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

The relationship between the intake of fruits, vegetables, and dairy products and dyslipidemia in STEPs study

OBJECTIVE

Due to the contradictory findings and the lack of a comprehensive study investigating the relationship between fruits, vegetables, and dairy intake with lipid profiles in Iran, the present study was conducted to further assess the potential role of fruits, vegetables, and dairy intake in influencing blood lipid levels.

RESULTS

The mean age and body mass index (BMI) of the participants were 46.67 ± 15.48 years and 26.89 ± 5.09 kg/m2, respectively. Regarding lipid profiles, the mean levels of triglycerides, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were 127.36 ± 81.13, 163.61 ± 36.52, 96.95 ± 31.24, and 41.23 ± 11.32, respectively. In the adjusted model, the odds of abnormal triglyceride levels decreased with the consumption of one serving (odds ratio (OR)= 0.90; 95% confidence interval (CI): 0.83-0.98) and two servings of dairy products (OR = 0.87; 95% CI 0.78-0.97). No significant association was observed for the other variables.

Formulation and characterization of low-fat breakfast cream using conjugated whey protein and modified starch

This study investigates the impact of conjugating whey protein (WP) with modified starch (MS), utilizing the Maillard reaction, on the characteristics of low-fat breakfast cream. The combination of WP and MS is significant due to its potential to improve the nutritional profile and textural attributes of low-fat dairy products, in response to consumer demand for healthier options. Various cream formulations were prepared with different ratios and concentrations of WP-MS conjugates, and their texture, water holding capacity, and sensory attributes were systematically analyzed. Results showed that creams with a MS-to-WP ratio of 2:1 at concentrations of 3 % and 4.5 %, as well as a ratio of 3:1 at 3 % concentration, exhibited superior texture properties including enhanced firmness, springiness, and gumminess. Structural analyses confirmed effective conjugation between MS and WP in these optimal formulations. However, higher WP content generally led to lower viscosity and hardness, as well as undesirable color darkening, resulting in lower sensory scores. Overall, these findings highlight the potential of WP-MS conjugates to optimize cream properties, offering valuable insights for producers seeking to develop low-fat dairy products with enhanced qualities and improved consumer acceptance.

A global analysis of dairy consumption and incident cardiovascular disease

The role of dairy products in cardiovascular disease (CVD) prevention remains controversial. This study investigates the association between dairy consumption and CVD incidence using data from the China Kadoorie Biobank and the UK Biobank, complemented by an updated meta-analysis. Among Chinese participants, regular dairy consumption (primarily whole milk) is associated with a 9% increased risk of coronary heart disease (CHD) and a 6% reduced risk of stroke compared to non-consumers. Among British participants, total dairy consumption is linked to lower risks of CVD, CHD, and ischemic stroke, with cheese and semi-skimmed/skimmed milk contributing to reduced CVD risk. Meta-analysis reveals that total dairy consumption is associated with a 3.7% reduced risk of CVD and a 6% reduced risk of stroke. Notably, inverse associations with CVD incidence are observed for cheese and low-fat dairy products. Current evidence suggests that dairy consumption, particularly cheese, may have protective effects against CVD and stroke.

Milk and yogurt consumption and its association with cardiometabolic risk factors in patients with type 2 diabetes: The Fukuoka Diabetes Registry

BACKGROUND AND AIM

The effects of dairy products on cardiometabolic risk factors in patients with diabetes, especially in Asians, have yet to be fully investigated. Therefore, we aimed to characterise the relationship between milk and yogurt consumption and cardiometabolic risk factors in Japanese patients with diabetes.

METHODS AND RESULTS

A total of 4,438 patients with type 2 diabetes were studied. Milk and yogurt consumption was assessed using a validated self-administered diet history questionnaire, and the relationships with cardiometabolic risk factors were evaluated cross-sectionally. High consumption of milk and yogurt was significantly associated with lower body mass index, blood pressure, serum triglyceride concentration and urinary albumin-to-creatinine ratio; and higher low-density lipoprotein-cholesterol concentration (P for trend <0.01). Greater milk and yogurt consumption was also associated with lower likelihood of having metabolic syndrome and chronic kidney disease (CKD) (P for trend <0.001). Multivariable-adjusted odds ratios for metabolic syndrome and CKD in the highest quartile of milk and yogurt consumption, vs. the lowest quartile, were 0.75 (95% confidence interval 0.62-0.91) and 0.72 (0.59-0.89), respectively. However, the likelihood of having a high low-density lipoprotein-cholesterol concentration became higher with greater milk and yogurt consumption (P for trend <0.001).

CONCLUSIONS

Higher milk and yogurt consumption is associated with superior control of cardiovascular risk factors, including CKD, in Japanese patients with type 2 diabetes.

Milk and dairy products - a scoping review for Nordic Nutrition Recommendations 2023

Milk and dairy products are major sources of protein, calcium, and other micronutrients. Milk and dairy products contribute with approximately half of the total intake of saturated fat in the Nordic and Baltic diets. Saturated fat is an important determinant of plasma total and low density lipoprotein (LDL)-cholesterol concentrations, and a causal relationship between high LDL-cholesterol and atherosclerotic cardiovascular disease has consistently been documented. The aim of this scoping review is to describe the evidence for the role of milk and dairy products for health-related outcomes as a basis for setting and updating food-based dietary guidelines. Two qualified systematic reviews were included (World Cancer Research Fund and a systematic review for the US Dietary Guidelines Advisory Committee 2020). In addition, systematic reviews published between January 2011 and January 2022 were considered, screened (555 records) and evaluated (159 records) for this review. The systematic reviews suggest that milk or dairy consumption is not associated with increased risk of cardiovascular disease and dyslipidaemia. Current evidence suggests an inverse association with some cardiometabolic risk factors, such as total and LDL-cholesterol, especially regarding fermented dairy products (i.e. yogurt and cheese). There was evidence of an association between intake of dairy products and reduced risk of colorectal cancer. Some studies reported an inverse association between intake of dairy and type 2 diabetes or markers of impaired glucose homeostasis, especially for low-fat dairy, yoghurt, and cheese. Most studies suggest that intake of milk or dairy is not associated with increased risk of cardiovascular risk and some suggestions of inverse association, especially with low-fat products and fermented dairy products, were found with respect to cardiovascular disease, type 2 diabetes, and colorectal cancer. Milk or dairy products are important dietary sources of calcium and iodine, and are fully compatible with a healthy dietary pattern.

A review of dairy food intake for improving health among black adults in the US

The adult life stage encompasses a range of new experiences, opportunities, and responsibilities that impact health and well-being. During this life stage, health disparities continue to increase for Black Americans, with Black adults having a disproportionate burden of obesity, chronic diseases, comorbidities, and worse treatment outcomes compared to their White peers. While many of the underlying factors for these disparities can be linked to longstanding sociopolitical factors such as systemic racism, food insecurity, and poor access to healthcare, there are also several modifiable risk factors that are known to significantly impact health outcomes, such as improving diet quality, increasing physical activity, and not smoking. Of all the modifiable risk factors known to impact health, improving dietary habits is the factor most consistently associated with better outcomes for body weight and chronic disease. Of the major food groups recommended by the 2020-2025 Dietary Guidelines for Americans (DGA) for achieving healthier dietary patterns, dairy foods have a nutrient profile which matches most closely to what Black Americans are inadequately consuming (e.g., vitamin A, vitamin D, calcium, magnesium). However, Black adults tend to consume less than half the recommended daily servings of dairy foods, in part, due to issues with lactose intolerance, making higher intake of dairy foods an ideal target for improving diet quality and health in this population. This review examines the current body of evidence exploring the links between dairy intake, obesity, cardiometabolic disease risk, chronic kidney disease, and the most common types of cancer, with a special focus on health and disparities among Black adults. Overall, the evidence from most systematic reviews and/or meta-analyses published in the last decade on dairy intake and health outcomes has been conducted on White populations and largely excluded research on Black populations. The findings from this extensive body of research indicate that when teamed with an energy-restricted diet, meeting or exceeding the DGA recommended 3 daily servings of dairy foods is associated with better body weight and composition outcomes and lower rates of most common chronic diseases than lower intake (<2 servings per day). In addition to the number of daily servings consumed, the specific types (e.g., milk, yogurt, cheese) and subtypes (e.g., low-fat, fermented, fortified) consumed have also been shown to play major roles in how these foods impact health. For example, higher intake of fermented dairy foods (e.g., yogurt) and vitamin D fortified dairy products appear to have the most protective effects for reducing chronic disease risk. Along with lactose-free milk and cheese, yogurt is also generally low in lactose, making it an excellent option for individuals with lactose intolerance, who are trying to meet the DGA recommendations for dairy food intake.

The association between dairy intake in adolescents on inflammation and risk markers of type 2 diabetes during young adulthood: results of the DONALD study

OBJECTIVE

The aim of this analysis was to investigate whether habitual intake of total dairy (TD) or different dairy types (liquid, solid, fermented, non-fermented, low-fat, high-fat, low-sugar and high-sugar dairy) during adolescence is associated with biomarkers of low-grade inflammation as well as risk factors of type 2 diabetes in young adulthood.

DESIGN

Multivariable linear regression analyses were used to investigate prospective associations between estimated TD intake as well as intake of different types of dairy and a pro-inflammatory score, based on high-sensitivity C-reactive protein, IL-6, IL-18, leptin and adiponectin, and insulin resistance assessed as Homeostasis Model Assessment Insulin Resistance in an open-cohort study.

SETTING

Dortmund, Germany.

PARTICIPANTS

Data from participants (n 375) of the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study were included, for whom at least two 3-d weighed dietary records during adolescence (median age: 11 years) and one blood sample in young adulthood (>18 years) were available.

RESULTS

There was no statistically significant association between TD intake or intake of any dairy type and the pro-inflammatory score (all P > 0·05). TD intake as well as each dairy type intake and insulin resistance also showed no association (all P > 0·05).

CONCLUSIONS

The habitual intake of dairy or individual types of dairy during adolescence does not seem to have a major impact on low-grade systemic inflammation and insulin resistance in the long term. There was no indication regarding a restriction of dairy intake for healthy children and adolescents in terms of diabetes risk reduction.

Lack of change in blood pressure and arterial stiffness after high dairy intake in hyperinsulinemic subjects: a cross-over randomized controlled trial

To evaluate the effects of high dairy (HD) (≥4 servings/day), compared to adequate dairy (AD) (2-3 servings/day as per Canada's Food Guide for Healthy Eating (2007)), on blood pressure (BP) and measures of arterial stiffness in hyperinsulinemic subjects. In this cross-over clinical trial, hyperinsulinemic adults were randomized to AD and HD for 6 weeks. Anthropometric, glycemic, and lipid parameters were analyzed and dietary intake was evaluated; BP, carotid-femoral pulse wave velocity, augmentation index, and measures of arterial stiffness were assessed. Twenty-seven participants completed the study. Dairy intake was 2.2 ± 1.2 servings/day during AD. In addition, lower total and low-density lipoprotein (LDL) cholesterol were observed without significant change in BP or arterial stiffness between before and after AD. During HD, the subjects consumed 5.8 ± 1.9 servings/day of dairy products, providing a higher intake of protein, saturated fat, calcium, phosphorus, sodium, and potassium compared to the baseline diet. After the HD, subjects had higher body fat, fasting insulin, homeostatic model assessment for insulin resistance (HOMA-IR) index, and triglycerides without altering BP or arterial stiffness compared to before HD. Overall, adequate or high intake of total dairy did not modify BP or arterial stiffness in hyperinsulinemic adults after 6 weeks.

The Role of Diet in the Prevention of Hypertension and Management of Blood Pressure: An Umbrella Review of Meta-Analyses of Interventional and Observational Studies

High blood pressure (BP) is a major pathological risk factor for the development of several cardiovascular diseases. Diet is a key modifier of BP, but the underlying relationships are not clearly demonstrated. This is an umbrella review of published meta-analyses to critically evaluate the wide range of dietary evidence from bioactive compounds to dietary patterns on BP and risk of hypertension. PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception until October 31, 2021, for relevant meta-analyses of randomized controlled trials or meta-analyses of observational studies. A total of 175 publications reporting 341 meta-analyses of randomized controlled trials (145 publications) and 70 meta-analyses of observational studies (30 publications) were included in the review. The methodological quality of the included publications was assessed using Assessment of Multiple Systematic Reviews 2 and the evidence quality of each selected meta-analysis was assessed using NutriGrade. This umbrella review supports recommended public health guidelines for prevention and control of hypertension. Dietary patterns including the Dietary Approaches to Stop Hypertension and the Mediterranean-type diets that further restrict sodium, and moderate alcohol intake are advised. To produce high-quality evidence and substantiate strong recommendations, future research should address areas where the low quality of evidence was observed (for example, intake of dietary fiber, fish, egg, meat, dairy products, fruit juice, and nuts) and emphasize focus on dietary factors not yet conclusively investigated.

Effects of Dairy Intake on Markers of Cardiometabolic Health in Adults: A Systematic Review with Network Meta-Analysis

The health effects of dairy products are still a matter of scientific debate owing to inconsistent findings across trials. Therefore, this systematic review and network meta-analysis (NMA) aimed to compare the effects of different dairy products on markers of cardiometabolic health. A systematic search was conducted in 3 electronic databases [MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science; search date: 23 September 2022]. This study included randomized controlled trials (RCTs) with a ≥12-wk intervention comparing any 2 of the eligible interventions [e.g., high dairy (≥3 servings/d or equal amount in grams per day), full-fat dairy, low-fat dairy, naturally fermented milk products, and low dairy/control (0-2 servings/d or usual diet)]. A pairwise meta-analysis and NMA using random-effects model was performed in the frequentist framework for 10 outcomes [body weight, BMI, fat mass, waist circumference, low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, fasting glucose, glycated hemoglobin, and systolic blood pressure]. Continuous outcome data were pooled using mean differences (MDs) and dairy interventions ranked using the surface under the cumulative ranking curve. Nineteen RCTs with 1427 participants were included. High-dairy intake (irrespective of fat content) showed no detrimental effects on anthropometric outcomes, blood lipids, and blood pressure. Both low-fat and full-fat dairy improved systolic blood pressure (MD: -5.22 to -7.60 mm Hg; low certainty) but, concomitantly, may impair glycemic control (fasting glucose-MD: 0.31-0.43 mmol/L; glycated hemoglobin-MD: 0.37%-0.47%). Full-fat dairy may increase HDL cholesterol compared with a control diet (MD: 0.26 mmol/L; 95% CI: 0.03, 0.49 mmol/L). Yogurt improved waist circumference (MD: -3.47 cm; 95% CI: -6.92, -0.02 cm; low certainty), triglycerides (MD: -0.38 mmol/L; 95% CI: -0.73, -0.03 mmol/L; low certainty), and HDL cholesterol (MD: 0.19 mmol/L; 95% CI: 0.00, 0.38 mmol/L) compared with milk. In conclusion, our findings indicate that there is little robust evidence that a higher dairy intake has detrimental effects on markers of cardiometabolic health. This review was registered at PROSPERO as CRD42022303198.

High-Fat Dairy Products May Decrease the Risk of Chronic Kidney Disease Incidence: A Long-Term Prospective Cohort Study

OBJECTIVE

The association between consumption of dairy products and risk of chronic kidney disease (CKD) is under debate. We aimed to determine the potential effects of total and subtypes of dairy intake on the occurrence of CKD.

METHODS

This study was conducted within the Tehran Lipid and Glucose Study (TLGS) on 2416 CKD-free adults. At baseline, consumption of dairy products was estimated using a validated 168-items semiquantitative food frequency questionnaire. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of CKD were calculated in tertile categories of dairy products. Also, the CKD risk was estimated with multivariable Cox regression to substitute total dairy with other dietary protein sources.

RESULTS

During 8.4 years of follow-up, the incidence rate of CKD was 21%. The participants' mean (±SD) age was 38 (±13) years and 46% were men. Dietary intakes of total dairy, low-fat dairy, and fermented dairy were not associated with CKD risk. There were significant lower risks of CKD in the highest compared to the lowest tertiles of high-fat dairy (HR = 0.76, 95% CI = 0.60-0.95) and high-fat milk (HR = 0.75, 95% CI = 0.59-0.96). However, no significant associations were found between other categories of dairy products and CKD incidence. Substitutions of total dairy with other dietary protein sources were not associated with CKD risk.

CONCLUSIONS

In this study, higher intakes of high-fat dairy and high-fat milk were associated with lower risks of CKD. No significant associations were found between other dairy products and CKD. More prospective and clinical trials are needed to clarify the issue.

Dairy Foods, Weight Change, and Risk of Obesity During the Menopausal Transition

BACKGROUND

Weight gain during the menopausal transition is common. Dairy consumption may impact weight change during this critical period, and different dairy foods may have different effects.

OBJECTIVES

This study aimed to investigate the associations of different types of dairy foods with weight gain and risk of obesity in perimenopausal women from the Nurses' Health Study II cohort.

METHODS

The examination at menopause was selected as the exam closest to the reported age at menopause. Weight change during 12 y surrounding menopause was derived from self-reported weight data for 3 exams before and 3 after menopause. The mean age of the first weight measure was 45.8 y and the average BMI was 25.0 kg/m2. Dairy food intakes were estimated as mean intakes over the same 12 y. Generalized linear models were used to assess the association between dairy foods and annualized weight change. Cox proportional hazard models were used to estimate the adjusted relative risks for becoming obese over 12 y surrounding menopause.

RESULTS

In longitudinal analyses, those with the highest yogurt intakes had the lowest weight gain at every exam. This was not the case for other forms of dairy. After adjusting for potential covariates, those consuming ≥2.0 servings/wk of yogurt (compared with <1.0 serving/month) had a 31% (RR: 0.69; 95% CI: 0.64, 0.74) lower risk of obesity. The highest total dairy intake (≥2.0 servings/d compared with <1.0) was associated with only a 12% (RR: 0.88; 95% CI: 0.82, 0.95) reduction in obesity risk. Higher activity levels and alternative healthy eating index scores were independently associated with statistically significant reductions in risk of obesity, but higher intakes of yogurt strengthened these beneficial associations.

CONCLUSION

Yogurt intake was associated with less weight gain and lower obesity risk in women during the menopausal transition.

Consumption of Dairy Products and the Risk of Overweight or Obesity, Hypertension, and Type 2 Diabetes Mellitus: A Dose-Response Meta-Analysis and Systematic Review of Cohort Studies

Dairy products have been suggested to be related to the prevention of overweight or obesity, hypertension, and type 2 diabetes mellitus (T2DM). These associations are currently controversial, however, and a systematic quantitative meta-analysis is lacking. In this study, we examined the associations between dairy products and the risk of overweight or obesity, hypertension, and T2DM and tested for dose-response relations. We comprehensively searched PubMed, Embase, and Web of Science up to April 2021. Cohort studies were included if dairy food consumption was reported at a minimum of 3 levels or as continuous variables, and the associations were assessed with overweight or obesity, hypertension, and T2DM. Summary RRs and 95% CIs were estimated for the dose-response association. Restricted cubic splines were used to evaluate the linear or nonlinear relations. Among the 9887 articles retrieved, 42 articles were included. For overweight or obesity, a linear association was observed for total dairy, milk, and yogurt. The risk decreased by 25%, 7%, and 12% per 200-g/d increase for total dairy, high-fat dairy, and milk, respectively, and by 13% per 50-g/d increment of yogurt. For hypertension, a nonlinear association was observed with total dairy, whereas significant inverse associations were found for low-fat dairy (RR: 0.94; 95% CI: 0.90, 0.98) and milk (RR: 0.94; 95% CI: 0.92, 0.97) per 200-g/d intake increase. For T2DM, all types of dairy food consumption except for milk and low-fat dairy products showed nonlinear associations, with total dairy and yogurt intake associated with 3% and 7% lower risk per 200-g/d and 50-g/d intake increase, respectively. In conclusion, our study suggests that total dairy is associated with a low risk of overweight or obesity, hypertension, and T2DM, especially milk and yogurt for overweight or obesity, low-fat dairy and milk for hypertension, and yogurt for T2DM.

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.

Associations of Calcium Intake and Calcium from Various Sources with Blood Lipids in a Population of Older Women and Men with High Calcium Intake

Promoting calcium intake is a cornerstone for osteoporosis management. Some individuals limit dairy product consumption, a major calcium source, due to their high content in saturated fats and their perceived negative impact on lipid profiles. This study explored the associations of calcium from various sources with blood lipids in community-dwelling elderly (n = 717) from the GERICO cohort. Dietary calcium intake was assessed at several timepoints using a validated food frequency questionnaire (FFQ) and calcium supplement use was recorded. Blood lipids were treated as categorical variables to distinguish those with normal and abnormal levels. Increasing total calcium intake was associated with lower risks for high total cholesterol (p = 0.038) and triglycerides (p = 0.007), and low HDL-cholesterol (p = 0.010). Dairy calcium (p = 0.031), especially calcium from milk (p = 0.044) and milk-based desserts (p = 0.039), i.e., low-fat (p = 0.022) and non-fermented (p = 0.005) dairy products, were associated with a lower risk of high total cholesterol. Greater calcium intakes from total dairies (p = 0.020), milk (p = 0.020) and non-fermented dairies (p = 0.027) were associated with a lower risk of hypertriglyceridemia. No association was observed between calcium from non-dairy sources, cheese or high-fat dairies and blood lipids. Increasing calcium through supplements was associated with lower risks for hypertriglyceridemia (p = 0.022) and low HDL-cholesterol (p = 0.001), but not after adjustments. Our results suggest that higher calcium intakes from dietary sources or supplements are not adversely associated with blood lipids in the elderly, whilst total, and particularly low-fat, dairy products are valuable calcium sources potentially related to favorable lipid profiles.

Consumption of Dairy Foods and Cardiovascular Disease: A Systematic Review

Limited consumption of dairy foods and use of low-fat products is recommended for cardiovascular (CV) prevention; however, other features besides fat content modulate their metabolic effects. We analyze updated evidence on the relationship of different dairy products (low/full-fat dairy, milk, cheese, yogurt) with CVD by reviewing meta-analyses of cohort studies and individual prospective cohort studies with CV hard endpoints (CVD/CHD incidence/mortality), together with meta-analyses of randomized controlled trials exploring the effect of dairy on major CV risk factors. The analyses provide evidence that moderate dairy consumption (up to 200 g/day, globally) has no detrimental effects on CV health and that their effect depends more on the food type (cheese, yogurt, milk) than on the fat content. These data expand current knowledge and may inform revision of current guidelines for CVD prevention.

Children's perceptions of fluid milk with varying levels of milkfat

Schools participating in federal meal programs are limited to serving skim or low-fat (≤1%) flavored and unflavored milk. Few studies have directly addressed child perceptions and preferences for milk containing different amounts of milkfat. The objective of this study was to determine whether children can differentiate between flavored and unflavored fluid milk containing varying levels of milkfat and whether preferences for certain levels of milkfat exist. Flavored and unflavored milks containing 4 different percentages of milkfat (≤0.5, 1, 2, and 3.25%) were high-temperature, short-time processed, filled into half-gallon light-shielded milk jugs, and stored at 4°C in the dark. Milks were evaluated by children (ages 8-13 yr) following 7 d at 4°C. Acceptance testing and tetrad difference testing were conducted on flavored and unflavored milks with and without visual cues to determine if differences were driven by visual or flavor or mouthfeel cues. Child acceptance testing (n = 138 unflavored; n = 123 flavored) was conducted to evaluate liking and perception of selected attributes. Tetrad testing (n = 127 unflavored; n = 129 flavored) was conducted to determine if children could differentiate between different fat levels even in the absence of a difference in acceptance. The experiment was replicated twice. When visual cues were present, children had higher overall liking for 1% and 2% milks than skim for unflavored milk and higher liking for chocolate milks containing at least 1% milk fat than for skim. Differences in liking were driven by appearance, viscosity, and flavor. In the absence of visual cues, no differences were observed in liking or flavor or mouthfeel attributes for unflavored milk but higher liking for at least 1% milk fat in chocolate milk compared with skim was consistent with the presence of visual cues. From tetrad testing, children could visually tell a difference between all unflavored pairs except 2% versus whole milk and could not detect consistent differences between milkfat pairs in the absence of visual cues. For chocolate milk, children could tell a difference between all milk fat pairs with visual cues and could tell a difference between skim versus 2% and skim versus whole milk without visual cues. These results demonstrate that in the absence of package-related flavors, school-age children like unflavored skim milk as well as milk with higher fat content in the absence of visual cues. In contrast, appearance as well as flavor and mouthfeel attributes play a role in children's liking as well as their ability to discriminate between chocolate milks containing different amounts of fat, with chocolate milk containing at least 1% fat preferred. The sensory quality of school lunch milk is vital to child preference, and processing efforts are needed to maximize school milk sensory quality.

Dietary sugars and subclinical vascular damage in moderate-to-high cardiovascular risk adults

BACKGROUND AND AIMS

The association between dietary sugars and vascular damage has been scarcely examined out of the context of established cardiovascular disease. We aimed to investigate the association between different types of sugars with subclinical atheromatosis and arteriosclerosis, in individuals free of cardiovascular disease being, however, at moderate-to-high cardiovascular risk.

METHODS AND RESULTS

Two 24-h dietary recalls were conducted to estimate sugars intake. Subclinical atheromatosis was assessed by B-mode ultrasonography and arteriosclerosis (arterial stiffness) via tonometry (carotid-to-femoral pulse wave velocity). Multiple logistic regression analysis was performed to determine the relationship of quartiles of total sugars, monosaccharides and disaccharides with atheromatosis and arteriosclerosis, adjusting for potential confounders [Odds Ratio (95%Confidence Interval)]. In 901 participants (52.4 ± 13.8 years, 45.2% males), total sugars intake was not associated with any type of subclinical vascular damage. Subjects at 4th quartile of lactose intake (15.3 ± 5.5 g/day) had lower probability to present atheromatosis compared to those at 1st quartile (0.00 ± 0.01 g/day) even in the fully adjusted model [0.586 (0.353-0.974)]. Subjects at 3rd quartile of total disaccharides intake and particularly sucrose (15.1 ± 2.2 g/day) had higher probability to present arteriosclerosis compared to those at 1st quartile (3.0 ± 1.9 g/day) even after adjustment for all potential confounders [2.213 (1.110-4.409)].

CONCLUSIONS

Overall, the present data suggest a distinct role of each type of sugars on vascular damage. These observations highlight the need for further studies investigating not only foods rich in sugars, but sugars as separate components of food as they probably contribute via different ways on the development of arterial pathologies.

Associations Between Intake of Fermented Dairy Products and Blood Lipid Concentrations Are Affected by Fat Content and Dairy Matrix - The Tromsø Study: Tromsø7

Introduction: Dairy fat is rich in saturated fatty acids known to increase serum low-density lipoprotein cholesterol (LDL-C) concentration, an important risk factor for cardiovascular disease (CVD). However, intake of fermented dairy products has been associated with reduced CVD risk in observational studies. How intakes of different fermented dairy products are associated with blood lipid concentrations may provide a possible explanation for the suggested reduced CVD risk. Aim: To examine the associations between different types of fermented dairy products, with various fat contents and dairy matrix structures, and blood lipid concentrations in a general population. Methods: In 11,377 women and men aged between 40-99 participating in the population-based Tromsø Study 2015-2016, multivariable linear regression was used to examine associations between total intake of fermented dairy products, intake of yogurt (including regular-fat, low-fat, and semi-solid yogurt), cheese (including regular-fat and low-fat), and liquid fermented dairy, and serum concentrations of total cholesterol, LDL-C, high-density lipoprotein cholesterol (HDL-C), and triglycerides. Dietary data was collected using a validated food frequency questionnaire. Analyses were adjusted for potential confounding factors, and cheese intake analyses were stratified by self-reported use of cholesterol-lowering drugs. Results: Cheese intake was positively associated with HDL-C [regression coefficient 0.02 mmol/l (95 % CI 0.01, 0.03)], and inversely associated with LDL-C [regression coefficient-0.03 mmol/l (95 % CI-0.04,-0.01)] and triglycerides [relative change -1.34 % (95 % CI: -2.29 %, -0.37 %)] per 25 g/day among non-users of cholesterol-lowering drugs, while no associations were found among users. Total intake of fermented dairy was inversely associated with triglycerides [relative change -1.11 % (95 % CI: -1.96 %, -0.24 %)] per 250 g/day, while no associations were found for yogurt intake. Intake of low-fat cheese was more favorably associated with blood lipids compared to regular-fat cheese, and semi-solid yogurt was inversely associated with LDL-C and triglycerides, while intake of liquid fermented dairy was not associated with any of the blood lipids. Conclusion: This study highlights the importance of investigating specific types of dairy products separately, based on fat content and dairy matrix, when examining effects on blood lipid concentrations, and stratifying statistical models by use of cholesterol-lowering drugs when relevant.

Long-Term and Carryover Effects of Supplementation with Whole Oilseeds on Methane Emission, Milk Production and Milk Fatty Acid Profile of Grazing Dairy Cows

Research is ongoing to find nutritional methane (CH4) mitigation strategies with persistent effects that can be applied to grazing ruminants. Lipid addition to dairy cow diets has shown potential as means to decrease CH4 emissions. This study evaluated the effects of oilseeds on CH4 emission and production performance of grazing lactating dairy cows. Sixty Holstein Friesian cows grazing pasture were randomly allocated to 1 of 4 treatments (n = 15): supplemented with concentrate without oilseeds (CON), with whole cottonseed (CTS), rapeseed (RPS) or linseed (LNS). Oilseeds were supplemented during weeks 1-16 (spring period) and 17-22 (summer period), and the autumn period (wk 23-27) was used to evaluate treatment carryover effects. Cows fed CTS decreased CH4 yield by 14% compared to CON in spring, but these effects did not persist after 19 weeks of supplementation (summer). Compared to CON, RPS decreased milk yield and CTS increased milk fat concentration in both spring and summer. In summer, CTS also increased milk protein concentration but decreased milk yield, compared to CON. In spring, compared to CON, CTS decreased most milk medium-chain fatty acids (FA; 8:0, 12:0, 14:0 and 15:0) and increased stearic, linoleic and rumenic FA, and LNS increased CLA FA. There were no carry-over effects into the autumn period. In conclusion, supplementation of grazing dairy cows with whole oilseeds resulted in mild effects on methane emissions and animal performance. In particular, supplementing with CTS can decrease CH4 yield without affecting milk production, albeit with a mild and transient CH4 decrease effect. Long term studies conducted under grazing conditions are important to provide a comprehensive overview of how proposed nutritional CH4 mitigation strategies affect productivity, sustainability and consumer health aspects.

Whole-fat dairy products do not adversely affect adiposity or cardiometabolic risk factors in children in the Milky Way Study: a double-blind randomized controlled pilot study

BACKGROUND

Limited evidence supports the common public health guideline that children >2 y of age should consume dairy with reduced fat content.

OBJECTIVES

We aimed to investigate the effects of whole-fat compared with reduced-fat dairy intake on measures of adiposity and biomarkers of cardiometabolic risk in healthy 4- to 6-y-old children.

METHODS

The Milky Way Study enrolled 49 children (mean ± SD age: 5.2 ± 0.9 y; 47% girls) who were habitual consumers of whole-fat dairy, then randomly assigned them in a double-blind fashion to remain on whole-fat dairy or switch their dairy consumption to reduced-fat products for 3 mo. Primary endpoints included measures of adiposity, body composition, blood pressure, fasting serum lipids, blood glucose, glycated hemoglobin (HbA1c), and C-reactive protein (CRP) and were assessed at baseline and study end. Pre- and postintervention results were compared using linear mixed models, adjusted for growth, age, and sex.

RESULTS

Dairy fat intake was reduced by an adjusted (mean ± SEM) 12.9 ± 4.1 g/d in the reduced-fat compared with the whole-fat dairy group (95% CI: -21.2, -4.6 g/d; P = 0.003), whereas dietary energy intakes remained similar (P = 0.936). We found no significant differential changes between dairy groups in any measure of adiposity, body composition, blood pressure, or fasting serum lipids, glucose, HbA1c, and CRP.

CONCLUSIONS

Our results suggest that although changing from whole-fat to reduced-fat dairy products does reduce dairy fat intake, it does not result in changes to markers of adiposity or cardiometabolic disease risk in healthy children.This trial was registered at www.anzctr.org.au as ACTRN12616001642471.

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.

Dairy product consumption reduces cardiovascular mortality: results after 8 year follow-up of ELSA-Brasil

PURPOSE

To investigate whether the consumption of dairy products and their subgroups is associated with the risk of death from cardiovascular disease (CVD) after 8-year follow-up, and verify if dairy products predict changes in high-sensitivity C-reactive protein (hs-CRP) between two follow-up visits of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS

Prospective study with 6671 participants without CVD at baseline. Consumption in grams/day of total dairy, full-fat and low-fat dairy, fermented dairy, and milk was obtained through a food frequency questionnaire and categorized into sex-specific quartiles. Cox regression and linear mixed-effect models were used to estimate associations of dairy products intake with death from CVD and changes in hs-CRP levels, respectively.

RESULTS

After adjustments, individuals in the 3rd and 4th quartiles of total dairy consumption presented, respectively, 62% (HR 0.38; 95% CI 0.15-0.99) and 64% (HR 0.36; 95% CI 0.14-0.94) lower hazards of death from CVD compared to the 1st quartile. Also, participants in the 4th quartile of milk consumption had 66% (HR 0.34; 95% CI 0.14-0.86) lower hazard to die from CVD, but only the 2nd quartile of full-fat dairy consumption indicated a lower hazard to die from CVD (HR 0.30; 95% CI 0.10-0.92). No association was observed between low-fat or fermented dairy products and cardiovascular mortality. Consumption of total dairy and their subgroups did not predict changes in hs-CRP levels after 4-year follow-up.

CONCLUSION

Results suggest beneficial effects of total dairy and milk, but only low-to-moderate full-fat dairy consumption, on the risk of death from CVD. Assuming true effects, public policies should encourage the consumption of dairy products, especially milk.

Association between Dietary Patterns and Low HDL-C among Community-Dwelling Elders in North China

We aimed to investigate the association between dietary patterns and low HDL-C among the elderly population living in North China. The data were from a national cross-sectional survey conducted in 2015. General information in terms of living habits, health status, and food intake using 24 h dietary recall for three consecutive days was procured, and the weight of edible oil and condiments recorded. Anthropometric index, blood pressure, and fasting serum lipids were measured using standard methods. Dietary patterns were derived from food categories by exploratory factor analysis, and multivariate logistic regression was used to estimate the odds ratios of low HDL-C across quartiles of dietary patterns. Among 3387 elderly participants, 21.9% had low HDL-C levels. After adjusting for potential confounding factors, participants with highest score versus lowest score in the balanced dietary pattern had a decreased risk of low HDL-C (OR = 0.38, 95% CI: 0.16-0.88, p for trend = 0.013) in the group with a BMI of 27.1 kg/m² and above. Compared to the lowest quartile, there was a statistically significant negative association between the highest scores of the Western dietary pattern and low HDL-C (OR = 0.37, 95% CI: 0.17-0.82, p for trend = 0.018) in the group with a BMI of 21.6-24.8 kg/m². However, greater adherence to a thrifty dietary pattern (highest quartiles vs. lowest quartiles) was associated with increased risk of low HDL-C (OR = 3.31, 95% CI: 1.05-10.40, p for trend = 0.044), especially in the subgroup with a BMI of 21.6 kg/m² and below. The study revealed that it is urgent to develop district-specific dietary improvement plans for dyslipidemia based on the nutritional status of the elderly population in North China.

Association between dietary diversity score and anthropometric indices among children and adolescents: the weight disorders survey in the CASPIAN-IV study

BACKGROUND

The aim of this study was to determine the association between the dietary diversity score (DDS) and anthropometric indices in a nationally representative sample of Iranian children and adolescents.

METHODS

The nationwide cross-sectional study included 5178 students aged 6-18 years. A validated 168-item food frequency questionnaire (FFQ) was used. The DDS was assessed by dividing food items into five groups.

RESULTS

An increase of 1 in the total DDS score was associated with 0.08 increase in the body mass index z-score (BMIz), 0.06 increase in waist circumference z-score (WCz), and 0.07 increase in hip circumference z-score (HCz) (P < 0.05) in girls. An increase of 1 in the DDS score of the dairy group was associated with an 0.11 increases in BMIz (P < 0.05). An increase of 1 in the DDS score of the fruit-vegetable group was associated with 0.09 and 0.08 increase in BMIz and HCz among girls respectively (P < 0.05). The odds of excess weight (overweight or obesity) and abdominal obesity increased with each unit increase in total DDS in girls (odds ratio, OR _{excess weight}  = 1.11 (95% confidence interval, CI: 1.003-1.23), OR _{abdominal obesity}  = 1.11 (95% CI: 1.001-1.23)). The odds of excess weight increased with each unit increase in dairy DDS (OR _{excess weight}  = 1.20 (95% CI: 1.002-1.43) among boys.

CONCLUSION

Higher DDS was associated with higher anthropometric indices and greater risk of obesity among children and adolescents. Our findings emphasize the importance of increasing the diversity of healthy food items to reduce weight disorders in the pediatric age group. © 2021 Society of Chemical Industry.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Milk-Fat Intake and Differences in Abdominal Adiposity and BMI: Evidence Based on 13,544 Randomly-Selected Adults

The primary purpose of this investigation was to evaluate the relationship between milk-fat intake and obesity, particularly abdominal obesity, in 13,544 U.S. adults. A lesser objective was to measure the degree to which the association was influenced by multiple potential confounding variables. This cross-sectional study used data from the 2011-2016 National Health and Nutrition Examination Survey (NHANES). Quantity of milk-fat regularly consumed was the exposure variable. Sagittal abdominal diameter (SAD), a measure of abdominal obesity, and body mass index (BMI) were the outcome variables. Sagittal abdominal diameter is a strong predictor of visceral abdominal fat, when measured by computed tomography, and has been shown to predict cardiometabolic disorders better than BMI. After controlling for age, race, gender, physical activity, leisure computer use and gaming, alcohol habits, and cigarette use, significantly lower BMIs were associated with consistent non-fat and full-fat milk consumption (F = 4.1, p = 0.0063). A significantly lower SAD was associated only with regular consumption of non-fat milk (F = 5.0, p = 0.0019). No significant differences were detected between the other milk-fat groups or milk abstainers. In this nationally representative sample, only 19.6% of adults regularly consumed low-fat milk. In conclusion, consistent non-fat milk intake was predictive of lower levels of abdominal adiposity compared to consumption of higher levels of milk-fat.

Associations of Dairy Intake with Circulating Biomarkers of Inflammation, Insulin Response, and Dyslipidemia among Postmenopausal Women

BACKGROUND

Cardiometabolic diseases are prevalent in aging Americans. Although some studies have implicated greater intake of dairy products, it is not clear how dairy intake is related to biomarkers of cardiometabolic health.

OBJECTIVE

Our aim was to test the hypothesis that associations of dairy foods with biomarkers of lipid metabolism, insulin-like growth factor signaling, and chronic inflammation may provide clues to understanding how dairy can influence cardiometabolic health.

DESIGN

This was a cross-sectional study in the Women's Health Initiative using baseline food frequency questionnaire data to calculate dairy intake.

PARTICIPANTS/SETTING

Participants were 35,352 postmenopausal women aged 50 to 79 years at 40 clinical centers in the United States.

MAIN OUTCOME MEASURES

Baseline (1993-1998) concentrations of 20 circulating biomarkers were measured.

STATISTICAL ANALYSES

Multivariable-adjusted linear regression was used to estimate percent difference in biomarker concentrations per serving of total dairy and individual foods (milk, cheese, yogurt, butter, and low-fat varieties).

RESULTS

Lower triglyceride concentrations were associated with greater intake of total dairy (-0.8% [95% CI -1.2% to -0.3%]), mainly driven by full-fat varieties. Individual dairy foods had specific associations with circulating lipid components. For example, greater total milk intake was associated with lower concentrations of total cholesterol (-0.4% [95% CI -0.7% to -0.2%]) and high-density lipoprotein cholesterol (-0.5% [95% CI -0.9% to -0.1%]), whereas greater butter intake was associated with higher total cholesterol (0.6% [95% CI 0.2% to 1.0%]) and high-density lipoprotein cholesterol (1.6% [95% CI 1.1% to 2.0%]) concentrations. In contrast, higher total yogurt intake was associated with lower total cholesterol (-1.1% [95% CI -2.0% to -0.2%]) and higher high-density lipoprotein cholesterol (1.8% [95% CI 0.5% to 3.1%]). Greater total dairy intake (regardless of fat content), total cheese, full-fat cheese, and yogurt were consistently associated with lower concentrations of glucose, insulin, and C-reactive protein. However, milk and butter were not associated with these biomarkers.

CONCLUSIONS

Higher dairy intake, except butter, was associated with a favorable profile of lipids, insulin response, and inflammatory biomarkers, regardless of fat content. Yet, specific dairy foods might influence these markers uniquely. Findings do not support a putative role of dairy in cardiometabolic diseases observed in some previous studies.

Plasma Free Fatty Acids and Metabolic Effect in Type 2 Diabetes, an Ancillary Study from a Randomized Clinical Trial

Most nutrition studies looking at the association of food with cardiometabolic markers rely on food frequency questionnaires, which are prone to recall bias. Pentadecanoic acid, heptadecanoic acid and trans-palmitoleic acid are fatty acids that are not synthesized endogenously but are obtained from the diet, particularly dairy, making them reasonable biomarkers of dairy consumption. We investigated the association of dairy fatty acid biomarkers with glycated hemoglobin (HbA1c) and cardiovascular risk factors in type 2 diabetes (T2D). In a clinical trial, 111 participants with T2D (age 58.5 ± 8.9 years, HbA1c 8.09 ± 0.96%) were randomized into three groups: a control group that maintained baseline dairy intake, a low-fat (LF) group that incorporated ≥3 servings/day of LF dairy and a high-fat (HF) group that incorporated ≥3 servings/day of HF dairy. We compared the fatty acids (FA) composition between the three groups at 24 weeks. Pentadecanoic acid and trans-palmitoleic acid increased in the HF group by 14.1% ± 5.4% and 17.5% ± 5.1%, respectively, but not in the control and LF groups (p = 0.0474 and p = 0.0025 for group-by-time interaction, respectively). Those increases were positively associated with changes in total cholesterol, very-low-density lipoprotein cholesterol VLDL-C and triglycerides but were not associated with changes in HbA1c from baseline to 24 weeks. These results suggest that the intervention was successful and that participants were likely compliant, which supports the validity of the main trial.

Changes in intake of dairy product subgroups and risk of type 2 diabetes: modelling specified food substitutions in the Danish Diet, Cancer and Health cohort

PURPOSE

We investigated the association between an increased intake of one dairy product subgroup at the expense of another within a 5-year period and the subsequent 10-year risk of type 2 diabetes.

METHODS

The cohort included 39,393 adults with two measurements of diet assessed using food frequency questionnaires (FFQ) administered in 1993-1997 and 1999-2003. Dairy products were milk (skimmed, semi-skimmed, whole fat), buttermilk, low-fat yogurt, whole-fat yogurt, cheese and butter. Type 2 diabetes cases were ascertained from the Danish National Diabetes Register. The pseudo-observation method was used to calculate risk differences (RD) with 95% confidence intervals (CI). The data were analysed in age strata to fulfil the assumption of independent entry.

RESULTS

Among participants aged 56-59 years at completion of the follow-up FFQ, increased intake of whole-fat yogurt in place of skimmed, semi-skimmed or whole-fat milk was associated with a reduced risk (RD% [95% CI]: - 0.8% [- 1.3, - 0.2]; - 0.6% [- 1,1, - 0.1]; - 0.7 [- 1.2, - 0.1]; per 50 g/d, respectively). Among participants aged 60-64 and 65-72, substitution of skimmed milk for semi-skimmed milk was associated with an increased risk of type 2 diabetes (0.5% [0.2, 0.7]; 0.4% [0.1, 0.7]; per 50 g/d, respectively). Similar patterns of associations were found after adjustment for potential mediators.

CONCLUSION

Our results suggest that substitution of whole-fat yogurt for milk among those aged 56-59 decreases risk of type 2 diabetes and substitution of skimmed milk for semi-skimmed milk may increase the risk among those aged 60-64 and 65-72.

Influence of Habitual Dairy Food Intake on LDL Cholesterol in a Population-Based Cohort

Background: Cholesterol has a pivotal role in human physiology, exerting both structural and functional activity. However, higher blood cholesterol levels, especially low-density lipoprotein cholesterol (LDL-C), are a major cardiovascular risk factor. Therefore, special attention has been given to the effect of dietary factors in influencing LDL-C blood levels. In particular, much research has focused on dairy products, since they are a main component of different dietary patterns worldwide. A large body of evidence did not support the hypothesis that dairy products significantly increase circulating LDL-C, but no definitive data are available. Hence, we aimed to assess the relationships among LDL-C, habitual dairy food intake and anthropometric variables in a cohort representative of the general population in a Mediterranean area. Methods: We evaluated 802 healthy adults included in the ABCD_2 (Alimentazione, Benessere Cardiovascolare e Diabete) study (ISRCTN15840340), a longitudinal observational single-center study of a cohort representative of the general population of Palermo, Sicily. The habitual intake of dairy products was assessed with a validated food frequency questionnaire, and LDL-C serum levels and several anthropometric parameters were measured. Results: The group with high LDL-C serum concentrations (≥130 vs. <130 mg/dL) exhibited higher age, body mass index (BMI), waist-to-hip ratio (WHR), body fat percentage, systolic and diastolic blood pressure, carotid intima-media thickness and glycated hemoglobin. The habitual diet was not different between the groups in terms of macronutrient, cholesterol, egg and dairy food intake, with the exception of the weekly number of portions of milk (higher in the low LDL-C group vs. the high LDL-C group) and ricotta cheese (higher in the high LDL-C group vs. the LDL-C group). No significant correlation was found between LDL-C blood levels and the habitual intake of dairy products or the dietary intake of cholesterol and fats. The multivariate regression analyses (R² = 0.94) showed that LDL-C blood levels were significantly associated with the habitual intake of milk (p < 0.005) and ricotta cheese (p < 0.001) and with BMI (p < 0.001). Conclusion: Our study reported that total dairy food consumption was not correlated with LDL-C blood levels. However, multivariate analyses showed an inverse association between serum LDL-C and milk intake as well as a positive association between ricotta cheese intake and LDL-C concentrations. More studies are needed to better characterize the relationship between dairy products and circulating LDL-C.

DHA content in milk and biohydrogenation pathway in rumen: a review

Docosahexaenoic acid (DHA) is an essential human nutrient that may promote neural health and development. DHA occurs naturally in milk in concentrations that are influenced by many factors, including the dietary intake of the cow and the rumen microbiome. We reviewed the literature of milk DHA content and the biohydrogenation pathway in rumen of dairy cows aim to enhance the DHA content. DHA in milk is mainly derived from two sources: α-linolenic acid (ALA) occurring in the liver and consumed as part of the diet, and overall dietary intake. Rumen biohydrogenation, the lymphatic system, and blood circulation influence the movement of dietary intake of DHA into the milk supply. Rumen biohydrogenation reduces DHA in ruminal environmental and limits DHA incorporation into milk. The fat-1 gene may increase DHA uptake into the body but this lacks experimental confirmation. Additional studies are needed to define the mechanisms by which different dietary sources of DHA are associated with variations of DHA in milk, the pathway of DHA biohydrogenation in the rumen, and the function of the fat-1 gene on DHA supply in dairy cows.

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.

Effect of dairy consumption and its fat content on glycemic control and cardiovascular disease risk factors in patients with type 2 diabetes: a randomized controlled study

BACKGROUND

Dietary Guidelines for Americans recommend the consumption of 3 servings/d of low-fat/nonfat dairy. The effects of higher dairy consumption and its fat content are unknown in patients with type 2 diabetes.

OBJECTIVE

Evaluate the impact of higher consumption of high- compared with low-fat dairy on glycated hemoglobin (HbA1c), body weight, and cardiovascular disease risk factors in patients with type 2 diabetes.

METHODS

We enrolled 111 subjects with type 2 diabetes (aged 58.5 ± 8.9 y, 47% females, diabetes duration 13.2 ± 8.3 y, HbA1c 8.09 ± 0.96%) who consumed <3 servings of dairy/d. We randomly assigned them into 3 groups: control group maintained baseline dairy intake, low-fat (LF) group incorporated ≥3 servings/d of LF dairy, and the high-fat (HF) group incorporated ≥3 servings/d of HF dairy. We evaluated HbA1c, body weight, BMI, body composition parameters, blood pressure (BP), lipid parameters, homeostatic model assessment of insulin resistance (HOMA-IR), and total energy and macronutrient intake at baseline, and after 12 and 24 wk.

RESULTS

At 24 wk, percent energy from saturated fat increased from baseline in the HF group by 3.6%, (95% CI: 2.2, 5.1) and decreased in the LF group by -1.9% (95% CI: -3.3, -0.4). The LF group increased their percent energy from protein by 4.5% (95% CI: 2.6, 6.4), whereas the HF group decreased their percent energy from carbohydrates by -3.4% (95% CI: -0.2, -6.7). There were no differences in the mean changes in HbA1c, body weight, BMI, body composition or lipid parameters, or BP between the 3 groups at 24 wk.

CONCLUSION

In patients with type 2 diabetes, increased dairy consumption to ≥3 servings/d compared with <3 servings/d, irrespective of its fat content, while maintaining energy intake has no effect on HbA1c, body weight, body composition, lipid profile, or BP. This trial was registered at clinicaltrials.gov as NCT02895867.

Whole-Fat or Reduced-Fat Dairy Product Intake, Adiposity, and Cardiometabolic Health in Children: A Systematic Review

Dietary guidelines commonly recommend that children aged >2 y consume reduced-fat dairy products rather than regular- or whole-fat dairy. In adults, most studies have not found the consumption of whole-fat dairy products to be associated with increased cardiometabolic or adiposity risk. Associations in children could differ due to growth and development. We systematically reviewed the literature in indexed, peer-reviewed journals to summarize pediatric studies (children aged from 2 to 18 y) assessing associations between whole- and reduced-fat dairy intake and measures of adiposity as well as biomarkers of cardiometabolic disease risk, including the serum lipid profile, blood pressure, low-grade chronic inflammation, oxidative stress, and measures of glucose homeostasis. For the purposes of this review, a "whole-fat" dairy product was defined as a product with the natural fat content, whereas a "reduced-fat" dairy product was defined as a product with some or all of the fat removed (including "low-fat" and "skim" versions). A total of 29 journal articles met our criteria for inclusion. The majority were conducted in the United States and were prospective or cross-sectional observational studies, with only 1 randomized controlled trial. Studies were consistent in reporting that whole-fat dairy products were not associated with increased measures of weight gain or adiposity. Most evidence indicated that consumption of whole-fat dairy was not associated with increased cardiometabolic risk, although a change from whole-fat to reduced-fat dairy improved outcomes for some risk factors in 1 study. Taken as a whole, the limited literature in this field is not consistent with dietary guidelines recommending that children consume preferably reduced-fat dairy products. High-quality randomized controlled trials in children that directly compare the effects of whole-fat compared with reduced-fat dairy intake on measures of adiposity or biomarkers of cardiometabolic disease risk are needed to provide better quality evidence in this area.

Cow's milk: Composition, nutritional, biological and cardioprotective benefits

Since several years, dairy products have been at the heart of nutritional deba-tes. High-fat dairy products can aggravate dyslipidemia and the consumption of satura-ted, and trans fats is associated with an increased cardiovascular diseases risk. In this re-gard, current dietary guidelines recommend a low fat content, and a significant reduc-tion in trans fatty acid intake. However, recent controversial epidemiological studies show that high-fat dairy products consumption may reduce diabetes, metabolic syndro-me, and the risk of cardiovascular diseases. This dairy paradox has led to a dietary guidelines re-evaluation.

Dietary habits, lipoprotein metabolism and cardiovascular disease: From individual foods to dietary patterns

Cardiovascular disease (CVD) remains the first cause of mortality in Western countries. Among cardiometabolic risk factors, dyslipidemia, and especially high low-density lipoprotein cholesterol (LDL-C) concentrations, have been extensively linked to the development and progression of atherosclerosis and to CVD events. Recent evidence has shown that the prevention of unhealthy dietary habits and sedentarism is crucial in the management of dyslipidemia. In this sense, a number of scientific societies recommend the adherence to certain healthy dietary patterns (DPs), such as the Mediterranean diet (MedDiet), the Dietary Approaches to Stop Hypertension (DASH), the Portfolio diet, the Vegetarian diet, the Nordic diet and low-carbohydrate diets, as well as increased physical activity between others. This nutritional and lifestyle advice could be adopted by government bodies and implemented in different health programs as a reliable way of providing health-care professionals with efficient tools to manage cardiometabolic risk factors and thus, prevent CVD. In this narrative review, we will discuss recent data about the effects of nutrition on dyslipidemia, mainly focusing on high LDL-C concentrations and other lipid particles related to atherogenic dyslipidemia such as triglycerides (TG) and non-high density lipoprotein cholesterol (non-HDL-C), that are related to CVD. On the other hand, we also comment on other cardiometabolic risk factors such as type 2 diabetes mellitus (T2DM), high blood pressure (HBP), inflammation and endothelial dysfunction. This review includes food groups as well as different healthy DPs.

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.

Effects of total fat intake on body fatness in adults

BACKGROUND

The ideal proportion of energy from fat in our food and its relation to body weight is not clear. In order to prevent overweight and obesity in the general population, we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of body fatness (including body weight, waist circumference, percentage body fat and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) of at least six months duration.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) to October 2019. We did not limit the search by language.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included adults aged at least 18 years, 3) randomised to a lower fat versus higher fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of body fatness (body weight, BMI, percentage body fat and waist circumference) independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity, funnel plot analyses and GRADE assessment.

MAIN RESULTS

We included 37 RCTs (57,079 participants). There is consistent high-quality evidence from RCTs that reducing total fat intake results in small reductions in body fatness; this was seen in almost all included studies and was highly resistant to sensitivity analyses (GRADE high-consistency evidence, not downgraded). The effect of eating less fat (compared with higher fat intake) is a mean body weight reduction of 1.4 kg (95% confidence interval (CI) -1.7 to -1.1 kg, in 53,875 participants from 26 RCTs, I² = 75%). The heterogeneity was explained in subgrouping and meta-regression. These suggested that greater weight loss results from greater fat reductions in people with lower fat intake at baseline, and people with higher body mass index (BMI) at baseline. The size of the effect on weight does not alter over time and is mirrored by reductions in BMI (MD -0.5 kg/m², 95% CI -0.6 to -0.3, 46,539 participants in 14 trials, I² = 21%), waist circumference (MD -0.5 cm, 95% CI -0.7 to -0.2, 16,620 participants in 3 trials; I² = 21%), and percentage body fat (MD -0.3% body fat, 95% CI -0.6 to 0.00, P = 0.05, in 2350 participants in 2 trials; I² = 0%). There was no suggestion of harms associated with low fat diets that might mitigate any benefits on body fatness. The reduction in body weight was reflected in small reductions in LDL (-0.13 mmol/L, 95% CI -0.21 to -0.05), and total cholesterol (-0.23 mmol/L, 95% CI -0.32 to -0.14), with little or no effect on HDL cholesterol (-0.02 mmol/L, 95% CI -0.03 to 0.00), triglycerides (0.01 mmol/L, 95% CI -0.05 to 0.07), systolic (-0.75 mmHg, 95% CI -1.42 to -0.07) or diastolic blood pressure(-0.52 mmHg, 95% CI -0.95 to -0.09), all GRADE high-consistency evidence or quality of life (0.04, 95% CI 0.01 to 0.07, on a scale of 0 to 10, GRADE low-consistency evidence).

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus a higher fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI, waist circumference and percentage body fat compared with higher fat arms. Greater fat reduction, lower baseline fat intake and higher baseline BMI were all associated with greater reductions in weight. There was no evidence of harm to serum lipids, blood pressure or quality of life, but rather of small benefits or no effect.

The associations of longitudinal changes in consumption of total and types of dairy products and markers of metabolic risk and adiposity: findings from the European Investigation into Cancer and Nutrition (EPIC)-Norfolk study, United Kingdom

BACKGROUND

The consumption of some types of dairy products has been associated with lower cardiometabolic disease incidence. Knowledge remains limited about habitual dairy consumption and the pathways to cardiometabolic risk.

OBJECTIVE

We aimed to investigate associations of habitual consumption of total and types of dairy products with markers of metabolic risk and adiposity among adults in the United Kingdom.

METHODS

We examined associations of changes in dairy consumption (assessed with a food-frequency questionnaire) with parallel changes in cardiometabolic markers using multiple linear regression among 15,612 adults aged 40-78 y at baseline (1993-1997) and followed up over 1998-2000 (mean ± SD: 3.7±0.7 y) in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study.

RESULTS

For adiposity, an increase in fermented dairy products [yogurt (total or low-fat) or low-fat cheese] consumption was associated with a lower increase in body weight and body mass index (BMI). For example, over 3.7 y, increasing yogurt consumption by 1 serving/d was associated with a smaller increase in body weight by 0.23 kg (95% CI: -0.46, -0.01 kg). An increase in full-fat milk, high-fat cheese, and total high-fat dairy was associated with greater increases in body weight and BMI [e.g., for high-fat dairy: β = 0.13 (0.05, 0.21) kg and 0.04 (0.01, 0.07) kg/m2, respectively]. For lipids, an increase in milk (total and low-fat) or yogurt consumption was positively associated with HDL cholesterol. An increase in total low-fat dairy was negatively associated with LDL cholesterol (-0.03 mmol/L; -0.05, -0.01 mmol/L), whereas high-fat dairy (total, butter, and high-fat cheese) consumption was positively associated [e.g., 0.04 (0.02, 0.06) mmol/L for total high-fat dairy]. For glycemia, increasing full-fat milk consumption was associated with a higher increase in glycated hemoglobin (P = 0.027).

CONCLUSIONS

The habitual consumption of different dairy subtypes may differently influence cardiometabolic risk through adiposity and lipid pathways.

Potential Cardiometabolic Health Benefits of Full-Fat Dairy: The Evidence Base

Since their inception in 1980, the Dietary Guidelines for Americans have promoted low- or fat-free dairy foods. Removing fat from dairy does not reduce putatively beneficial nutrients per serving, including calcium, vitamin D, and potassium. Additionally, links between saturated fat and dietary cholesterol intakes with cardiovascular disease risk have helped to sustain the view that low-fat dairy foods should be recommended. Emerging evidence shows that the consumption of full-fat dairy foods has a neutral or inverse association with adverse cardiometabolic health outcomes, including atherosclerotic cardiovascular disease, type 2 diabetes, and associated risk factors. Thus, although low-fat dairy is a practical, practice-based recommendation, its superiority compared with full-fat dairy is not obviously supported by results from recent prospective cohort studies or intervention trials. To evaluate the emerging science on full-fat dairy, a group of nutrition experts convened to summarize and discuss the scientific evidence regarding the health effects of consuming full-fat dairy foods. Future studies should focus on full-fat dairy foods (milk, yogurt, and cheese) in the context of recommended dietary patterns and consider meal composition and metabolic phenotype in assessing the relation between full-fat dairy consumption and cardiometabolic health.

Dietary and modifiable factors contributing to hyper-LDL-cholesterolemia prevalence in nationwide time series data and the implications for primary prevention strategies

BACKGROUND/OBJECTIVES

A number of studies examined secular trends in blood lipid profiles using time series data of national surveys whereas few studies investigated individual-level factors contributing to such trends. The present study aimed to examine secular trends in dietary and modifiable factors and hyper-LDL-cholesterolemia (HC) prevalence and evaluate their associations using time series data of nationwide surveys.

SUBJECTS/METHODS

The study included 41,073 Korean adults aged ≥ 30 years from the 2005, 2007–2009, 2010–2012, 2013–2015, and 2016 Korea National Health and Nutrition Examination Surveys. Stepwise logistic regression analysis was performed to select significant factors associated with HC, which was defined as serum LDL cholesterol levels ≥130 mg/dL.

RESULTS

The following factors showed a positive association with HC (P < 0.05): for men having higher body mass index (BMI), being married, having an office job, and consuming higher dairy and vegetable oil products; for women having higher age or BMI, having no job or a non-office job, not in a low-income household, and consuming higher dairy products. In the given model, the 2016 survey data showed that a 2 kg/m² reduction in BMI of obese persons resulted in a decreased HC prevalence from 30.8% to 29.3% among men and from 33.6% to 32.5% among women.

CONCLUSIONS

Based on these findings, it is suggested that primary prevention programs should advocate having proper BMI for Korean adults with a high-risk of HC. However, whether discouraging consumption of dairy and vegetable oil products can reduce HC prevalence warrants further studies with a prospective longitudinal design.

Effects of regular-fat and low-fat dairy consumption on daytime ambulatory blood pressure and other cardiometabolic risk factors: a randomized controlled feeding trial

BACKGROUND

The extent to which dairy products and their fat content influence cardiovascular health remains uncertain.

OBJECTIVE

This study aimed to assess how consumption of low-fat milk and regular-fat cheese enriched in γ-aminobutyric acid (GABA) influences daytime ambulatory blood pressure (BP) and other cardiometabolic risk factors.

METHODS

In this crossover controlled feeding study, 55 healthy men and women with high-normal daytime BP were randomly assigned to sequences of three 6-wk isoenergetic diets, each comprising 1) no dairy (control diet), 2) 3 daily servings of 1% fat milk, and 3) 1 daily serving of 31% fat cheddar cheese naturally enriched in GABA. Total proteins, carbohydrates, and fats were matched across all 3 diets. The additional 2% of energy from SFAs in the cheese diet was replaced by n-6 PUFAs in the other diets.

RESULTS

Comparison of postdiet ambulatory systolic BP revealed no difference (P = 0.34), which was also the case for ambulatory diastolic BP (P = 0.45). The cheese diet increased serum LDL-cholesterol concentrations compared with the control and milk diets (+5.8%, P = 0.006 and +7.0%, P = 0.0008, respectively) and increased LDL particle size compared with the milk diet (P = 0.02). HDL-cholesterol concentrations after the milk diet were lower than after the control diet (-4.1%; P = 0.009). The milk and cheese diets increased triglycerides compared with the control diet (+9.9%, P = 0.01 and +10.5%, P = 0.007, respectively). There was no significant difference between all diets for C-reactive protein concentrations and markers of glucose/insulin homeostasis.

CONCLUSIONS

These results suggest that short-term consumption of dairy products, whether low or regular in fat, has no overall effect on daytime ambulatory BP compared with a dairy-free diet. Other cardiometabolic risk factors may be differently modified according to the fat content of the dairy product. This trial was registered at clinicaltrials.gov as NCT02763930.