The effect of fermented and unfermented milks on serum cholesterol

Exploring the Cholesterol-Modifying Abilities of Lactobacilli Cells in Digestive Models and Dairy Products

This study aimed to investigate the ability of lactic acid bacteria to remove cholesterol in simulated gastric and intestinal fluids. The findings showed that the amount of cholesterol removed was dependent on the biomass, viability, and bacterial strain. Some cholesterol binding was stable and not released during gastrointestinal transit. The presence of cholesterol affected the fatty acid profile of bacterial cells, potentially influencing their metabolism and functioning. However, adding cholesterol did not significantly impact the survival of lactic acid bacteria during gastrointestinal transit. Storage time, passage, and bacterial culture type did not show significant effects on cholesterol content in fermented dairy products. Variations in cell survival were observed among lactic acid bacteria strains in simulated gastric and intestinal fluids, depending on the environment. Higher milk protein content was found to be more protective for bacterial cells during gastrointestinal transit than fat content. Future research should aim to better understand the impact of cholesterol on lactic acid bacteria metabolism and identify potential health benefits.

Evidence for a causal association between milk intake and cardiometabolic disease outcomes using a two-sample Mendelian Randomization analysis in up to 1,904,220 individuals

BACKGROUND

High milk intake has been associated with cardio-metabolic risk. We conducted a Mendelian Randomization (MR) study to obtain evidence for the causal relationship between milk consumption and cardio-metabolic traits using the lactase persistence (LCT-13910 C > T, rs4988235) variant as an instrumental variable.

METHODS

We tested the association of LCT genotype with milk consumption (for validation) and with cardio-metabolic traits (for a possible causal association) in a meta-analysis of the data from three large-scale population-based studies (1958 British Birth Cohort, Health and Retirement study, and UK Biobank) with up to 417,236 participants and using summary statistics from consortia meta-analyses on intermediate traits (N = 123,665-697,307) and extended to cover disease endpoints (N = 86,995-149,821).

RESULTS

In the UK Biobank, carriers of 'T' allele of LCT variant were more likely to consume milk (P = 7.02 × 10^-14). In meta-analysis including UK Biobank, the 1958BC, the HRS, and consortia-based studies, under an additive model, 'T' allele was associated with higher body mass index (BMI) (P_{meta-analysis} = 4.68 × 10^-12) and lower total cholesterol (TC) (P = 2.40 × 10^-36), low-density lipoprotein cholesterol (LDL-C) (P = 2.08 × 10^-26) and high-density lipoprotein cholesterol (HDL-C) (P = 9.40 × 10^-13). In consortia meta-analyses, 'T' allele was associated with a lower risk of coronary artery disease (OR:0.86, 95% CI:0.75-0.99) but not with type 2 diabetes (OR:1.06, 95% CI:0.97-1.16). Furthermore, the two-sample MR analysis showed a causal association between genetically instrumented milk intake and higher BMI (P = 3.60 × 10^-5) and body fat (total body fat, leg fat, arm fat and trunk fat; P < 1.37 × 10^-6) and lower LDL-C (P = 3.60 × 10^-6), TC (P = 1.90 × 10^-6) and HDL-C (P = 3.00 × 10^-5).

CONCLUSIONS

Our large-scale MR study provides genetic evidence for the association of milk consumption with higher BMI but lower serum cholesterol levels. These data suggest no need to limit milk intakes with respect to cardiovascular disease risk, with the suggested benefits requiring confirmation in further studies.

Effects of probiotics and prebiotics on blood lipids

Since the early work of Mann and Spoerry, probiotics in the form of fermented milk products have been reputed to have cholesterol-lowering properties in humans. However, studies conducted since the early 1970s have produced equivocal findings, with interpretation of the outcomes complicated by use of excessive quantities of product, inadequate sample sizes, failure to control nutrient intake and energy expenditure and variations in baseline blood lipids. More recent studies are of better quality, but fail to provide convincing evidence that ‘live’ fermented milk products have cholesterol-lowering efficacy in man. Future studies using probiotics should ensure adequate sample sizes sufficient to detect relatively small changes in blood cholesterol and should be conducted over longer periods of time. The recent introduction of the concept of prebiotics has directed attention towards the possibility that alterations in gut microflora induced by the fermentation of non-digestible components of the diet may also have the potential to influence systemic lipid metabolism. This possibility has been strengthened by the observation that in animals, dietary oligofructosaccharides cause suppression of hepatic triglyceride and VLDL synthesis, resulting in marked reductions in triglyceride, and to a lesser extent cholesterol, levels. Evidence for similar effects in humans is sparse and more studies are needed, particularly with respect to effects on postprandial triglyceride concentrations.

Effects of Prebiotic and Synbiotic Supplementation on Glycaemia and Lipid Profile in Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials

Purpose: Diabetes Mellitus (T2DM) as a chronic disease, is on rise in parallel with other non-communicable diseases. Several studies have shown that probiotics and prebiotics might exert beneficial effects in chronic diseases including diabetes. Because of controversial results from different trials, the present study aims to assess the effects of prebiotic/synbiotic consumption on metabolic parameters in patients with type2 diabetes. Methods: A systematic literature search was performed on randomized controlled trial published in PubMed/Medline, SciVerse Scopus, Google scholar, SID and Magiran up to March 2018. Of a total number of 255 studies found in initial literature search, ten randomized controlled trials were included in the meta-analysis. The pooled mean net change were calculated in fasting blood-glucose [FBG], Hemoglobin A1c [HbA1c] and lipid markers (total cholesterol [TC], triglyceride [TG], low-density lipoprotein cholesterol [LDL-C], high density lipoprotein cholesterol [HDL-C]). The meta-analyses was conducted using Revman Software (v5.3). Results: The pooled estimate indicated a significant difference for the mean change in FBG, HbA1c and HDL in treatment group in comparison with control group. Subgroup analysis by intervention showed a significant difference in TG, LDL and HDL (synbiotic group) and in TG, TC, FBG, HDL and HbA1c (prebiotic group) compared with placebo. In another subgroup analysis, high quality studies showed significant reductions in TG, TC, FBG and HbA1c in intervention group compared with placebo group. Conclusion: In summary, diets supplemented with either prebiotics or synbiotics can result in improvements in lipid metabolism and glucose homeostasis in type 2 diabetic patients.

Effect of ewe's (semi-skimmed and whole) and cow's milk yogurt consumption on the lipid profile of control subjects: a crossover study

Yogurt is the most widely consumed fermented milk product worldwide. Studies have mainly used milk and dairy products from cow, which have a lower fat content than those from ewe and a different lipid profile. This study investigated the effect on the lipid profile of control subjects of three different set yogurts: (a) semi-skimmed ewe´s milk yogurt (2.8% milk fat); (b) whole ewe´s milk yogurt (5.8 % milk fat); (c) cow´s milk yogurt (3 % milk fat). A randomized crossover study included 30 healthy adults (16 women) to consume 250 g/yogurt/day during three consecutive 5-weeks periods separated by 4-week washouts. Blood samples were collected at the start and end of each period for the analysis of serum cholesterol (total, HDL-, LDL-) and triglycerides. We found no differences in the serum concentrations of lipid and lipoprotein fractions of the volunteers after the intake of any of the three types of yogurts. When the volunteers were grouped into two risk groups of risk according to their total cholesterol/HDL cholesterol ratio, the same differences between the groups in terms of the cholesterol (HDL-, LDL-) and triglyceride responses at baseline and after yogurt intake were found, with no effects due to the different types of yogurts. Moreover, we performed compositional analysis of the yogurts including determination of protein, fat, minerals and fatty acids (FA). Contents in protein, calcium, magnesium, non-protein nitrogen and some FA (mainly short-chain-FA) were higher for ewe's than for cow's milk yogurt. n6-n3 ratio was lower in the ewe's milk yogurt. In conclusion, yogurt intake, from ewe's and cow's milk, at levels of consumption compatible with a varied diet, neither decreases nor increases plasma lipoprotein cholesterol levels in apparently healthy individuals. As ewe's milk yogurt has a high content of macro- and micronutrients, certain target populations could benefit from its consumption.

Regular-Fat Dairy and Human Health: A Synopsis of Symposia Presented in Europe and North America (2014-2015)

In recent history, some dietary recommendations have treated dairy fat as an unnecessary source of calories and saturated fat in the human diet. These assumptions, however, have recently been brought into question by current research on regular fat dairy products and human health. In an effort to disseminate, explore and discuss the state of the science on the relationship between regular fat dairy products and health, symposia were programmed by dairy industry organizations in Europe and North America at The Eurofed Lipids Congress (2014) in France, The Dairy Nutrition Annual Symposium (2014) in Canada, The American Society for Nutrition Annual Meeting held in conjunction with Experimental Biology (2015) in the United States, and The Federation of European Nutrition Societies (2015) in Germany. This synopsis of these symposia describes the complexity of dairy fat and the effects regular-fat dairy foods have on human health. The emerging scientific evidence indicates that the consumption of regular fat dairy foods is not associated with an increased risk of cardiovascular disease and inversely associated with weight gain and the risk of obesity. Dairy foods, including regular-fat milk, cheese and yogurt, can be important components of an overall healthy dietary pattern. Systematic examination of the effects of dietary patterns that include regular-fat milk, cheese and yogurt on human health is warranted.

Fragmented Lactic Acid Bacterial Cells Activate Peroxisome Proliferator-Activated Receptors and Ameliorate Dyslipidemia in Obese Mice

Recent studies suggest that peroxisome proliferator-activated receptor (PPAR) activation ameliorates metabolic disorders, including dyslipidemia. To identify an effective PPAR agonist, we screened the in vitro PPARα/γ activation ability of organic solvent extracts from food-oriented bacterial strains belonging to 5 genera and 32 species, including lactic acid bacteria, and of these, Lactobacillus amylovorus CP1563 demonstrated the highest PPARα/γ agonist activity. We also found that physical fragmentation of the strain could substitute organic solvent extraction for the expression of CP1563 activity in vitro. For functional food manufacturing, we selected the fragmented CP1563 and conducted subsequent animal experiments. In an obese mouse model, we found that treatment with fragmented CP1563 for 12 weeks decreased the levels of low-density lipoprotein (LDL)-cholesterol and triglyceride in plasma, significantly decreased the atherosclerosis index, and increased the plasma high-density lipoprotein (HDL)-cholesterol level. Thus, we conclude that fragmented CP1563 may be a candidate for the prevention and treatment of dyslipidemia.

The scale of the evidence base on the health effects of conventional yogurt consumption: findings of a scoping review

BACKGROUND

The health effects of conventional yogurt have been investigated for over a century; however, few systematic reviews have been conducted to assess the extent of the health benefits of yogurt.

OBJECTIVE

The aim of this scoping review was to assess the volume of available evidence on the health effects of conventional yogurt.

METHODS

The review was guided by a protocol agreed a priori and informed by an extensive literature search conducted in November 2013. Randomized controlled trials were selected and categorized according to the eligibility criteria established in the protocol.

RESULTS

213 studies were identified as relevant to the scoping question. The number of eligible studies identified for each outcome were: bone health (14 studies), weight management and nutrition related health outcomes (81 studies), metabolic health (6 studies); cardiovascular health (57 studies); gastrointestinal health (24 studies); cancer (39 studies); diabetes (13 studies), Parkinson's disease risk (3 studies), all-cause mortality (3 studies), skin complaints (3 studies), respiratory complaints (3 studies), joint pain/function (2 studies); the remaining 8 studies reported a variety of other outcomes. For studies of a similar design and which assessed the same outcomes in similar population groups, we report the potential for the combining of data across studies in systematic reviews.

CONCLUSIONS

This scoping review has revealed the extensive evidence base for many outcomes which could be the focus of systematic reviews exploring the health effects of conventional yogurt consumption.

Is consuming yoghurt associated with weight management outcomes? Results from a systematic review

Background:

Yoghurt is part of the diet of many people worldwide and is commonly recognised as a ‘health food'. Epidemiological studies suggest that yoghurt may be useful as part of weight management programs. In the absence of comprehensive systematic reviews, this systematic review investigated the effect of yoghurt consumption by apparently healthy adults on weight-related outcomes.

Methods:

An extensive literature search was undertaken, as part of a wider scoping review, to identify yoghurt studies. A total of 13 631 records were assessed for their relevance to weight-related outcomes.

Results:

Twenty-two publications were eligible according to the review protocol. Cohort studies (n=6) and cross-sectional studies (n=7) all showed a correlation between yoghurt and lower or improved body weight/composition. Six randomised controlled trials (RCTs) and one controlled trial had various limitations, including small size and short duration. One RCT showed significant effects of yoghurt on weight loss, but was confounded by differences in calcium intake. One trial showed nonsignificant weight gain and the remaining five trials showed nonsignificant weight losses that were greater in yoghurt consumers.

Conclusions:

Yoghurt consumption is associated with lower body mass index, lower body weight/weight gain, smaller waist circumference and lower body fat in epidemiological studies. RCTs suggest weight reduction effects, but do not permit determination of a cause–effect relationship. Well-controlled, adequately powered trials in research and community settings appear likely to identify a modest but beneficial effect of yoghurt consumption for prevention of weight gain and management of obesity. The ready availability of yoghurt (a nutrient-dense food) and its ease of introduction to most diets suggests that educating the public to eat yoghurt as part of a balanced and healthy diet may potentially contribute to improved public health. Future carefully designed RCTs could provide proof of principle and large community-based studies could determine the practical impact of yoghurt on body weight/composition.

Impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol homeostasis in men and women

BACKGROUND AND AIMS

Sphingolipids (SL) are important components of the milk fat globule membrane (MFGM) found in buttermilk. While studies in animal models suggest that dietary SL may have cholesterol-lowering properties, data in human are lacking. The aim of this study was to investigate the impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol (C) homeostasis in humans.

METHODS AND RESULTS

Men and women (n = 34) with serum LDL-C <5.0 mmol/L at screening (mean LDL-C = 3.8 mmol/L) were recruited in this double-blinded randomized crossover placebo controlled study. Their diets were supplemented with 45 g/d of buttermilk and with 45 g/d of a macro/micronutrient matched placebo (4 weeks each in random order). Serum lipid concentrations and surrogate markers of cholesterol homeostasis were measured post diet and compared using mixed models for repeated measures. Consumption of buttermilk led to reduction in serum cholesterol (-3.1%, P = 0.019), LDL-C (-3.1%, P = 0.057) and triacylglycerol (-10.7%, P = 0.007). Buttermilk consumption increased plasma lathosterol concentrations (+12.1%, P = 0.001), but multiple regression analysis indicated that variations in β-sitosterol concentrations (P = 0.002) were the only significant predictor of the LDL-C response to buttermilk consumption.

CONCLUSION

Buttermilk consumption may be associated with reduced cholesterol concentrations in men and women, primarily through inhibition of intestinal absorption of cholesterol.

REGISTRATION NUMBER

This trial is registered at clinicaltrials.gov as NCT01248026.

Alteration of the intestinal microbiome: fecal microbiota transplant and probiotics for Clostridium difficile and beyond

Clostridium difficile infection is increasingly common with a high risk of recurrence despite antibiotic treatment. In cases of recurrent C. difficile infection, fecal microbiota transplant (FMT) is a highly effective treatment option promoting the restoration of normal gut microbiota. Furthermore, preliminary uncontrolled evidence demonstrates possible benefit of FMT in the management of some cases of inflammatory bowel disease and chronic constipation. In addition to presenting an overview of FMT, we discuss the role of probiotics, a more common approach to modifying the intestinal microbiome. Probiotics have been utilized broadly for many disease processes, including gastrointestinal, cardiovascular and allergic disease settings, although with limited and inconsistent results. Multiple potential areas for research are also identified.

Biomarkers of dairy intake and the risk of heart disease

BACKGROUND AND AIMS

Despite their relatively high content of saturated fat, studies of dairy product intake and the risk of cardiovascular disease have often yielded null or inverse results. The use of fatty acid biomarkers to reflect dairy intake could elucidate this association. This study aims to evaluate the association between dairy intake, assessed by adipose pentadecanoic (15:0) and heptadecanoic (17:0) fatty acids and food frequency questionnaire (FFQ), and the risk of nonfatal myocardial infarction (MI), in a matched case-control study of Costa Rican adults (n=3630).

METHODS AND RESULTS

The association was examined using conditional logistic regression, adjusted for potential confounders. The associations of adipose tissue 15:0 and 17:0 with the risk of MI were not statistically significant (for 15:0: multivariate-adjusted OR for 5th quintile vs. 1st=1.14 (95% CI=0.85, 1.53), p-value for linear trend=0.77; for 17:0: multivariate-adjusted OR for 5th quintile vs. 1st=1.15 (95% CI=0.88, 1.51), p-value for linear trend=0.18). The association between the FFQ measure of dairy intake and MI showed evidence of a possible threshold effect, with a protective association observed for all but the top quintile of the exposure distribution.

CONCLUSION

Dairy product intake as assessed by adipose tissue 15:0, 17:0, and by FFQ is not associated with a linear increase in the risk of MI in the study population. It is possible that the adverse effect of saturated fat in dairy products on cardiovascular health is offset by presence of beneficial nutrients.

Influence of dairy product and milk fat consumption on cardiovascular disease risk: a review of the evidence

Although evidence has linked the consumption of saturated fat (SF) to increased LDL levels and an increased risk of the development of cardiovascular disease (CVD), recent findings have indicated that the link between CVD and SF may be less straightforward than originally thought. This may be due to the fact that some food sources high in SF contain an array of saturated and unsaturated fatty acids, each of which may differentially affect lipoprotein metabolism, as well as contribute significant amounts of other nutrients, which may alter CVD risk. The purpose of this review is to examine the published research on the relationship between milk fat containing dairy foods and cardiovascular health. The findings indicate that the majority of observational studies have failed to find an association between the intake of dairy products and increased risk of CVD, coronary heart disease, and stroke, regardless of milk fat levels. Results from short-term intervention studies on CVD biomarkers have indicated that a diet higher in SF from whole milk and butter increases LDL cholesterol when substituted for carbohydrates or unsaturated fatty acids; however, they may also increase HDL and therefore might not affect or even lower the total cholesterol:HDL cholesterol ratio. The results from the review also indicate that cheese intake lowers LDL cholesterol compared with butter of equal milk fat content. In addition, the review highlights some significant gaps in the research surrounding the effects of full-fat dairy on CVD outcomes, pointing to the need for long-term intervention studies.

Dairy Products in the Food Chain: Their Impact on Health

Milk is a complex and complete food containing an array of essential nutrients that contribute toward a healthy, balanced diet. Numerous epidemiological studies have revealed that high consumption of milk and dairy products may have protective effects against coronary heart disease (CHD), stroke, diabetes, certain cancers (such as colorectal and bladder cancers), and dementia, although the mechanisms of action are unclear. Despite this epidemiological evidence, milk fatty acid profiles often lead to a negative perception of milk and dairy products. However, altering the fatty acid profile of milk by changing the dairy cow diet is a successful strategy, and intervention studies have shown that this approach may lead to further benefits of milk/dairy consumption. Overall, evidence suggests individuals who consume a greater amount of milk and dairy products have a slightly better health advantage than those who do not consume milk and dairy products.

The hypocholesterolaemic effects of Lactobacillus acidophilus American type culture collection 4356 in rats are mediated by the down-regulation of Niemann-Pick C1-like 1. Br J Nutr. 2010;104:807-812. [PMID: 20441669 DOI: 10.1017/S0007114510001285]

The objective of the present study was to evaluate the effect of Lactobacillus acidophilus 4356 on cholesterol metabolism in vivo. Rats were fed a cholesterol-enriched experimental diet with or without L. acidophilus 4356 supplementation at a dose of 10(9) colony-forming units per d. L. acidophilus 4356 feeding significantly lowered total serum cholesterol, LDL-cholesterol and TAG concentrations, but there was no change in the serum HDL-cholesterol concentrations. In addition, total liver cholesterol and TAG were decreased in the L. acidophilus 4356-fed group. The expression of Niemann-Pick C1-Like 1 (NPC1L1) in the duodenum and jejunum was significantly decreased following L. acidophilus 4356 feeding. Lactobacillus acidophilus 4356 increased the population of lactobacilli and bifidobacteria in the small intestine and faeces compared with the control. These results indicate that the probiotic potential of the L. acidophilus 4356 strain in the control of cholesterol is at least partially mediated by the down-regulation of NPC1L1. Furthermore, these results also potentially suggest a new mechanism that is responsible for the cholesterol-reducing effects of probiotics.

Effects of Lactobacillus plantarum MA2 isolated from Tibet kefir on lipid metabolism and intestinal microflora of rats fed on high-cholesterol diet

The objective of this study was to evaluate the effects of Lactobacillus plantarum MA2, an isolate from Chinese traditional Tibet kefir, on cholesterol-lowering and microflora of rat in vivo. Rats were fed on cholesterol-enriched experimental diet, supplemented with lyophilized L. plantarum MA2 powder, with a dose of 10(11) cells/day per mice. The results showed that L. plantarum MA2 feeding significantly lowered serum total cholesterol, low-density lipoprotein cholesterol, and triglycerides level, while there was no change in high-density lipoprotein cholesterol. In addition, liver total cholesterol and triglycerides was also decreased. However, fecal cholesterol and triglycerides was increased significantly (P < 0.05) in comparison with the control. Also, L. plantarum MA2 increased the population of lactic acid bacteria and bifidobacteria in the fecal, but it did not change the number of Escherichia coli as compared to control. Moreover, pH, moisture, and organic acids in the fecal were also measured. The present results indicate the probiotic potential of the L. plantarum MA2 strain in hypocholesterolemic effect and also increasing the probiotic count in the intestine.

The survival advantage of milk and dairy consumption: an overview of evidence from cohort studies of vascular diseases, diabetes and cancer

OBJECTIVES

To conduct a detailed evaluation, with meta-analyses, of the published evidence on milk and dairy consumption and the incidence of vascular diseases and diabetes. Also to summarise the evidence on milk and dairy consumption and cancer reported by the World Cancer Research Fund and then to consider the relevance of milk and dairy consumption to survival in the UK, a typical Western community. Finally, published evidence on relationships with whole milk and fat-reduced milks was examined.

METHODS

Prospective cohort studies of vascular disease and diabetes with baseline data on milk or dairy consumption and a relevant disease outcome were identified by searching MEDLINE, and reference lists in the relevant published reports. Meta-analyses of relationships in these reports were conducted. The likely effect of milk and dairy consumption on survival was then considered, taking into account the results of published overviews of relationships of these foods with cancer.

RESULTS

From meta-analysis of 15 studies the relative risk of stroke and/or heart disease in subjects with high milk or dairy consumption was 0.84 (95% CI 0.76, 0.93) and 0.79 (0.75, 0.82) respectively, relative to the risk in those with low consumption. Four studies reported incident diabetes as an outcome, and the relative risk in the subjects with the highest intake of milk or diary foods was 0.92 (0.86, 0.97).

CONCLUSIONS

Set against the proportion of total deaths attributable to the life-threatening diseases in the UK, vascular disease, diabetes and cancer, the results of meta-analyses provide evidence of an overall survival advantage from the consumption of milk and dairy foods.

Different effects of whole milk and a fermented milk with the same fat and lactose content on gastric emptying and postprandial lipaemia, but not on glycaemic response and appetite

Longitudinal studies indicate that milk and fermented milk products lower basal plasma cholesterol concentrations, despite their high content of saturated fat, and therefore have favourable health effects. However, there have been few studies on the postprandial effects of milk products. The present study compared the effect of whole milk with a fermented milk, A-38, on postprandial carbohydrate and lipid metabolism, gastric emptying and appetite. Eight healthy young men participated. On the two test days, they arrived fasting for collection of baseline values before consuming the meals, which for a 75 kg subject consisted of 1·4 litre milk or fermented milk, plus 165 mg [13C]acetate (for later determination of gastric emptying by a [13C]acetate breath test). Lactose (15 g) was added to the A-38 meal to equalize the lactose content. Postprandially the A-38 meal resulted in a slower gastric emptying rate than milk (P>0·001). Furthermore, the A-38 meal resulted in a greater increase and a quicker decrease of the triacylglycerol content in all lipoprotein fractions (LDL-fraction,P>0·05; other fractions,P>0·001) and of the gastrointestinal hormones (cholecystokinin and peptide YY,P>0·05; gastric inhibitory polypeptide and glucagon-like polypeptide-1,P>0·001). There were no significant differences in appetite sensations (measured by visual analogue scale) or in the glucose and insulin response (P<0·10). The slower emptying rate of the liquid phase after the A-38 meal is probably due to the higher viscosity of A-38. The lower and more prolonged triacylglycerol response after the milk meal might be caused by coagulation of milk in the stomach.

Effects of a Lactobacillus casei Synbiotic on Serum Lipoprotein, Intestinal Microflora, and Organic Acids in Rats

The main aim of this study was to evaluate the effectiveness of 3 synbiotic diets: 1) containing Lactobacillus casei ASCC 292 and fructooligosaccharides (LF diet); 2) containing L. casei ASCC 292 and maltodextrin (LM diet); and 3) containing L. casei ASCC 292, fructooligosaccharide, and maltodextrin (LFM diet) to reduce serum cholesterol in male Wistar rats. The effect of the synbiotic diets on intestinal microflora, concentration of organic acids, and the possibility of translocation of lactobacilli were also investigated. The LFM diet lowered serum total cholesterol and triglyceride levels, whereas the LM diet increased serum high-density lipoprotein cholesterol level. However, synbiotic diets did not contribute to a change in low-density lipoprotein cholesterol level compared with the control diet. There was a decrease in the population of staphylococci, bacteroides, Escherichia coli, and total coliforms in most bowel regions with the LFM diet compared with the control (which did not contain any synbiotic). In general, the LFM diet contributed to a higher concentration of lactic acid that may have contributed to the decrease in the population of pathogenic microorganisms compared with the control. Fructooligosaccharide was the preferred substrate for production of acetic acid. Results from this study showed that the synbiotic diet that contained L. casei ASCC 292, fructooligosaccharide, and maltodextrin beneficially altered cholesterol levels and produced a healthier bowel microbial population without translocation of lactobacilli to other organs.

Dairy products and cardiovascular disease

PURPOSE OF REVIEW

Although it has often been postulated that the consumption of dairy products is associated with a high risk of coronary heart disease, study results have been conflicting. This review summarizes recent observational and human intervention trial findings on dairy products and cardiovascular disease.

RECENT FINDINGS

Results from more recent observational studies on dairy products and milk disagree. This may be because of the very different methods used combined with several methodological problems. A somewhat surprising beneficial association between the intake of dairy products and the metabolic syndrome was observed in some studies, although not in a single study of elderly women. Milk may have the same cholesterol-raising properties as butter, whereas cheese does not seem to increase plasma cholesterol. Some milk products fermented by specific bacterial strains have been shown to have rather moderate cholesterol-reducing properties. There is also good evidence that certain fermented products (especially by Lactobacillus helveticus) have a mildly decreasing effect on hypertension, probably because of bioactive peptides.

SUMMARY

When guiding principles such as balance, variety and moderation are stressed, there is no strong evidence that dairy products increase the risk of coronary heart disease in healthy men of all ages or young and middle-aged healthy women. Human studies should investigate the role of dairy products with respect to sex and age by including classic and novel risk markers of coronary heart disease. Specific fermented milks may be beneficial in the future prevention of hypertension. The beneficially neutral effect of cheese on coronary heart disease risk factors should be elucidated further.

Fermented mushroom milk-supplemented dietary fibre prevents the onset of obesity and hypertriglyceridaemia in Otsuka Long-Evans Tokushima fatty rats

AIM

Fermented milk product containing edible mushroom water extracts (mushroom yogurt; MY) has been reported to have glycaemic control and triglyceride-lowering effects in streptozotocin (STZ)-induced diabetic rats and Zucker diabetic fatty (ZDF) rats. Here, we investigated how MY-supplemented dietary fibre (10 and 20%, v/w) influences the onset of obesity and hypertriglyceridaemia in Otsuka Long-Evans Tokushima fatty (OLETF) rats.

METHODS

The OLETF rats were fed a powdered chow diet supplemented with MY at the levels of 10 (v/w) and 20% for 6 weeks from 10 weeks of age, but the OLETF control rats were not supplemented. Their weight, fat distribution and lipid profile have been determined.

RESULTS

The body weights in MY-fed rats were reduced compared with the control rats. The perirenal fat was decreased in both MY groups, but the visceral and epididymal fats reduced only in the MY 20% group. The concentrations of serum triglyceride and non-esterified fatty acid in MY-fed rats were decreased in a dose-dependent manner. However, the levels of other serum lipid profiles [total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol] were comparable among all rats.

CONCLUSION

Anti-obesity and triglyceride lowering by MY-supplemented dietary fibre in OLETF rats might have resulted from the synergistic effect of components in the fermented mushroom-milk product.

A double-blind placebo-controlled study of the effects of Lactobacillus acidophilus on plasma lipids

OBJECTIVE

To select a probiotic bacteria that would reduce serum lipids in hypercholesterolaemic volunteers.

DESIGN

A strain of lactobacillus was selected for its ability to metabolise cholesterol under varying conditions in vitro. Freeze-dried Lactobacillus acidophilus or placebo were then given in a double-blind randomised crossover study to volunteers with high cholesterols.

SUBJECTS

A total of 80 volunteers with elevated cholesterols.

INTERVENTIONS

Volunteers were randomly allocated to receive either two capsules containing freeze-dried L. acidophilus 3 x 10(10) CFU or placebo three times a day for 6 weeks. After a 6-week washout period, volunteers were crossed over to another 6 weeks of capsules. Serum lipids were measured at the beginning and end of each interventional period.

RESULTS

L. acidophilus was able to reduce cholesterol and survive in an acid and bile environment. No changes in anthropomorphic measurements or in dietary records were seen between the baseline and final records or between the two sets of baseline records. There were no changes in serum lipids seen throughout the study.

CONCLUSION

Despite the ability in vitro for L. acidophilus to reduce cholesterol, no effect was seen in volunteers.

Cholesterol-lowering effects of bovine serum immunoglobulin in participants with mild hypercholesterolemia

BACKGROUND

The consumption of milk products has been shown to lower cholesterol. The mechanism of action surrounding this observation has been attributed to the protein fraction of milk and serum.

OBJECTIVE

We examined the effect of an oral serum bovine immunoglobulin protein fraction (bIg) derived from US Department of Agriculture-approved beef (aged <30 mo) on lipid indexes in humans.

DESIGN

Participants included men and women (aged 25-70 y) with hypercholesterolemia (5.44-6.99 mmol/L) who were not receiving cholesterol-lowering medication. Treatment consisted of the randomized, double-blind, parallel-group, placebo-controlled administration of 5 g bIg for 6 wk in 52 participants (n = 26 each in treatment and control groups).

RESULTS

Mean (+/-SD) total cholesterol (TC) at baseline was 6.33 +/- 0.1 mmol/L for bIg and 6.16 +/- 0.1 mmol/L for placebo. A repeated-measures multivariate analysis of covariance covaried for change in total energy and alcohol intake and Tukey's post hoc examination of our data showed that the bIg-treated group had a significant reduction in TC at 3 wk (5.98 +/- 0.5 mmol/L; P < 0.05) and 6 wk (5.97 +/- 0.7 mmol/L; P < 0.05). The concentration at 6 wk was significantly different from that in the placebo group (P < 0.05). This reduction was largely due to a decrease in LDL cholesterol in the bIg-treated group from baseline (4.12 +/- 0.6 mmol/L) at 3 wk (3.92 +/- 0.7 mmol/L, P < 0.05) and at 6 wk (3.84 +/- 0.6 mmol/L, P < 0.05); the 6-wk concentration differed significantly between the treatment and placebo groups (P < 0.05). We observed no significant changes in the placebo group or in any other lipid indexes or markers associated with hepatorenal or cardiovascular function.

CONCLUSION

Consumption of bIg appears to positively modulate the primary lipid indexes associated with cardiovascular disease.

Does Fat in Milk, Butter and Cheese Affect Blood Lipids and Cholesterol Differently?

OBJECTIVE

To compare the effects of isoenergetic amounts of milk, cheese and butter (adjusted to the same content of lactose and casein) on fasting and postprandial blood lipids and lipoproteins, and on postprandial glucose and insulin response.

DESIGN

The experiments were designed to provide 20% of total energy from dairy fat, as either whole milk, mean (+/-SD) 2164 (+/-97) g, butter 93 (+/-4) g, and hard cheese 305 (+/-45) g, which were served to 14 healthy young men for three periods of three weeks each, separated by washout periods, in a randomized, cross-over study with strictly controlled dietary intake. Fasting blood samples were taken at the end of the study periods. Measurements of the postprandial effect of the three different dairy test products (0.7 g of milk fat/kg body weight) were carried out on day 4 of each intervention period. Blood samples were taken before and at 2, 4, 6 and 8 hours following intake of the meals.

RESULTS

Fasting LDL cholesterol concentration was significantly higher after butter than cheese diet (p = 0.037), with a borderline significant difference in total cholesterol (p = 0.054) after the experimental periods of three weeks. Postprandial glucose showed a higher response after cheese diet than after milk diet (p = 0.010, diet x time interaction).

CONCLUSIONS

A different effect of fat in milk and butter could not be confirmed in this study. The moderately lower LDL cholesterol after cheese diet compared to butter diet should be investigated further.

Effects of milk products fermented by Bifidobacterium longum on blood lipids in rats and healthy adult male volunteers

The effects of milk products fermented by Bifidobacterium longum strain BL1, a probiotic strain, on blood lipids in rats and humans were studied. Rats were fed a cholesterol-enriched experimental diet, supplemented with lyophilized powders of 1) acid milk (control), 2) milk fermented with a mixed culture of ordinary yogurt starters composed of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (SL), and 3) bifidobacterium milk fermented with the probiotic B. longum strain BL1, respectively. The bifidobacterium milk feeding brought about significant lowering of the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, and triglycerides, in comparison with the control, while no change in high-density lipoprotein cholesterol concentration was observed. On the other hand, supplementation with SL milk resulted in only slight, nonsignificant decreases in serum lipid concentrations in comparison with the control. In the human study, 32 subjects with serum total cholesterol ranging from 220 to 280 mg/dl were randomly assigned to two treatments: 1) intake of a low-fat drinking yogurt prepared with ordinary yogurt starters composed of S. thermophilus and L. delbrueckii subsp. bulgaricus (P-group) and 2) intake of a low-fat drinking yogurt prepared with the two ordinary yogurt starters plus B. longum strain BL1 (B-group). After intake for 4 wk at 3 x 100 ml/day, reduction of serum total cholesterol was observed in approximately half of the B-group subjects; a particularly significant decrease in serum total cholesterol was found among subjects with moderate hypercholesterolemia (serum total cholesterol > 240 mg/dl). However, the serum lipid concentrations in the P-group subjects were almost stable during the experimental periods. The present results indicate the potential of the probiotic B. longum strain BL1 in serum lipid improvement.

Nutritional impact of pre- and probiotics as protective gastrointestinal organisms

The health benefits of pre- and probiotics have been the subject of increased research interests. These food supplements have been demonstrated to alter the pre-existing intestinal flora so as to provide an advantage to the host. This review focuses on the scientific evidence both for and against their role in promoting health and treating disease. Specific attention is turned to their effects on immunomodulation, lipid metabolism, cancer prevention, diarrhea, Helicobacter pylori, necrotizing enterocolitis, allergy, and inflammatory bowel disease.

Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial [ISRCTN10820810]

BACKGROUND

Fermented milk products have been shown to affect serum cholesterol concentrations in humans. Kefir, a fermented milk product, has been traditionally consumed for its potential health benefits but has to date not been studied for its hypocholesterolemic properties.

METHODS

Thirteen healthy mildly hypercholesterolemic male subjects consumed a dairy supplement in randomized crossover trial for 2 periods of 4 wk each. Subjects were blinded to the dairy supplement consumed. Blood samples were collected at baseline and after 4 wk of supplementation for measurement of plasma total, low-density lipoprotein, and high-density lipoprotein cholesterol and triglyceride concentrations, as well as fatty acid profile and cholesterol synthesis rate. Fecal samples were collected at baseline and after 2 and 4 wk of supplementation for determination of fecal short chain fatty acid level and bacterial content.

RESULTS

Kefir had no effect on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglyceride concentrations nor on cholesterol fractional synthesis rates after 4 wk of supplementation. No significant change on plasma fatty acid levels was observed with diet. However, both kefir and milk increased (p < 0.05) fecal isobutyric, isovaleric and propionic acids as well as the total amount of fecal short chain fatty acids. Kefir supplementation resulted in increased fecal bacterial content in the majority of the subjects.

CONCLUSIONS

Since kefir consumption did not result in lowered plasma lipid concentrations, the results of this study do not support consumption of kefir as a cholesterol-lowering agent.

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.

Effect of administration of Lactobacillus gasseri on serum lipids and fecal steroids in hypercholesterolemic rats

The effects of milk and nonfermented milks produced from Lactobacillus gasseri on serum lipids and total bile acids and fecal steroids and microflora were estimated in rats fed cholesterol-enriched diets. Lactobacilli decreased and coliforms increased in feces of the control group; however, the concentrations of fecal lactobacilli remained unchanged when rats were fed nonfermented milks. Fecal coliforms in rats receiving milk and nonfermented milk produced from L. gasseri SBT0270 increased, while rats receiving nonfermented milk produced from L. gasseri SBT0274 had lower fecal coliform count than did the control group. Only NFM-A significantly reduced serum total cholesterol and low-density lipoprotein (LDL) cholesterol, and bile acids. High-density lipoprotein (HDL) cholesterol was significantly decreased when rats were given milk and nonfermented milks. Milk and NFM-A lowered serum triglycerides levels. Milk and nonfermented milks did not affect the total neutral steroids, but higher levels of acidic steroid were detected in the feces than the control group. The results showed that the hypocholesterolemic effect of L. gasseri SBT0270 was attributed to its ability to suppress the reabsorption of bile acids into the enterohepatic circulation and to enhance the excretion of acidic steroids in feces of hypercholesterolemic rats.

Consumption of fermented and nonfermented dairy products: effects on cholesterol concentrations and metabolism

The objective of this article was to review existing literature concerning the effects and mechanisms of action of fermented dairy products on serum cholesterol concentrations. Although not without exception, existing evidence from animal and human studies suggests a moderate cholesterol-lowering action of fermented dairy products. Mechanistically, fermented milk has been shown to cause an increase in human gut bacterial content. These bacteria, once resident in the large intestine, are believed to ferment food-derived indigestible carbohydrates. Such fermentation causes increased production of short-chain fatty acids, which decreases circulatory cholesterol concentrations either by inhibiting hepatic cholesterol synthesis or by redistributing cholesterol from plasma to the liver. Furthermore, increased bacterial activity in the large intestine results in enhanced bile acid deconjugation. Deconjugated bile acids are not well absorbed by the gut mucosa and are excreted. Consequently, cholesterol, being a precursor of bile acids, is utilized to a greater extent for de novo bile acid synthesis. These actions combined are proposed as contributing mechanisms to the association of fermented milk consumption with decreased circulating cholesterol concentrations.

Effect of administration of fermented milk containing whey protein concentrate to rats and healthy men on serum lipids and blood pressure

The effect of fermented milk supplemented with whey protein concentrate on the serum lipid level of rats was investigated. The serum total cholesterol level for the group fed fermented milk with both Lactobacillus casei TMC0409 and Streptococcus thermophilus TMC 1543 was significantly lower than that of the control group (P<0.05) in rats. Furthermore, the effect of the longterm intake of this fermented milk on the serum lipid level of twenty healthy adult men was investigated. During the 8-wk study, the volunteers consumed 200 ml of fermented milk or placebo in the morning and evening. Blood samples were drawn for analysis three times, just before taking the experimental diet, and after 4 wk and 8 wk of consumption. After 8 wk, the high density lipoprotein cholesterol level for the fermented milk group showed a significant rise after 4 wk (P<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The triglyceride level for the fermented milk group lowered significantly after 4 wk (<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The atherogenic index [(total cholesterol - high density lipoprotein cholesterol)/high-density lipoprotein cholesterol] for the fermented milk group decreased significantly from 4.24 to 3.52 (P<0.05). The systolic blood pressure lowered significantly by the intake of fermented milk (P<0.05) On the other hand, such effect was not observed in the placebo group (P>0.05). These results indicate potential of the development of fermented milk with multiple therapeutic effects.

Saponins and phenolic content in plant dietary additives of a traditional subsistence community, the Batemi of Ngorongoro District, Tanzania

Reports of plants added to milk and meat-based soups by the Maasai and Batemi in East Africa support a role for phenolic antioxidants and hypocholesterolemic agents in the diet, and provide explanation of the low incidence of cardiovascular disease of populations that traditionally consume high levels of dietary fat and cholesterol. Plant food additives used by the Batemi of Ngorongoro District, Tanzania, were tabulated, based on interviews with 22 informants, while 17 specimens were collected in the field and analyzed for saponin and phenolic content. A total of 81% of the Batemi additives and 82% of those known to be used by the Maasai contain potentially hypocholesterolemic saponins and/or phenolics.

Influence of yogurt and acidophilus yogurt on serum cholesterol levels in mice

The effects of yogurt and acidophilus yogurt on the weight gain, serum cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triglycerides, and the numbers of fecal lactobacilli and coliforms were investigated in mice assigned to three dietary treatments for 56 d: 1) commercial rodent chow and water (control), 2) commercial rodent chow and yogurt made from milk inoculated with a 3% (vol/vol) liquid culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus (yogurt), and 3) commercial rodent chow plus yogurt made from milk inoculated with a 0.01% (wt/vol) freeze-dried culture of Streptococcus thermophilus plus Lactobacillus acidophilus. The weight gains of mice receiving yogurt or acidophilus yogurt were higher than those of the mice in the control group. The mean values for serum cholesterol concentrations and LDL cholesterol concentrations were significantly decreased when acidophilus yogurt was fed on d 28 and 56. High density lipoprotein cholesterol and triglycerides were not affected by yogurt or acidophilus yogurt. The highest number of fecal lactobacilli was found in mice receiving acidophilus yogurt, and the number of fecal coliforms of that group was also lower than in the other two groups.

Serum lipid profile in relation to milk consumption in a Japanese population

OBJECTIVE

To investigate relationships between serum lipid profiles, milk consumption and lifestyle, in a Japanese population.

METHODS

A cross-sectional study in 12,610 Japanese men aged 30 to 69 years. Serum total-cholesterol (TC), HDL-cholesterol (HDLC), LDL-cholesterol (LDLC), TC/HDLC ratio, and triglycerides (TG) were determined. Milk consumption was classified into "Yes" (3553 men) and "No" (9057 men) groups by a self-administered questionnaire "Do you drink a glass of cow's milk (180 to 200 mL) or more everyday?". Five variables (age, body mass index, habitual exercise, and smoking and drinking habits) were considered confounding factors for the serum lipids.

RESULTS

Regardless of age, the "Yes" group had higher levels of serum TC, HDLC and LDLC than the "No" group except for one comparison (HDLC in 50 to 54 year old group). The differences in serum TC (p < 0.001), HDLC (p < 0.001) and LDLC (p < 0.001) between the two groups were significant by ANOVA. However, milk consumption had no significant relations to serum TC/HDLC ratio or TG level. Multivariate models including the five confounding factors confirmed these results, and indicated that the "Yes" group had higher adjusted means of serum TC by 0.079 mmol/L (+1.5%, 5.280 vs. 5.201 mmol/L, p < 0.001), HDLC by 0.018 mmol/L (+1.4%, 1.260 vs. 1.242 mmol/L, p < 0.01), and LDLC by 0.066 mmol/L (+2.0%, 3.382 vs. 3.316 mmol/L, p < 0.001) than the "No" group.

CONCLUSION

Milk consumption is part of a lifestyle related to hypercholesterolemia in the Japanese.

Modulation of proliferation, second messenger levels, and morphotype expression of the rat intestinal epithelial cell line IEC-6 by fermented milk

Trophic effects of milk fermented with Lactobacillus helveticus, Lactobacillus paracasei ssp. paracasei, Bifidobacterium sp., or the combination of Lactobacillus bulgaricus and Streptococcus thermophilus (yogurt) were studied on the IEC-6 intestinal epithelial cell line. Incorporation of [methyl-3H]thymidine, mitochondrial dehydrogenase activities, cyclic AMP production, and differentiation of levels of the IEC-6 strain were evaluated between the 15th and 30th passage in culture. All fermented and unfermented milks enhanced trophic responses of IEC-6 cells in a dose-dependent manner. Compared with the corresponding milks, supernatant fractions were more effective in stimulating mitochondrial dehydrogenase response. Fermented milk supernatants were also more effective than the corresponding unfermented fractions. Increases in DNA synthesis and cyclic AMP confirmed the activation observed with mitochondrial dehydrogenase. Yogurt induced the more trophic response with an increased number of the more differentiated cell morphotype. Fermentation with L. casei also demonstrated an important trophic adaptation of IEC-6 cells. Milk processing by lactic acid bacteria enhanced trophic and proliferation responses of intestinal epithelial cell line IEC-6. These results suggested that IEC-6 cells could represent an accurate and easy in vitro model for testing the trophic quality of various nutrients and for an optimization of physiological digestive functions.

Potential of using lactic acid bacteria for therapy and immunomodulation in man

There is in 1993 no proven medical indication of lactic acid bacteria (LAB) for therapy or immunomodulation in man. However, within the bulk of publications, rigorous trials have now opened rational fields of research on beneficial effects of LAB. These include lactose digestion, cholesterol metabolism, diarrheal disorders, prophylaxis of intestinal or urogenital infections, immunomodulation or even oral vaccination. We try here to analyse these studies, considering LAB as pharmacological agents, and conclude that pursuit of research could be promising for ecological therapy of mucosal diseases, and for development of original and flexible vectors for targeting in the gastrointestinal tract.