Effect of consumption of whole milk and skim milk on blood lipid profiles in healthy men

Impact of low-fat and full-fat dairy foods on fasting lipid profile and blood pressure: exploratory endpoints of a randomized controlled trial

BACKGROUND

Dietary guidelines traditionally recommend low-fat dairy because dairy's high saturated fat content is thought to promote cardiovascular disease (CVD). However, emerging evidence indicates that dairy fat may not negatively impact CVD risk factors when consumed in foods with a complex matrix.

OBJECTIVE

The aim was to compare the effects of diets limited in dairy or rich in either low-fat or full-fat dairy on CVD risk factors.

METHODS

In this randomized controlled trial, 72 participants with metabolic syndrome completed a 4-wk run-in period, limiting their dairy intake to ≤3 servings/wk of nonfat milk. Participants were then randomly assigned to 1 of 3 diets, either continuing the limited-dairy diet or switching to a diet containing 3.3 servings/d of either low-fat or full-fat milk, yogurt, and cheese for 12 wk. Exploratory outcome measures included changes in the fasting lipid profile and blood pressure.

RESULTS

In the per-protocol analysis (n = 66), there was no intervention effect on fasting serum total, LDL, and HDL cholesterol; triglycerides; free fatty acids; or cholesterol content in 38 isolated plasma lipoprotein fractions (P > 0.1 for all variables in repeated-measures ANOVA). There was also no intervention effect on diastolic blood pressure, but a significant intervention effect for systolic blood pressure (P = 0.048), with a trend for a decrease in the low-fat dairy diet (-1.6 ± 8.6 mm Hg) compared with the limited-dairy diet (+2.5 ± 8.2 mm Hg) in post hoc testing. Intent-to-treat results were consistent for all endpoints, with the exception that systolic blood pressure became nonsignificant (P = 0.08).

CONCLUSIONS

In men and women with metabolic syndrome, a diet rich in full-fat dairy had no effects on fasting lipid profile or blood pressure compared with diets limited in dairy or rich in low-fat dairy. Therefore, dairy fat, when consumed as part of complex whole foods, does not adversely impact these classic CVD risk factors. This trial was registered at clinicaltrials.gov as NCT02663544.

Application of Comparative Lipidomics to Elucidate Postprandial Metabolic Excursions Following Dairy Milk Ingestion in Individuals with Prediabetes

Nutrient-dense dairy foods are an important component of a healthy diet. Recommendations, however, advise non- and low-fat dairy foods despite controversy concerning whether full-fat dairy foods adversely impact cardiometabolic health. Therefore, in this study, our objective is to examine the differential plasma lipidomic responses to non-fat or full-fat milk ingestion during postprandial hyperglycemia. Seven adults with prediabetes completed a randomized cross-over study in which glucose was consumed alone or with non-fat or full-fat dairy milk. Plasma samples collected at 90 min and 180 min post milk ingestion were used to perform untargeted lipidomics analysis. A total of 332 lipids from 20 classes and five lipid categories were detected at different time points during the postprandial period. Dairy milk, especially non-fat milk, protected against lipid changes otherwise induced by glucose ingestion. Co-ingestion of dairy milk with glucose, regardless of fat content, significantly altered lipid profiles although full-fat milk more substantially modulated lipid profiles. For the identified lipid biomarkers, 68.0% and 66.7% of the lipids significantly increased at 90 and 180 min, respectively, while phosphatidylcholines (GPs) contributed most for the significant increase. Comparative lipidomics analysis indicated that both types of dairy milk induced significant changes in several lipid pathways, including glycerophospholipid metabolism and α-linolenic acid metabolism, to protect against postprandial hyperglycemia. In summary, our comparative lipidomics results suggested that dairy milk-mediated lipid modulation may be an effective dietary approach to reduce the risk of metabolic diseases among those with prediabetes.

The Structure of Relationships between the Human Exposome and Cardiometabolic Health: The Million Veteran Program

The exposome represents the array of dietary, lifestyle, and demographic factors to which an individual is exposed. Individual components of the exposome, or groups of components, are recognized as influencing many aspects of human physiology, including cardiometabolic health. However, the influence of the whole exposome on health outcomes is poorly understood and may differ substantially from the sum of its individual components. As such, studies of the complete exposome are more biologically representative than fragmented models based on subsets of factors. This study aimed to model the system of relationships underlying the way in which the diet, lifestyle, and demographic components of the overall exposome shapes the cardiometabolic risk profile. The current study included 36,496 US Veterans enrolled in the VA Million Veteran Program (MVP) who had complete assessments of their diet, lifestyle, demography, and markers of cardiometabolic health, including serum lipids, blood pressure, and glycemic control. The cohort was randomly divided into training and validation datasets. In the training dataset, we conducted two separate exploratory factor analyses (EFA) to identify common factors among exposures (diet, demographics, and physical activity) and laboratory measures (lipids, blood pressure, and glycemic control), respectively. In the validation dataset, we used multiple normal regression to examine the combined effects of exposure factors on the clinical factors representing cardiometabolic health. The mean ± SD age of participants was 62.4 ± 13.4 years for both the training and validation datasets. The EFA revealed 19 Exposure Common Factors and 5 Physiology Common Factors that explained the observed (measured) data. Multivariate regression in the validation dataset revealed the structure of associations between the Exposure Common Factors and the Physiology Common Factors. For example, we found that the factor for fruit consumption was inversely associated with the factor summarizing total cholesterol and low-density lipoprotein cholesterol (LDLC, p = 0.008), and the latent construct describing light levels of physical activity was inversely associated with the blood pressure latent construct (p < 0.0001). We also found that a factor summarizing that participants who frequently consume whole milk are less likely to frequently consume skim milk, was positively associated with the latent constructs representing total cholesterol and LDLC as well as systolic and diastolic blood pressure (p = 0.0006 and <0.0001, respectively). Multiple multivariable-adjusted regression analyses of exposome factors allowed us to model the influence of the exposome as a whole. In this metadata-rich, prospective cohort of US Veterans, there was evidence of structural relationships between diet, lifestyle, and demographic exposures and subsequent markers of cardiometabolic health. This methodology could be applied to answer a variety of research questions about human health exposures that utilize electronic health record data and can accommodate continuous, ordinal, and binary data derived from questionnaires. Further work to explore the potential utility of including genetic risk scores and time-varying covariates is warranted.

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.

Probiotic characteristics of Lactobacillus plantarum E680 and its effect on Hypercholesterolemic mice

BACKGROUND

Probiotics have been reported to reduce total cholesterol levels in vitro, but more evidence is needed to determine the clinical relevance of this activity. Chinese traditional fermented pickles are a good source of lactic acid bacteria. Therefore, pickle samples were collected for screening lactic acid bacteria based on their ability to survive stresses encountered during gastrointestinal passage and cholesterol reducing potency.

RESULTS

Seventy five lactic acid bacteria strains were isolated from 22 fermented pickles. From these bacteria, Lactobacillus plantarum E680, showed the highest acid (85.25%) and bile tolerance (80.79%). It was sensitive to five of the eight antibiotics tested, inhibited the growth of four pathogenic bacteria, and reduced the total cholesterol level by 66.84% in broth culture. In vivo testing using hypercholesterolemic mice fed high-fat emulsion, independent of food intake, found that L. plantarum E680 suppressed body weight gain and reduced total cholesterol and low-density lipoprotein cholesterol levels, with no effect on high-density lipoprotein cholesterol.

CONCLUSIONS

Chinese traditional fermented pickles are a good source for probiotics. L. plantarum E680, isolated from pickles, was acid and bile tolerant, sensitive to antibiotics, and reduced cholesterol levels both in vitro and in vivo. Based on these results, L. plantarum E680 may have potential as a novel probiotic for the development of cholesterol-lowering functional food.

Dairy versus other saturated fats source and cardiometabolic risk markers: Systematic review of randomized controlled trials

To analyze the effects of dairy intake on cardiometabolic risk markers compared to other dietary fat sources in adults. Literature database and gray literature were searched for studies published up to October 2018. Two independent authors selected and extracted data from articles. Summary tables were constructed to present data for all outcomes. The intake of dairy appears to have a protective effect on some cardiovascular risk factors, or it is not worse than other SFA sources. The higher intake of dairy can decrease total cholesterol and reduce waist circumference and increase HDL cholesterol. However, it can also increase LDL and triglycerides, although those were small changes. It was observed that the effect of dairy on several serum lipids varied according to the type dairy product used on intervention. Dairy products seem to present a different effect on cardiometabolic risk factors than other fat sources, with evidence of improvement on metabolic parameters compared to another animal source of SFA.

Effect of Preheating Treatment before Defatting on the Flavor Quality of Skim Milk

Skim milk has a poor flavor due to the lack of fat. Finding ways to improve the flavor quality of skim milk has attracted the attention of more and more researchers. The purpose of this study was to create a skim milk product with good flavor by processing. Briefly, raw milk was treated by preheating at pasteurization (85 °C, 15 s) and ultra-high temperature (UHT) instantaneous sterilization (137–141 °C, 4 s). Subsequently, the sample was centrifuged to remove fat and obtain two kinds of skim milk, namely, PSM (skim milk obtained by preheating at 85 °C, 15 s) and USM (skim milk obtained by preheating at 137–141 °C, 4 s). The results showed that the intensity of the main sensory attributes (overall liking, milk aroma, etc.) and the concentrations of the key flavor compounds (2-heptanone, 2-nonanone, decanal, hexanoic acid, etc.) were significantly higher in the USM (p < 0.05) than that of the PSM and RSM (skim milk without preheating). Principal component analysis (PCA) with E-Nose (electronic nose) showed that the RSM had significant differences in the milk aroma compared with the PSM and USM. Furthermore, it was found that there were good relationships between volatile compounds and sensory attributes by partial least squares regression (PLSR) analysis. These findings provided insights into improving the flavor quality of skim milk by preheating treatment instead of any flavor additives.

The Lipid and Glyceride Profiles of Infant Formula Differ by Manufacturer, Region and Date Sold

We tested the hypothesis that the lipid composition of infant formula is consistent between manufacturers, countries and target demographic. We developed techniques to profile the lipid and glyceride fraction of milk and formula in a high throughput fashion. Formula from principal brands in the UK (2017-2019; bovine-, caprine-, soya-based), the Netherlands (2018; bovine-based) and South Africa (2018; bovine-based) were profiled along with fresh British animal and soya milk and skimmed milk powder. We found that the lipid and glyceride composition of infant formula differed by region, manufacturer and date of manufacture. The formulations within some brands, aimed at different target age ranges, differed considerably where others were similar across the range. Soya lecithin and milk lipids had characteristic phospholipid profiles. Particular sources of fat, such as coconut oil, were also easy to distinguish. Docosahexaenoic acid is typically found in triglycerides rather than phospholipids in formula. The variety by region, manufacturer, date of manufacture and sub-type for target demographics lead to an array of lipid profiles in formula. This makes it impossible to predict its molecular profile. Without detailed profile of the formula fed to infants, it is difficult to characterise the relationship between infant nutrition and their growth and development.

Intake of fermented and non-fermented dairy products and risk of incident CHD: the Kuopio Ischaemic Heart Disease Risk Factor Study

Recent dairy product studies have suggested that fermented rather than non-fermented dairy products might provide benefits on cardiovascular health, but the evidence is inconclusive. Therefore, we investigated whether fermented and non-fermented dairy products have distinct associations with the risk of incident CHD in a population with high dairy product intake. The present study included a total of 1981 men, aged 42-60 years, from the Kuopio Ischaemic Heart Disease Risk Factor Study, with no CHD at baseline. Dietary intakes were assessed with instructed 4-d food records. We used Cox's proportional hazards regression model to estimate the associations with the risk of CHD. Fatal and non-fatal CHD events were ascertained from national registries. During a mean follow-up of 20·1 years, 472 CHD events were recorded. Median intakes were 105 g/d for fermented (87 % low-fat products) and 466 g/d for non-fermented dairy products (60 % low-fat products). After adjusting for potential confounders, those in the highest (v. lowest) intake quartile of fermented dairy products had 27 % (95 % CI 5, 44; P-trend=0·02) lower risk of CHD. In contrast, those in the highest intake quartile of non-fermented dairy products had 52 % (95 % CI 13, 104; P-trend=0·003) higher risk of CHD. When analysed based on fat content, low-fat (<3·5 % fat) fermented dairy product intake was associated with lower risk (hazard ratio in the highest quartile=0·74; 95 % CI 0·57, 0·97; P-trend=0·03), but high-fat fermented dairy and low-fat or high-fat non-fermented dairy products had no association. These results suggest that fermented and non-fermented dairy products can have opposite associations with the risk of CHD.

Dairy Fats and Cardiovascular Disease: Do We Really Need to be Concerned?

Cardiovascular diseases (CVD) remain a major cause of death and morbidity globally and diet plays a crucial role in the disease prevention and pathology. The negative perception of dairy fats stems from the effort to reduce dietary saturated fatty acid (SFA) intake due to their association with increased cholesterol levels upon consumption and the increased risk of CVD development. Institutions that set dietary guidelines have approached dairy products with negative bias and used poor scientific data in the past. As a result, the consumption of dairy products was considered detrimental to our cardiovascular health. In western societies, dietary trends indicate that generally there is a reduction of full-fat dairy product consumption and increased low-fat dairy consumption. However, recent research and meta-analyses have demonstrated the benefits of full-fat dairy consumption, based on higher bioavailability of high-value nutrients and anti-inflammatory properties. In this review, the relationship between dairy consumption, cardiometabolic risk factors and the incidence of cardiovascular diseases are discussed. Functional dairy foods and the health implications of dairy alternatives are also considered. In general, evidence suggests that milk has a neutral effect on cardiovascular outcomes but fermented dairy products, such as yoghurt, kefir and cheese may have a positive or neutral effect. Particular focus is placed on the effects of the lipid content on cardiovascular health.

Optimising Milk Composition

During recent decades, the UK dairy industry has had to adjust to the introduction of milk quotas in 1984, the deregulation of milk markets in 1994, and accommodate changes in the demand for dairy products. The combination of these factors, in addition to Bovine Spongiform Encephalopathy and Foot and Mouth disease, and a fall in milk price has inevitably resulted in a restructuring of the industry, but also reinforced the need for all sectors of the industry to respond to the prevailing economic climate and changes in consumer preferences.

Effect of whole milk compared with skimmed milk on fasting blood lipids in healthy adults: a 3-week randomized crossover study

BACKGROUND/OBJECTIVES

Dietary guidelines have for decades recommended choosing low-fat dairy products due to the high content of saturated fat in dairy known to increase blood concentration of LDL cholesterol. However, meta-analyses including observational studies show no association between overall dairy intake and risk of cardiovascular disease and even point to an inverse association with type 2 diabetes. The objective was to compare the effects of whole milk (3.5% fat) with skimmed milk (0.1% fat) on fasting serum blood lipids, insulin, and plasma glucose in healthy subjects.

SUBJECT/METHODS

A randomized, controlled 2 × 3-week crossover dietary intervention in 18 healthy adults randomly assigned to a sequence of treatments consisting of 0.5 L/d of whole milk and skimmed milk as part of their habitual diet. A total of 17 subjects completed the intervention.

RESULTS

Whole milk increased HDL cholesterol concentrations significantly compared to skimmed milk (P < 0.05). There were no significant differences between whole milk and skimmed milk in effects on total and LDL cholesterol, triacylglycerol, insulin, and glucose concentrations.

CONCLUSIONS

Intake of 0.5 L/d of whole milk did not adversely affect fasting blood lipids, glucose, or insulin compared to skimmed milk. Moreover, intake of whole milk increased HDL cholesterol concentration compared to skimmed milk. These findings suggest that if the higher energy content is taken into account, whole milk might be considered a part of a healthy diet among the normocholesterolemic population.

Associations of Calcium and Dairy Products with All-Cause and Cause-Specific Mortality in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Prospective Cohort Study

Associations of calcium and dairy product intakes with cardiovascular disease risk and cancer mortality are controversial. We investigated associations of calcium and dairy product intakes with mortality in the prospective REasons for Geographic and Racial Differences in Stroke study (n = 30,239). Of 2,966 total deaths, 32.3% were from CVD and 28.8% from cancer. For those in the upper relative to the lowest quintile of intakes, from Cox proportional hazards regression models, the multivariable-adjusted hazard ratios (HRs) for all-cause mortality were 1.13 (95% confidence intervals [CI] 0.95-1.35; P-trend 0.004) for whole milk, and 0.75 (CI 0.61-0.93; P-trend 0.001) for nonfat milk; for CVD mortality the corresponding HRs were 0.80 (CI 0.55-1.16; P-trend 0.80) and 0.72 (CI 0.49-1.05; P-trend 0.06); and for cancer mortality they were 1.56 (CI 1.17-2.08; P-trend 0.006) and 0.89 (CI 0.62-1.28; P-trend 0.86). Calcium (total, dietary, supplemental) and total dairy product intakes were not associated with all-cause, cardiovascular, or cancer mortality. These results suggest that whole milk consumption may be directly associated with cancer mortality; non-fat milk consumption may be inversely associated with all-cause and cardiovascular- and cancer-specific mortality; and calcium intake independent of milk product intakes may not be associated with mortality.

Comprehensive Review of the Impact of Dairy Foods and Dairy Fat on Cardiometabolic Risk

Because regular-fat dairy products are a major source of cholesterol-raising saturated fatty acids (SFAs), current US and Canadian dietary guidelines for cardiovascular health recommend the consumption of low-fat dairy products. Yet, numerous randomized controlled trials (RCTs) have reported rather mixed effects of reduced- and regular-fat dairy consumption on blood lipid concentrations and on many other cardiometabolic disease risk factors, such as blood pressure and inflammation markers. Thus, the focus on low-fat dairy in current dietary guidelines is being challenged, creating confusion within health professional circles and the public. This narrative review provides perspective on the research pertaining to the impact of dairy consumption and dairy fat on traditional and emerging cardiometabolic disease risk factors. This comprehensive assessment of evidence from RCTs suggests that there is no apparent risk of potential harmful effects of dairy consumption, irrespective of the content of dairy fat, on a large array of cardiometabolic variables, including lipid-related risk factors, blood pressure, inflammation, insulin resistance, and vascular function. This suggests that the purported detrimental effects of SFAs on cardiometabolic health may in fact be nullified when they are consumed as part of complex food matrices such as those in cheese and other dairy foods. Thus, the focus on low-fat dairy products in current guidelines apparently is not entirely supported by the existing literature and may need to be revisited on the basis of this evidence. Future studies addressing key research gaps in this area will be extremely informative to better appreciate the impact of dairy food matrices, as well as dairy fat specifically, on cardiometabolic health.

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.

Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence

Milk is a widely consumed beverage that is essential to the diet of several millions of people worldwide because it provides important macro- and micronutrients. Milk is recognized as being useful during childhood and adolescence because of its composition; however, its relatively high saturated fat proportion raises issues of potential detrimental effects, namely on the cardiovascular system. This review evaluates the most recent literature on dairy and human health, framed within epidemiologic, experimental, and biochemical evidence. As an example, the effects of milk (notably skimmed milk) on body weight appear to be well documented, and the conclusions of the vast majority of published studies indicate that dairy consumption does not increase cardiovascular risk or the incidence of some cancers. Even though the available evidence is not conclusive, some studies suggest that milk and its derivatives might actually be beneficial to some population segments. Although future studies will help elucidate the role of milk and dairy products in human health, their use within a balanced diet should be considered in the absence of clear contraindications.

Dairy intake in relation to cardiovascular disease mortality and all-cause mortality: the Hoorn Study

PURPOSE

Existing data from prospective cohort studies on dairy consumption and cardiovascular diseases are inconsistent. Even though the association between total dairy and cardiovascular diseases has been studied before, little is known about the effect of different types of dairy products on cardiovascular diseases (CVD). The objective of this study was to examine the relationship between (type of) dairy intake and CVD mortality and all-cause mortality in a Dutch population.

METHODS

We examined the relationship between dairy intake and CVD mortality and all-cause mortality in 1956 participants of the Hoorn Study (aged 50-75 years), free of CVD at baseline. Hazard ratios with 95 % CIs were obtained for CVD mortality and all-cause mortality per standard deviation (SD) of the mean increase in dairy intake, with adjustment for age, sex, BMI, smoking, education, total energy intake, alcohol consumption, physical activity, and dietary intakes.

RESULTS

During 12.4 years of follow-up, 403 participants died, of whom 116 had a fatal CVD event. Overall dairy intake was not associated with CVD mortality or all-cause mortality. Each SD increase in high-fat dairy intake was associated with a 32 % higher risk of CVD mortality (95 % CI; 7-61 %).

CONCLUSION

In this prospective cohort study, the intake of high-fat dairy products was associated with an increased risk of CVD mortality.

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.

Encouraging healthy beverage intake in child care and school settings

PURPOSE OF REVIEW

Inappropriate intake of sugar-sweetened beverages, fruit juice, and whole milk is associated with obesity and obesity-related comorbidities. As numerous children spend many hours in schools and child care, these settings provide a potential means for general pediatricians to reach children and their parents with interventions to encourage intake of guideline-recommended beverages. This review describes the beverages currently offered within child care facilities and schools and summarizes school and child care-based interventions and policies to encourage healthy beverage intake.

RECENT FINDINGS

The major sources of beverages available in schools and child care include beverages provided through federal programs, competitive beverages (e.g., beverages for purchase through vending machines), water from drinking fountains, and beverages brought into facilities. Policies governing the types of beverages available in schools and child care settings have increased, but still vary in scope and jurisdiction. Although there are no child care-based interventions that exclusively target beverage intake, there are examples of school-based interventions to encourage healthy beverage consumption.

SUMMARY

Although interventions and policies to encourage healthy beverage intake in schools and child care are increasing, there is a need for additional research, programs, and policies to guide beverage availability and intake in these settings.

Dairy food consumption and obesity-related chronic disease

Dairy food comprises a range of different products with varying nutritional components. In the context of a healthy diet, dairy food may provide protection against and amelioration of chronic diseases related to obesity. These include overweight, insulin resistance/metabolic syndrome/type 2 diabetes, hypertension/stroke, and cardiovascular disease. Eliciting how dairy food may have this impact represents a challenge for modern nutritional science and requires an integration of knowledge from observational studies of population dietary patterns and disease prevalence, and experimental studies testing the effect of dairy food consumption. It also benefits from the recent identification of biomarkers of dairy fat intake and from mechanistic studies that support the plausibility of the observed effects. Future research might discriminate between types of dairy foods and focus on the synergy provided by the food matrix, rather than simply the component parts of the food.

Dairy consumption and patterns of mortality of Australian adults

BACKGROUND/OBJECTIVES

Dairy foods contain various nutrients that may affect health. We investigated whether intake of dairy products or related nutrients is associated with mortality due to cardiovascular disease (CVD), cancer and all causes.

SUBJECTS/METHODS

We carried out a 16-year prospective study among a community-based sample of 1529 adult Australians aged 25-78 years at baseline. Habitual intakes of dairy products (total, high/low-fat dairy, milk, yoghurt and full-fat cheese), calcium and vitamin D were estimated as mean reported intake using validated food frequency questionnaires (FFQs) self-administered in 1992, 1994 and 1996. National Death Index data were used to ascertain mortality and cause of death between 1992 and 2007. Hazard ratios (HRs) were calculated using Cox regression analysis.

RESULTS

During an average follow-up time of 14.4 years, 177 participants died, including 61 deaths due to CVD and 58 deaths due to cancer. There was no consistent and significant association between total dairy intake and total or cause-specific mortality. However, compared with those with the lowest intake of full-fat dairy, participants with the highest intake (median intake 339 g/day) had reduced death due to CVD (HR: 0.31; 95% confidence interval (CI): 0.12-0.79; P for trend=0.04) after adjustment for calcium intake and other confounders. Intakes of low-fat dairy, specific dairy foods, calcium and vitamin D showed no consistent associations.

CONCLUSIONS

Overall intake of dairy products was not associated with mortality. A possible beneficial association between intake of full-fat dairy and cardiovascular mortality needs further assessment and confirmation.

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.

Long-term effect of calcium-vitamin D(3) fortified milk on blood pressure and serum lipid concentrations in healthy older men

BACKGROUND/OBJECTIVES

Some epidemiological and clinical studies have shown that increased dairy consumption or calcium and/or vitamin D supplementation can have a beneficial effect on blood pressure, and lipid and lipoprotein concentrations. The aim of this study was to assess the long-term effects of calcium-vitamin D(3) fortified milk on blood pressure and lipid-lipoprotein concentrations in community-dwelling older men.

SUBJECTS/METHODS

This is a substudy of a 2-year randomized controlled trial in which 167 men aged >50 years were assigned to receive either 400 ml per day of reduced fat (approximately 1%) milk fortified with approximately 1000 mg of calcium and 800 IU of vitamin D(3) or to a control group receiving no additional fortified milk. Weight, blood pressure, lipid and lipoprotein concentrations were measured every 6 months. Participants on lipid-lowering (n=32) or antihypertensive medication (n=39) were included, but those who commenced, increased or decreased their medication throughout the intervention were excluded (n=27).

RESULTS

In the 140 men included in this study (milk, n=73; control, n=67), there were no significant effects of the calcium-vitamin D(3) fortified milk on weight, systolic or diastolic blood pressure, total cholesterol, high-density lipoprotein or low-density lipoprotein cholesterol or triglyceride concentrations at any time throughout the intervention. Similar results were observed after excluding men taking antihypertensive or lipid-lowering medication or limiting the analysis to those with baseline calcium intakes <1000 mg per day and/or with hypovitaminosis D (25(OH)D <75 nmol/l).

CONCLUSIONS

Supplementation with reduced-fat calcium-vitamin D(3) fortified milk did not have a beneficial (nor detrimental) effect on blood pressure, lipid or lipoprotein concentrations in healthy community-dwelling older men.

Modelling dairy intake on the development of acute coronary syndromes: the CARDIO2000 study

BACKGROUND

Dairy consumption may be associated with a small but worthwhile reduction in cardiovascular disease risk, but results from epidemiological studies are inconsistent. The aim of the present study was to evaluate the association between dairy consumption and the prevalence of a first, non-fatal event of an acute coronary syndrome, in a Greek sample.

DESIGN

Seven hundred male and 148 female patients with first event of an acute coronary syndrome and 1078 population-based controls, age and sex matched, were randomly selected.

METHODS

Detailed information regarding their medical records, alcohol intake, physical activity and smoking habits was recorded. Nutritional habits were evaluated with a semi-quantitative food-frequency questionnaire. Multiple logistic regression analysis estimated the odds ratio of having acute coronary syndrome by level of dairy intake, after taking into account the effect of several confounders.

RESULTS

An inverse relationship was observed between dairy products consumption and odds of having acute coronary syndrome. One portion increase in weekly dairy products intake was associated with 12% lower likelihood of having acute coronary syndrome, after controlling for various potential confounders (P<0.001). Cut-off analysis showed that 7.4 portions per week are the optimal consumption that benefits people from having acute coronary syndrome.

CONCLUSIONS

Dairy consumption seems to offer significant protection against coronary heart disease, irrespective of various clinical, lifestyle and other characteristics of the participants.

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.

Milk consumption, stroke, and heart attack risk: evidence from the Caerphilly cohort of older men

OBJECTIVE

To examine associations between milk consumption and incident heart disease and stroke.

DESIGN

A representative population sample of men was asked to weigh and record their food intake for seven days. The total consumption of milk was obtained from these records. Details of all deaths and vascular events were collected during the following 20 years. Incident ischaemic strokes and heart disease events were diagnosed by standard criteria.

SETTING

The Caerphilly cohort, a representative population sample of men in South Wales, aged 45-59 when first seen in 1979-83.

PARTICIPANTS

A representative 3:10 subsample of the men in the cohort.

MAIN RESULTS

665 men (87% of those approached) returned satisfactory seven day diet diaries. After adjustment, the relative odds of an event in the men whose milk consumption was the median or higher, relative to those with lower intakes of milk, were 0.52 (0.27 to 0.99) for an ischaemic stroke and 0.88 (0.56 to 1.40) for an ischaemic heart disease event. Deaths from all causes were similar in the two milk consumption groups (relative odds 1.08; 0.74 to 1.58).

CONCLUSIONS

These results give no convincing evidence of an increased risk of vascular disease from milk drinking. Rather, the subjects who drank more than the median amount of milk had a reduced risk of an ischaemic stroke, and possibly a reduced risk of an ischaemic heart disease event. These conclusions are in agreement with the results of a previously reported overview of 10 large, long term cohort studies based on food frequency intake records.

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.

Milk drinking, ischaemic heart disease and ischaemic stroke I. Evidence from the Caerphilly cohort

OBJECTIVE

To test the hypothesis that milk drinking increases the risk of ischaemic heart disease (IHD) and ischaemic stroke in a prospective study.

DESIGN

In the Caerphilly Cohort Study dietary data, including milk consumption, were collected by a semiquantitative food frequency questionnaire in 1979-1983. The cohort has been followed for 20-24 y and incident IHD and stroke events identified.

SUBJECTS

A representative population sample in South Wales, of 2512 men, aged 45-59 y at recruitment.

MAIN OUTCOME MEASURES

In total, 493 men had an IHD event and 185 an ischaemic stroke during follow-up.

RESULTS

After adjustment, the hazard ratio in men with a milk consumption of one pint (0.57 l) or more per day, relative to men who stated that they consumed no milk, is 0.71 (0.40-1.26) for IHD and 0.66 (0.24-1.81) for ischaemic stroke. At baseline, 606 men had had clinical or ECG evidence of vascular disease, and in these the vascular risk was even lower (0.37; 0.15-0.90). The hazard ratio for IHD and ischaemic stroke combined is 0.64 (0.39-1.06) in all men and 0.37 (0.15-0.90) in those who had had a prior vascular event.

CONCLUSION

The data provide no convincing evidence that milk consumption is associated with an increase in vascular disease risk. Evidence from an overview of all published cohort studies on this topic should be informative.

SPONSORSHIP

: The Medical Research Council, the University of Wales College of Medicine and Bristol University. Current support is from the Food Standards Agency.

Lymphatic fat absorption varies among rats administered dairy products differing in physiochemical properties

We examined in rats the intestinal absorption of fat from dairy products differing in physiochemical properties. Five dairy products (cream cheese, cream, sour cream, butter, and mixed butter) with minor differences in fatty acid composition were administered by gavage to rats, and lymphatic fat absorption was examined. Absorption was followed for 8 h after administration of 300 mg fat from the dairy products. Administration of cream and sour cream resulted in faster lymphatic fat absorption than cream cheese, butter, and mixed butter, and at 8 h the accumulated absorption of fat was significantly higher. The lymphatic absorption of fat after cream cheese administration was similar to the absorption after butter and mixed butter administration up to the 4-h time point; then it increased to a level between that of rats administered cream or sour cream and butter or mixed butter. Overall, these results demonstrated different lymphatic absorption patterns of fat from dairy products differing in physiochemical properties. Because the fatty acid composition of the dairy products differed only slightly, other factors such as viscosity, type of emulsion, particle size, and likely also protein content may have contributed to the differences in absorption.

Effect of a modified milk fat and calcium in purified diets on cholesterol metabolism in hamsters

Modification of milk fat both by partially replacing saturated FA with oleic acid (18:1) and by increasing calcium intake independently reduces plasma cholesterol. Whether modification of both factors together would synergistically reduce plasma cholesterol is unknown. Seventy-two male golden Syrian hamsters were separated into four diet treatment groups (n = 18/group) and fed ad libitum for 7 wk. Diets contained either modified milk fat (MMF) or regular milk fat (RMF) with either 0.5% (MMF and RMF) or 1.3% calcium (w/w) (MMFC and RMFC). All diets contained 11% test fat, 4% soybean oil, and 0.15% cholesterol (w/w). During the last week, feces were collected for three consecutive days for analysis of fecal FA, cholesterol, and calcium excretion. Overnight-fasted animals were sacrificed, and plasma and livers were collected for lipid analysis. Neither MMF nor additional calcium significantly affected plasma lipids. However, significant interactions existed between MMF and additional calcium for the ratio of LDL cholesterol to HDL cholesterol (LDL/HDL), indicating that increased calcium intake reduced this ratio only in RMF animals. In addition, MMF reduced LDL/HDL relative to RMF. MMF significantly increased hepatic total and esterified cholesterol. Additional calcium significantly increased fecal calcium and saturated FA (SFA) excretion, whereas MMF significantly reduced SFA excretion. RMFC induced the highest excretion of 16:0 among all groups. Replacement of SFA with 18:1 in the MMF reduced the impact of high calcium on LDL/HDL. Additional calcium reduced LDL/HDL only in the presence of RMF, which may be achieved through an increased excretion of 16:0.

Milk drinking, ischaemic heart disease and ischaemic stroke II. Evidence from cohort studies

OBJECTIVE

Milk consumption is considered a risk factor for vascular disease on the basis of relevant biological mechanisms and data from ecological studies. The aim was to identify published prospective studies of milk drinking and vascular disease, and conduct an overview.

DESIGN

The literature was searched for cohort studies, in which an estimate of the consumption of milk, or the intake of calcium from dairy sources, has been related to incident vascular disease.

MAIN OUTCOME MEASURES

Ischaemic heart disease and ischaemic stroke.

RESULTS

In total, 10 studies were identified. Their results show a high degree of consistency in the reported risk for heart disease and stroke, all but one study suggesting a relative risk of less than one in subjects with the highest intakes of milk. A pooled estimate of relative odds in these subjects, relative to the risk in subjects with the lowest consumption, is 0.87 (95% CI 0.74-1.03) for ischaemic heart disease and 0.83 (0.77-0.90) for ischaemic stroke. The odds ratio for any vascular event is 0.84 (0.78-0.90).

CONCLUSIONS

Cohort studies provide no convincing evidence that milk is harmful. While there still could be residual confounding from unidentified factors, the studies, taken together, suggest that milk drinking may be associated with a small but worthwhile reduction in heart disease and stroke risk.

SPONSORSHIP

The University of Wales College of Medicine and Bristol University. Current support is from the Food Standards Agency.

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.

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.

Lipid-lowering effects of a modified butter-fat: a controlled intervention trial in healthy men

OBJECTIVE

To investigate the lipid-lowering potential of a butter-fat modified through manipulations in bovine feeding to increase the unsaturated:saturated fatty acid ratio.

DESIGN

Double-blind, randomised, cross-over intervention trial.

SETTING

University of Auckland Human Nutrition Unit, New Zealand.

SUBJECTS

Twenty healthy, male subjects.

INTERVENTION

A residential trial in which all foods and beverages were provided during two intervention periods, comprising 3 weeks of high unsaturated 'modified' vs. 3 weeks of saturated 'control' butter feeding separated by a 4 week washout. Diets were of typical composition of 39 percentage energy (en%) fat (20 en% butter-fat), 48 en% CHO, 13 en% protein.

RESULTS

There was a significant decrease in both total (P<0.05, -7.9%) and LDL-cholesterol (P<0.01, -9.5%) during modified butter feeding. There was no significant effect of treatment on a range of other risk factors including HDL-cholesterol, triglyceride, apolipoprotein A or B, nonesterified fatty acids (NEFA), haemostatic clotting factor VII and fibrinogen or glucose (P>0.05). Subjects were maintained in energy balance and there was no significant change in body weight during intervention. Butter-fat composition alone differed between treatments.

CONCLUSIONS

A significant improvement in cardiovascular risk can be achieved by moderate changes in dietary fatty acid profile, achieved through a common and well accepted food source, butter-fat.

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.

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.