Effect of dairy calcium from cheese and milk on fecal fat excretion, blood lipids, and appetite in young men

Comparison of the impact of saturated fat from full-fat yogurt or low-fat yogurt and butter on cardiometabolic factors: a randomized cross-over trial

PURPOSE

Dairy foods are often a major contributor to dietary saturated fatty acids (SFA) intake. However, different SFA-rich foods may not have the same effects on cardiovascular risk factors. We compared full-fat yogurt with low-fat yogurt and butter for their effects on cardiometabolic risk factors in healthy individuals.

METHODS

Randomized, two-period crossover trial conducted from October 2022 to April 2023 among 30 healthy men and women (15 to receive full-fat yogurt first, and 15 to receive low-fat yogurt and butter first). Participants consumed a diet with 1.5-2 servings of full-fat (4%) yogurt or low-fat (< 1.5) yogurt and 10-15 g of butter per day for 4 weeks, with 4 weeks wash-out when they consumed 1.5-2 servings of low-fat milk. At baseline, and the end of each 4 weeks, fasting blood samples were drawn and plasma lipids, glycemic and inflammatory markers as well as expression of some genes in the blood buffy coats fraction were determined.

RESULTS

All 30 participants completed the two periods of the study. Apolipoprotein B was higher for the low-fat yogurt and butter [changes from baseline, + 10.06 (95%CI 4.64 to 15.47)] compared with the full-fat yogurt [-4.27 (95%CI, -11.78 to 3.23)] and the difference between two treatment periods was statistically significant (p = 0.004). Non-high-density lipoprotein increased for the low-fat yogurt and butter [change, + 5.06 (95%CI (-1.56 to 11.69) compared with the full-fat yogurt [change, - 4.90 (95%CI, -11.61 to 1.81), with no significant difference between two periods (p = 0.056). There were no between-period differences in other plasma lipid, insulin, and inflammatory biomarkers or leukocyte gene expression of ATP-binding cassette transporter 1 and CD36.

CONCLUSION

This study suggests that short-term intake of SFAs from full-fat yogurt compared to intake from butter and low-fat yogurt has fewer adverse effects on plasma lipid profile.

CLINICALTRIALS

GOV: NCT05589350, 10/15/2022.

Dairy Matrix Effects: Physicochemical Properties Underlying a Multifaceted Paradigm

When food products are often considered only as a source of individual nutrients or a collection of nutrients, this overlooks the importance of interactions between nutrients, but also interactions between nutrients and other constituents of food, i.e., the product matrix. This product matrix, which can be defined as 'The components of the product, their interactions, their structural organization within the product and the resultant physicochemical properties of the product', plays a critical role in determining important product properties, such as product stability, sensory properties and nutritional and health outcomes. Such matrix effects can be defined as 'the functional outcome of specific component(s) as part of a specific product matrix'. In this article, dairy matrix effects are reviewed, with particular emphasis on the nutrition and health impact of dairy products. Such matrix effects are critical in explaining many effects of milk and dairy products on human nutrition and health that cannot be explained solely based on nutrient composition. Examples hereof include the low glycemic responses of milk and dairy products, the positive impact on dental health, the controlled amino acid absorption and the absence of CVD risk despite the presence of saturated fatty acids. Particularly, the changes occurring in the stomach, including, e.g., coagulation of casein micelles and creaming of aggregated fat globules, play a critical role in determining the kinetics of nutrient release and absorption.

Whole-Milk Dairy Foods: Biological Mechanisms Underlying Beneficial Effects on Risk Markers for Cardiometabolic Health

Lifestyle modifications that include adherence to healthy dietary patterns that are low in saturated fat have been associated with reduced risk for cardiovascular disease, the leading cause of death globally. Whole-milk dairy foods, including milk, cheese, and yogurt, are leading sources of saturated fat in the diet. Dietary guidelines around the world recommend the consumption of low-fat and fat-free dairy foods to obtain overall healthy dietary patterns that help meet nutrient recommendations while keeping within recommended calorie and saturated fat limitations. A body of observational and clinical evidence indicates, however, that whole-milk dairy food consumption, despite saturated fat content, does not increase the risk for cardiovascular disease. This review describes the proposed biological mechanisms underlying inverse associations between whole-milk dairy food consumption and risk markers for cardiometabolic health, such as altered lipid digestion, absorption, and metabolism; influence on the gut microflora; and regulation of oxidative stress and inflammatory responses. The dairy food matrix, a term used to describe how the macronutrients and micronutrients and other bioactive components of dairy foods are differentially packaged and compartmentalized among fluid milk, cheese, and yogurt, may dictate how each affects cardiovascular risk. Current evidence indicates consideration of dairy foods as complex food matrices, rather than delivery systems for isolated nutrients, such as saturated fatty acids, is warranted.

Effect of Isoenergetic Substitution of Cheese with Other Dairy Products on Blood Lipid Markers in the Fasted and Postprandial State: An Updated and Extended Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults

Consumption of fat as part of a cheese matrix may differentially affect blood lipid responses when compared with other dairy foods. This systematic review was conducted to compare the impact of consuming equal amounts of fat from cheese and other dairy products on blood lipid markers in the fasted and postprandial state. Searches of PubMed (Medline), Cochrane Central and Embase databases were conducted up to mid-June 2022. Eligible human randomized controlled trials (RCTs) investigated the effect of isoenergetic substitution of hard or semi-hard cheese with other dairy products on blood lipid markers. Risk of bias (RoB) was assessed using the Cochrane RoB 2.0 tool. Random-effects meta-analyses assessed the effect of ≥2 similar dietary replacements on the same blood lipid marker. Of 1491 identified citations, 10 articles were included (RoB: all some concerns). Pooled analyses of 7 RCTs showed a reduction in fasting total cholesterol, LDL-C and HDL-C concentrations after ≥14 d mean daily intake of 135 g cheese (weighted mean difference [WMD]: -0.24 mmol/L; 95% confidence interval (CI): -0.34, -0.15; I2 = 59.8%, WMD: -0.19 mmol/L; 95% CI: -0.27, -0.12; I2 = 42.8%, and WMD: -0.04 mmol/L; 95% CI: -0.08, -0.00; I2 = 58.6%, respectively) relative to ∼52 g/d butter. We found no evidence of a benefit from replacing cheese for ≥14 d with milk on fasting blood lipid markers (n = 2). Limited postprandial RCTs, described in narrative syntheses, suggested that cheese-rich meals may induce differential fed-state lipid responses compared with some other dairy matrix structures, but not butter (n ≤ 2). In conclusion, these findings indicate that dairy fat consumed in the form of cheese has a differential effect on blood lipid responses relative to some other dairy food structures. However, owing to considerable heterogeneity and limited studies, further confirmation from RCTs is warranted. TRIAL REGISTRATION NUMBER: This systematic review protocol was registered at https://www.crd.york.ac.uk/PROSPERO/ as CRD42022299748.

Dairy product consumption and risk of non-alcoholic fatty liver disease: A systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

It is unclear whether regular consumption of dairy products is associated with the risk of developing non-alcoholic fatty liver disease (NAFLD). Thus, we conducted a systematic review followed by a meta-analysis of studies reporting on the association of dairy consumption with NAFLD risk.

METHODS AND RESULTS

We comprehensively searched PubMed, Web of Science, and Scopus for observational studies that evaluated the association between dairy intake and NAFLD likelihood that were published before September 1, 2022. The reported odds ratios (ORs) of fully adjusted models and their 95% confidence intervals (CIs) were pooled using a random-effects model for the meta-analysis. Out of 1206 articles retrieved, 11 observational studies, including 43,649 participants and 11,020 cases, were included. Pooled OR indicated a significant association between dairy intake and NAFLD (OR = 0.90; 95% CI: 0.83, 0.98; I² = 67.8%, n = 11). Pooled ORs revealed that milk (OR: 0.86; 95% CI: 0.78, 0.95; I² = 65.7%, n = 6), yogurt (OR: 0.88; 95% CI: 0.82; I² = 0.0%, n = 4), and high-fat dairy (OR: 0.38; 95% CI: 0.19, 0.75; I² = 0.0%, n = 5) consumption was inversely associated with NAFLD while cheese was not linked to NAFLD risk.

CONCLUSION

We observed that consumption of dairy products is linked to a reduced risk of developing NAFLD. Overall, the data in the source articles is of low to moderate quality; therefore, further observational studies are required to support the current findings (PROSPERO Reg. number: CRD42022319028).

Harnessing the Magic of the Dairy Matrix for Next-Level Health Solutions: A Summary of a Symposium Presented at Nutrition 2022

An emerging body of scientific evidence demonstrates that the food matrix-the interaction among nutrients, bioactive components, and physical structure of a food-can affect health in significant, unexpected ways beyond its individual nutrients. In particular, research suggests that consumption of dairy foods such as milk, yogurt, and cheese may affect human health in a matrix-dependent fashion. To disseminate and discuss the growing body of evidence surrounding the role of the dairy food matrix on cardiometabolic health, 3 expert researchers on the topic of the food matrix shared the latest science in a session entitled "Next-Level Health Solutions: The Magic of the Matrix" at the American Society for Nutrition's 2022 LIVE ONLINE Conference. This article is a summary of the literature presented and discussed during that session. A substantial body of literature demonstrates that full-fat dairy foods, particularly fermented dairy foods, may beneficially modulate cardiometabolic outcomes depending on an individual's health status. These findings have important implications for current authoritative dietary guidance that recommends the consumption of low-fat or fat-free dairy foods. Furthermore, this evidence may inform practical applications of harnessing dairy's unique profile of bioactives for health promotion and disease prevention at the individual and community levels.

Deep phenotyping and biomarkers of various dairy fat intakes in an 8-week randomized clinical trial and 2-year swine study

Health effects of dairy fats (DF) are difficult to evaluate, as DF intakes are hard to assess epidemiologically and DF have heterogeneous compositions that influence biological responses. We set out to find biomarkers of DF intake and assess biological response to a summer DF diet (R2), a winter DF diet (R3), and a R3 supplemented with calcium (R4) compared to a plant-fat-based diet (R1) in a randomized clinical trial (n=173) and a 2-year study in mildly metabolically disturbed downsized pigs (n=32). Conventional clinical measures were completed by LC/MS plasma metabolomics/lipidomics. The measured effects were modeled as biological functions to facilitate interpretation. DF intakes in pigs specifically induced a U-shaped metabolic trajectory, reprogramming metabolism to close to its initial status after a one-year turnaround. Twelve lipid species repeatably predicted DF intakes in both pigs and humans (6.6% errors). More broadly, in pigs, quality of DF modulated the time-related biological response (R2: 30 regulated functions, primarily at 6 months; R3: 26 regulated functions, mostly at 6-12 months; R4: 43 regulated functions, mostly at 18 months). Despite this heterogeneity, 9 functions overlapped under all 3 DF diets in both studies, related to a restricted area of amino acids metabolism, cofactors, nucleotides and xenobiotic pathways and the microbiota. In conclusion, over the long-term, DF reprograms metabolism to close to its initial biological status in metabolically-disrupted pigs. Quality of the DF modulates its metabolic influence, although some effects were common to all DF. A resilient signature of DF consumption found in pigs was validated in humans.

Effect of reduced-calcium and high-calcium cheddar cheese consumption on the excretion of faecal fat: a 2-week cross-over dietary intervention study

PURPOSE

Studies show that dairy fat consumed in the form of cheese reduce LDL-cholesterol concentration (LDL-c) compared to butter and mechanistic suggestions include the calcium content of cheese leading to enhanced faecal fat excretion. The aim of this study was to test the effect of varying the calcium content within a cheese, on faecal fat excretion as a primary outcome, and blood lipid markers, fasting glucose and calcium excretion as secondary outcomes.

METHODS

7 healthy males (BMI 18-25) participated in this randomized, cross-over control intervention, of 3 × 2 week periods. Diets contained 240 g/day cheese; a High Calcium Cheese (HCC) diet, a Reduced Calcium Cheese (RCC) diet, and a control arm: Reduced Calcium Cheese + CaCO₃ Supplement (RCC + Supp) diet. Diets differed in calcium content and form but were otherwise controlled for energy and key macronutrients. Blood and 5-day faecal samples were collected.

RESULTS

There was no significant difference in faecal fat excretion (g/day) between the diets (P = 0.066). Percent fat of faecel excretion was higher after RCC + Supp (P = 0.016). None of the individual fatty acids were different. Fasting LDL-c was significantly lower following the HCC diet vs. the other arms (P = 0.002). Faecal Ca was different across all diets (P = 0.001), lowest after RCC, and greatest after RCC + Supp. No differences were observed for fasting blood parameters or changes in anthropometry.

CONCLUSION

Varying the calcium content within a cheese matrix significantly affected fasting LDL-c values. Results did not support higher faecal fat excretion as an underlying mechanism, but the high attrition rate was a limitation. Trial registerer Trial Registered at ISRCTN.org, registration number ISRCTN11663659 on 12.07.2022. Retrospectively registered.

Intake of Calcium, Magnesium, and Phosphorus and Risk of Pancreatic Cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

ObjectiveFew epidemiological studies have investigated the associations between calcium, magnesium, and phosphorus intake and pancreatic cancer. We examined these associations in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.MethodsDiet was assessed using the Dietary Questionnaire (DQX) at baseline in the intervention arm and the Dietary History Questionnaire (DHQ) in 1999 or around the third anniversary of randomization in both the intervention and control arms. During a median follow-up of 12.2 years, 279 cases of pancreatic cancer occurred from 58,477 participants who completed DQX; 380 cases arose from 101,622 participants who responded to DHQ over a median follow-up of 8.9 years. Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI).ResultsTotal calcium intake was inversely associated with pancreatic cancer [HR (95% CI) for the fourth vs. the first quartiles in the DHQ cohort: 0.67 (0.47, 0.96); p-trend: 0.035]. An inverse association was also observed for total magnesium intake [HR (95% CI) for the fourth vs. the first quartiles in the DQX cohort: 0.61 (0.37, 1.00); p-trend: 0.023]. Reduced risk associated with total calcium intake was confined to subjects with a high fat intake (>73 g/day) in the DHQ cohort (p-interaction: 0.16).ConclusionsThere was not a significant association between dietary phosphorus intake and pancreatic cancer risk in both cohorts. Total intake of calcium and magnesium are associated with a lower pancreatic cancer risk. The effect of total calcium intake was modified by fat intake.

Dietary supplements for lipedema

Lipedema is a chronic disease that mostly manifests in females as the abnormal distribution of subcutaneous adipose connective tissue, usually coupled with bruising, pain, and edema. Lipedema molecular pathophysiology is currently not clear, but several studies suggest that genetics and hormonal imbalance participate in lipedema pathogenesis. Women with lipedema present in some cases with elevated body mass index, and the appearance of obesity in addition to lipedema, where the obesity can cause serious health issues as in lipedema-free individuals with obesity, such as diabetes and cardiovascular disorders. Unlike obesity, lipedema tissue does not respond well to diet or physical exercise alone. Therefore, in this review we discuss the effect of various dietary supplements that, along with diet and physical exercise, cause fat burning and weight loss, and which could potentially be important in the treatment of lipedema. Indeed, an effective fat burner should convert stored fats into energy, mobilize and break down triglycerides in adipocytes, boost metabolism and inhibit lipogenesis. Common ingredients of fat burning supplements are green tea, caffeine, chromium, carnitine, and conjugated linoleic acid. The use of fat burners could act synergistically with a healthy diet and physical exercise for decreasing adipose tissue deposition in patients with lipedema and resolve related health issues. The effects of fat burners in human studies are sometimes contradictory, and further studies should test their effectiveness in treating lipedema.

Effects of high dairy protein intake and vitamin D supplementation on body composition and cardiometabolic markers in 6-8-y-old children-the D-pro trial

BACKGROUND

Increasing evidence suggests that prevention of lifestyle diseases should begin early. Dairy protein and vitamin D can affect body composition and cardiometabolic markers, yet evidence among well-nourished children is sparse.

OBJECTIVES

We investigated combined and separate effects of high dairy protein intake and vitamin D on body composition and cardiometabolic markers in children.

METHODS

In a 2 × 2-factorial, randomized trial, 200 white, Danish, 6-8-y-old children substituted 260 g/d dairy in their diet with high-protein (HP; 10 g protein/100 g) or normal-protein (NP; 3.5 g protein/100 g) yogurt and received blinded tablets with 20 µg/d vitamin D3 or placebo for 24 wk during winter. We measured body composition (by DXA), blood pressure, and fasting blood glucose, insulin, C-peptide, and lipids.

RESULTS

In total, 184 children (92%) completed the study. Baseline median (25th-75th percentile) dairy protein intake was median: 3.7 (25th-75th percentile: 2.5-5.1) energy percentage (E%) and increased to median: 7.2 (25th-75th percentile: 4.7-8.8) E% and median: 4.2 (25th-75th percentile: 3.1-5.3) E% with HP and NP. Mean ± SD serum 25-hydroxyvitamin D concentration changed from 81 ± 17 to 89 ± 18 nmol/L and 48 ± 13 nmol/L with vitamin D and placebo, respectively. There were no combined effects of dairy protein and vitamin D, except for plasma glucose, with the largest increase in the NP-vitamin D group (Pinteraction = 0.005). There were smaller increases in fat mass index (P = 0.04) with HP than with NP, and the same pattern was seen for insulin, HOMA-IR, and C-peptide (all P = 0.06). LDL cholesterol was reduced with vitamin D compared with placebo (P < 0.05). Fat-free mass and blood pressure were unaffected.

CONCLUSIONS

High compared with normal dairy protein intake hampered an increase in fat mass index. Vitamin D supplementation counteracted the winter decline in 25-hydroxyvitamin D and the increase in LDL cholesterol observed with placebo. This study adds to the sparse evidence on dairy protein in well-nourished children and supports a vitamin D intake of ∼20 µg/d during winter. This trial was registered at clinicaltrials.gov as NCT03956732.

Consumption of dairy products and CVD risk: results from the French prospective cohort NutriNet-Santé

In France, dairy products contribute to dietary saturated fat intake, of which reduced consumption is often recommended for CVD prevention. Epidemiological evidence on the association between dairy consumption and CVD risk remains unclear, suggesting either null or inverse associations. This study aimed to investigate the associations between dairy consumption (overall and specific foods) and CVD risk in a large cohort of French adults. This prospective analysis included participants aged ≥18 years from the NutriNet-Santé cohort (2009-2019). Daily dietary intakes were collected using 24-h dietary records. Total dairy, milk, cheese, yogurts, fermented and reduced-fat dairy intakes were investigated. CVD cases (n 1952) included cerebrovascular disease (n 878 cases) and CHD (n 1219 cases). Multivariable Cox models were performed to investigate associations. This analysis included 104 805 French adults (mean age at baseline 42·8 (sd 14·6) years, mean follow-up 5·5 (sd 3·0) years, i.e. 579 155 person-years). There were no significant associations between dairy intakes and total CVD or CHD risks. However, the consumption of at least 160 g/d of fermented dairy (e.g. cheese and yogurts) was associated with a reduced risk of cerebrovascular diseases compared with intakes below 57 g/d (hazard ratio = 0·81 (95 % CI 0·66, 0·98), Ptrend = 0·01). Despite being a major dietary source of saturated fats, dairy consumption was not associated with CVD or CHD risks in this study. However, fermented dairy was associated with a lower cerebrovascular disease risk. Robust randomised controlled trials are needed to further assess the impact of consuming different dairy foods on CVD risk and potential underlying mechanisms.

Perspectives on the systematic review for the 2020 Dietary Reference Intakes for Koreans for calcium

An accurate assessment of the recommended calcium (Ca) intake may contribute to reducing the risk of fractures and chronic diseases, ultimately improving quality of life. This review was performed to summarize key findings of Ca studies, investigate the effect of Ca intake on health outcomes, and determine the adequacy of evidence to revise the 2015 Dietary Reference Intakes for Koreans (KDRIs) for Ca in 2020. Databases were searched for intervention studies that assessed health outcomes by providing Ca in diets or as supplements. The framework of the systematic review comprised conducting literature searches, data extraction, quality assessment of the literature, and summarizing key findings relevant to set the Estimated Average Requirement (EAR) and Tolerable Upper Intake Level (UL) for Ca for the 2020 KDRI. The final search was performed in June 2019. A total of 13,309 studies were identified through databases and manual search. Sixtyfive studies were included in the final quality assessment and were summarized according to health indicators. As bone health was used as an indicator of the EAR for Ca, literature reports on bone health were further categorized by the life-cycle stage of the participants. This systematic review did not find new evidence that could be applied to the general Korean adult population, including postmenopausal women, for defining a new EAR for Ca in the 2020 KDRIs. Evidence in most of the reviewed literature was considered weak; however, some evidence was found that could improve the criteria on how the EAR for Ca was determined in children and adolescents. A review of the literature for the 2020 KDRIs for Ca did not find strong evidence in order to change the recommended values of the 2015 KDRIs. More clinical interventions are required among Koreans to strengthen the body of evidence to warrant the revision of the KDRIs.

Associations between intake of calcium, magnesium and phosphorus and risk of pancreatic cancer: a population-based, case-control study in Minnesota

Experimental studies suggest that abnormal levels of Ca, Mg and phosphorus are implicated in pancreatic carcinogenesis. We investigated the associations between intakes of these minerals and the risk of pancreatic cancer in a case-control study conducted in 1994-1998. Cases of pancreatic cancer (n 150) were recruited from all hospitals in the metropolitan area of the Twin Cities and Mayo Clinic, Minnesota. Controls (n 459) were randomly selected from the general population and frequency matched to cases by age, sex and race. All dietary variables were adjusted for energy intake using the residual method prior to data analysis. Logistic regression was performed to evaluate the associations between intake of three nutrients examined and the risk of pancreatic cancer. Total intake of Ca (936 v. 1026 mg/d) and dietary intake of Mg (315 v. 331 mg/d) and phosphorus (1350 v. 1402 mg/d) were significantly lower in cases than in controls. After adjustment for confounders, there were not significant associations of total and dietary intakes of Ca, Mg and phosphorus with the risk of pancreatic cancer. In addition, no significant interactions exist between intakes of these minerals and total fat on pancreatic cancer risk. In conclusion, the present study does not suggest that intakes of Ca, Mg and phosphorus were significantly associated with the risk of pancreatic cancer.

Independent and Combined Effects of Calcium and Vitamin D Supplementation on Blood Lipids in Overweight or Obese Premenopausal Women: A Triple-Blind Randomized Controlled Clinical Trial

Background:

Dyslipidemia is often associated with obesity and contributes to the increased risk of atherosclerosis, heart disease, and stroke. This study was designed to evaluate the independent or combined effect of calcium and vitamin D (Ca + Vit D) supplementation on blood lipid profile in overweight or obese premenopausal women.

Methods:

This study is a triple-blind, randomized, parallel, placebo-controlled trial. About 100 overweight or obese (body mass index (BMI) of 25–40 kg/m²) premenopausal (aged 30–50 years) women, recruited from Shiraz University of Medical Sciences (SUMS) clinics, were allocated into 4 groups: (1) calcium (Ca) supplementation (2 tablets per day; each containing 500 mg calcium carbonate), (2) vitamin D (Vit D) supplementation (2 tablets per day; each containing 200 IU vitamin D3), (3) Ca + Vit D supplementation (2 tablets per day; each containing 500 mg calcium carbonate plus 200 IU vitamin D3), (4) placebo supplementation (2 tablets per day, containing micro-cellulose). All participants received a 500 kcal energy-restricted diet. Blood lipids, serum vitamin D, and anthropometric indices were measured at baseline and after 8 weeks. Physical activity and 3-day dietary records were taken at baseline and every 4 weeks during the intervention.

Results:

At 8 weeks, triglyceride levels were significantly decreased in the Ca group (P = 0.002). Low-density lipoprotein (LDL) levels were decreased in the Ca + Vit D group (P = 0.04) and high-density lipoprotein (HDL) levels decreased in both the Ca and Ca + Vit D groups (P = 0.006, P = 0.004, respectively). The results of one-way ANOVA indicated that changes in the serum lipid profile levels were not significantly different among the four groups (P = 0.90, P = 0.86, P = 0.61, P = 0.27, and P = 0.19, respectively for TG, TC, LDL, HDL, and LDL/HDL). The results were not significant even after adjusting for potential covariates.

Conclusions:

Although the results were not significantly different among the four treated groups at 8 weeks, within-group changes like the reduction in triglyceride and LDL levels, respectively in the Ca group and Ca + Vit D group, and HDL levels in both the Ca and Ca + Vit D groups were significant. These changes may have potentially significant public health implications.

Role of calcium on lipid digestion and serum lipids: a review

Calcium is an essential nutrient for humans that can be taken as supplement or in a food matrix (e.g. dairy products). It is suggested that dietary calcium may have a beneficial effect on cardiovascular risk but the mechanism is not clear. In this review, the main mechanisms of the possible cholesterol-lowering effect of calcium, i.e. interaction with fatty acids and bile acids, are described and clinical evidences are presented. The observations from interventional studies of the possible cholesterol-lowering effect in terms of the main related mechanisms are variable and do not seem to fulfill all the related aspects. It seems that the interplay of calcium in blood lipid metabolism might be due to its complex and multiple roles in the lipid digestion in the small intestine. The interactions between calcium and, fatty acids and bile may lead to impaired mixed micelle formation and solubilization, which is crucial in the lipid absorption and metabolism. In addition, the calcium source and its surrounding matrix will have an influence over the physiological outcome. This research is important for the delivery and formulation of calcium, particularly with the move toward plant-based diets.

Progression of Postprandial Blood Plasma Phospholipids Following Acute Intake of Different Dairy Matrices: A Randomized Crossover Trial

Studies have indicated that the dairy matrix can affect postprandial responses of dairy products, but little is known about the effect on postprandial plasma phospholipid levels. This study investigated postprandial plasma phospholipid levels following consumption of four different dairy products that are similar in micro and macro nutrients, but different in texture and structure: cheddar cheese (Cheese), homogenized cheddar cheese (Hom. Cheese), micellar casein isolate with cream (MCI Drink) or a gel made from the MCI Drink (MCI Gel). The study was an acute randomized, crossover trial in human volunteers with four test days. Blood samples were collected during an 8 h postprandial period and the content of 53 plasma phospholipids was analysed using liquid chromatography-mass spectrometry (LC-MS). No meal-time interactions were revealed; however, for nine of the 53 phospholipids, a meal effect was found. Thus, the results indicated a lower plasma level of specific lyso-phosphatidylethanolamines (LPEs) and lyso-phosphatidylcholines (LPCs) following consumption of the MCI Gel compared to the MCI Drink and Hom. Cheese, which might be attributed to an effect of viscosity. However, further studies are needed in order to reveal more details on the effect of the dairy matrix on postprandial phospholipids.

Microbiota and Metabolite Modifications after Dietary Exclusion of Dairy Products and Reduced Consumption of Fermented Food in Young and Older Men

The gut microbiota adapts to age-related changes in host physiology but is also affected by environmental stimuli, like diet. As a source of both pre- and probiotics, dairy and fermented foods modulate the gut microbiota composition, which makes them interesting food groups to use for the investigation of interactions between diet and ageing. Here we present the effects of excluding dairy products and limiting fermented food consumption for 19 days on gut microbiota composition and circulating metabolites of 28 healthy, young (YA) and older (OA) adult men. The intervention affected gut microbial composition in both groups, with significant increases in Akkermansia muciniphila and decreases in bacteria of the Clostridiales order. Lower fasting levels of glucose and insulin, as well as dairy-associated metabolites like lactose and pentadecanoic acid, were observed after the intervention, with no effect of age. The intervention also decreased HDL and LDL cholesterol levels. Dairy fat intake was positively associated with the HDL cholesterol changes but not with the LDL/HDL ratio. In conclusion, restricting the intake of dairy and fermented foods in men modified their gut microbiota and blood metabolites, while the impact of the dietary restrictions on these outcomes was more marked than the effect of age.

Influence of type of dairy matrix micro- and macrostructure on in vitro lipid digestion

Recent research indicates that the food matrix can influence digestion kinetics and uptake of nutrients, thus affecting human health. The aim of this study was to obtain knowledge on how variations in microstructure and texture of foods represented by four dairy products; (i) cheddar cheese, (ii) a homogenized cheddar cheese, (iii) a micellar casein and cream drink or (iv) a micellar casein and cream gel, all of identical nutrient ratios of protein : fat and calcium : fat, affect the in vitro digestibility kinetics of lipids. Rheology of the four dairy structures was measured at 10 °C and 37 °C before digestion, and during the gastric phase of in vitro digestion. During digestion cheddar cheese was most resistant to enzymatic and mechanical disintegration, followed by homogenized cheese, while both the drink and gel had low resistance and dissolved in the gastric juice. Particle size, fat droplet size and microstructure were assessed by light scattering and confocal microscopy during digestion. Significantly larger fat droplets were observed during digestion of the cheddar cheese sample. The release of free fatty acids during the initial intestinal digestion showed cheddar cheese to provide a significantly lower release than homogenized cheese, whereas the drink and gel both had significantly higher free fatty acid release. The results suggest that the cheese matrix resistance to degradation and its large fat droplets were responsible for a slower fat digestion.

Acute Oral Calcium Suppresses Food Intake Through Enhanced Peptide-YY Secretion Mediated by the Calcium-Sensing Receptor in Rats

BACKGROUND

Dietary calcium has been proposed to reduce appetite in human studies. Postprandial satiety is mainly controlled by gut hormones. However, the effect of calcium on appetite and the role of gut hormones remain unclear.

OBJECTIVES

We examined whether oral administration of calcium reduces food intake in rats and investigated the underlying mechanism.

METHODS

Male Sprague Dawley rats (8-12 wk old) were used after an overnight fastifffng. In a series of 2 trials with 1-wk interval between challenges, food intake was measured 0.5-24 h after oral gavage of a vehicle (saline containing 1.5% carboxymethyl cellulose) as the control treatment, or the vehicle containing various calcium compounds [calcium chloride (CaCl2), calcium carbonate, calcium lactate, in a random order] at 150 mg calcium/kg dose. A conditional taste aversion test was conducted. In separate experiments, plasma calcium and gut hormone concentrations were measured 15 or 30 min after oral administration of the calcium compounds. In anesthetized rats, portal peptide-YY (PYY) concentrations were measured after intraluminal administration of a liquid meal with or without additional calcium.

RESULTS

Oral CaCl2 reduced food intake acutely (30 min, ∼20%, P < 0.05) compared with control rats, without taste aversion. Plasma PYY concentration was higher (100%, P < 0.05) in CaCl2-preloaded rats than in control rats, 15 min after administration. In anesthetized rats, luminal meal + CaCl2 induced a 4-fold higher increase in plasma PYY than the control treatment did. Oral administration of a calcium-sensing receptor (CaSR) agonist suppressed food intake (∼30%, P < 0.05), but CaCl2 and CaSR agonist did not suppress food intake under treatment with a PYY receptor antagonist. Furthermore, the CaSR antagonist attenuated the effect of CaCl2 on food intake.

CONCLUSIONS

CaCl2 suppresses food intake partly by increasing CaSR-mediated PYY secretion in rats. Our findings could at least partially explain the satiating effect of calcium.

Food Matrix and Macronutrient Digestion

Food digestion may be regarded as a physiological interface between food and health. During digestion, the food matrix is broken down and the component nutrients and bioactive compounds are absorbed through a synergy of mechanical, chemical, and biochemical processes. The food matrix modulates the extent and kinetics to which nutrients and bioactive compounds make themselves available for absorption, hence regulating their concentration profile in the blood and their utilization in peripheral tissues. In this review, we discuss the structural and compositional aspects of food that modulate macronutrient digestibility in each step of digestion. We also discuss in silico modeling approaches to describe the effect of the food matrix on macronutrient digestion. The detailed knowledge of how the food matrix is digested can provide a mechanistic basis to elucidate the complex effect of food on human health and design food with improved functionality.

Measuring the health effects of food by metabolomics

Metabolomics of human biological fluids or tissues is used to discover markers for diseases by comparing the metabolome of the patients against healthy individuals. Ultimately, these markers can be used in drug discovery to determine how medications normalize (at least in part) the human metabolome at specific disease stages to homeostatic. Likewise, the health effects of food can be studied. Even metabolomics of the food can be combined with metabolomics of the treated patients to correlate compounds from food with measurable health effects from clinical studies. Various chemometric analyses of these metabolomics data are used to identify markers for diseases and to obtain evidence for health effects. This review discusses recent researches (published from 2013 to 2021) on whether specific dietary intervention to humans suffering from metabolic disorders may improve their pathological status. The scope is limited to those associated with major lifestyle diseases such as diabetes, obesity, and cardiovascular diseases, for which food is thought may have detrimental as well as beneficial effects on human health. It includes metabolites characterization of different biological samples such as the human serum/plasma, urine, saliva, feces, or ileal fluid. Whether the study results supported the claimed health benefits and whether the research was conducted with appropriate study design, was criticized.

Cow's Milk and Dairy Consumption: Is There Now Consensus for Cardiometabolic Health?

Cow's milk and dairy products derived from this complex food source have long been proposed as beneficial to human health, yet underlying clinical evidence of direct benefit continues to raise controversy. Limited evidence supports positive cardiometabolic effects of a number of dairy macro- and micronutrient components including whey protein and casein, unsaturated fats, milk fat globule membrane (MFGM) and polar phospholipids, vitamin D and calcium, in addition to non-bovine components including bacterial and yeast probiotics. More controversial remain lipid components trans fats, including trans vaccenic acid, trans palmitoleic acid, and conjugated cis trans linoleic acid (CLA), plus medium-chain and odd-chain dairy fats. New evidence is rapidly identifying multiple pathways by which these dairy nutrients may effect health. Processing, including fermentation and homogenization, may also have positive effects. Conversely, the high saturated fat content of dairy has long raised concern, aligned with international guidelines to minimize dietary intake of animal-origin saturated fatty acids (SFA) to achieve better cardiometabolic health. However, led in part by observational studies and meta-analyses showing dairy to have no or even an inverse association with cardiometabolic health, evidence from randomized controlled trials (RCTs) has been scrutinized over the last 5 years, and focus on low-fat dairy has been challenged. Recent evidence supports the hypothesis that adverse effects of SFAs on metabolic health may be ameliorated when these fats are consumed within a complex matrix such as milk, cheese or yogurt, and that dairy food categories may influence outcomes as much as total fat content. For example, yogurt and high-fat, high-SFA cheese have a negative association with risk of type 2 diabetes (T2D) in many, not all, published trials. However, large sample dairy RCTs of long duration with CVD or T2D incidence as primary endpoints are lacking. This is a clear research gap, with these clinical studies required if a causative link between dairy and improved cardiometabolic health is to be confirmed and in turn promoted through dietary guidelines. Current advisories from national guidance groups such as American Heart Association (AHA) and European Society of Cardiology (ESC) continue to promote consumption of low-fat dairy products, whilst liquid milk and yogurt remain part of nutrition guidelines from joint American Diabetes Association (ADA)/European Association for Study of Diabetes (EASD) reports, and as part of a "no-one-size-fits-all" answer to diet and T2D by the ADA in their most recent 2019 Consensus Report.

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.

Ameliorative effect of kefir against γ-irradiation induced liver injury in male rats: impact on oxidative stress and inflammation

Ionizing radiation is a double-edged sword because of its benefits and risks to human health. Therefore, protecting human organs from harmful effects of radiation is an important concern of researchers. Kefir, as a good source of probiotics, received growing interest in protective medicine owing to its antioxidant, anti-inflammatory, and immunomodulatory properties. Thus, this study was planned to investigate the protective role of kefir against γ-radiation-induced hepatotoxicity. Thirty-two male rats were distributed in four groups: (I) control, (II) received Kefir orally (5 ml/kg body weight) for 28 days, (III) exposed to whole body γ-irradiation (6.5 Gy) to induce hepatotoxicity, and (IV) was pretreated with kefir for 21 days then exposed to γ-irradiation followed by 7 days of kefir treatment. At the end of the experiment, complete blood picture (CBC), liver function, and lipid profile were estimated. Furthermore, levels of lipid peroxidation, nitric oxide content, and endogenous antioxidants, in addition to concentrations of copper, iron, and calcium were measured in liver tissue. Furthermore, monocyte chemoattractant protein-1 (MCP-1) and relative gene expression of nuclear factor kappa (NF-κB) were assessed. The results revealed that oral administration of kefir significantly reduced the radiation-induced hepatic histological alterations, hepatic function impairment, and dyslipidemia. Moreover, kefir notably ameliorated the state of oxidative stress and appeared to inhibit the induced inflammation. This study provides a possible counteracting role of kefir against hepatotoxicity induced γ-radiation. This can focus the benefit of kefir application as a prophylactic treatment to limit hepatic inflammation during radiotherapy.

Skim milk as a recovery beverage after exercise is superior to a sports drink for reducing next-day postprandial blood glucose and increasing postprandial fat oxidation

We determined the effect of consuming low-glycemic index (LGI) skim milk compared to a high-glycemic index (HGI) sports drink following evening exercise on fat oxidation and blood lipids after a subsequent high-energy breakfast. We hypothesized that postexercise skim milk consumption, compared to sports drink, would increase fat oxidation and lower harmful blood lipid and glucose concentrations after a next-day high-energy breakfast. In this randomized counterbalanced crossover trial, 20 overweight-obese participants (body mass index ≥ 25 kg/m²) underwent 4 conditions: 90-minute exercise (50% Vo_2peak) followed by sports drink (EX-HGI), exercise followed by isoenergetic skim milk (EX-LGI), exercise followed by water (Exercise), and a control condition (Control). The amount of the sports drink or milk consumed postexercise was based on the energy used during exercise plus 10%. Blood lipids, glucose, and fat oxidation were assessed before and for 6 hours after a high-energy breakfast the next morning. Fat oxidation was highest for EX-LGI (6.7 ± 2.7 g/h) and lowest for EX-HGI (6.0 ± 1.8 g/h) (condition main effect; P = .042). Triglyceride concentration and total area under the curve were higher with EX-HGI than Exercise (1.7 ± 1.6 vs 1.3 ± 1.0 mmol/L, P = .037, and 11.7 ± 9.4 vs 8.6 ± 6.0 mmol L^-1 h, P = .005, respectively). Glucose concentration was lower with EX-LGI than EX-HGI (4.1 ± 1.1 vs 4.4 ± 1.1 mmol/L, P = .027). Homeostatic model assessment of insulin resistance was higher with EX-HGI than Control (2.32 ± 1.15 vs 1.86 ± 0.97, P = .005). In conclusion, evening postexercise skim milk consumption, compared with a high-GI sports drink, significantly reduced blood glucose and possibly increased fat oxidation after a high-energy breakfast the next morning.

Whole Milk and Full-Fat Dairy Products and Hypertensive Risks

Lifestyle modifications in the form of diet and exercise are generally a first-line approach to reduce hypertensive risk and overall cardiovascular disease (CVD) risk. Accumulating research evidence has revealed that consumption of non- and low-fat dairy products incorporated into the routine diet is an effective means to reduce elevated blood pressure and improve vascular functions. However, the idea of incorporating whole-fat or full-fat dairy products in the normal routine diet as a strategy to reduce CVD risk has been met with controversy. The aim of this review is to review both sides of the argument surrounding saturated fat intake and CVD risk from the standpoint of dairy intake. Throughout the review, we examined observational studies on relationships between CVD risk and dairy consumption, dietary intervention studies using non-fat and whole-fat dairy, and mechanistic studies investigating physiological mechanisms of saturated fat intake that may help to explain increases in cardiovascular disease risk. Currently available data have demonstrated that whole-fat dairy is unlikely to augment hypertensive risk when added to the normal routine diet but may negatively impact CVD risk. In conclusion, whole-fat dairy may not be a recommended alternative to non- or low-fat dairy products as a means to reduce hypertensive or overall CVD risk.

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

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

Effects of kefir or milk supplementation on zonulin in overweight subjects

Increased intestinal permeability has been shown to be involved in several diseases associated with low-grade chronic inflammation, including obesity and metabolic syndrome. In the last decade, growing evidence shows the beneficial effects of probiotic-containing food supplementation on these conditions. In this crossover intervention study on 28 asymptomatic overweight adults, we tested the effects of a 3-wk kefir supplementation compared with a 3-wk milk supplementation on serum zonulin levels. The effects on serum glucose, triacylglycerols, low-density lipoproteins, high-density lipoproteins, total cholesterol, markers of inflammation (C-reactive protein and adiponectin), anthropometric variables, mood, and appetite were also determined. Kefir supplementation resulted in a greater improvement of serum zonulin levels (F = 6.812, η² = 0.275), whereas a significant yet similar improvement in lipid profile and serum glucose levels was found in both supplementations. Positive mood was slightly but significantly enhanced with kefir supplementation, and reduced with milk supplementation. The C-reactive protein, adiponectin, and appetite were unaffected. In conclusion, supplementation with both dairy products had health beneficial effects, but only kefir showed an effect on the intestinal barrier dysfunction marker.

Science dialogue mapping of knowledge and knowledge gaps related to the effects of dairy intake on human cardiovascular health and disease

Dairy has been described as everything from a superfood to a poison; yet, arguments, assumptions, and data justifying these labels are not always clear. We used an issue-based information system, "dialogue mapping™," to summarize scientific points of a live panel discussion on the putative effects of dairy on cardiovascular diseases (CVD) from a day-long session among experts in nutrition and CVD. Dialogue mapping captures relations among ideas to explicitly, logically, and visually connect issues/questions, ideas, pro/con arguments, and agreements, even if discussed at different times. Experts discussed two propositions: for CVD risk, consumption of full-fat dairy products 1) should be minimized, in part because of their saturated fat content, or 2) need not be minimized, despite their saturated fat content. The panel discussed the dairy-CVD relation through blood lipids, diabetes, obesity, energy balance, blood pressure, dairy bioactives, biobehavioral components, and other putative causal pathways. Associations and effects reported in the literature have varied by fat content of dairy elements considered, study design, intake methods, and biomarker versus disease outcomes. Two conceptual topics emerged from the discussion: 1) individual variability: whether recommendations should be targeted only to those at high CVD risk; 2) quality of evidence: whether data on dairy-CVD relations are strong enough for reliable conclusions-positive, negative, or null. Future procedural improvements for science dialog mapping include using singular rather than competing propositions for discussion.

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.

Associations between Dairy Intake, Body Composition, and Cardiometabolic Risk Factors in Spanish Schoolchildren: The Cuenca Study

Full-fat dairy has been traditionally associated with obesity and cardiovascular disease (CVD); however, recent evidence shows that the amount of dairy intake might have a beneficial effect over these pathologies, regardless of their fat content. The aim of this study was to examine the association between the intake of dairy products (including milk with different fat contents) with both adiposity and serum lipid concentration, adjusted by cardiorespiratory fitness (CRF), in Spanish schoolchildren. A cross-sectional study of 1088 children, aged 8 to 11 years, was conducted in which anthropometric variables (body mass index (BMI), waist circumference (WC), fat mass percentage (FM%) and fat mass index (FMI)), blood lipid profile, and dairy intake (using a food frequency questionnaire), and CRF (through a 20-m shuttle run test) were measured. Results showed that children with lower BMI, WC, FM%, and FMI had higher whole-fat milk intake and lower skimmed and semi-skimmed milk intake than children with higher BMI, WC, FM%, and FMI. Children with normal levels of triglycerides and high density lipoproteins (HLD) cholesterol consumed more whole-fat milk and less reduced-fat milk than children with dyslipidemic patterns. These relationships persisted after adjustment for CRF. Our findings suggest that full-fat milk intake should be promoted in children without obesity or high cardiometabolic risk.

Effects of Full-Fat and Fermented Dairy Products on Cardiometabolic Disease: Food Is More Than the Sum of Its Parts

Current dietary recommendations to limit consumption of saturated fat are largely based on early nutrition studies demonstrating a direct link between dietary saturated fat, elevated blood cholesterol levels, and increased risk of cardiovascular disease. As full-fat dairy products are rich in saturated fat, these dietary guidelines recommend consumption of fat-free or low-fat dairy products in place of full-fat dairy. However, dairy products vary greatly in both their nutrient content and their bioactive ingredients, and research increasingly highlights the importance of focusing on whole foods (i.e., the food matrix) as opposed to single nutrients, such as saturated fat. In fact, the weight of evidence from recent large and well-controlled studies, systematic reviews, and meta-analyses of both observational studies and randomized controlled trials indicates that full-fat dairy products, particularly yogurt and cheese, do not exert the detrimental effects on insulin sensitivity, blood lipid profile, and blood pressure as previously predicted on the basis of their sodium and saturated fat contents; they do not increase cardiometabolic disease risk and may in fact protect against cardiovascular disease and type 2 diabetes. Although more research is warranted to adjust for possible confounding factors and to better understand the mechanisms of action of dairy products on health outcomes, it becomes increasingly clear that the recommendation to restrict dietary saturated fat to reduce risk of cardiometabolic disease is getting outdated. Therefore, the suggestion to restrict or eliminate full-fat dairy from the diet may not be the optimal strategy for reducing cardiometabolic disease risk and should be re-evaluated in light of recent evidence.

[Nutritional value of dairy products and recommended daily consumption]

INTRODUCTION

Objective: messages that are given recently have encouraged to reduce the consumption of dairy products, by noting them as dispensable or even harmful in relation to certain pathologies. The objective of this present work is to review the nutritional value of this group of foods and their recommended consumption. Methods: bibliographic search related to the topic. Results: dairy products provide proteins of high biological value, vitamins and minerals, especially calcium and vitamins B2 and B12, as well as essential fatty acids, and some antioxidants, among other nutrients. Although its fat is mostly saturated (65%), it does not seem to adversely affect cardiovascular risk and may even have a slight protective effect. More than 75% of individuals have calcium intakes lower than recommended, and since more than 50% of the calcium in the diet comes from dairy products, increasing their consumption may be recommended. Moderate milk intake during pregnancy is positively associated with birth weight and length of the offspring and bone mineral content during childhood. In adults, dairy consumption it is associated with a lower risk of metabolic syndrome, coronary heart disease and myocardial infarction, colorectal and gallbladder cancer, and type 2 diabetes. Moreover in older people it is associated with a lower risk of sarcopenia and vertebral fractures. Conclusions: the population ignores what is the nutritional value of dairy products and their advisable consumption (2-4 servings / day). The latest studies support the need to have an adequate consumption in all stages of life due to its relationship with the prevention and control of chronic diseases. Dairy consumption is less than 2 servings / day in 37.1% of children and 42.3% of adults, so it would be desirable to improve this situation.

A Positive Association Between Dietary Intake of Higher Cow's Milk-Fat Percentage and Non-High-Density Lipoprotein Cholesterol in Young Children

OBJECTIVES

To determine the association between cow's milk-fat and non-high-density lipoprotein (non-HDL) cholesterol, a marker of cardiovascular disease (CVD) risk in young children, and whether this association is mediated by the typical volume of cow's milk consumed.

STUDY DESIGN

A longitudinal study in 2- to 8-year-old children (n = 2890) was conducted through The Applied Research Group for Kids (TARGet Kids!), a practice-based research network in Toronto, Canada. Generalized estimating equations were used to examine the relationship between parent-reported cow's milk-fat percentage intake and serum non-HDL cholesterol concentrations as well as having high non-HDL cholesterol (≥3.75 mmol/L [145 mg/dL]), adjusting for covariates including age, sex, body mass index z score, breastfeeding duration, mother's ethnicity, and parental history of CVD. Bootstrap resampling (10 000 repetitions) was used to assess whether typical volume consumed mediated the association between cow's milk-fat percentage and non-HDL cholesterol.

RESULTS

In total, 156 (5.4%) had high non-HDL cholesterol. Each percent increase in cow's milk-fat was associated with a 0.035 mmol/L (1.35 mg/dL) (P < .001) and 0.024 mmol/L (0.92 mg/dL) (P = .01) increase in non-HDL cholesterol, unadjusted and adjusted for covariates respectively. Cow's milk-fat percentage was not associated with greater odds of having high non-HDL cholesterol. Volume of cow's milk partially mediated the association between cow's milk-fat percentage and non-HDL cholesterol, accounting for 28% of the relationship (P < .001).

CONCLUSIONS

Consumption of higher-fat cow's milk was associated with a small increase in non-HDL cholesterol but not greater odds of having high non-HDL cholesterol. Further research is needed to assess this relationship with other CVD risk factors in young children.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01869530.

Milk and Dairy Product Consumption and Cardiovascular Diseases: An Overview of Systematic Reviews and Meta-Analyses

Milk and dairy products containing milk fat are major food sources of saturated fatty acids, which have been linked to increased risk of cardiovascular-related clinical outcomes such as cardiovascular disease (CVD), coronary heart disease (CHD), and stroke. Therefore, current recommendations by health authorities advise consumption of low-fat or fat-free milk. Today, these recommendations are seriously questioned by meta-analyses of both prospective cohort studies and randomized controlled trials (RCTs) reporting inconsistent results. The present study includes an overview of systematic reviews and meta-analyses of follow-up studies, an overview of meta-analyses involving RCTs, and an update on meta-analyses of RCTs (2013-2018) aiming to synthesize the evidence regarding the influence of dairy product consumption on the risk of major cardiovascular-related outcomes and how various doses of different dairy products affect the responses, as well as on selected biomarkers of cardiovascular disease risk, i.e., blood pressure and blood lipids. The search strategies for both designs were conducted in the MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Web of Science databases from their inception to April 2018. From the 31 full-text articles retrieved for cohort studies, 17 met the eligibility criteria. The pooled risk ratio estimated for the association between the consumption of different dairy products at different dose-responses and cardiovascular outcomes (CVD, CHD, and stroke) showed a statistically significant negative association with RR values <1, or did not find evidence of significant association. The overview of 12 meta-analyses involving RCTs as well as the updated meta-analyses of RCTs did not result in significant changes on risk biomarkers such as systolic and diastolic blood pressure and total cholesterol and LDL cholesterol. Therefore, the present study states that the consumption of total dairy products, with either regular or low fat content, does not adversely affect the risk of CVD.

Fat from dairy foods and 'meat' consumed within recommended levels is associated with favourable serum cholesterol levels in institutionalised older adults

CVD is common in older adults. Consumption of ‘meat’ (beef, pork, lamb, game, poultry, seafood, eggs) and dairy foods (milk, cheese, yoghurt) is encouraged in older adults as these foods provide protein and nutrients such as essential fatty acids, Ca, Fe, Zn and vitamins A, D and B₁₂ required for healthy ageing. However, these foods also contain saturated fats considered detrimental to cardiovascular health. To determine the effect of their consumption on CVD risk we assessed associations between fat intake from ‘meat’ and dairy foods and serum cholesterol levels in 226 aged-care residents (mean age 85·5 years, 70 % female). Dietary intake was determined over 2 d using visual estimation of plate waste. Fat content of foods was determined using nutrition analysis software (Xyris, Australia). Fasting serum total cholesterol (TC), LDL-cholesterol and HDL-cholesterol were measured, and the TC:HDL-cholesterol ratio calculated. Associations were determined using random-effect models adjusted for CVD risk factors using STATA/IC 13.0. Total fat and saturated fat from ‘meat’ and dairy foods were associated with higher serum HDL-cholesterol levels, and dairy fat intake and number of servings were associated with a lower TC:HDL-cholesterol ratio. Every 10 g higher intake of fat and saturated fat from dairy products, and each additional serving was associated with a −0·375 (95 % CI −0·574, −0·175; P = 0·0002), a −0·525 (95 % CI −0·834, −0·213; P = 0·001) and a −0·245 (95 % CI −0·458, −0·033; P = 0·024) lower TC:HDL-cholesterol ratio, respectively. Provision of dairy foods and ‘meat’ in recommended amounts to institutionalised older adults potentially improves intakes of key nutrients with limited detriment to cardiovascular health.

Meals with Similar Fat Content from Different Dairy Products Induce Different Postprandial Triglyceride Responses in Healthy Adults: A Randomized Controlled Cross-Over Trial

BACKGROUND

Postprandial lipemia is a risk factor for cardiovascular disease. Dairy products differ in nutrient content and food matrix, and little is known about how different dairy products affect postprandial triglyceride (TG) concentrations.

OBJECTIVE

We investigated the effect of meals with similar amounts of fat from different dairy products on postprandial TG concentrations over 6 h in healthy adults.

METHODS

A randomized controlled cross-over study was performed on 47 subjects (30% men), with median (25th-75th percentile) age of 32 (25-46) y and body mass index of 23.6 (21.0-25.8) kg/m2. Meals included 1 of butter, cheese, whipped cream, or sour cream, corresponding to 45 g of fat (approximately 60 energy%). Serum concentrations of TGs (primary outcome), and total cholesterol (TC), low density lipoprotein cholesterol (LDL cholesterol), high density lipoprotein cholesterol (HDL cholesterol), insulin, glucose, non-esterified fatty acids, and plasma glucose-dependent insulinotropic polypeptide (secondary outcomes) were measured before the meal and 2, 4, and 6 h postprandially. Incremental AUC (iAUC) was calculated for the responses, and data were analyzed using a linear mixed model.

RESULTS

Sour cream induced a 61% larger TG-iAUC0-6 h compared to whipped cream (P < 0.001), a 53% larger TG-iAUC0-6 h compared to butter (P < 0.001), and a 23% larger TG-iAUC0-6 h compared to cheese (P = 0.05). No differences in TG-iAUC0-6 h between the other meals were observed. Intake of sour cream induced a larger HDL cholesterol-iAUC0-6 h compared to cheese (P = 0.01). Intake of cheese induced a 124% larger insulin iAUC0-6 h compared to butter (P = 0.006). No other meal effects were observed.

CONCLUSIONS

High-fat meals containing similar amount of fat from different dairy products induce different postprandial effects on serum TGs, HDL cholesterol, and insulin in healthy adults. The potential mechanisms and clinical impact of our findings remain to be further elucidated. The study was registered at www.clinicaltrials.gov as NCT02836106.

Effects of Milk and Milk-Product Consumption on Growth among Children and Adolescents Aged 6-18 Years: A Meta-Analysis of Randomized Controlled Trials

Although studies have suggested that milk and milk-product consumption may influence growth during childhood and puberty, results are inconsistent. This meta-analysis was performed to evaluate the available evidence of randomized controlled trials (RCTs) assessing whether milk and milk-product consumption could affect growth and body composition among children and adolescents aged 6-18 y. PubMed, EMBASE, Web of Science, and The Cochrane Library databases were systematically searched for all RCTs published up to December 2017 that investigated milk and milk-product consumption (≥12 wk) on growth and body composition among participants (aged 6-18 y) without undernourishment or diseases. Study screening and data extraction by 2 reviewers followed established PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The Cochrane Collaboration's tool was used to assess the quality of the trials. Data were pooled using a random-effects model. Seventeen trials with 2844 children and adolescents were included. Milk and milk-product interventions resulted in a greater increase in body weight (0.48 kg; 95% CI: 0.19, 0.76 kg; P  =  0.001), lean mass (0.21 kg; 95% CI: 0.01, 0.41 kg; P  = 0.04), and attenuated gain in percentage body fat (-0.27%; 95% CI: -0.45%, -0.09%; P  = 0.003) compared with control groups. However, there were no significant changes in fat mass, height, or waist circumference in the intervention groups compared with the control groups (P ≥ 0.05). In subgroup analyses, the baseline weight and age, and the duration of intervention were associated with the efficacy of milk and milk-product intake on the change in lean mass, percentage body fat, and waist circumference, respectively (test for subgroup differences: P < 0.05). Children and adolescents aged 6-18 y consuming milk and milk products are more likely to achieve a lean body phenotype. This meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) as CRD42018086850.

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.

Both low- and regular-fat cheeses mediate improved insulin sensitivity and modulate serum phospholipid profiles in insulin-resistant rats

Dietary recommendations for cheese usually promote low (LOW)- over regular (REG)-fat versions due to the saturated fat. Conversely, epidemiological evidence shows that cheese consumption associates with reduced risk of type 2 diabetes. To investigate how cheese influences diabetes-related outcomes, a feeding trial comparing LOW and REG cheese was conducted in high-fat, lard-based diet (HFD)-fed insulin-resistant rats followed by evaluation of potential mechanisms. After 4 weeks of HFD, LOW or REG was added at 7 and 10 g/100 g diet, respectively, for another 8 weeks. Following either an oral glucose or insulin tolerance test to assess glucoregulation, rats were euthanized and serum was collected for metabolomic and lipid analyses. Hepatic tissue was used to measure glucoregulatory enzymes and lipid content. Both LOW and REG improved insulin sensitivity without effect on oral glucose tolerance, insulin secretion or body weight. Serum metabolomics identified 33 metabolites of interest, with 21 being phosphatidylcholines (PCs) or lysophosphatidylcholines (LPCs). HFD rats had significantly reduced LPC C16:1, C17:0, C18:1, C20:3 and C24:0, and these effects were normalized by LOW or REG cheese. Fourteen PC species were lowest in the HFD group and normalized by cheese feeding. Serum choline was elevated sevenfold in HFD- but not cheese-fed rats compared with rats fed low-fat diet. Liver triglyceride was elevated by LOW feeding. In conclusion, inclusion of both LOW and REG cheeses in the diet of insulin-resistant rats improves in vivo glucoregulation. This is associated with altered phospholipid metabolism, including cheese-mediated normalization of species that are decreased by high-fat feeding.

Dairy matrix effects: response to consumption of dairy fat differs when eaten within the cheese matrix-a randomized controlled trial

Background

Dairy fat consumed as cheese has different effects on blood lipids than that consumed as butter. It is unknown whether the effect is specific to fat interaction with other cheese nutrients (calcium, casein proteins), or to the cheese matrix itself.

Objective

We aimed to test the effect of 6 wk daily consumption of ∼40 g dairy fat, eaten within macronutrient-matched food matrices, on markers of metabolic health, in overweight adults aged ≥50 y.

Design

The study was a 6-wk randomized parallel intervention; 164 volunteers (75 men) received ∼40 g of dairy fat/d, in 1 of 4 treatments: (A) 120 g full-fat Irish cheddar cheese (FFCC) (n = 46); (B) 120 g reduced-fat Irish cheddar cheese + butter (21 g) (RFC + B) (n = 45); (C) butter (49 g), calcium caseinate powder (30 g), and Ca supplement (CaCO3) (500 mg) (BCC) (n = 42); or (D) 120 g FFCC, for 6 wk (as per A) (n = 31). Group D first completed a 6-wk "run-in" period, where they excluded all dietary cheese before commencing the intervention.

Results

There was no difference in anthropometry, fasting glucose, or insulin between the groups at pre- or postintervention. However, a stepwise-matrix effect was observed between the groups for total cholesterol (TC) (P = 0.033) and LDL cholesterol (P = 0.026), with significantly lower postintervention TC (mean ± SD) (5.23 ± 0.88 mmol/L) and LDL cholesterol (2.97 ± 0.67 mmol/L) when all of the fat was contained within the cheese matrix (Group A), compared with Group C when it was not (TC: 5.57 ± 0.86 mmol/L; LDL cholesterol: 3.43 ± 0.78 mmol/L).

Conclusion

Dairy fat, eaten in the form of cheese, appears to differently affect blood lipids compared with the same constituents eaten in different matrices, with significantly lower total cholesterol observed when all nutrients are consumed within a cheese matrix This trial was registered at ISRCTN as ISRCTN86731958.

Biomarker of food intake for assessing the consumption of dairy and egg products

Dairy and egg products constitute an important part of Western diets as they represent an excellent source of high-quality proteins, vitamins, minerals and fats. Dairy and egg products are highly diverse and their associations with a range of nutritional and health outcomes are therefore heterogeneous. Such associations are also often weak or debated due to the difficulty in establishing correct assessments of dietary intake. Therefore, in order to better characterize associations between the consumption of these foods and health outcomes, it is important to identify reliable biomarkers of their intake. Biomarkers of food intake (BFIs) provide an accurate measure of intake, which is independent of the memory and sincerity of the subjects as well as of their knowledge about the consumed foods. We have, therefore, conducted a systematic search of the scientific literature to evaluate the current status of potential BFIs for dairy products and BFIs for egg products commonly consumed in Europe. Strikingly, only a limited number of compounds have been reported as markers for the intake of these products and none of them have been sufficiently validated. A series of challenges hinders the identification and validation of BFI for dairy and egg products, in particular, the heterogeneous composition of these foods and the lack of specificity of the markers identified so far. Further studies are, therefore, necessary to validate these compounds and to discover new candidate BFIs. Untargeted metabolomic strategies may allow the identification of novel biomarkers, which, when taken separately or in combination, could be used to assess the intake of dairy and egg products.