Effects of probiotics and prebiotics on blood lipids

Efficacy and Safety of Probiotics for the Treatment of Alzheimer's Disease, Mild Cognitive Impairment, and Parkinson's Disease: A Systematic Review and Meta-Analysis

Background

Alzheimer's disease (AD) and Parkinson's disease (PD) are two of the most common neurodegenerative diseases, and mild cognitive impairment (MCI) is considered a prodromal stage of clinical AD. Animal studies have shown that probiotics can improve cognitive function and mitigate inflammatory response, however, results from randomized controlled trials in humans are still unclear.

Objectives

A systematic review and meta-analysis was conducted to evaluate the efficacy and safety of probiotic therapy on cognitive function, oxidative stress, and gastrointestinal function in patients with AD, MCI, and PD.

Methods

We searched the electronic databases such as PubMed, EMBASE, Cochrane Library until October 2020 for the eligible randomized controlled trials, as well as the unpublished and ongoing trials. Our primary endpoints were cognitive function, inflammatory and oxidative stress biomarkers, gastrointestinal function, and adverse events.

Results

After screening 2,459 titles and abstracts about AD or MCI, we selected 6 eligible studies (n = 499 patients). After screening 1,923 titles and abstracts about PD, we selected 5 eligible studies (n = 342 patients). Compared with the control group, treatment with probiotics improved the cognitive function of patients with AD in the intervention group (P = 0.023). Cognitive function also improved in MCI patients (P = 0.000). Inflammation-related indicators: Malondialdehyde (MDA) was significantly reduced (P = 0.000); and hs-CRP decreased (P = 0.003). Lipid-related indicators: VLDL decreased (P = 0.026); triglyceride decreased (P = 0.009); and insulin resistance level improved: decreased Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (P = 0.019).

Conclusion

Our analyses suggest that probiotics can improve cognitive and gastrointestinal symptoms in patients with AD, MCI, and PD, which is possibly through reducing inflammatory response and improving lipid metabolism. The safety has also been proven. However, more RCTs with rigorous study design are needed to support our findings.

Systematic Review Registration

PROSPERO, Identifier: CRD42021231502.

Characterization of Latilactobacillus curvatus MS2 isolated from Korean traditional fermented seafood and cholesterol reduction effect as synbiotics with isomalto-oligosaccharide in BALB/c mice

This study investigated the properties of Latilactobacillus curvatus MS2 isolated from Korean traditional fermented seafood as probiotics and the effect of reducing cholesterol as a synbiotic with isomalto-oligosaccharide (IMO) in BALB/c mice. The isolated strain showed high resistance to acids and bile acids and exhibited a high DPPH scavenging capacity of 72.27 ± 0.38 %. In the intestinal adhesion test using HT-29 cells, the adhesion rate of MS2 was 17.10 ± 1.78 %, which was higher than the adhesion rate of the other investigated probiotics. MS2 showed good antimicrobial activity against food-borne pathogens, especially Staphylococcus aureus, S. epidermidis, Escherichia coli, and Vibrio vulnificus. This strain had high availability for IMO among the prebiotics of fructo-oligosaccharide, inulin and IMO. Oral administration of MS2 and IMO to BALB/c mice for 5 weeks resulted in a significant reduction in blood cholesterol levels by regulating liver lipid metabolism. These results suggest that the combination of MS2 and IMO has potential for application in functional foods.

Potential beneficial effects of kefir and its postbiotic, kefiran, on child food allergy

Food allergies are known as the public health problem, affecting people of all age groups, but more commonly in babies and children, with consequences for nutritional status and quality of life. The increase in the consumption of healthy foods has consequently led to an increased demand for functional foods with specific health benefits. Thus, the pharmaceutical industry's interest in natural products has grown every time and is therefore considered as an alternative to synthetic drugs. Kefir has been outstanding for several years as promising in the manufacture of various pharmaceutical products, due to its nutritional and therapeutic properties for the treatment of many diseases. Currently, a wide variety of new functional foods are appearing on the market, representing an important segment. Postbiotics, for example, has stood out for being a product with action similar to probiotics, without offering side effects. The kefiran is the postbiotic from kefir that promotes potential beneficial effects on food allergy from the intestinal microbiome to the immune system. In this context, it is necessary to know the main promoting component of this functional effect. This review compiles the benefits that kefir, and especially its postbiotic, kefiran, can bring to food allergy. In addition, it serve as a subsidy for studies on the development of innovative nutraceutical products, including the use of kefiran as an alternative therapy in food allergy.

Chemical Constitution and Antimicrobial Activity of Kefir Fermented Beverage

Kefir beverage (KB) is a fermented milk initiated by kefir grains rich with starter probiotics. The KB produced in this study seemed to contain many chemical compounds elucidated by gas chromatography-mass spectrometry (GC-MS) and IR spectra. These compounds could be classified into different chemical groups such as alcohols, phenols, esters, fatty esters, unsaturated fatty esters, steroids, polyalkenes, heterocyclic compounds and aromatic aldehydes. Both KB and neutralized kefir beverage (NKB) inhibited some pathogenic bacteria including Escherichia coli ATCC11229 (E. coli), Listeria monocytogenes ATCC 4957 (L. monocytogenes), Bacillus cereus ATCC 14579 (B. cereus), Salmonella typhimurium ATCC 14028 (Sal. typhimurium) as well as some tested fungal strains such as Aspergillus flavus ATCC 16872 (A. flavus) and Aspergillus niger ATCC 20611 (A. niger), but the inhibitory activity of KB was more powerful than that obtained by NKB. It also appeared to contain four lactic acid bacteria species, one acetic acid bacterium and two yeast species. Finally, the KB inhibited distinctively both S. aureus and Sal. typhimurium bacteria in a brain heart infusion broth and in some Egyptian fruit juices, including those made with apples, guava, strawberries and tomatoes.

Antiobesity and Uric Acid-Lowering Effect of Lactobacillus plantarum GKM3 in High-Fat-Diet-Induced Obese Rats

Objective: Obesity has become one of the world's biggest issues. This condition has a great impact on several metabolic and chronic diseases. For example, obesity is often accompanied by hyperuricemia or gout. However, few drugs are available for the treatment of obesity. The present study is to evaluate the antiobesity effect of Lactobacillus plantarum GKM3 in high-fat-diet-induced obese rats and whether taking L plantarum GKM3 can effectively reduce uric acid accumulation caused by obesity and ameliorate other harmful factors. Method: Sixty male Wistar rats were divided into five groups as follows: ( 1 ) ND group, fed normal diet; ( 2 ) HFC group, fed AIN93G-based high-fat diet containing 65% solids, 7% soybean oil, and 25% lard; ( 3 ) HFL group, fed AIN93G-based high-fat diet supplemented with 102.7 mg/kg/d L plantarum GKM3; ( 4 ) HFM group, fed AIN93G-based high-fat diet supplemented with 205.4 mg/kg/d L plantarum GKM3; and ( 5 ) HFH group, fed AIN93G-based high-fat diet supplemented with 513.5 mg/kg/d L plantarum GKM3. After 6 weeks, the body, organ, and fat weights; food intake; blood serum levels; and adipocyte size were measured. Results: Results showed that rats fed on the high-fat diet showed more body weight, increased feed efficiency, higher fat deposition, higher total liver weight, elevated serum lipid levels, and increased adipocyte size compared with those on the normal diet. All these effects were reversed by supplementation of L plantarum GKM3. Conclusions: In conclusion, we suggest that the L plantarum GKM3 supplement may have beneficial antiobesity and uric acid-lowering effects.

Biological Activities of Lactose-Based Prebiotics and Symbiosis with Probiotics on Controlling Osteoporosis, Blood-Lipid and Glucose Levels

Lactose-based prebiotics are synthesized by enzymatic- or microbial- biotransformation of lactose and have unique functional values. In this comprehensive review article, the biochemical mechanisms of controlling osteoporosis, blood-lipid, and glucose levels by lactose-based prebiotics and symbiosis with probiotics are reported along with the results of clinical investigations. Interaction between lactose-based prebiotics and probiotics reduces osteoporosis by (a) transforming insoluble inorganic salts to soluble and increasing their absorption to gut wall; (b) maintaining and protecting mineral absorption surface in the intestine; (c) increasing the expression of calcium-binding proteins in the gut wall; (d) remodeling osteoclasts and osteoblasts formation; (e) releasing bone modulating factors; and (f) degrading mineral complexing phytic acid. Lactose-based prebiotics with probiotics control lipid level in the bloodstream and tissue by (a) suppressing the expressions of lipogenic- genes and enzymes; (b) oxidizing fatty acids in muscle, liver, and adipose tissue; (c) binding cholesterol with cell membrane of probiotics and subsequent assimilation by probiotics; (d) enzymatic-transformations of bile acids; and (e) converting cholesterol to coprostanol and its defecation. Symbiosis of lactose-based prebiotics with probiotics affect plasma glucose level by (a) increasing the synthesis of gut hormones plasma peptide-YY, glucagon-like peptide-1 and glucagon-like peptide-2 from entero-endocrine L-cells; (b) altering glucose assimilation and metabolism; (c) suppressing systematic inflammation; (d) reducing oxidative stress; and (e) producing amino acids. Clinical investigations show that lactose-based prebiotic galacto-oligosaccharide improves mineral absorption and reduces hyperlipidemia. Another lactose-based prebiotic, lactulose, improves mineral absorption, and reduces hyperlipidemia and hyperglycemia. It is expected that this review article will be of benefit to food technologists and medical practitioners.

A Double-Blind Controlled Study to Evaluate the Effects of Yogurt Enriched with Lactococcus lactis 11/19-B1 and Bifidobacterium lactis on Serum Low-Density Lipoprotein Level and Antigen-Specific Interferon-γ Releasing Ability

In order to clarify the effects of the Lactococcus lactis (L. lactis) 11/19-B1 strain, a double-blind controlled study of yogurt fermented with the strain was carried out. For the study, two kinds of yogurt, the control and test yogurt, were prepared; the control yogurt was fermented with Streptococcus thermophiles, Lactobacillus delbrueckii subspecies bulgaricus, and Lactobacillus acidophilus, and the test yogurt was enriched with L. lactis 11/19-B1 and Bifidobacterium lactis (B. lactis) BB-12 strains. Seventy-six volunteers who had not received treatment with pharmaceuticals were randomly divided into two groups with each group ingesting 80 g of either the test or control yogurt every day for 8 weeks. Before and after yogurt intake, fasting blood was taken and blood sugar, blood lipids, and anti-cytomegalovirus cellular immunity were estimated. In the test yogurt group, low-density lipoprotein (LDL) was significantly decreased (159.1 ± 25.7 to 149.3 ± 24.4; p = 0.02), but this effect was not observed in the control yogurt group. When the test yogurt group was divided into two groups based on LDL levels of over or under 120 mg/dL, this effect was only observed in the high LDL group. No LDL-lowering effect of B. lactis BB-12 strain was previously reported; therefore, the hypocholesterolemic effects observed in this study are thought to be caused by the L. lactis 11/19-B1 strain alone or its combination with the B. lactis BB-12 strain.

Influence of Probiotics Administration on Gut Microbiota Core: A Review on the Effects on Appetite Control, Glucose, and Lipid Metabolism

An increasing number of studies has shown that dietary probiotics exert beneficial health effects in both humans and animals. It is well established that gut microbiota play a pivotal role in regulating host metabolism, and a growing number of studies has elucidated that probiotics positively interfere with gut microbiota. Accumulating evidence shows that probiotics, through their metabolic activity, produce metabolites that in turn contribute to positively affect host physiology. For these reasons, probiotics have shown significant potential as a therapeutic tool for a diversity of diseases, but the mechanisms through which probiotics act has not been fully elucidated yet. The goal of this review was to provide evidence on the effects of probiotics on gut microbiota changes associated with host metabolic variations, specifically focusing on feed intake and lipid and glucose metabolism. In addition, we review probiotic interaction with the gut microbiota. The information collected here will give further insight into the effects of probiotics on the gut microbiota and their action on metabolite release, energy metabolism, and appetite. This information will help to improve knowledge to find better probiotic therapeutic strategies for obesity and eating disorders.

Effect of symbiotic supplementation on glycemic control, lipid profiles and microalbuminuria in patients with non-obese type 2 diabetes: a randomized, double-blind, clinical trial

BACKGROUND

The prevalent raise of type 2 diabetes (T2D) around the globe, are creating higher risk for cardiovascular diseases (CVDs) and increasing strain on each country's health care budget in the world. Microalbuminuria has appeared as a key parameter in diabetic patients. Microalbuminuria is also related to increased cardiovascular morbidity in people who are non-obese diabetic. Some studies have suggested that consumption of symbiotic foods might help improve the metabolic profile, inflammatory factors and biomarkers of oxidative stress. The aim of trial was to determine the effect of symbiotic supplementation on glycemic control, lipid profiles and microalbuminuria in non-obese T2D.

METHODS

In this randomized, double-blind, clinically controlled trial, 70 patients with T2D (28 females, 42 males) were randomly divided into two groups (n = 35 for each group). The symbiotic group (SG) consumed 500 mg/d of symbiotic supplementations containing probiotics (Lactobacillus family, Bifidobacterium family, Streptococus thermophilus), Prebiotics (Fructo oligosaccharide) and B group vitamins (1 mg), lactose (0.5 mg), malt-dextrin, magnesium saturate and the placebo group (PG) consumed capsules filled with row starch and also B group vitamins (1 mg), lactose (0.5 mg), malt-dextrin, magnesium saturate for 9 weeks. Fasting blood glucose (FBG), hemoglobin A1c (HbA1c), blood lipid profiles, 24-h dietary recalls, and anthropometric measurements were measured at the baseline and at the end of trial. SPSS software, version 16 was used to test the data and the results were expressed as mean ± standard deviation. Paired samples T-Test were used to compare continuous variables within groups. Comparison between different groups was performed through two independent samples T-Test. In the absence of normal distribution, the comparison between the groups was made using non-parametric Wilcoxon on signed ranks and Mann-Whitney tests. P values <0.05 was considered significant.

RESULTS

Symbiotic supplementation decreased significantly, FBG (P = 0.05) and HbA1c (P < 0.01). There were no significant differences in lipid profiles within and between the groups at the end of study (P > 0.05). Microalbuminuria (P < 0.05) and HbA1c (P < 0.05) are increased significantly in PG at the end of the study. Furthermore, the mean changes of microalbuminuria and HbA1c experienced significant between the two groups. There was significant reduction in urea between two groups from baseline (P = 0.051). No significant changes in baseline were shown in creatinine among the two groups or within either groups (P > 0.05).

CONCLUSION

The consumption of 500 mg/d symbiotic supplementation for 9 weeks could improve the HbA1c, BMI and Microalbuminuria in T2D. Although, No effect has been indicated on FBS, lipid profiles, urea and creatinine.

TRIAL REGISTRATION

The trial has been registered in the Iranian Registry of Clinical Trials IRCT2015072223284N1, identifier. Registered 21 May 2016 "retrospectively registered".

Kefir reduces insulin resistance and inflammatory cytokine expression in an animal model of metabolic syndrome

There is growing evidence that kefir can be a promising tool in decreasing the risk of many diseases, including metabolic syndrome (MetS). The aim of the present study was to evaluate the effect of kefir supplementation in the diet of Spontaneously Hypertensive Rats (SHR) in which MetS was induced with monosodium glutamate (MSG), and to determine its effect on metabolic parameters, inflammatory and oxidation marker expression and glycemic index control. Thirty animals were used in this experiment. For the induction of MetS, twenty two-day-old male SHR received five consecutive intradermal injections of MSG. For the Negative Control, ten newborn male SHR received intradermal injections of saline solution (0.9% saline solution). After weaning, animals received standard diet and water ad libitum until reaching 3 months old, for the development of MetS. They were then divided into three groups (n = 10): negative control (NC, 1 mL saline solution per day), positive control (PC, 1 mL saline solution per day) and the Kefir group (1 mL kefir per day). Feeding was carried out by gavage for 10 weeks and the animals received standard food and water ad libitum. Obesity, insulin resistance, pro- and anti-inflammatory markers, and the histology of pancreatic and adipose tissues were among the main variables evaluated. Compared to the PC group, kefir supplementation reduced plasma triglycerides, liver lipids, liver triglycerides, insulin resistance, fasting glucose, fasting insulin, thoracic circumference, abdominal circumference, products of lipid oxidation, pro-inflammatory cytokine expression (IL-1β) and increased anti-inflammatory cytokine expression (IL-10). The present findings indicate that kefir has the potential to benefit the management of MetS.

Gut Function-Enhancing Properties and Metabolic Effects of Dietary Indigestible Sugars in Rodents and Rabbits

Indigestible sugars (iS) have received particular interest in food and nutrition research due to their prebiotic properties and other health benefits in humans and animals. The main aim of this review article is to summarize the current knowledge regarding digestive and health-enhancing properties of iS such as sugar alcohols, oligosacharides, and polysaccharides, in rodents and rabbits. Besides ameliorating gut health, iS ingestion also elicits laxative effects and stimulate intestinal permeability and fluid secretions, thereby shortening digesta transit time and increasing stool mass and quality. In rodents and rabbits, as hindgut fermenters, consumption of iS leads to an improved nutrient digestibility, too. Cecal fermentation of iS reduces luminal pH and extends wall tissue facilitating absorption of key dietary minerals across hindgut. The microbial fermentation of iS also enhances excessive blood nitrogen (N) flowing into the cecum to be used as N source for bacterial growth, enhancing N retention in cecotrophic animals. This review also highlights the impact of iS on improving lipid metabolism, mainly by lowering cholesterol and triglycerides levels in the blood. The paper serves as an index of the current knowledge of iS effects in rodents and rabbits and also identifies gaps of knowledge that need to be addressed by future research.

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols: role in irritable bowel syndrome

Irritable bowel syndrome (IBS) was previously left poorly treated despite its high prevalence and cost. Over the past decade, significant research has been conducted providing new dietary strategies for IBS management. The 'low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet' has shown symptom improvement in 68-76% of patients. Randomized, controlled trials have now proven its efficacy. The diet, low in poorly absorbed and fermentable carbohydrates, uses dietary restriction and re-challenge to determine individual tolerance to various short-chain carbohydrates. However there may be potential detrimental effects of the diet in the long term, due to potential changes to the gastrointestinal microbiota. Appropriate dietary education and management of the diet is imperative. Future research should focus on the relevance of changes to the microbiota and ways to liberalize the dietary restrictions.

Effects of soya oligosaccharides and soya oligopeptides on lipid metabolism in hyperlipidaemic rats

In the present study, we aimed to examine the effects of soya oligosaccharides (SOS) and soya oligopeptides (SOP) on blood lipid levels, release of vasoactive substances, antioxidant activity and faecal bile acid (FBA) excretion in rats fed a high-fat diet (HFD). Male Sprague-Dawley rats were evenly divided into five groups according to diets as follows: regular diet (control), HFD, HFD enriched with 2 % of SOS (SOS), HFD enriched with 3 % of SOP (SOP) and HFD enriched with 2 % SOS and 3 % SOP (SOSP). The results showed that SOS and SOP significantly reduced plasma total cholesterol, LDL-cholesterol and TAG, whereas HDL-cholesterol concentration was significantly increased. Furthermore, SOS and SOP reduced plasma apoB, apoE and the apoB:apoAI ratio, whereas apoAI was significantly increased. Moreover, SOS and SOP also reduced plasma thromboxane A₂ (TXA₂) and the TXA₂:prostacyclin (PGI₂) ratio, whereas plasma PGI₂ and nitric oxide were significantly increased. In addition, SOS and SOP significantly reduced serum and liver malondialdehyde concentrations and increased FBA excretion. However, we did not observe obvious influences of SOS and SOP on superoxide dismutase activities in the liver of HFD-fed rats. The combination of 2 % SOS and 3 % SOP showed a more marked effect than SOS or SOP alone in improving the lipid profile, release of vasoactive substances and increasing FBA excretion (P < 0.05). In summary, SOS and SOP might help prevent atherosclerosis through improving abnormal blood lipid levels, regulating vasoactive substances and protecting against oxidative stress.

Antiobesity and lipid-lowering effects of Bifidobacterium spp. in high fat diet-induced obese rats

BACKGROUND

Recent studies have reported the preventive effects of probiotics on obesity. Among commensal bacteria, bifidobacteria is one of the most numerous probiotics in the mammalian gut and are a type of lactic acid bacteria. The aim of this study was to assess the antiobesity and lipid-lowering effects of Bifidobacterium spp. isolated from healthy Korean on high fat diet-induced obese rats.

METHODS

Thirty-six male Sprague-Dawley rats were divided into three groups as follows: (1) SD group, fed standard diet; (2) HFD group, fed high fat diet; and (3) HFD-LAB group, fed high fat diet supplemented with LAB supplement (B. pseudocatenulatum SPM 1204, B. longum SPM 1205, and B. longum SPM 1207; 108 ~ 109 CFU). After 7 weeks, the body, organ, and fat weights, food intake, blood serum levels, fecal LAB counts, and harmful enzyme activities were measured.

RESULTS

Administration of LAB reduced body and fat weights, blood serum levels (TC, HDL-C, LDL-C, triglyceride, glucose, leptin, AST, ALT, and lipase levels), and harmful enzyme activities (β-glucosidase, β-glucuronidase, and tryptophanase), and significantly increased fecal LAB counts.

CONCLUSION

These data suggest that Bifidobacterium spp. used in this study may have beneficial antiobesity effects.

In vitro assay of the antimicrobial activity of kephir against bacterial and fungal strains

Kephir is a fermented carbonated refreshing milk, with a slightly acidic aromatic taste and creamy foam composition which contains lactobacilli, leuconostocci, acetic acid bacteria, lactostreptococci and yeasts. Recent studies have demonstrated its antibacterial, immunostimulating, antitumoral and cholesterol-lowering activities.

PURPOSE

The purpose of this study was to investigate the antimicrobial activity of kephir against Bacillus subtilis spp. spizizenii ATCC 6633, Staphylococcus aureus ATCC 6538, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 8739, Salmonella enteritidis ATCC 13076, Pseudomonas aeruginosa ATCC 9027 and Candida albicans ATCC 10231. The kephir fermented for 24 h and 48 h, as well and after 7 days preservation at 4-8 °C was tested by in vitro disk diffusion method. The intensity of the antimicrobial activity was interpreted by comparison with two antibiotics, i.e. ampicillin and neomycin.

RESULTS

The antimicrobial activity of 24 h as well as 48 fermented kephir, fresh or after 7 days preservation at 4-8 °C was similar and observed against B. subtilis, S. aureus, E. coli, E. faecalis and S. enteritidis. For E. coli, E. faecalis and S. enteritidis the antimicrobial activity was superior to both tested antibiotics and for B. subtilis and S. aureus to one antibiotic. The tested products exhibited no activity against P. aeruginosa and C. albicans.

CONCLUSION

Kephir is exhibiting large spectrum and strong antibacterial activity probably due to the complex viable probiotic strains association producing antimicrobial substances.

[Probiotics and pregnancy]

Prenatal care is one of the great challenges in medicine. Aims of therapies and protocols may influence the life of mothers and babies. Diseases occurring during pregnancy are even more dangerous, because of the difficulties in their treatment strategy. Prevention must be emphasized using safe and natural drugs. Pre- and probiotics are in focus of the medical sciences. Various publications and studies emphasize the importance of these drugs in evidence-based medicine. Safe methods are essential in prenatal care. Authors review published data on the effect and potential use of pre- and probiotics during pregnancy.

Effects of probiotics and commensals on intestinal epithelial physiology: implications for nutrient handling

Eukaryotes and prokaryotes have developed mutually beneficial relationships over millennia of evolutionary adaptation. Bacteria in our gut rely on our diet and the protected environment of our bodies just as our health depends on byproducts of microbial metabolism. Microorganisms of the gut microbiota ferment carbohydrates into short-chain fatty acids, convert dietary and endogenous nitrogenous compounds into ammonia and microbial protein, and synthesize and activate B vitamins and vitamin K. The benefit from their activity is multiplex and translates into increased energy for the gut epithelial cells, balanced absorption of salt and water, nitrogen recycling, breakdown of complex lipids and cholesterol, and detoxification of waste compounds.

Oral administration of dahi containing probioticLactobacillus acidophilusandLactobacillus caseidelayed the progression of streptozotocin-induced diabetes in rats

In this study, the effect of dahi containing probioticLactobacillus acidophilusNCDC14 andLactobacillus caseiNCDC19 (∼73×108 cfu/g) on progression of streptozotocin (STZ)-induced diabetes in rats (15 g/day/rat) for 28 days was investigated. Feeding of probiotic dahi significantly suppressed the incremental peaks and area under the curve and delayed reduction of insulin secretion during oral glucose tolerance test more than skim milk or control dahi. The feeding of milk products reduced the total cholesterol, triglycerides, LDL and VLDL-cholesterol and increased HDL-cholesterol levels (P<0·05). Moreover, probiotic dahi significantly suppressed STZ-induced oxidative damage in pancreatic tissues by inhibiting the lipid peroxidation and formation of nitric oxide, and preserving antioxidant pool such as glutathione content and activities of superoxide dismutase, catalase and glutathione peroxidase. The results suggest that the supplementation of probioticLb. acidophilusandLb. caseiwith dahi cultures increased the efficacy of dahi to suppress STZ-induced diabetes in rats by inhibiting depletion of insulin as well as preserving diabetic dyslipidemia, and inhibiting lipid peroxidation and nitrite formation. This may empower antioxidant system of β-cells and may slow down the reduction of insulin and elevation of blood glucose levels.

Dietary combination of soy with a probiotic or prebiotic food significantly reduces total and LDL cholesterol in mildly hypercholesterolaemic subjects

OBJECTIVE

We hypothesized that a dietary combination of soy with either a probiotic (yoghurt) or a prebiotic (resistant starch) would result in enhanced lipid-lowering effects compared with a control soy diet, possibly via improvements in isoflavone bioavailability.

SUBJECTS

Mildly hypercholesterolaemic subjects (men and post-menopausal women) older than 45 years were recruited via the local media. Thirty-six subjects commenced the study; five withdrew.

RESULTS

Soy+probiotic significantly decreased total cholesterol (4.7+/-2.0%; P=0.038) and soy+prebiotic significantly decreased total and low-density lipoprotein cholesterol (5.5+/-1.6%; P=0.003 and 7.3+/-2.2%; P=0.005, respectively). The bioavailabilities of daidzein, genistein or equol were not affected by probiotic or prebiotic consumption or associated with lipid changes.

CONCLUSION

Dietary combination of soy with either a probiotic or a prebiotic resulted in significant lipid lowering, not related to isoflavone bioavailability.

Influence of long-term administration of lactulose and Saccharomyces boulardii on the colonic generation of phenolic compounds in healthy human subjects

OBJECTIVE

Proteins are degraded in the colon by bacterial fermentation into potentially toxic metabolites such as phenolic compounds. The aim of the present study was to investigate whether long-term administration of lactulose or Saccharomyces boulardii cells would result in a lower protein degradation. In addition, the influence of a long-term dietary intake on different gastrointestinal parameters was investigated.

METHODS

The effect of long-term intervention of the substrates was evaluated in a randomized, cross-over study in 43 healthy volunteers. At the start of the study and at the end of each 4-week treatment period, urine was collected during 48 h in different fractions and faeces during 72 h. Breath test samples and blood samples were taken to study gastrointestinal parameters.

RESULTS

No influence of long-term administration of both substrates was found on GE, OCTT and serum lipids. A significant decrease in small intestinal permeability was found after long-term dietary intervention with lactulose. Long-term administration of lactulose significantly decreased urinary p-cresol excretion, but did not lower fecal p-cresol excretion. No significant effects were observed after S. boulardii intake.

CONCLUSION

The results obtained in present study have indicated that colonic amino acid fermentation can be reduced by the administration of lactulose as a fermentable carbohydrate.

Non-digestible Oligosaccharides with Prebiotic Properties

The search for functional foods or functional food ingredients, i.e. foods or food ingredients that can enhance health, is beyond any doubt one of the leading trends in today's food industry. In this context, probiotics, i.e. living microbial food supplements, and prebiotics, i.e. non-digestible food ingredients, receive much attention. Both popular concepts target the gastrointestinal microbiota. While in the Western world, intake of probiotics has been recommended for long, prebiotics in general, and non-digestible oligosaccharides in particular, have only recently received attention. This review deals with production and characterization of non-digestible oligosaccharides and focuses on their role in promoting health and treating diseases. Attention is paid to the effects of non-digestible oligosaccharides on constipation, mineral absorption, lipid metabolism, cancer prevention, hepatic encephalopathy, glycemia/insulinemia, and immunomodulation.

Influence of Daily Consumption of Probiotic and Conventional Yoghurt on the Plasma Lipid Profile in Young Healthy Women

BACKGROUND

A number of studies have found conflicting results concerning the modulation of plasma lipids induced by probiotics. Therefore, the aim of this study was to verify and compare the effects of probiotic and conventional yoghurt on the plasma lipid profile of normocholesterolemic women.

METHODS

In this study, female volunteers consumed 100 g/day of probiotic (n = 17) or conventional yoghurt (n = 16) for 2 weeks (T1-T2) and 200 g/day for further 2 weeks (T2-T3). A washout phase lasting 2 weeks followed (T4). Total and HDL cholesterol and triglycerides were determined by enzymatic methods; LDL cholesterol was calculated using the Friedewald formula.

RESULTS

The average concentration of total cholesterol was consistent throughout the whole study in the control group, but decreased significantly (p < 0.01) in the probiotic group consuming 200 g yoghurt/day (T2-T3). During the period of daily yoghurt intake (T1-T3) the mean HDL cholesterol level increased significantly (p < 0.05) in the probiotic group, resulting in a significant (p < 0.05) improvement of the total/HDL cholesterol ratio. The significant (p < 0.01) reduction of the average plasma LDL cholesterol values found in this period (T1-T3) in the probiotic and the control groups was associated with a significant (p < 0.05) improvement of the LDL/HDL cholesterol ratios in both tested groups.

CONCLUSION

Although several lipid parameters changed during the study in both the probiotic and the control group, no significant differences between the groups were observed. Therefore, it can be concluded that the regular consumption of both probiotic and conventional yoghurt for 4 weeks had a positive effect on the lipid profile in plasma of healthy women.

Modulation of carbohydrate metabolism and peptide hormones by soybean isoflavones and probiotics in obesity and diabetes

Soybean and its isoflavones have been shown to have beneficial effects on carbohydrate and lipid metabolism and on renal function. Probiotics may potentiate the beneficial effects of isoflavones by converting the inactive isoflavone glycoside to aglycones, which are biologically active, thereby producing a synergistic effect. We therefore studied the effects of soybean isoflavones in the presence and absence of probiotics on glucose and triglyceride metabolism and the peptide hormones involved in their metabolism. Lean and obese SHR/N-cp rats were fed AIN-93 diets containing 0.1% soybean isoflavone mixture, 0.1% probiotics mixture or both. Plasma was analyzed for glucose, triglycerides, parameters of renal function and peptide hormones -- insulin, leptin, glucagon and ACTH -- that are involved in glucose and lipid metabolism. Isoflavones given alone lowered plasma glucose in both phenotypes while triglyceride was decreased only in lean animals. Isoflavones also lowered aspartate amino transferase and alanine amino transferase in both phenotypes. Isoflavones had significant effect on plasma insulin, leptin and glucagon in lean rats but not in obese rats. Thus, our data show that in lean animals, isoflavones have hypoglycemic and hypolipidemic effect, and the effect is mediated by changes in peptide hormones. When lipid levels are very high as in obese rats, isoflavones fail to lower plasma triglyceride levels. Probiotics do not appear to enhance the effect of isoflavones.

Effects of soybean isoflavones, probiotics, and their interactions on lipid metabolism and endocrine system in an animal model of obesity and diabetes

The effects of soybean isoflavones with or without probiotics on tissue fat deposition, plasma cholesterol, and steroid and thyroid hormones were studied in SHR/N-cp rats, an animal model of obesity, and were compared to lean phenotype. We tested the hypothesis that probiotics by promoting the conversion of isoflavone glycosides to their metabolically active aglycone form will have a synergistic effect on body fat, cholesterol metabolism, and the endocrine system. Obese and lean SHR/N-cp rats were fed AIN-93 diets containing 0.1% soy isoflavone mixture, 0.1% probiotic mixture, or both together. Different fat tissues were teased and weighed. Plasma was analyzed for cholesterol and steroid and thyroid hormones. In both phenotypes, isoflavones lowered fat deposition in several fat depots. Probiotics alone had no significant effect on fat depots. Isoflavones lowered total, LDL, and HDL cholesterol in lean rats, but in obese rats isoflavones lowered only total and LDL cholesterol. Isoflavones also lowered many of the steroid hormones involved in lipid metabolism but had no significant effect on thyroid hormones. Probiotics had no significant effect on cholesterol or hormones. Thus, our data show that soy isoflavones also lower plasma cholesterol and that this hypocholesterolemic effect appears to be due in part to the modulation of steroid hormones. Probiotics do not seem to enhance the effect of isoflavones.

Investigating the prebiotic and gas-generating effects of selected carbohydrates on the human colonic microflora

AIMS

To compare the fermentation of dietary carbohydrates with reference to their prebiotic and gas-generating capacity.

METHODS AND RESULTS

Static anaerobic batch culture fermentations were carried out measuring gas generation and the prebiotic effect of five selected substrates (including various fructo-oligosaccharides, levan and maltodextrin). The largest gas producer was levan, whilst those showing no significant difference to Actilight included oligofructose and maltodextrin. Gas composition data showed that hydrogen and carbon dioxide were the two most quantitatively important gases. The substrate that appeared to have the best prebiotic effect in vitro was branched chain fructo-oligosaccharide (FOS), followed by oligofructose, Actilight and maltodextrin which each exerted a similar effect. The substrate with the least bifidogenic effect was levan.

CONCLUSIONS

The composition and total gas generation data showed that there was much variation between and within donor inocula. Generally, the lower gas producers had a more selective fermentation whilst larger gas producers were less specific.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study of these three parameters enabled a more complete picture of carbohydrate breakdown to be drawn and hence highlighted the need for potential prebiotics to be more extensively evaluated in order to reduce negative side-effects such as gas distension.

Carbohydrate fractions of legumes: uses in human nutrition and potential for health

Starch and fibre can be extracted, using wet or dry processes, from a variety of grain legumes and used as ingredients for food. alpha-Galactosides can be isolated during wet processes from the soluble extract. Starch isolates or concentrates are mostly produced from peas, whereas dietary fibre fractions from peas and soyabean are commercially available. The physico-chemical characteristics of fibre fractions very much depend on their origin, outer fibres being very cellulosic whereas inner fibres contain a majority of pectic substances. Inner fibres are often used as texturing agents whereas outer fibres find their main uses in bakery and extruded products, where they can be introduced to increase the fibre content of the food. Most investigations on impacts on health have been performed on soyabean fibres. When positive observations were made on lipaemia, glucose tolerance or faecal excretion, they were unfortunately often obtained after non-realistic daily doses of fibres. Legume starches contain a higher amount of amylose than most cereal or tuber starches. This confers these starches a lower bioavailability than that of most starches, when raw or retrograded. Their low glycaemic index can be considered as beneficial for health and especially for the prevention of diseases related to insulin resistance. When partly retrograded, these starches can provide significant amount of butyrate to the colonic epithelium and may help in colon cancer prevention. alpha-Galactosides are usually considered as responsible for flatus but their apparent prebiotic effects may be an opportunity to valorize these oligosaccharides.

Effect of pH and Dose on the Growth of Gut Bacteria on Prebiotic Carbohydrates in vitro

The effect of pH and substrate dose on the fermentation profile of a number of commercial prebiotics was analysed in triplicate using stirred, pH and temperature controlled anaerobic batch culture fermentations, inoculated with a fresh faecal slurry from one of three healthy volunteers. Bacterial numbers were enumerated using fluorescence in situ hybridisation. The commercial prebiotics investigated were fructooligosaccharides (FOS), inulin, galactooligosaccharides (GOS), isomaltooligosaccharides (IMO) and lactulose. Two pH values were investigated, i.e. pH 6 and 6.8. Doses of 1% and 2% (w/v) were investigated, equivalent to approximately 4 and 8 g per day, respectively, in an adult diet. It was found that both pH and dose altered the bacterial composition. It was observed that FOS and inulin demonstrated the greatest bifidogenic effect at pH 6.8 and 1% (w/v) carbohydrate, whereas GOS, IMO and lactulose demonstrated their greatest bifidogenic effect at pH 6 and 2% (w/v) carbohydrate. From this we can conclude that various prebiotics demonstrate differing bifidogenic effects at different conditions in vitro.

Cholesterol assimilation by lactic acid bacteria and bifidobacteria isolated from the human gut

The objective of this study was to evaluate the effect of human gut-derived lactic acid bacteria and bifidobacteria on cholesterol levels in vitro. Continuous cultures inoculated with fecal material from healthy human volunteers with media supplemented with cholesterol and bile acids were used to enrich for potential cholesterol assimilators among the indigenous bacterial populations. Seven potential probiotics were found: Lactobacillus fermentum strains F53 and KC5b, Bifidobacterium infantis ATCC 15697, Streptococcus bovis ATCC 43143, Enterococcus durans DSM 20633, Enterococcus gallinarum, and Enterococcus faecalis. A comparative evaluation regarding the in vitro cholesterol reduction abilities of these strains along with commercial probiotics was undertaken. The degree of acid and bile tolerance of strains was also evaluated. The human isolate L. fermentum KC5b was able to maintain viability for 2 h at pH 2 and to grow in a medium with 4,000 mg of bile acids per liter. This strain was also able to remove a maximum of 14.8 mg of cholesterol per g (dry weight) of cells from the culture medium and therefore was regarded as a candidate probiotic.

Long-term consumption of fermented dairy products over 6 months increases HDL cholesterol

OBJECTIVE

Assessment of the hypocholesterolaemic effect of yoghurt supplemented with Lactobacillus acidophilus 145 and Bifidobacterium longum 913 in women.

DESIGN

The cross-over study consisted of three periods (7 weeks each): first period, control yoghurt for all 29 women; second period, probiotic yoghurt for 18 women, control yoghurt for 11 women; third period, the reverse of that in the second period.

SETTING

Department of Nutritional Physiology, Institute of Nutritional Science, Friedrich Schiller University, Jena.

SUBJECTS

Twenty-nine healthy women, aged 19-56 y. Fifteen of these were normocholesterolaemic and 14 women were hypercholesterolaemic.

INTERVENTION

Yoghurt (300 g) daily containing 3.5% fat and starter cultures of Streptococcus thermophilus and L. lactis. Probiotic yoghurt was the control yoghurt enriched with L. acidophilus 145, B. longum 913 and 1% oligofructose (synbiotic).

RESULTS

The mean serum concentration of total cholesterol and the LDL cholesterol was not influenced by the synbiotic (P>0.05). The HDL concentration increased significantly by 0.3 mmol/l (P=0.002). The ratio of LDL/HDL cholesterol decreased from 3.24 to 2.48 (P=0.001).

CONCLUSIONS

The long-term daily consumption of 300 g yoghurt over a period of 21 weeks (control and synbiotic) increased the serum concentration of HDL cholesterol and lead to the desired improvement of the LDL/HDL cholesterol ratio.

Prebiotics and lipid metabolism

Prebiotics are defined as nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth or the activity of one or a limited number of bacteria (bifidobacteria, lactobacilli) in the colon. Dietary fructans are nutritionally interesting oligosaccharides that strictly conform to the definition of prebiotics and (in view of experimental studies in animals and of less numerous studies in humans) exhibit interesting serum or hepatic lipid lowering properties. Other nondigestible/fermentable nutrients, which also modulate intestinal flora activity, exhibit cholesterol or triglyceride lowering effects. Are changes in intestinal bacterial flora composition or fermentation activity responsible for those effects? What is the future of prebiotics in the nutritional control of lipidaemia and cardiovascular disease risk in humans? Those questions only receive partial response in the present review because studies of the systemic effects of prebiotics are still in their infancy, and require fundamental research devoted to elucidating the biochemical and physiological events that allow prebiotics to exert systemic effects on lipid metabolism.

Invited review: the scientific basis of Lactobacillus acidophilus NCFM functionality as a probiotic

Lactobacillus acidophilus NCFM is a probiotic strain available in conventional foods (milk, yogurt, and toddler formula) and dietary supplements. Its commercial availability in the United States since the mid-1970s is predicated on its safety, its amenability to commercial manipulation, and its biochemical and physiological attributes presumed to be important to human probiotic functionality. The strain has been characterized in vitro, in animal studies, and in humans. NCFM is the progenitor of the strain being used for complete chromosome sequencing and therefore will be a cornerstone strain for understanding the relationship between genetics and probiotic functionality. Both phenotypic and genotypic techniques have verified its taxonomic status as a type A1 L. acidophilus strain. It adheres to Caco-2 and mucus-secreting HT-29 cell culture systems, produces antimicrobial compounds, and is amenable to genetic manipulation and directed DNA introduction. NCFM survives gastrointestinal tract transit in both healthy and diseased populations. NCFM inhibits aberrant crypt formation in mutagenized rats, indicative of activity that could decrease the risk of colon cancer. A blend of probiotic strains containing NCFM decreased the incidence of pediatric diarrhea. NCFM led to a significant decrease in levels of toxic amines in the blood of dialysis patients with small bowel bacterial overgrowth. At adequate daily feeding levels, NCFM may facilitate lactose digestion in lactose-intolerant subjects. Further validation of the probiotic properties of NCFM in humans and clarification of its mechanisms of probiotic action are needed to better understand the role this strain might play in promoting human health.