Effects of low-fat dairy consumption on markers of low-grade systemic inflammation and endothelial function in overweight and obese subjects: an intervention study

Blood orange juice intake modulates plasma and PBMC microRNA expression in overweight and insulin-resistant women: impact on MAPK and NFκB signaling pathways

Blood orange consumption presents potential health benefits and may modulate epigenetic mechanisms such as microRNAs (miRNAs) expression. MiRNAs are non-coding RNAs responsible for post-transcriptional gene regulation, and these molecules can also be used as biomarkers in body fluids. This study was designed to investigate the effect of chronic blood orange juice (BOJ) intake on the inflammatory response and miRNA expression profile in plasma and blood cells in overweight women. The study cohort was comprised of twenty women aged 18-40 years old, diagnosed as overweight, who consumed 500 mL/d of BOJ for four weeks. Clinical data were collected at baseline and after 4 weeks of juice consumption, e.g., anthropometric and hemodynamic parameters, food intake, blood cell count, and metabolic and inflammatory biomarkers. BOJ samples were analyzed and characterized. Additionally, plasma and blood cells were also collected for miRNA expression profiling and evaluation of the expression of genes and proteins in the MAPK and NFκB signaling pathways. BOJ intake increased the expression of miR-144-3p in plasma and the expression of miR-424-5p, miR-144-3p, and miR-130b-3p in peripheral blood mononuclear cells (PBMC). Conversely, the beverage intake decreased the expression of let-7f-5p and miR-126-3p in PBMC. Computational analyses identified different targets of the dysregulated miRNA on inflammatory pathways. Furthermore, BOJ intake increased vitamin C consumption and the pJNK/JNK ratio and decreased the expression of IL6 mRNA and NFκB protein. These results demonstrate that BOJ regulates the expression of genes involved in the inflammatory process and decreases NFкB-protein expression in PBMC.

Saturated fat from dairy sources is associated with lower cardiometabolic risk in the Framingham Offspring Study

BACKGROUND

Current dietary guidance recommends limiting intakes of saturated fats, but most fails to consider that saturated fats from different food sources may have different health effects.

OBJECTIVES

We aimed to evaluate the associations of saturated fats from dairy and nondairy sources with measures of body fat, inflammatory biomarkers, lipid concentrations, and lipid particle sizes and concentrations.

METHODS

The Framingham Offspring Study is a prospective cohort study. Participants (n = 2391) ≥30 y of age who had dietary records and data on the outcomes of interest were included.

RESULTS

Among females, those in the highest quintile (compared with the lowest) of dairy-derived saturated fat had lower multivariable-adjusted levels of body fat [BMI (in kg/m2): 26.2 compared with 27.8, P < 0.01; and percentage fat mass: 36.7% compared with 38.0%, P = 0.09) and larger LDL particle sizes. Nondairy saturated fat in females was inversely associated with the triglyceride (TG):HDL ratio (P = 0.03). Among males, intakes of dairy-derived saturated fats were inversely associated with C-reactive protein (P < 0.01), fibrinogen (P < 0.01), TGs (P < 0.01), and the TG:HDL ratio (P < 0.01). HDL cholesterol was 2.8 mg/dL (P = 0.04) higher among males in the highest (compared with the lowest) quintile of saturated fat from dairy sources. Males with the highest intakes of dairy-derived saturated fats had larger HDL and LDL particle sizes (P < 0.01 for both), a higher HDL particle concentration (P < 0.01), and a lower VLDL particle concentration (P < 0.01). There were no statistically significant adverse effects of saturated fats from nondairy sources on any of these outcomes in either males or females.

CONCLUSIONS

Males with higher intakes of dairy-derived saturated fats had a less atherogenic profile than males with lower intakes of these fats. These effects were weaker in females. Nondairy saturated fats were not associated with these cardiometabolic outcomes.

Effect of whey protein consumption on IL-6 and TNF-α: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Due to inconsistent data about WP supplementation on inflammatory markers, present systematic review and meta-analysis was done to summarize its effect on TNF-α and IL-6.

METHODS

Our search was done in Pubmed, Scopus, Embase, and Cochrane up to June 2021. Weighted mean difference (WMD) and 95% confidence intervals (CI) was used to indicate the effect sizes. Conceivable sources of heterogeneity were detected by subgroup analysis.

RESULTS

Overall, 11 eligible RCTs were included. The pooled results showed that WP supplementation had no significant effect on TNF-α and IL-6 status compare to those receiving carbohydrate and other types of proteins as placebo. Results from subgroup analysis based on health status, study duration, WP dosage and sex, expressed no favorable effect of WP on TNF-α and IL-6 levels.

CONCLUSION

It can be concluded that whey supplementation had no favorable effects on inflammatory biomarkers including TNF- α and IL-6.

Exploring the Links between Diet and Inflammation: Dairy Foods as Case Studies

Systemic chronic inflammation may be a contributing factor to many noncommunicable diseases, including diabetes, cardiovascular disease, and obesity. With the rapid rise of these conditions, identifying the causes of and treatment for chronic inflammation is an important research priority, especially with regard to modifiable lifestyle factors such as diet. An emerging body of evidence indicates that consuming certain foods, including dairy foods like milk, cheese, and yogurt, may be linked to a decreased risk for inflammation. To discuss both broader research on diet and inflammation as well as research on links between individual foods and inflammation, the National Dairy Council sponsored a satellite session entitled "Exploring the Links between Diet and Inflammation: Dairy Foods as Case Studies" at the American Society for Nutrition's 2020 LIVE ONLINE Conference. This article, a review based on the topics discussed during that session, explores the links between diet and inflammation, focusing most closely on the relations between intake of dairy fat and dairy foods like milk, cheese, and yogurt, and biomarkers of inflammation from clinical trials. While there is currently insufficient evidence to prove an "anti-inflammatory" effect of dairy foods, the substantial body of clinical research discussed in this review indicates that dairy foods do not increase concentrations of biomarkers of chronic systemic inflammation.

Effect of dairy intake with or without energy restriction on body composition of adults: overview of systematic reviews and meta-analyses of randomized controlled trials

CONTEXT

Some studies suggest that consumption of dairy products can aid in weight loss, while others suggest a negative effect or no effect.

OBJECTIVE

An overview of systematic reviews and meta-analyses was conducted to examine the effect of dairy product consumption on changes in body composition.

DATA SOURCES

PRISMA guidelines were followed to ensure transparent reporting of evidence. The MEDLINE, Embase, Cochrane Central Database of Systematic Reviews, and Web of Science databases were searched from inception to April 2018.

STUDY SELECTION

Six systematic reviews and 47 associated meta-analyses (which included the results of 58 different randomized controlled trials) published in English or Spanish and reporting data on dairy intake and changes in weight, fat mass, lean mass, or waist circumference were included.

DATA EXTRACTION

Two authors independently extracted the data and assessed the risk of bias using the AMSTAR2 tool.

RESULTS

Dairy consumption interventions without dietary energy restriction had no significant effects on weight, fat mass, lean mass, or waist circumference. Interventions in energy-restricted settings had significant effects on fat mass and body weight.

CONCLUSIONS

Increasing total dairy intake without energy restriction in adults does not affect body composition. In the context of an energy-restricted diet, however, increased dairy intake results in lower fat mass and body weight but has no conclusive effects on waist circumference or lean mass.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42018094672.

Yogurt Consumption Is Associated with Lower Levels of Chronic Inflammation in the Framingham Offspring Study

Some studies suggest that dairy foods may be linked with less chronic inflammation. However, few studies have investigated the separate effects of different types of dairy on inflammation. Therefore, the current study aims to examine the separate prospective impacts of milk, yogurt and cheese on biomarkers of chronic inflammation in 1753 community-dwelling participants of the Framingham Offspring Study (FOS). Mean intakes of dairy foods were derived from two sets of three-day diet records. Six inflammatory biomarkers were assessed approximately seven years later at exam 7. Results showed that those who consumed yogurt (vs. those who did not) had statistically significantly lower levels of interleukin-6 (IL-6) (mean log-transformed levels of 1.31 and 1.26 in consumers/non-consumers, respectively, p = 0.02) and fibrin (mean log-transformed levels of 5.91 and 5.89 in consumers/non-consumers, respectively, p = 0.03). The inverse association between IL-6 and yogurt consumption was similar in participants who were of normal weight and those who were overweight. For fibrin, the effects were stronger in overweight individuals. No statistically significant associations were observed between any of these inflammation biomarkers and milk or cheese intakes. Overall, our study compared the separate impacts of three types of dairy foods on chronic inflammation and found that only yogurt intake was linked with lower levels of chronic inflammation.

Functional foods modulating inflammation and metabolism in chronic diseases: a systematic review

Chronic diseases are responsible for approximately 71% global deaths. These are characterized by chronic low-grade inflammation and metabolic alterations. "Functional foods" have been attributed with anti-inflammatory properties, demonstrated in cell lines and murine models; however, studies in humans are inconclusive. The purpose of this systematic review is to identify clinical trials that analyzed changes in inflammatory and metabolic mediators, in response to consumption of specific functional foods. A total of 3581 trials were screened and 88 were included for this review. Foods identified to regulate inflammation included cranberries, grapes, pomegranate, strawberries, wheat, whole grain products, low fat dairy products, yogurt, green tea, cardamom, turmeric, soy foods, almonds, chia seeds, flaxseed, pistachios, algae oil, flaxseed oil and grape seed oil. Clinical trials that focus on a dietary pattern rich in functional foods are necessary to explore if the additive effect of these foods lead to more clinically relevant outcomes.

Dairy Consumption and Metabolic Health

Milk and dairy foods are naturally rich sources of a wide range of nutrients, and when consumed according to recommended intakes, contribute essential nutrients across all stages of the life cycle. Seminal studies recommendations with respect to intake of saturated fat have been consistent and clear: limit total fat intake to 30% or less of total dietary energy, with a specific recommendation for intake of saturated fat to less than 10% of total dietary energy. However, recent work has re-opened the debate on intake of saturated fat in particular, with suggestions that recommended intakes be considered not at a total fat intake within the diet, but at a food-specific level. A large body of evidence exists examining the impact of dairy consumption on markers of metabolic health, both at a total-dairy-intake level and also at a food-item level, with mixed findings to date. However the evidence suggests that the impact of saturated fat intake on health differs both across food groups and even between foods within the same food group such as dairy. The range of nutrients and bioactive components in milk and dairy foods are found in different levels and are housed within very different food structures. The interaction of the overall food structure and the nutrients describes the concept of the 'food matrix effect' which has been well-documented for dairy foods. Studies show that nutrients from different dairy food sources can have different effects on health and for this reason, they should be considered individually rather than grouped as a single food category in epidemiological research. This narrative review examines the current evidence, mainly from randomised controlled trials and meta-analyses, with respect to dairy, milk, yoghurt and cheese on aspects of metabolic health, and summarises some of the potential mechanisms for these findings.

The Effects of Dairy Product and Dairy Protein Intake on Inflammation: A Systematic Review of the Literature

Systemic inflammation is associated with obesity and chronic disease risk. Intake of dairy foods is associated with reduced risk of type 2 diabetes and cardiovascular disease; however, the impact of dairy foods on inflammation is not well-established. The objective of this study was to conduct a systematic review to evaluate the effect of dairy product (milk, cheese, and yogurt) and dairy protein consumption on low-grade systemic inflammation in adults without severe inflammatory disorders. A literature search was completed in September 2019 using PubMed and CENTRAL as well as inspection of reference lists from relevant review articles. The search resulted in the identification of 27 randomized controlled trials which were included in this analysis. In the 19 trials which evaluated dairy products, 10 reported no effect of the intervention, while 8 reported a reduction in at least one biomarker of inflammation. All 8 trials that investigated dairy protein intake on markers of inflammation reported no effect of the intervention. The available literature suggests that dairy products and dairy proteins have neutral to beneficial effects on biomarkers of inflammation. Additional clinical studies designed using inflammatory biomarkers as the primary outcome are needed to fully elucidate the effects of dairy intake on inflammation.

Effects of dairy products consumption on inflammatory biomarkers among adults: A systematic review and meta-analysis of randomized controlled trials

AIMS

This study aimed to summarize earlier studies on the effects of dairy consumption on inflammatory biomarkers in adults and to quantify these effects through meta-analysis.

DATA SYNTHESIS

A comprehensive search of all relevant articles, published up to December 2019 indexed in PubMed, ISI (Institute for Scientific Information), EmBase, Scopus, and Google Scholar was done using relevant keywords. Randomized controlled trials (RCTs) that examined the effect of dairy products consumption, compared with low or no dairy intake, on inflammatory biomarkers in adults were included. Overall, 11 RCTs with 663 participants were included in this meta-analysis. We found that high consumption of dairy products, compared with low or no dairy intake, might significantly reduce CRP [weighed mean difference (WMD): -0.24 mg/L; 95% CI, -0.35, -0.14], TNF-α (WMD:- 0.66 pg/mL; 95% CI, -1.23, -0.09), IL-6 (WMD: -0.74 pg/mL; 95% CI, -1.36, -0.12), and MCP concentrations (WMD: -25.58 pg/mL; 95% CI, -50.31, -0.86). However, when the analyses were confined to cross-over trials, no such beneficial effects of dairy intake on inflammation were observed. In addition, high dairy intake might result in increased adiponectin levels (WMD: 2.42 μg/mL; 95% CI, 0.17, 4.66). No significant effect of dairy consumption on serum leptin (WMD: -0.32 ng/mL; 95% CI, -3.30, 2.65), ICAM-1 (WMD: -3.38 ng/ml; 95% CI, -15.57, 8.96) and VCAM-1 (WMD: 3.1 ng/mL; 95% CI, -21.38, 27.58) levels was observed.

CONCLUSIONS

In summary, the current meta-analysis indicated that dairy intake might improve several inflammatory biomarkers in adults. In most subgroups without heterogeneity, effects tended to be null. Study design and participants' age were the main sources of heterogeneity. More research, with a particular focus on fat content of dairy foods, is recommended.

The Impact of Dairy Products in the Development of Type 2 Diabetes: Where Does the Evidence Stand in 2019?

The prevalence of type 2 diabetes (T2D) has increased rapidly. Adopting a heathy diet is suggested as one of the effective behaviors to prevent or delay onset of T2D. Dairy consumption has been recommended as part of a healthy diet, but there remains uncertainty in both the scientific community and the public about the effect of different dairy products on T2D risk. In a recent workshop, the evidence on dairy products and T2D risk was presented and discussed by a group of experts. The main conclusions from the workshop are presented in this position paper and are as follows. 1) Available evidence from large prospective cohort studies and limited randomized controlled trials (RCTs) suggests that total dairy consumption has a neutral or moderately beneficial effect on T2D risk. 2) Increasing evidence from prospective cohort studies indicates that yogurt is most strongly associated with a lower T2D risk, but evidence from RCTs is scarce. 3) Fatty acids from dairy (medium-chain, odd, and very long-chain SFAs as well as trans-palmitoleic acid) are associated with lower T2D risk and improved metabolic health, but more research is needed on studies that explore cause and effect relations to exclude the possibility that the dairy fatty acids simply serve as markers of overall dairy consumption. 4) The food matrix can be a stronger determinant of health effects than SFA content. This review further identifies research gaps in the existing knowledge and highlights key research questions that need to be addressed to better understand the impact of dairy consumption on future T2D risk.

The Effects of Dairy Intake on Insulin Resistance: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

The incidence of type 2 diabetes mellitus (DM) has increased in the US over the last several years. The consumption of low-fat dairy foods has been linked with decreasing the risk of DM but studies have yet to show a clear correlation. We conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) evaluating the effects of dairy intake on homeostatic model assessment of insulin resistance (HOMA-IR), waist circumference, and body weight. In MEDLINE and Embase, we identified and reviewed 49 relevant RCTs: 30 had appropriate data format for inclusion in the meta-analysis. Using the Review Manager 5 software, we calculated the pooled standardized mean differences comparing dairy dietary interventions to control for our outcomes of interest. For HOMA-IR (794 individuals), we found a mean difference of −1.21 (95% CI −1.74 to −0.67; p-value < 0.00001; I² = 92%). For waist circumference (1348 individuals), the mean difference was −1.09 cm (95% CI 1.68 to −0.58; p-value < 0.00001; I² = 94%). For body weight (2362 individuals), the dairy intake intervention group weighed 0.42 kg less than control (p-value < 0.00001; I² = 92%). Our findings suggest that dairy intake, especially low-fat dairy products, has a beneficial effect on HOMA-IR, waist circumference, and body weight. This could impact dietary recommendations to reduce DM risk.

Effect of whole foods and dietary patterns on markers of subclinical inflammation in weight-stable overweight and obese adults: a systematic review

Context

Reduction of subclinical inflammation is a potential target for chronic disease management. Adiposity is a known modifier of meta-inflammation; however, the influence of dietary factors is less clear.

Objective

This review examines evidence from human trials evaluating effects of whole foods or dietary patterns on circulating inflammatory markers in weight-stable overweight and obese adults. It is the first review to investigate effects of diet on inflammation, independent of changes in adiposity.

Data Sources

The Ovid MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched.

Data Extraction

Data extraction was conducted using the Cochrane Collaboration Handbook for Systematic Reviews of Interventions.

Data Analysis

Study quality was evaluated using the Cochrane Collaboration Risk of Bias Assessment tool. Thirty-three studies were included assessing effects of 17 foods and dietary patterns on 39 inflammatory markers.

Conclusions

Overall, foods and dietary patterns were not found to have significant effects on inflammatory markers in weight-stable individuals. Inconsistencies among studies were largely due to methodological limitations. Future research should invest in longer intervention periods and standardization of inflammatory marker panels paired with novel technologies, while ensuring anthropometric measures are monitored and adequately controls are used.

Systematic Review Registration

Prospero registration number CRD42017067765.

Dairy product consumption and its association with metabolic disturbance in a prospective study of urban adults

The role of dairy foods and related nutrients in cardiometabolic health aetiology is poorly understood. We investigated longitudinal associations between the metabolic syndrome (MetS) and its components with key dairy product exposures. We used prospective data from a bi-racial cohort of urban adults (30-64 years at baseline (n 1371)), the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS), in Baltimore City, MD (2004-2013). The average of two 24-h dietary recalls measured 4-10 d apart was computed at baseline (V1) and follow-up (V2) waves. Annual rates of change (Δ) in dairy foods and key nutrients were estimated. Incident obesity, central obesity and the MetS were determined. Among key findings, in the overall urban adult population, both cheese and yogurt (V1 and Δ) were associated with an increased risk of central obesity (hazard ratio (HR) 1·13; 95 % CI 1·05, 1·23 per oz equivalent of cheese (V1); HR 1·21; 95 % CI 1·01, 1·44 per fl oz equivalent of yogurt (V1)]. Baseline fluid milk intake (V1 in cup equivalents) was inversely related to the MetS (HR 0·86; 95 % CI 0·78, 0·94), specifically to dyslipidaemia-TAG (HR 0·89; 95 % CI 0·81, 0·99), although it was directly associated with dyslipidaemia-HDL-cholesterol (HR 1·10; 95 % CI 1·01, 1·21). Furthermore, ΔCa and ΔP were inversely related to dyslipidaemia-HDL and MetS incidence, respectively, whereas Δdairy product fat was positively associated with incident TAG-dyslipidaemia and HDL-cholesterol-dyslipidaemia and the MetS. A few of those associations were sex and race specific. In sum, various dairy product exposures had differential associations with metabolic disturbances. Future intervention studies should uncover how changes in dairy product components over time may affect metabolic disorders.

Effects of Dairy Products Consumption on Body Weight and Body Composition Among Adults: An Updated Meta-Analysis of 37 Randomized Control Trials

SCOPE

Effects of dairy consumption on body weight and body composition have been inconsistently observed in randomized control trials (RCTs). Our meta-analysis aims to systematically evaluate the effects of dairy consumption on body weight and body composition among the adults.

METHODS AND RESULTS

We conducted a comprehensive search of the Cochrane Library, PubMed, and Embase databases of the relevant studies from 1966 to Mar 2017 regarding dairy consumption on body weight and body composition including body fat, lean mass, and waist circumference (WC). The summary results are pooled by using a random-effects meta-analysis. Thirty-seven RCTs with 184 802 participants are included in this meta-analysis. High dairy intervention increased body weight (0.01, 95% CI: -0.25, 0.26, I² = 78.3%) and lean mass (0.37, 95% CI: 0.11, 0.62, I² = 83.4%); decreased body fat (-0.23, 95% CI: -0.48, 0.02, I² = 78.2%) and WC (-1.37, 95% CI: -2.28, -0.46, I² = 98.9%) overall. In the subgroup analysis, we found that consumption of dairy products increases body weight (0.36, 95% CI: 0.01, 0.70, I² = 83.1%) among participants without energy restriction. Dairy consumption decreases body weight (-0.64, 95% CI: -1.05, -0.24, I² = 60.2%), body fat (-0.56, 95%CI: -0.95, -0.17, I² = 66.6%), and waist circumference (-2.18, 95%CI: -4.30, -0.06, I² = 99.0%) among the adults with energy restriction.

CONCLUSIONS

This meta-analysis suggests a beneficial effect of energy-restricted dairy consumption on body weight and body composition. However, high dairy consumption in the absence of caloric restriction may increase body weight.

Prevalence and factors associated with nonalcoholic fatty pancreas disease and its severity in China

Pancreatic lipidosis (nonalcoholic fatty pancreas disease, NAFPD) causes insulin resistance and dysfunction of pancreatic β-cells, with the risk of type 2 diabetes mellitus (T2DM). However, the prevalence and pathogenic factors associated with NAFPD are not clear. The aim of the study was to explore the prevalence of NAFPD in a Chinese adult population, and investigate factors associated with NAFPD aggravation.This was a cross-sectional study; 4419 subjects were enrolled for NAFPD screening and were divided into NAFPD (n = 488) and without NAFPD (n = 3930) groups. The sex, age, related concomitant diseases, general physical parameters, and serum glucose and lipid metabolism were compared between the 2 groups.The overall NAFPD prevalence was 11.05%, but increased with age. In those <55 years NAFPD prevalence was lower in females than males (P < .05), but prevalence was similar >55 years. Nonalcoholic fatty liver disease (NAFLD), T2DM, homeostasis model assessment-insulin resistance index, total cholesterol, triglyceride, lipoprotein, adiponectin, and glucagon-like peptide 1 (GLP-1) were the independent risk factors for NAFPD (P < .05). Analaysis of mild NAFPD (MN) and severe NAFPD (SN) subgroups, according to the extent of fat deposition, suggested that NAFLD, triglyceride, lipoprotein, and adiponectin were independent risk factors for NAFPD aggravation (P < .05).The NAFPD prevalence was about 11% in Chinese adults. Its development and progression was related to NAFLD, T2DM, insulin resistance, dyslipidemia, and GLP-1 levels. Severe NAFPD was associated with NAFLD and dyslipidemia.

Food pyramid for subjects with chronic pain: foods and dietary constituents as anti-inflammatory and antioxidant agents

Emerging literature suggests that diet constituents may play a modulatory role in chronic pain (CP) through management of inflammation/oxidative stress, resulting in attenuation of pain. We performed a narrative review to evaluate the existing evidence regarding the optimum diet for the management of CP, and we built a food pyramid on this topic. The present review also describes the activities of various natural compounds contained in foods (i.e. phenolic compounds in extra-virgin olive oil (EVO)) listed on our pyramid, which have comparable effects to drug management therapy. This review included 172 eligible studies. The pyramid shows that carbohydrates with low glycaemic index should be consumed every day (three portions), together with fruits and vegetables (five portions), yogurt (125 ml), red wine (125 ml) and EVO; weekly: legumes and fish (four portions); white meat, eggs and fresh cheese (two portions); red or processed meats (once per week); sweets can be consumed occasionally. The food amounts are estimates based on nutritional and practical considerations. At the top of the pyramid there is a pennant: it means that CP subjects may need a specific customised supplementation (vitamin B12, vitamin D, n-3 fatty acids, fibre). The food pyramid proposal will serve to guide dietary intake with to the intent of alleviating pain in CP patients. Moreover, a targeted diet can also help to solve problems related to the drugs used to combat CP, i.e. constipation. However, this paper would be an early hypothetical proposal due to the limitations of the studies.

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.

Dairy consumption and inflammatory profile: A cross-sectional population-based study, São Paulo, Brazil

OBJECTIVES

The aim of this study was to investigate the association between dairy product consumption and plasma inflammatory biomarkers levels among a representative sample of Brazilian adults from São Paulo City.

METHODS

Data were acquired from the Health Survey for São Paulo, a cross-sectional population-based study. All individuals 20 to 59 y of age with complete food consumption information (24-h dietary recall and food frequency questionnaire) and blood sample analysis were included (N = 259). The sample was separated into two groups according to systemic inflammatory pattern considering plasma levels of C-reactive protein; tumor necrosis factor-α; soluble intracellular adhesion molecule; soluble vascular cell adhesion molecule, monocyte chemoattractant protein; interleukin-1β, -6, -8, -10, and -12; adiponectin; leptin; and homocysteine. Multiple logistic regression tests were conducted to estimate the odds ratio for the inflammatory cluster across tertiles of dairy consumption.

RESULTS

When adjusted by age, smoking status, and energy intake the odds ratio for the inflammatory cluster group in the highest tertile of yogurt consumption was 0.34 (95% confidence interval [CI], 0.14-0.81) relative to the reference tertile, demonstrating also a linear effect (P_trend = 0.015). Cheese consumption exhibited an odds ratio of 2.49 (95% CI, 1.09-5.75) relative to the reference.

CONCLUSIONS

Increasing yogurt consumption might have a protective effect on inflammation, whereas cheese consumption appears to be associated with a proinflammatory status. The results of the present study aggregate a new perspective on existing evidence demonstrating the importance of assessing the contribution of dairy products on diet and their effect on the development of non-communicable diseases and associated risk factors.

Does dietary fat affect inflammatory markers in overweight and obese individuals?-a review of randomized controlled trials from 2010 to 2016

Background

Obesity, a major cause of death and disability, is increasing worldwide. Obesity is characterized by a chronic, low-grade inflammatory state which is suggested to play a critical role in the development of obesity-related diseases like cardiovascular diseases and type 2 diabetes. In fact, in the hours following consumption of a meal, a transient increase in inflammatory markers occurs, a response that is exaggerated in obese subjects. Dietary composition, including content of dietary fatty acids, may affect this inflammatory response both acutely and chronically, and thereby be predictive of progression of disease. The aim of the review was to summarize the literature from 2010 to 2016 regarding the effects of dietary fat intake on levels of inflammatory markers in overweight and obesity in human randomized controlled trials.

Methods and results

We performed a literature search in MEDLINE, EMBASE, and PubMed databases. The literature search included human randomized controlled trials, both postprandial and long-term interventions, from January 2010 to September 2016. In total, 37 articles were included. Interventions with dairy products, vegetable oils, or nuts showed minor effects on inflammatory markers. The most consistent inflammatory-mediating effects were found in intervention with whole diets, which suggests that many components of the diet reduce inflammation synergistically. Furthermore, interventions with weight reduction and different fatty acids did not clearly show beneficial effects on inflammatory markers.

Conclusion

Most interventions showed either no or minor effects of dietary fat intake on inflammatory markers in overweight and obese subjects. To progress our understanding on how diet and dietary components affect our health, mechanistic studies are required. Hence, future studies should include whole diets and characterization of obese phenotypes at a molecular level, including omics data and gut microbiota.

Changes in Lipids and Inflammatory Markers after Consuming Diets High in Red Meat or Dairy for Four Weeks

There is a body of evidence linking inflammation, altered lipid metabolism, and insulin resistance. Our previous research found that insulin sensitivity decreased after a four-week diet high in dairy compared to a control diet and to one high in red meat. Our aim was to determine whether a relationship exists between changes in insulin sensitivity and inflammatory biomarkers, or with lipid species. Fasting Tumor Necrosis Factor alpha (TNF-α), Tumor Necrosis Factor Receptor II (sTNF-RII), C-reactive protein (CRP), and lipids were measured at the end of each diet. TNF-α and the ratio TNF-α/sTNF-RII were not different between diets and TNF-α, sTNF-RII, or the ratio TNF-α/sTNF-RII showed no association with homeostasis model assessment-estimated insulin resistance (HOMA-IR). A number of phosphatidylethanolamine (PE) and phosphatidylinositol (PI) species differed between dairy and red meat and dairy and control diets, as did many phosphatidylcholine (PC) species and cholesteryl ester (CE) 14:0, CE15:0, lysophosphatidylcholine (LPC) 14:0, and LPC15:0. None had a significant relationship (p = 0.001 or better) with log homeostasis model assessment-estimated insulin resistance (HOMA-IR), although LPC14:0 had the strongest relationship (p = 0.004) and may be the main mediator of the effect of dairy on insulin sensitivity. LPC14:0 and the whole LPC class were correlated with CRP. The correlations between dietary change and the minor plasma phospholipids PI32:1 and PE32:1 are novel and may reflect significant changes in membrane composition. Inflammatory markers were not altered by changes in protein source while the correlation of LPC with CRP confirms a relationship between changes in lipid profile and inflammation.

Invited review: The anti-inflammatory properties of dairy lipids

Dairy product consumption is often associated with negative effects because of its naturally high levels of saturated fatty acids. However, recent research has shown that dairy lipids possess putative bioactivity against chronic inflammation. Inflammation triggers the onset of several chronic diseases, including cardiovascular disease, type 2 diabetes mellitus, obesity, and cancer. This review discusses the anti-inflammatory properties of dairy lipids found in milk, yogurt, and cheese, and it examines them in relation to their implications for human health: their protective effects and their role in pathology. We also consider the effect of lipid profile alteration in dairy products-by using ruminant dietary strategies to enrich the milk, or by lipid fortification in the products. We critically review the in vivo, in vitro, ex vivo, and epidemiological studies associated with these dairy lipids and their role in various inflammatory conditions. Finally, we discuss some suggestions for future research in the study of bioactive lipids and dairy products, with reference to the novel field of metabolomics and epidemiological studies.

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.

Association between serum soluble tumor necrosis factor-α receptors and early childhood obesity

This study aimed to characterize the inflammatory cytokine profiles and further validate the significantly different cytokines in the serum obtained from obese children aged 36-48 months. Four obese children and four lean controls were randomly selected for inflammatory cytokine array assay, in which two cytokines [soluble tumor necrosis factor-α receptors (sTNFRs) 1 and 2] were found to be significantly different. Both cytokines (sTNFR1 and sTNFR2) were then further validated through enzyme-linked immunosorbent assay (ELISA) in 61 obese children and 52 lean children. ELISA results revealed that serum sTNFR1 level in obese children significantly increased (p = 0.003), whereas sTNFR2 did not change significantly (p = 0.069). Stratified analysis by gender showed that only obese girls presented increased sTNFR1 (p = 0.005) and sTNFR2 (p = 0.049) levels. We conclude that serum sTNFR1 is elevated in early childhood obesity. Moreover, serum sTNFR1 and sTNFR2 are associated with obese girls but not obese boys, thereby suggesting that serum sTNFRs in early childhood obesity may be sex related.

Protective role of dairy and its constituents on vascular function independent of blood pressure-lowering activities

Greater intakes of dairy are frequently associated with reduced risk of cardiovascular disease. These observational studies have served as the basis for controlled interventions aimed at defining the cardioprotective mechanisms of dairy. Understanding these relationships is of public health importance because most of the US population fails to meet dietary recommendations for dairy, suggesting that many individuals could lower their cardiovascular disease risk by relatively simple dietary modification. Clinical studies investigating the acute ingestion of dairy or its constituents, including short-term (≤2 week) supplementation studies or those assessing postprandial responses, have largely shown benefits on vascular function without concomitant improvements in blood pressure. Chronic interventions have been less conclusive, with some showing benefits and others indicating a lack of improvement in vascular function regardless of blood pressure changes. Vasoprotective activities of dairy are likely mediated through improvements in nitric oxide bioavailability, oxidative stress, inflammation, and insulin resistance. Future controlled studies are needed to determine if these health benefits are mediated directly by dairy or indirectly by displacing other dietary components that otherwise impair vascular health.

Effects of calcium supplementation on biomarkers of inflammation and oxidative stress in colorectal adenoma patients: a randomized controlled trial

Inflammation and oxidative stress play important roles in colorectal carcinogenesis. There is strong evidence that calcium reduces risk for colorectal neoplasms, possibly through its ability to bind bile acids and prevent their colonic toxicity (which occurs via an oxidative mechanism and results in an inflammatory response). In a previously reported pilot, randomized, controlled trial among sporadic colorectal adenoma patients we found that those on 2.0 g/day of calcium, relative to those on placebo, had an estimated drop in a combined cytokine z-score of 48% (P = 0.18) over 6 months. To follow-up these promising preliminary findings, we tested the efficacy of two doses of supplemental calcium (1.0 or 2.0 g/day) relative to placebo on modulating circulating biomarkers of inflammation [C-reactive protein (CRP) and 10 cytokines] and oxidative stress (F2-isoprostanes) over a 4-month treatment period among 193 patients with previous sporadic, colorectal adenoma in a randomized, double-blinded, placebo-controlled clinical trial. The inflammation markers were measured in plasma using electrochemiluminescence detection-based immunoassays, and F2-isoprostanes were measured in plasma using gas chromatography-mass spectrometry. Over a 4-month treatment period, we found no appreciable effects of calcium on CRP, cytokines, or F2-isoprostanes (P > 0.4), overall or within strata of several major risk factors for colorectal carcinogenesis, such as body mass index and regular use of nonsteroidal anti-inflammatory drugs. Overall, our results provide no evidence that calcium supplementation favorably modulates concentrations of circulating biomarkers of inflammation or oxidative stress over 4 months among patients with a previous colorectal adenoma.

Dairy consumption and insulin sensitivity: a systematic review of short- and long-term intervention studies

AIM

Evidence from epidemiological studies suggests that higher consumption of dairy products may be inversely associated with risk of type 2 diabetes and other components of the metabolic syndrome, although the evidence is mixed. Intervention studies that increase dairy intake often involve lifestyle changes, including weight loss, which alone will improve insulin sensitivity. The aim of this review was to examine weight stable intervention studies that assess the effect of an increased intake of dairy products or dairy derived supplements on glucose metabolism and insulin sensitivity.

DATA SYNTHESIS

An electronic search was conducted using MEDLINE, EMBASE, the Cochrane Database and Web of Science for randomised controlled trials altering only dairy intake in humans with no other lifestyle or dietary change, particularly no weight change, and with measurement of glucose or insulin. Healthy participants and those with features of the metabolic syndrome were included. Chronic whey protein supplementation was also included. Ten studies were included in this systematic review.

CONCLUSIONS

In adults, four of the dairy interventions showed a positive effect on insulin sensitivity as assessed by Homeostasis Model Assessment (HOMA); one was negative and five had no effect. As the number of weight stable intervention studies is very limited and participant numbers small, these findings need to be confirmed by larger trials in order to conclusively determine any relationship between dairy intake and insulin sensitivity.

Dairy product consumption has no impact on biomarkers of inflammation among men and women with low-grade systemic inflammation

BACKGROUND

Randomized controlled trials specifically designed to assess inflammation-related outcomes in response to dairy consumption are lacking.

OBJECTIVE

We investigated the impact of dairy food consumption on biomarkers of inflammation in healthy men and women with low-grade systemic inflammation.

METHODS

In a multicenter randomized crossover study, 112 adult men and women with high-sensitivity C-reactive protein (hs-CRP) values >1 mg/L consumed 3 servings/d of dairy (375 mL low-fat milk, 175 g low-fat yogurt, and 30 g regular-fat cheddar cheese) or energy-matched control (fruit juice, vegetable juice, cashews, and 1 cookie) products as part of prudent 4-wk diets, each separated by a 4- to 8-wk washout period. Serum concentrations of inflammation biomarkers were measured at the beginning and end of each dietary phase. Expression levels of key inflammatory genes and transcription factors in whole blood cells were assessed at the end of each diet by real-time polymerase chain reaction in a random subset of 53 subjects.

RESULTS

Analysis of within-diet changes (post- vs. prediet values) showed a significant reduction in hs-CRP concentrations after the control diet (-11.7%, P = 0.05) but no change after the dairy diet (-7.3%, P = 0.47). As a result, changes in hs-CRP differed between the dairy and control diets (P = 0.04). Both the control and dairy diets similarly reduced interleukin-6 concentrations compared with diet-specific baseline values (-17.6% and -19.9%, respectively; P < 0.0001 for both, P = 0.77 for between-diet comparison). No between- or within-diet difference was observed in adiponectin concentrations, and there was also no between-diet difference in the expression of inflammatory genes and transcription factors.

CONCLUSION

Consistent with data from previous work, these results suggest that short-term consumption of a combination of low- and high-fat dairy products as part of a healthy diet has no adverse effects on inflammation. This trial was registered at www.clinicaltrials.gov as NCT01444326.

Dairy products on metabolic health: current research and clinical implications

Dairy products have been thought to have a beneficial role in the metabolic syndrome (MetS). MetS constitutes a cluster of risk factors for an increased mortality, including obesity, impaired glucose homeostasis, hypertension and atherogenic dyslipidemia. Individuals with MetS are also often in a chronic, low-grade inflammatory state. The objective of this review is to examine recent meta-analyses and clinical studies on the association between dairy products consumption and these MetS risk factors. Findings from studies demonstrate that weight loss related to dairy product intake is due to the combination of an energy-restricted diet with consumption of dairy products. Further, a limited number of studies have shown beneficial effects of dairy consumption on plasma lipids, blood pressure, glucose homeostasis or inflammatory and oxidative stress profiles. Overall, this review article suggests that adults should consume at least 2-3 servings of dairy products per day within a well-balanced diet and a healthy lifestyle for metabolic health. Yet, higher dairy product consumption may have additional beneficial effects, but more well-designed intervention studies are needed to ascertain these effects.

Effects of high and low fat dairy food on cardio-metabolic risk factors: a meta-analysis of randomized studies

IMPORTANCE

Clear guidelines on the health effects of dairy food are important given the high prevalence of obesity, cardiovascular disease and diabetes, and increasing global consumption of dairy food.

OBJECTIVE

To evaluate the effects of increased dairy food on cardio metabolic risk factors.

DATA SOURCES

Searches were performed until April 2013 using MEDLINE, Science Direct, Google,Embase, the Cochrane Central Register of Controlled Trials, reference lists of articles, and proceedings of major meetings.

STUDY SELECTION

Randomized controlled studies with healthy adults randomized to increased dairy food for more than one month without additional interventions.

DATA EXTRACTION AND SYNTHESIS

A standard list was used to extract descriptive, methodological and key variables from all eligible studies. If data was not included in the published report corresponding authors were contacted.

RESULTS

20 studies with 1677 participants with a median duration of dietary change of 26 (IQR 10-39) weeks and mean increase in dairy food intake of 3.6 (SD 0.92) serves/day were included. Increased dairy food intake was associated with a modest weight gain (+0.59, 95% confidence interval 0.34 to 0.84kg, p<0.0001) but no significant change in waist circumference (0.35 , -0.75 to 1.45 cm); insulin resistance (HOMA –IR -0.94 , -1.93 to 0.05 units); fasting glucose (0.87, -0.27 to 2.01 mg/dl); LDL-cholesterol (1.36 ,-2.38 to 5.09 mg/dl); HDL-cholesterol (0.45, -2.13 to 3.04 mg/dl); systolic (-0.13, -1.73 to 1.98 mmHg) and diastolic blood pressure (0.13, -1.73 to 1.98 mmHg) or C-reactive protein (-0.08, -0.63 to 0.48 mg/L). Results were similar for studies with low-fat and whole-fat dairy interventions.

LIMITATIONS

Most clinical trials were small and of modest quality. .

CONCLUSION

Increasing whole fat and low fat dairy food consumption increases weight but has minor effects on other cardio-metabolic risk factors.

TRIAL REGISTRATION ACTRN

Australian New Zealand Clinical Trials Registry ACTRN12613000401752, http://www.anzctr.org.au.

ETHICS APPROVAL NUMBER

NTX/10/11/115.

Monitoring immune modulation by nutrition in the general population: identifying and substantiating effects on human health

Optimal functioning of the immune system is crucial to human health, and nutrition is one of the major exogenous factors modulating different aspects of immune function. Currently, no single marker is available to predict the effect of a dietary intervention on different aspects of immune function. To provide further guidance on the assessment and interpretation of the modulation of immune functions due to nutrition in the general population, International Life Sciences Institute Europe commissioned a group of experts from academia, government and the food industry to prepare a guidance document. A draft of this paper was refined at a workshop involving additional experts. First, the expert group defined criteria to evaluate the usefulness of immune function markers. Over seventy-five markers were scored within the context of three distinct immune system functions: defence against pathogens; avoidance or mitigation of allergy; control of low-grade (metabolic) inflammation. The most useful markers were subsequently classified depending on whether they by themselves signify clinical relevance and/or involvement of immune function. Next, five theoretical scenarios were drafted describing potential changes in the values of markers compared with a relevant reference range. Finally, all elements were combined, providing a framework to aid the design and interpretation of studies assessing the effects of nutrition on immune function. This stepwise approach offers a clear rationale for selecting markers for future trials and provides a framework for the interpretation of outcomes. A similar stepwise approach may also be useful to rationalise the selection and interpretation of markers for other physiological processes critical to the maintenance of health and well-being.

Effects of low-fat or full-fat fermented and non-fermented dairy foods on selected cardiovascular biomarkers in overweight adults

The association between consumption of full-fat dairy foods and CVD may depend partly on the nature of products and may not apply to low-fat dairy foods. Increased circulating levels of inflammatory biomarkers after consumption of dairy product-rich meals suggest an association with CVD. In the present study, we tested the effects of low-fat and full-fat dairy diets on biomarkers associated with inflammation, oxidative stress or atherogenesis and on plasma lipid classes. Within full-fat dairy diets, we also compared fermented v. non-fermented products. In a randomised cross-over study, twelve overweight/obese subjects consumed during two 3-week periods two full-fat dairy diets containing either yogurt plus cheese (fermented) or butter, cream and ice cream (non-fermented) or a low-fat milk plus yogurt diet, with the latter being consumed between and at the end of the full-fat dairy dietary periods. The concentrations of six inflammatory and two atherogenic biomarkers known to be raised in CVD were measured as well as those of plasma F2-isoprostanes and lipid classes. The concentrations of six of the eight biomarkers tended to be higher on consumption of the low-fat dairy diet than on that of the fermented dairy diet and the concentrations of two plasmalogen lipid classes reported to be associated with increased oxidisability were also higher on consumption of the low-fat dairy diet than on that of the fermented dairy diet (P< 0.001), although plasma F2-isoprostane concentrations did not differ on consumption of any of the diets. On the other hand, the concentrations of plasma sphingomyelin and IL-6 were significantly higher on consumption of the non-fermented dairy diet than on that of the low-fat dairy diet (P< 0.02). In conclusion, short-term diets containing low-fat dairy products did not lead to a more favourable biomarker profile associated with CVD risk compared with the full-fat dairy products, suggesting that full-fat fermented dairy products may be the more favourable.

Impact of dairy products on biomarkers of inflammation: a systematic review of randomized controlled nutritional intervention studies in overweight and obese adults

BACKGROUND

Recent data from cross-sectional studies suggest that consumption of dairy products is inversely associated with low-grade systemic inflammation, but a cause-and-effect relation can be confirmed only with results from randomized controlled trials.

OBJECTIVE

We reviewed the results of randomized controlled nutritional intervention studies that have assessed the impact of dairy product consumption (ie, milk, yogurt, and/or cheese) on biomarkers of inflammation in adults (aged ≥18 y).

DESIGN

We performed a systematic literature search in PubMed in April 2012, which was limited to randomized controlled trials in humans published in English. Studies that included pregnant or lactating women or that did not include a low-dairy control intervention were excluded.

RESULTS

Eight trials that were conducted in overweight or obese adults were included in the review. The only study that had identified change in the inflammatory profile as its primary outcome measure showed that dairy food consumption improved pro- and antiinflammatory biomarker concentrations compared with the low-dairy control diet. Three of the 7 studies in which inflammation was a secondary or undefined outcome showed improvement in key inflammatory biomarkers, ie, C-reactive protein, IL-6, or TNF-α after dairy product consumption, whereas the other 4 studies showed no effect.

CONCLUSIONS

Dairy product consumption does not exert adverse effects on biomarkers of inflammation in overweight or obese adults. Several methodologic factors and limitations among existing studies do not allow differentiation between a beneficial or neutral impact of dairy products on inflammation. Further studies specifically designed to assess inflammation-related outcomes are warranted.

Effect of flavonoids on circulating levels of TNF-α and IL-6 in humans: a systematic review and meta-analysis

Epidemiological or in vitro evidence suggests a potential role for flavonoids as anti-inflammatory agents; we investigated the effect of flavonoids-rich foods or supplements on tumor necrosis factor- alpha (TNF-α) and interleukin-6 (IL-6) in long-term placebo-controlled human intervention trials. From 110 human intervention studies selected (MEDLINE, EMBASE, CHORANE, and FSTA databases), 32 long-term placebo-controlled trials were suitable for meta-analysis. After sensitivity analysis, seven studies imputed of bias were excluded and 25 studies were analyzed (TNF-α, n = 2404; IL-6, n = 2174). Levels of TNF-α decreased after flavonoid consumption in the fixed model only (mean difference (MD) (95% CI): -0.098 (-0.188, -0.009), p = 0.032), but metaregression results showed that neither higher dose, nor a longer duration of intervention were associated with a greater effect size. Subgroup analysis did not reveal any significant effect for quercetin and soy, but other sources (red wine, pomegranate, and tea extracts) showed a significant effect size both in fixed (MD (95% CI): TNF-α -0.449 (-0.619, -0.280), p < 0.001; IL-6 -0.346 (-0.612, -0.079), p = 0.011) and random (MD (95% CI): TNF-α -0.783 (-1.476, -0.090), p = 0.027; IL-6, -0.556 (-1.062, -0.050), p = 0.031) effect models. High-quality placebo-controlled trials are needed in order to identify flavonoids as the active ingredients.

Meeting and exceeding dairy recommendations: effects of dairy consumption on nutrient intakes and risk of chronic disease

The 2010 Dietary Guidelines for Americans indicate the US population is experiencing an epidemic of overweight and obesity while maintaining a nutrient-poor, energy-dense diet associated with an increased risk of osteoarthritis, cardiovascular disease, and type 2 diabetes. To build upon the review of published research in the Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010, this article aims to review the scientific literature pertaining to the consumption of dairy foods and the effects of dairy consumption on nutrient intakes and chronic disease risk published between June 2010, when the report was released, and September 2011. PubMed was searched for articles using the following key words: dairy, milk, nutrient intake, bone health, body composition, cardiovascular disease, type 2 diabetes, and blood pressure. Evidence indicates that increasing dairy consumption to the recommended amount, i.e., three servings daily for individuals ≥9 years of age, helps close gaps between current nutrient intakes and recommendations. Consuming more than three servings of dairy per day leads to better nutrient status and improved bone health and is associated with lower blood pressure and reduced risk of cardiovascular disease and type 2 diabetes.

Effects of dairy intake on body weight and fat: a meta-analysis of randomized controlled trials

BACKGROUND

Some intervention studies have suggested that dairy products may influence body weight, but the results remain controversial.

OBJECTIVE

We identified and quantified the effects of dairy consumption on body weight and fat mass from randomized controlled trials (RCTs).

DESIGN

We conducted a comprehensive search of PubMed and EMBASE databases (to April 2012) of English reports of RCTs regarding dairy consumption on body weight, body fat, or body weight and body fat in adults. The results across studies were pooled by using a random-effects meta-analysis.

RESULTS

Twenty-nine RCTs were included with a total of 2101 participants. Overall, consumption of dairy products did not result in a significant reduction in weight (-0.14 kg; 95% CI: -0.66, 0.38 kg; I² = 86.3%). In subgroup analysis, consumption of dairy products reduced body weight in the context of energy restriction or short-term intervention (<1 y) trials but had the opposite effect in ad libitum dietary interventions or long-term trials (≥1 y). Twenty-two RCTs that reported results on body fat showed a modest reduction in the dairy group (-0.45 kg; 95% CI: -0.79, -0.11 kg; I² = 70.9%), and further stratified analysis indicated significant beneficial effects of dairy intervention on body fat in energy-restricted or short-term trials but not in long-term or ad libitum studies.

CONCLUSIONS

This meta-analysis does not support the beneficial effect of increasing dairy consumption on body weight and fat loss in long-term studies or studies without energy restriction. However, dairy products may have modest benefits in facilitating weight loss in short-term or energy-restricted RCTs.

Dairy constituents and neurocognitive health in ageing

Age-related cognitive decline (ARCD) and dementia are of increasing concern to an ageing population. In recent years, there has been considerable research focused on effective dietary interventions that may prevent or ameliorate ARCD and dementia. While a number of studies have considered the impact that dairy products may have on physiological health, particularly with regard to the metabolic syndrome and cardiovascular health, further research is currently needed in order to establish the impact that dairy products have in the promotion of healthy brain function during ageing. The present review considers the available evidence for the positive effects of dairy products on the metabolic syndrome and glucose regulation, with consideration of the implications for neurocognitive health. A literature search of current (September 2010) meta-analyses/reviews and original research regarding dairy products and cognition was conducted through SCOPUS using the following search terms for dairy consituents: dairy, milk, cheese, yoghurt, probiotics, whey protein, alpha lactalbumin, calcium, B-12, bioactive peptides and colostrinin (CLN). These search terms for dairy products were combined with the following search terms related to cognition and health: cognition, cognitive decline, dementia, Alzheimer's disease, metabolic syndrome, diabetes, insulin resistance and glucose regulation. Concerns regarding SFA and other fatty acids found in dairy products are also reviewed in relation to different forms of dairy products. The review also considers recent evidence for positive neurocognitive effects associated with bioactive peptides, CLN and proline-rich polypeptides, α-lactalbumin, vitamin B12, calcium and probiotics. Future directions for the extraction and purification of beneficial constituents are also discussed. It is concluded that low-fat dairy products, when consumed regularly as part of a balanced diet, may have a number of beneficial outcomes for neurocognitive health during ageing.

Does calcium intake affect cardiovascular risk factors and/or events?

Dietary intervention is an important approach in the prevention of cardiovascular disease. Over the last decade, some studies have suggested that a calcium-rich diet could help to control body weight, with anti-obesity effects. The potential mechanism underlying the impact of calcium on body fat has been investigated, but it is not fully understood. Recent evidence has also suggested that a calcium-rich diet could have beneficial effects on other cardiovascular risk factors, such as insulin resistance, dyslipidemia, hypertension and inflammatory states. In a series of studies, it was observed that a high intake of milk and/or dairy products (the main sources of dietary calcium) is associated with a reduction in the relative risk of cardiovascular disease. However, a few studies suggest that supplemental calcium (mainly calcium carbonate or citrate) may be associated with an increased risk of cardiovascular events. This review will discuss the available evidence regarding the relationship between calcium intake (dietary and supplemental) and different cardiovascular risk factors and/or events.

Dairy consumption and cardiometabolic health: outcomes of a 12-month crossover trial

Background

A growing body of research suggests that regular consumption of dairy foods may counteract obesity and other components of the metabolic syndrome. However, human intervention trials are lacking. We aimed to determine the cardiometabolic health effects of increasing the consumption of reduced fat dairy foods in adults with habitually low dairy intakes in the absence of energy restriction.

Methods

An intervention trial was undertaken in 61 overweight or obese adults who were randomly assigned to a high dairy diet (HD, 4 serves of reduced fat dairy/day) or a low dairy control diet (LD, ≤1 serve/day) for 6 months then crossed over to the alternate diet for a further 6 months. A range of anthropometric and cardiometabolic parameters including body composition, metabolic rate, blood lipids, blood pressure and arterial compliance were assessed at the end of each diet phase.

Results

Total energy intake was 1120 kJ/day higher during the HD phase, resulting in slight weight gain during this period. However, there were no significant differences between HD and LD in absolute measures of waist circumference, body weight, fat mass or any other cardiometabolic parameter.

Conclusion

Recommended intakes of reduced fat dairy products may be incorporated into the diet of overweight adults without adversely affecting markers of cardiometabolic health.

Trial Registration

The trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12608000538347) on 24th October, 2008.

Role of dietary proteins and peptides in cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death for both men and women in the United States and most other countries. Therefore, a disease of such wide-ranging impact calls for the development of multiple viable strategies for prevention. Diet plays an important role in the development of the major risk factors of CVD such as low-grade systemic inflammation, hypertension, obesity, diabetes and atherosclerosis, the most significant. Thus, diet-based methods of prevention would not only be more feasible, but ultimately more cost-effective than relying on drugs to combat this condition. In recent years, peptides derived from either animal or plant sources have been found to have various bioactive properties. Nevertheless, their potential impact on inflammation and prevention of atherosclerosis has not been fully explored, particularly at the molecular level. In this review, the most current scientific information from in vitro, in vivo and clinical studies on the role of dietary proteins and peptides on CVD has been summarized and discussed.

Dairy attentuates oxidative and inflammatory stress in metabolic syndrome

BACKGROUND

Oxidative and inflammatory stress are elevated in obesity and are further augmented in metabolic syndrome. We showed previously that dairy components suppress the adipocyte- and macrophage-mediated generation of reactive oxygen species and inflammatory cytokines and systemic oxidative and inflammatory biomarkers in obesity.

OBJECTIVE

The objective of this study was to determine the early (7 d) and sustained (4 and 12 wk) effects of adequate-dairy (AD) compared with low-dairy (LD) diets in subjects with metabolic syndrome.

DESIGN

Forty overweight and obese adults with metabolic syndrome were randomly assigned to receive AD (3.5 daily servings) or LD (<0.5 daily servings) weight-maintenance diets for 12 wk. Oxidative and inflammatory biomarkers were assessed at 0, 1, 4, and 12 wk as primary outcomes; body weight and composition were measured at 0, 4, and 12 wk as secondary outcomes.

RESULTS

AD decreased malondialdehyde and oxidized LDL at 7 d (35% and 11%, respectively; P < 0.01), with further decreases by 12 wk. Inflammatory markers were suppressed with intake of AD, with decreases in tumor necrosis factor-α at 7 d and further reductions through 12 wk (35%; P < 0.05); decreases in interleukin-6 (21%; P < 0.02) and monocyte chemoattractant protein 1 (14% decrease at 4 wk, 24% decrease at 12 wk; P < 0.05); and a corresponding 55% increase in adiponectin at 12 wk (P < 0.01). LD exerted no effect on oxidative or inflammatory markers. Diet had no effect on body weight; however, AD significantly reduced waist circumference and trunk fat (P < 0.01 for both), and LD exerted no effect.

CONCLUSION

An increase in dairy intake attenuates oxidative and inflammatory stress in metabolic syndrome. This trial was registered at clinicaltrials.gov as NCT01266330.