasma leptin concentrations was observed between the two meals. A moderate but significant increase in mean plasma leptin was found over time. We conclude that postprandial plasma leptin concentrations do not significantly differ between two meals inducing different effects on hunger subjective feelings. These data are in agreement with a role for leptin in the regulation of energy balance as a long-term adiposity-related signal rather than a short-term meal-related factor.

Adult↗
PubMed1998

Functional food science and substrate metabolism.

The present review addresses the role of food constituents in the aetiology of metabolic conditions and chronic diseases, mostly related to energy metabolism and substrate regulation, such as obesity and non-insulin-dependent diabetes mellitus. Second, attention is paid to malnutrition, a major cause of mortality and morbidity in developing countries, which may be a cause of concern in Europe because of the increasing number of elderly people in the population. Finally, the role of diet during exercise, a condition of enormous substrate demands, is evaluated. Based on a critical evaluation of the existing knowledge in the literature, implications for future research in relation to functional foods are discussed.

Adolescent↗
PubMed1998

Small-intestinal digestion of partially resistant cornstarch in healthy subjects.

The aims of this study were to measure the amount of starch from partially resistant starches (retrograded and complexed high-amylose cornstarches) escaping small-intestinal digestion in healthy humans by use of an intubation method and to compare these data with data obtained by indirect in vitro methods. Experiments were carried out in vivo in 6 healthy humans by using ileal intubation and stool analysis and in vitro by using 3 different methods for analyzing resistant starch. In intubated subjects, 51 +/- 2% of the retrograded and 21 +/- 2% of the complexed starch was delivered to the ileum and was fermented almost completely in the colon. In vitro estimates of the absorption of resistant starch were much lower. We conclude that technologically modified starches may substantially increase the amount of carbohydrate available for colonic fermentation in humans, but that in vitro measurements of resistant starch are inaccurate for predicting malabsorption in healthy humans.

Adult↗
PubMed1998

Plasma lipids and fatty acid synthase activity are regulated by short-chain fructo-oligosaccharides in sucrose-fed insulin-resistant rats.

The aim of this study was to evaluate the chronic effects of a short-chain fructo-oligosaccharide (FOS)-containing diet on plasma lipids and the activity of fatty acid synthase (FAS) in insulin-resistant rats. Normal male Sprague-Dawley rats, 5 wk old, were randomly assigned to two groups and fed either a sucrose-rich diet (S, 575 g sucrose /kg diet and 140 g lipids/kg diet) or a sucrose-rich diet supplemented with 10 g/100 g short-chain fructo-oligosaccharides (S/FOS). A third reference group (R) was fed a standard nonpurified diet (g/kg, 575 g starch, 50 g fat). After 3 wk the sucrose-fed rats (compared with the R group) were characterized by the following: 1) higher insulin responses after a glucose challenge (P < 0.05); 2) heavier liver (P < 0.001) and retroperitoneal adipose tissue (P < 0.01); 3) hypertriglyceridemia (P < 0.0001) and higher plasma free fatty acids (P < 0.0001); and 4) higher fatty acid synthase activity in the liver but a low activity in the adipose tissue (P < 0.001). The addition of FOS to the diet resulted in 11% lower liver weight than in the S group (P < 0.05) and tended to result in lower adipose tissue weight (P < 0.11). Plasma triglycerides and plasma free fatty acids were lower in S/FOS- than in S-fed rats (P < 0.05). Chylomicrons + VLDL, and intermediate density lipoprotein (IDL) concentrations did not differ between groups, nor was plasma cholesterol influenced by diet. Hepatic FAS activity was lower in S/FOS-fed rats than in the S-fed rats (P < 0.05). In adipose tissue, however, this activity tended to be greater in rats fed S/FOS than in rats fed the S diet (P < 0.07). In conclusion, in a rat model of diet-induced (57.5% sucrose and 14% lipids) insulin resistance, the addition of short-chain FOS prevented some lipid disorders, lowered fatty acid synthase activity in the liver and tended to raise this activity in the adipose tissue. Short-chain FOS, in addition to being a nondigestible sweetener with good bulking capacity, might be useful in the treatment of insulin resistance and hyperlipidemia.

Animals↗
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

Whole-body protein turnover in humans fed a soy protein-rich vegetable diet.

OBJECTIVES: This study was designed to compare the whole-body protein turnover in humans after the ingestion of a soy protein-rich vegetable diet with that of a control group fed a western animal protein-rich diet. SUBJECTS: Twelve male volunteers were divided into two groups of six subjects who were given for two weeks either a 85% vegetable protein diet (diet VP) or a control western animal protein-rich diet (diet AP). INTERVENTIONS: Whole-body protein turnover was estimated at the end of the two-week controlled diet period using the [15N]-glycine end-product method. Nitrogen flux rates were determined in the fed state (1.3 g protein/kg) over a 9 h period after the dose of [15N]-glycine was given. RESULTS: After the 9 h of the test, the urinary ammonia excretion was significantly higher in the group receiving the diet AP than that in the group receiving the diet VP (P < 0.05). In contrast, there was no significant difference for both total nitrogen and urea nitrogen excretions. Both the protein synthesis and the protein breakdown were similar in both groups. In the same way, the net protein deposition measured in the fed state during 9 h was similar for both diets at 0.07 g/kg/h. CONCLUSIONS: Young adults fed 1.3 g/kg/d of either meat or vegetable protein-rich diet for two weeks did not show a different protein turnover.

Adult↗
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↗