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Bornet brouns 2002nutritional aspects short chai fructo oligo S
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Bifidobacteria are harbored in the intestine of specific animals and humans at different ages. In this study, we examined the immune responses affected by Bifidobacterium longum and B. animalis, focusing upon the cytokines produced by mouse peritoneal cells. Both B. longum and B. animalis induced the expression of IL-1β, IL-6, IL-10 and TNF-α mRNA in mouse peritoneal cells, as determined by RTPCR. The amount of IL-6 secreted by thioglycollate-induced peritoneal exudate cells (TG-PEC) in the presence of these bacteria were similarly augmented, as shown by ELISA. More TNF-α was induced in B. longum than in B. animalis. A difference in the level of TNF production was also suggested from the in vivo tumor suppression test using TNF-sensitive Meth A tumors, although both species of bacteria profoundly suppressed the tumor incidence and tumor growth. Taken together, both B. longum and B. animalis promote the induction and/or secretion of inflammatory cytokines (IL-6 and TNF-α) in mouse peritoneal cells. However, the level of TNF-α production induced by B. animalis was lower than that by B. longum.
In recent years there have been some startling advances made in the taxonomy of bifidobacteria. The bifidobacteria are classified as a distinct genus Bifidobacterium, and a number of species and biovars are now recognized. As better techniques for the study of bacteria are devised, more definitive information on importance of bifidobacteria as part of the intestinal flora of humans and animals has been obtained. Some ecological relationships of this organism are reviewed in this paper.
Propionate caused an inhibition of ketogenesis from butyrate by bovine liver slices. When succinate, fumarate and aspartate were included in the incubation mixtures as sources of oxaloacetate, they were not as inhibitory as propionate. The possibility of competition between propionate and butyrate for cofactors required for activation was discounted when neither ATP (17 mM), nor carnitine (3.5 mM), added to expand the coenzyme A (CoA) pool, relieved the antiketogenic effect of propionate. The 3-hydroxy-3-methylglutaryl-CoA pathway appeared to be the major route for formation of acetoacetate from acetoacetyl-CoA in liver extracts, on the basis of enzyme assays. At a concentration of 0.5 mM, propionyl-CoA caused an apparent decrease of 3-hydroxy-3-methylglutaryl-CoA synthase activity of 46%, whereas propionate and methylmalonyl-CoA were not effective. At a concentration of 15 mM, propionate resulted in 30% inhibition of synthase activity. Propionyl-CoA did not affect the activity of 3-hydroxy-3-methylglutaryl-CoA lyase. It was suggested that in bovine liver the antiketogenic effect of propionate is achieved, at least in part, through inhibition of formation of acetoacetate from acetoacetyl-CoA.
The ability for such lymphocyte activation as growth of the spleen and Peyer’s patch (PP) cells from unprimed BALB/c mice, and of lymph node (LN) cells from mice immunized with hen’s egg ovomucoid (OM) was assayed by using sonicated microorganisms. The occurrence of immunopotentiating activity was strikingly dependent on the properties of individual strains, rather than on the species or microbial culture conditions. All the tested Bifidobacterium strains, especially B. adolescentis M101-4, showed strong mitogenic activity in those assays, and also enhanced the production of the anti-OM antibody by LN cells, while they did not induce the growth of thymocytes. Similar results were obtained from experiments using germ-free (GF) mice. These results suggest that the activation with B. adolescentis M101-4 was not due to any secondary stimulation of lymphocytes primed with bacteria in the gut or environment, but to direct or indirect activity toward B cells that was intrinsic to the strain.
Neosugar, a fructooligosaccharide mixture, was tested for genotoxicity in three assays: (1) microbial reverse mutation assays in Salmonella typhimurium (Ames assay) and Escherichia coli WP2 uvr A, (2) the L5178Y mouse lymphoma TK± mammalian cell mutation assay, and (3) an assay for the induction of unscheduled DNA synthesis (UDS) in human epithelioid cells (HeLa S3). Each assay was conducted at a wide range of dose levels, both with and without metabolic activation. Test results gave no indication that neosugar possessed any genotoxic potential. The carcinogenicity and chronic toxicity of neosugar were examined in Fischer 344 rats. Rats were fed diets containing 0, 8000, 20,000, or 50,000 ppm neosugar for 104 weeks. No dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or nonneoplastic lesions were observed. The incidence of rare and spontaneous tumors was comparable between control and neosugar treatment groups, with the exception of pituitary adenomas in male rats. In light of the background incidence of this tumor and an equivocal dose-response trend, it is unlikely that neosugar treatment is related to the incidence of pituitary adenomas in male rats. The results of this study indicate that neosugar is nonmutagenic and that rats are not adversely affected by chronic neosugar exposure.
Despite an increasing awareness of the relationships between the intestinal microbiota and health, there are few definitive guidelines about dietary interventions to adventitiously influence species composition of the microbiota. Therefore, standard microbiological methods were used to determine changes in the abundance of selected bacteria in anaerobic faecal samples from ten adult human volunteers who consumed 4 g of neosugar, a mixture of short-chain fructooligosaccharides, daily for 2 wks. The diet was not otherwise controlled. Total anaerobic counts increased or remained relatively stable in nine subjects. The percentage of total bacteria counts represented by aerobes increased over ten-fold, but enterics declined by over 90 per cent (from 2.3 per cent to <0.2 per cent). Although bifidobacteria increased from 1 3 per cent to 6.8 per cent of the total bacteria, there was wide individual variation in responses; bifidobacteria were not detected in two subjects at either date (<104 colony forming units/g faeces). Lactobacilli increased in six of the subjects, but were not a significant component of the microbiota at either date (<00001 per cent). Individual variation in responses to supplemental neosugar are probably caused by differences in diet, initial microbiota, and environmental conditions. The results demonstrate that supplementing the diet with neosugar influences the relative abundances of selected bacteria with some of the changes consistent with those considered advantageous.
An in vitro screening test using the murine Peyer's patch cell culture method was developed for detection of bifidobacteria which induce large quantities of IgA. Bifidobacteria grown for 48 h were added at a dose corresponding to an absorbance value of 0.275 at 660 nm to BALB/c mouse Peyer's patch cells, and 7 days later the quantities of IgA antibody in the culture supernatants were measured by an ELISA method. With this screening test, three strains of bifidobacteria capable of inducing large quantities of IgA were selected from 120 strains isolated from human faeces and identified as Bifidobacterium breve (two strains) and B. longum (one strain). When one of the three strains (B. breve Y1T 4064) was administered orally along with cholera toxin (CT) into mice, the amount of anti-CT IgA antibody in faeces and anti-CT IgA antibody production and proliferation in Peyer's patch cells tended to be greater and were significantly greater, respectively, than after administration of only CT or CT and B. breve Ka-6, which did not induce IgA.
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 isotope25Mg together with a fecal marker. Subsequently, feces were collected for 5–7 days. An inductively coupled plasma mass spectrometer (ICP/MS) was used for25Mg 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 plasma25Mg level and led to a higher urinary25Mg 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.
There is a strong interest in strategies to reduce the risks of osteoporosis and the related health care costs. The age of the population in civilized countries is ever increasing. One of the concerns is to maintain a high quality of life after retirement. Another concern is the continuous and explosive growth of public health care costs. This has lead to governmental measures to let people pay relatively high own risks and self-contributions for medical treatment. One of the results of these developments is a growing trend towards self-medication. Because drugs cannot be obtained without prescription, consumers seek for natural products to fit their needs and expectations. The food industry is aware of these developments and targets this ever growing market segment with an intensified search for food substances, which may have a positive effect on health, disease prevention or disease management. Once established, the benefits are usually communicated as claims related to either the product or the consumer benefit. One of the basic questions consumers are dealing with is whether the claims made are true and not just misleading selling arguments. Recent developments in international food legislation point to a need to avoid the launch of products with unsubstantiated claims. Thus, functional or health claims related to specific food ingredients or functional foods may only be approved by legal food authorities, if there is an international consensus on the supporting scientific evidence. This article reviews current opinions on osteoporosis and highlights a number of epidemiological, physiological and nutritional aspects.