Effects of low-fat milk consumption on metabolic and atherogenic biomarkers in Korean adults with the metabolic syndrome: a randomised controlled trial

Dairy products and constituents: a review of their effects on obesity and related metabolic diseases

Obesity has become a global public health problem that seriously affects the quality of life. As an important part of human diet, dairy products contain a large number of nutrients that are essential for maintaining human health, such as proteins, peptides, lipids, vitamins, and minerals. A growing number of epidemiological investigations provide strong evidence on dairy interventions for weight loss in overweight/obese populations. Therefore, this paper outlines the relationship between the consumption of different dairy products and obesity and related metabolic diseases. In addition, we dive into the mechanisms related to the regulation of glucose and lipid metabolism by functional components in dairy products and the interaction with gut microbes. Lastly, the role of dairy products on obesity of children and adolescents is revisited. We conclude that whole dairy products exert more beneficial effect than single milk constituent on alleviating obesity and that dairy matrix has important implications for metabolic health.

Exploratory analysis of the effect of a controlled lifestyle intervention on inflammatory markers - the Healthy Lifestyle Community Programme (cohort 2)

BACKGROUND

Chronic low-grade inflammation is associated with an increased risk of chronic disease and mortality. The objective of the study was to test the effect of a healthy lifestyle intervention on biomarkers of inflammation (among other risk markers).

METHODS

We conducted a non-randomized controlled trial with mostly middle-aged and elderly participants from the general population in rural northwest Germany (intervention: n = 114; control: n = 87). The intervention consisted of a 1-year lifestyle programme focusing on diet (largely plant-based; strongest emphasis), physical activity, stress management, and social support. High-sensitivity C-reactive protein (hs-CRP) was assessed at baseline, 10 weeks, 6 months, and 1 year. Homocysteine (Hcy) was assessed at baseline, 10 weeks, and 1 year. Adiponectin (Apn) was assessed at baseline and 10 weeks. An exploratory analysis of these inflammatory markers assessing the between-group differences with ANCOVA was conducted.

RESULTS

The 1-year trajectory of hs-CRP was significantly lower in the intervention group compared to control (between-group difference: -0.8 (95% CI -1.2, -0.3) mg/l; p = 0.001; adjusted for baseline). The 1-year trajectory of Hcy was non-significantly higher in the intervention compared to control (between-group difference: 0.2 (95% CI -0.3, 0.7) µmol/l; p = 0.439; adjusted for baseline). From baseline to 10 weeks, Apn decreased significantly more in the intervention group compared to control (between-group difference: -1.6 (95% CI -2.7, -0.5) µg/ml; p = 0.004; adjusted for baseline).

CONCLUSIONS

Our study shows that healthy lifestyle changes can lower hs-CRP and Apn levels and are unlikely to significantly affect Hcy levels within 1 year.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS; reference: DRKS00018775 , registered 12 Sept 2019; retrospectively registered; www.drks.de ).

The Effect of Dietary Interventions on Hypertriglyceridemia: From Public Health to Molecular Nutrition Evidence

Approximately 25–50% of the population worldwide exhibits serum triglycerides (TG) (≥150 mg/dL) which are associated with an increased level of highly atherogenic remnant-like particles, non-alcoholic fatty liver disease, and pancreatitis risk. High serum TG levels could be related to cardiovascular disease, which is the most prevalent cause of mortality in Western countries. The etiology of hypertriglyceridemia (HTG) is multifactorial and can be classified as primary and secondary causes. Among the primary causes are genetic disorders. On the other hand, secondary causes of HTG comprise lifestyle factors, medical conditions, and drugs. Among lifestyle changes, adequate diets and nutrition are the initial steps to treat and prevent serum lipid alterations. Dietary intervention for HTG is recommended in order to modify the amount of macronutrients. Macronutrient distribution changes such as fat or protein, low-carbohydrate diets, and caloric restriction seem to be effective strategies in reducing TG levels. Particularly, the Mediterranean diet is the dietary pattern with the most consistent evidence for efficacy in HTG while the use of omega-3 supplements consumption is the dietary component with the highest number of randomized clinical trials (RCT) carried out with effective results on reducing TG. The aim of this review was to provide a better comprehension between human nutrition and lipid metabolism.

Unraveling the molecular mechanisms of hyperlipidemia using integrated lncRNA and mRNA microarray data

Long non-coding RNAs (lncRNAs) have key roles in various diseases; however, their functions in hyperlipidemia (HLP) have remained elusive. In the present study, microarray technology was utilized to analyze the differential expression of lncRNAs and mRNAs in liver tissues of apolipoprotein E^-/- mice as a model of HLP compared with control mice. A total of 104 and 96 differentially expressed lncRNAs and mRNAs, respectively, were identified. Differentially expressed genes were significantly enriched in biological processes such as nitric oxide biosynthesis, innate immune response and inflammatory response. Finally, two pairs of target genes and 38 transcription factors with regulatory functions in HLP were predicted based on the lncRNA and mRNA co-expression network. The lncRNA expression profile was significantly altered in liver tissues of the mouse model of HLP and may provide novel targets for research into treatments.

No adverse effects of dairy products on lipid profile: A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND AND AIMS

The current study aimed to review the effects of dairy foods on lipid profile in randomized controlled clinical trials (RCTs).

METHODS

We searched PubMed, Scopus, Embase, and Central. RCTs that assess the effects of dairy foods on lipid profile were included.

RESULTS

The overall effects of dairy foods on lipid profile were non-significant. Dairy foods were associated with a non-significant reduction in triacylglycerol level, and a non-significant increase in total cholesterol, low density lipoprotein cholesterol, and high-density lipoprotein cholesterol level.

CONCLUSION

We conclude that dairy foods doesn't have any unfavorable effects on lipids.

Effect of low-fat dairy products fortified with 1500IU nano encapsulated vitamin D3 on cardiometabolic indicators in adults with abdominal obesity: a total blinded randomized controlled trial

BACKGROUND & AIMS

Vitamin D deficiency is widespread worldwide. In this study, we aimed to evaluate the effect of a nano encapsulated form of vitamin D used for fortifying low-fat dairy products (milk and yogurt) on anthropometric indices, glycemic status, and lipid profile in subjects with abdominal obesity.

METHODS

In a totally (quadruple) blinded, randomized, and parallel-controlled trial, 306 individuals with abdominal obesity were randomly allocated to one of four groups: fortified low-fat yogurt (FY, 1500 IU nano encapsulated vitamin D₃ per 150 g/d), non-fortified low-fat yogurt (nFY), fortified low-fat milk (FM, 1500 IU nano encapsulated vitamin D₃ per 200 g/d), non-fortified low-fat milk (nFM), for 10 weeks (nFM and nFY, were considered as the control groups). Anthropometric and biochemical parameters were measured at baseline and after a ten-week trial in Mashhad, Iran.

RESULTS

After the ten-week intervention, we found a significant increase in serum concentration of 25(OH)D in both the FM and FY groups compared to the respective control groups (19.10 ± 5.69 ng/mL and 20.88 ± 5.76 ng/mL respectively, p < .001). We observed a significant reduction in weight to hip ratio (p = .04) and a significant improvement in triglyceride (p < .001) and HDL-C (p = .01) only in FM group compared to nFM group. Also, we found a significant reduction in fasting serum insulin (p < .001), and a significant improvement of HOMA-IR (p < .001) and QUICKI (p < .001) in both intervention groups compared to their placebos.

CONCLUSIONS

An intake of fortified dairy products containing nano-encapsulated vitamin D₃ was associated with an improvement in some measures of anthropometric indices, glucose homeostasis, and lipid profiles, particularly in individuals receiving fortified milk. Hence, along with other benefits, fortification of dairy products with vitamin D may be an effective approach to improve some cardiometabolic indicators, such as insulin resistance.

TRIAL REGISTRATION NUMBER

IRCT20101130005280N27.

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.

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.

Dairy intake and type 2 diabetes risk factors: A narrative review

AIM

The interest regarding the potential role of dairy products in the prevention of type 2 diabetes (T2D) has emerged. Although results remain mixed, numerous cohort studies have shown that increased dairy consumption is inversely associated with T2D risk. This narrative review evaluates the recent evidence of dairy products intake on T2D risk factors for the prevention of T2D.

MATERIAL AND METHOD

The review is framed within the systematic review and meta-analyses of cohort studies and the individual randomized controlled trials evidence. We searched for existing meta-analyses of cohort studies that addressed the association of dairy intake with incidence of T2D in adults using the MEDLINE (via PubMed) database. For the interventional studies, the literature searched was conducted using MEDLINE (via PubMed) with the following Medical Subjects Heading (MeSH) terms i.e. dairy OR milk OR cheese OR yogurt AND glucose OR diabetes OR insulin resistance OR insulin sensitivity OR pre-diabetes.

RESULTS

Most of the meta-analyses and systematic reviews of the cohort studies point to a reduced risk of T2D with dairy intake of 3 servings per day. This effect was mainly attributed to low-fat dairy, particularly yogurt and cheese. However, there is no evidence in cohort studies that high-fat dairy intake poses any harm.

CONCLUSION

Dairy products, when incorporated into a healthy diet, likely do not have detrimental effects on glucose-related outcomes. The potential impact of dairy consumption on glucose tolerance tests, insulin levels, insulin sensitivity measures, and plasma glucose levels warrant future investigation.

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.

Increased Dairy Product Intake Modifies Plasma Glucose Concentrations and Glycated Hemoglobin: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Dairy product intake is inversely associated with the risk of type 2 diabetes (T2D) in numerous cohort studies; yet, the beneficial effects of increased dairy product intake on T2D risk factors such as fasting plasma glucose, fasting insulin, insulin resistance with the homeostasis model assessment, and glycated hemoglobin (HbA1c) remain inconclusive in clinical trials. The objective of this study was to systematically review clinical trials observing the effects of elevated compared with minimal intake of dairy products on T2D risk factors in subjects without diabetes. Five databases [Medline, EMBASE, Central, CINAHL, AMED (Allied and Complementary Medicine)] were searched to identify randomized controlled trials that used elevated quantities of dairy products from ruminant sources in comparison with a lower intake in control groups. The review outcomes were fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and HbA1c. Risk of bias and quality of evidence according to Grading of Recommendations Assessment, Development, and Evaluation were addressed. From the 10,627 citations screened, 44 studies (3016 participants) were included, 38 of which were used in the meta-analyses. Fasting glucose was positively associated with elevated dairy intake [34 studies, n = 2678; mean difference (MD): 0.07 mmol/L; 95% CI: 0.01, 0.12 mmol/L; P = 0.01, I2 = 23%]. Fasting insulin (29 studies, n = 1902; MD: -2.97 pmol/L; 95% CI: -7.05, 1.10 pmol/L; P = 0.15, I2 = 21%) and HOMA-IR (13 studies, n = 840; standardized MD: -0.07; 95% CI: -0.26, 0.12; P = 0.49, I2 = 38%) were not associated with elevated dairy consumption. HbA1c was negatively associated with elevated dairy product intake in 4 studies (n = 512; MD: -0.09%; 95% CI: -0.09%, -0.03%; P = 0.005, I2 = 0%). Most studies had high risk of bias and the quality of evidence was very low or low. In conclusion, evidence suggests that elevated dairy product intake is associated with increased fasting plasma glucose concentrations together with reduced HbA1c in nondiabetic subjects. Hence, the clinical significance of these results remains uncertain. Additional well-designed, long-term studies are required.

Description of the healthy eating indices-based diet quality in Turkish adults: a cross-sectional study

OBJECTIVES

This study aims to describe the dietary status of Turkish adults using two different versions of the Healthy Eating Index (HEI).

METHODS

In this cross sectional study, 494 healthy participants (311 females) with randomly selected and living in Ankara were included between September 2013 and March 2014. A questionnaire was completed and anthropometric measurements (weight and height) were performed. The 24-h dietary recall of individuals was collected. Diet quality was measured through HEI-2005 and HEI-2010 scores.

RESULTS

The mean age, body mass index (BMI), HEI-2005 and HEI-2010 scores of individuals were 32.9 ± 10.8 years; 25.0 ± 4.8 kg/m²; 56.1 ± 13.9 and 41.5 ± 13.7 points, respectively. Significant differences were found between mean HEI-2005 and HEI-2010 scores (p < 0.05). The individual's whose diet quality needs to be improved according to mean HEI-2005 score, had poorer diet based on mean HEI-2010 scores. The highest mean HEI-2005 and HEI-2010 scores were stated in female, in subjects had low education levels, aged 51 years or older and in overweight groups (p <0.05). Both versions of healthy eating indices were correlated positively with BMI and age CONCLUSION: Diet qualities of the individuals are associated with age, gender, education and BMI. Although the components and scores in HEI-2010 version were changed from the version of HEI-2005, the changes may encourage healthy choices of some food group. HEI-2010 gives more attention to food quality than HEI-2005. Thus, in the present study it was concluded that HEI-2010 provided more precise results about diet quality.

Effect of various diets on biomarkers of the metabolic syndrome

The impact of the normal whole diet in different countries and of special types of diet on the biomarkers of the metabolic syndrome (MetS) is reviewed. Diet type, specification, risk of MetS and studied biomarkers, as far as could be traced, are included. Critical points in published studies are mentioned. Description of the traditional dietary patterns for the various countries is not always well-defined and numbers of persons in the studied population are sometimes quite limited, which hamper drawing definite conclusions. Since a Nordic diet, a dietary approach to stop hypertension (DASH), and especially a Mediterranean diet are quite promising, due to its health claims, the food pattern is studied more in detail and a large spectrum of vegetarian diets are included as well. Most of the time lipid profile and high sensitive C-reactive protein (hsCRP) are the studied biomarkers in response to diet intake.

Effects of milk proteins on blood pressure: a meta-analysis of randomized control trials

Certain foods or their components are widely used in the prevention and/or management of cardiovascular disease. Milk proteins have been suggested to have hypotensive properties. A number of clinical trials have been carried out to evaluate the effect of milk proteins from whole foods and supplements on blood pressure (BP). However, the effect of milk proteins on BP is not well understood. Therefore, we conducted a meta-analysis of randomized control trials to provide insight into and robust evidence concerning the overall impact of milk proteins on BP. The PubMed and Cochrane databases were searched for literature concerning the effects of milk proteins on BP up to May 2016. A random effects model was used to calculate the pooled estimates and 95% confidence intervals of effect sizes. The final analysis included seven randomized control trials involving 412 participants. Overall, milk protein interventions significantly lowered systolic BP by -3.33 mm Hg (95% confidence interval -5.62, -1.03) and diastolic BP by -1.08 mm Hg (95% confidence interval -3.38, -0.22). There was no statistical evidence of publication bias across the studies. In conclusion, this meta-analysis provides further evidence that milk proteins slightly but significantly lower both systolic and diastolic BP.