Changes in dairy product consumption and risk of type 2 diabetes: results from 3 large prospective cohorts of US men and women

Dynamics of Dairy Product Consumption, Confounding Factors, and Their Influence on the Risk of Type 2 Diabetes

It has long been debated whether or not dairy consumption increases the risk of type 2 diabetes (T2D). This link has been assessed by a large number of case-control studies, prospective cohort studies, systematic reviews, and meta-analyses. The majority of their studies demonstrated an inverse relationship between the risk of T2D and dairy consumption. It is yet unclear how dairy products specifically contribute to metabolic diseases like type 2 diabetes. However, a surprising number of studies have indicated either no association or a positive correlation between the development of type 2 diabetes and certain dairy products. The objective of this narrative review is to collate research findings from diverse geographical contexts, exploring the impact of dairy product consumption on the incidence and risk of Type 2 diabetes (T2D). This review includes studies that addressed this research issue and were released between the years 2000 and 2023. This will help the public draw logical inferences and validate the body of recent research. To shed light on this matter, the writers conduct a comprehensive search of electronic scientific databases such as PubMed, Scopus, and Web of Science. Thus, this review emphasizes the connection between the usage of different dairy products and the risk of T2D. After controlling for confounding variables, this review indicates that the relationship between the incidence of type 2 diabetes and consumption of dairy products is context-dependent. In conclusion, not all dairy products help to prevent type 2 diabetes. There is no association between most other dairy products and T2D, while in some cases benefits of yogurt and other low-fat dairy products have been reported.

Dairy products and hypertension: Cross-sectional and prospective associations

BACKGROUND

The association between dairy intake and prevalence or incidence of hypertension remains controversial. We aimed to investigate the association between intake of different dairy products and prevalence and incidence of hypertension in a community-dwelling sample.

METHODS

Three cross-sectional studies (2009-12, 2014-17 and 2018-21) and one prospective study (2009-12 to 2018-21) were conducted in Lausanne, Switzerland. Dietary intake was assessed via a validated food frequency questionnaire. Dairy consumption was compared between participants with and without prevalent or incident hypertension.

RESULTS

For the cross-sectional analyses, data from 4437 (2009-12, 54.0% women, 57.7 ± 10.5 years), 2925 (2014-17, 53.4% women, 62.5 ± 10.0 years), and 2144 (2018-21; 53.3% women, 65.5 ± 9.6 years) participants were used. No consistent differences between participants with and without hypertension were found for all dairy products (total dairy, milk, yogurt, cheese, low-fat dairy, and full-fat dairy) although participants with hypertension tended to consume less cheese (51 ± 1 vs. 55 ± 1, p = 0.014, 52 ± 1 vs. 56 ± 1, p = 0.053, and 54 ± 1 vs. 56 ± 1 g/day for 2009-12, 2014-17 and 2018-21, respectively). For the prospective study, data from 2303 participants (60.8% women, 53.9 ± 9.0 years) were used. Irrespective of the dairy product considered, no association was found between quartiles of dairy consumption and development of hypertension. Similar findings were obtained after stratifying on dietary quality.

CONCLUSION

In this population-based study, no association was found between the consumption of different dairy products and the prevalence or incidence of hypertension.

Full-fat dairy products and cardiometabolic health outcomes: Does the dairy-fat matrix matter?

Reducing dairy fat intake is a common dietary guideline to limit energy and saturated fatty acid intake for the promotion of cardiometabolic health. However, research utilizing a holistic, food-based approach to assess the consumption of the fat found in dairy, a broad and diverse food group, may provide new insight into these guidelines. Dairy fat is comprised of a diverse assembly of fatty acids, triacylglycerols, sterols, and phospholipids, all uniquely packaged in a milk fat globule. The physical structure of this milk fat globule and its membrane is modified through different processing methods, resulting in distinctive dairy-fat matrices across each dairy product. The objectives of this narrative review were to first define and compare the dairy-fat matrix in terms of its unique composition, physical structure, and fat content across common dairy products (cow's milk, yogurt, cheese, and butter). With this information, we examined observational studies and randomized controlled trials published within the last 10 years (2013-2023) to assess the individual effects of the dairy-fat matrix in milk, yogurt, cheese, and butter on cardiometabolic health and evaluate the implications for nutrition guidance. Searches conducted on Ovid MEDLINE and PubMed® utilizing search terms for cardiometabolic health, both broadly and regarding specific disease outcomes and risk factors, yielded 59 studies that were analyzed and included in this review. Importantly, this review stratifies by both dairy product and fat content. Though the results were heterogeneous, most studies reported no association between intake of these individual regular-fat dairy products and cardiometabolic outcome measures, thus, the current body of evidence suggests that regular-fat dairy product consumption may be incorporated within overall healthy eating patterns. Research suggests that there may be a beneficial effect of regular-fat milk and yogurt intake on outcome measures related to body weight and composition, and an effect of regular-fat cheese intake on outcome measures related to blood lipids, but more research is necessary to define the directionality of this relationship. Lastly, we identify methodological research gaps and propose future research directions to bolster the current evidence base available for ascertaining the role of dairy fat in a healthy diet.

A new era for food in health? The FDA announces a qualified health claim for yogurt intake and type 2 diabetes mellitus risk reduction

INTRODUCTION

Over the last two decades research has grown regarding dairy intake and health. It has been reported by many that yogurt intake may be associated with reduced risk of type 2 diabetes mellitus (T2D). In this report, the United States Food and Drug Administration (FDA) decision to announce a qualified health claim for yogurt products regarding reduced risk of T2D in response to a Danone North America petition is discussed.

METHODS

Relevant literature cited in the petition along with supporting evidence from PubMed and Google Scholar databases until April 1st, 2024 were used. Literature was found using relevant keywords.

RESULTS

On March 1st, 2024, the United States Food and Drug Administration (FDA) announced the first ever qualified health claim, stating that eating yogurt regularly may reduce the risk of T2D according to limited scientific evidence. The enforcement discretion letter was critically reviewed and discussed regarding its future implications for people with T2M and public health.

CONCLUSIONS

It is unclear how this FDA decision will affect public health and nutrition in the long-term. Limited scientific evidence suggests that at least 3 servings of yogurt per week may reduce the risk of T2D incidence for the general population. Yogurt will not cure or treat people with T2D.

Role of fermented dairy products in the health benefits of a mediterranean diet

Mediterranean diet includes fermented dairy products like yogurt and cheese. These foods provide calcium, phosphorus, fat, carbohydrates and protein, all nutrients influencing various systems including bone, cardiovascular system, intermediary metabolism, cancer, central nervous system, and inflammation. In addition, they contain prebiotics and provide probiotics which are capable of modifiying microbiota composition and metabolism, potentially acting also indirectly on the various systems. A large body of evidence indicates that fermented dairy products consumption significantly contributes to the beneficial effects of a Mediterranean diet on various systems' health.

Production, Composition and Nutritional Properties of Organic Milk: A Critical Review

Milk is one of the most valuable products in the food industry with most milk production throughout the world being carried out using conventional management, which includes intensive and traditional systems. The intensive use of fertilizers, antibiotics, pesticides and concerns regarding animal health and the environment have given increasing importance to organic dairy and dairy products in the last two decades. This review aims to compare the production, nutritional, and compositional properties of milk produced by conventional and organic dairy management systems. We also shed light on the health benefits of milk and the worldwide scenario of the organic dairy production system. Most reports suggest milk has beneficial health effects with very few, if any, adverse effects reported. Organic milk is reported to confer additional benefits due to its lower omega-6-omega-3 ratio, which is due to the difference in feeding practices, with organic cows predominantly pasture fed. Despite the testified animal, host, and environmental benefits, organic milk production is difficult in several regions due to the cost-intensive process and geographical conditions. Finally, we offer perspectives for a better future and highlight knowledge gaps in the organic dairy management system.

From Gut to Glucose: A Comprehensive Review on Functional Foods and Dietary Interventions for Diabetes Management

BACKGROUND

In the realm of diabetes research, considerable attention has been directed toward elucidating the intricate interplay between the gastrointestinal tract and glucose regulation. The gastrointestinal tract, once exclusively considered for its role in digestion and nutrient assimilation, is presently acknowledged as a multifaceted ecosystem with regulatory supremacy over metabolic homeostasis and glucose metabolism. Recent studies indicate that alterations in the composition and functionality of the gut microbiota could potentially influence the regulation of glucose levels and glucose homeostasis in the body. Dysbiosis, characterized by perturbations in the equilibrium of gut microbial constituents, has been irrevocably linked to an augmented risk of diabetes mellitus (DM). Moreover, research has revealed the potential influence of the gut microbiota on important factors, like inflammation and insulin sensitivity, which are key contributors to the onset and progression of diabetes. The key protagonists implicated in the regulation of glucose encompass the gut bacteria, gut barrier integrity, and the gut-brain axis. A viable approach to enhance glycemic control while concurrently mitigating the burden of comorbidities associated with diabetes resides in the strategic manipulation of the gut environment through adapted dietary practices.

OBJECTIVE

This review aimed to provide a deep understanding of the complex relationship between gut health, glucose metabolism, and diabetes treatment.

CONCLUSION

This study has presented an exhaustive overview of dietary therapies and functional foods that have undergone extensive research to explore their potential advantages in the management of diabetes. It looks into the role of gut health in glucose regulation, discusses the impact of different dietary elements on the course of diabetes, and evaluates how well functional foods can help with glycemic control. Furthermore, it investigates the mechanistic aspects of these therapies, including their influence on insulin sensitivity, β-cell activity, and inflammation. It deliberates on the limitations and potential prospects associated with integrating functional foods into personalized approaches to diabetes care.

Association between dairy products consumption and the prevalences of combined prediabetes and type 2 diabetes mellitus in Brazilian adolescents: a cross-sectional study

The association between dairy products consumption in adults and the likelihood of type 2 diabetes mellitus (T2DM) has been described, but more information on the adolescent population is needed. This nationally representative, cross-sectional school-based study aimed to describe the consumption of dairy products and their subtypes and to evaluate their association with prediabetes and T2DM in adolescents. The Study of Cardiovascular Risks in Adolescents (ERICA) includes adolescents aged 12-17 years. Dairy products consumption was evaluated by 24-h food recall. Associations with fasting glucose, glycated hemoglobin (HbA1c) and insulin resistance, as measured by homeostatic model assessment-insulin resistance (HOMA-IR), were evaluated by multivariate linear regression. Poisson regression was also used to assess the association between dairy products consumption and the combined prevalence of prediabetes and T2DM. Models were adjusted for sociodemographic, nutritional, behavioural and anthropometrics. The final sample analysed consisted of 35 614 adolescents. Total intake of dairy products was inversely associated with fasting blood glucose levels after adjusting for all covariates (β = -0·452, 95 % CI -0·899, -0·005). The associations were stronger for overweight and obese adolescents. Findings were similar for full-fat dairy products and yogurt. Higher consumption of low-fat dairy products and cheese were associated with a 46 % (prevalence ratio, PR 1·46, 95 % CI 1·18, 1·80) and 33 % (PR 1·33, 95 % CI 1·14, 1·57) higher combined prevalence of prediabetes and T2DM, respectively. The total consumption of dairy products and full-fat dairy products was associated with a lower combined prevalence of prediabetes and T2DM, while the consumption of cheese and low-fat dairy products was associated with higher combined prevalence of prediabetes and T2DM in Brazilian adolescents.

Dairy intake and risk of type 2 diabetes: results of a large prospective cohort

Background and aims: Previous studies of primarily Western populations have consistently documented a lower risk of type 2 diabetes (T2D) among people with a higher yogurt intake, but an inconsistent association with milk intake. However, little is known about the association between dairy intake and risk of T2D among Chinese adults who consume considerably less dairy (mainly milk and yogurt) compared with Western populations. The aim is to investigate the associations of dairy intake with the risk of incident T2D in the general adult population in China. Methods: This cohort study consisted of 22 843 participants without prevalent cardiovascular disease, cancer, or diabetes at the baseline. Dietary data were collected using a validated food frequency questionnaire at the baseline (2013-2018); dairy intake was categorized into tertiles after zero consumers were taken as the reference. Incident T2D was ascertained by medical examinations and self-report of physician-diagnosed diabetes during follow-up visits. Cox proportional hazards models were performed to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs). Results: In total, 735 incident T2D cases were recorded over a median follow-up of 4.0 years. Relative to zero consumers, the HRs (95% CIs) for incident T2D among participants in the highest tertiles were 0.70 (0.57, 0.87) for total dairy, 0.73 (0.60, 0.90) for milk, and 0.81 (0.66, 1.00) for yogurt. Such associations were slightly attenuated by additional adjustment for the body mass index. In addition, such inverse associations were robust in sensitivity analyses and consistent in most of the subgroups defined by baseline characteristics. Conclusion: Higher intakes of total dairy, milk, and yogurt were all associated with a lower risk of T2D among Chinese adults.

Dairy Foods: Beneficial Effects of Fermented Products on Cardiometabolic Health

PURPOSE OF REVIEW

This review of recent observational studies and understanding of the complex nature of dairy foods is intended to reappraise the effects of different types of dairy foods on cardiovascular disease (CVD).

RECENT FINDINGS

Recent guidelines from major cardiovascular societies suggest that apart from the adverse effect of butter, consumption of more complex dairy products notably fermented varieties and yogurt in particular, appear to be inversely associated with outcomes of CVD and type 2 diabetes (T2D). Reduced fat in dairy food remains preferred for people at increased CVD risk. Changed evidence has led to new advice regarding consumption of some dairy foods. The apparent beneficial effects of fermented milk products, particularly yogurt, allow for increased consumption of nutritious staple foods. Recent national guidelines reflect this view.

Dairy foods and cardiometabolic diseases: an update and a reassessment of the impact of SFA

Type 2 diabetes (T2D) and CVD are major causes of mortality and chronic morbidity. Whilst mortality from CVD has decreased they remain the largest cause of death in Europe and the prevalence of T2D is increasing rapidly. A consistent component of public health advice is to reduce intake of SFA to reduce CVD in particular, which implies limiting dairy food consumption. The prospective studies and randomised controlled trials included in this review show that for dairy foods at least, SFA are not consistently associated with CVD or T2D risk. For CVD the association with dairy foods is generally neutral despite dairy foods being the major source of SFA in many diets. This creates considerable doubt, at least for dairy foods, concerning the validity of the traditional diet-heart hypothesis which positively relates SFA intake to increased serum LDL-cholesterol and subsequent increased CVD. There is now emerging evidence to explain this which is highly relevant to dairy foods. These include the potentially counterbalancing effect of SFA-stimulated HDL-cholesterol and specific food matrix factors. In addition, SFA are associated with the less atherogenic large buoyant LDL particles and possible counterbalancing hypotensive effects of dairy proteins. Overall, dairy foods have either a neutral or beneficial association with CVD and T2D. Beneficial associations are seen for blood pressure and the reduced T2D risk linked to yoghurt consumption, a subject that needs urgent attention given the sharp rise in T2D prevalence in many countries.

Positive Health Outcomes Associated with Live Microbe Intake from Foods, Including Fermented Foods, Assessed using the NHANES Database

BACKGROUND

Live dietary microbes have been hypothesized to contribute to human health but direct evidence is lacking.

OBJECTIVES

This study aimed to determine whether the dietary consumption of live microbes is linked to improved health outcomes.

METHODS

Data from the NHANES 2001-2018 were used to assess microbial intake and their adjusted associations with selected physiological parameters (e.g., blood pressure, anthropometric measures, and biomarkers) among adults aged 19 y and older. Regression models were constructed to assess the microbial intake with each physiological parameter and adjusted for demographics and other covariates. Microbial intake was assessed as both a continuous variable and a 3-level categorical variable. Fermented foods were assessed in a separate model.

RESULTS

In continuous models, an additional 100-g intake of microbe-containing foods was associated with a lower systolic blood pressure (regression coefficient: -0.331; 95% CI: -0.447, -0.215 mm Hg), C-reactive protein (-0.013; 95% CI: -0.019, -0.008 mg/dL), plasma glucose -0.347; 95% CI: -0.570, -0.124 mg/dL), plasma insulin (-0.201; 95% CI: -0.304, -0.099 μU/mL), triglyceride (-1.389; 95% CI: -2.672, -0.106 mg/dL), waist circumference (-0.554; 95% CI: -0.679, -0.428 cm), and BMI -0.217; 95% CI: -0.273, -0.160 kg/m2) levels and a higher level of high density lipoprotein cholesterols (0.432; 95% CI: 0.289, 0.574 mg/dL). Patterns were broadly similar when microbial intake was assessed categorically and when fermented foods were assessed separately.

CONCLUSIONS

To our knowledge, this study is the first to quantify, in a nationally representative data set of American adults and using stable sets of covariates in the regression models, the adjusted associations of dietary intakes of live microbes with a variety of outcomes, such as anthropometric measures, biomarkers, and blood pressure levels. Our findings suggest that foods with higher microbial concentrations are associated with modest health improvements across a range of outcomes.

Dairy product consumption and incident prediabetes in the Australian Diabetes, Obesity and Lifestyle Study with 12 years follow up

BACKGROUND

Investigating modifiable risk factors of early stages of the development of type 2 diabetes is essential for effective prevention. Some studies show protective associations between dairy and prediabetes, yet associations are heterogenous by type and fat content of dairy foods.

OBJECTIVE

To examine the relationship between the consumption of dairy, including different types of dairy products and the risk of prediabetes.

METHODS

The study included 4,891 participants with normal glucose tolerance (aged 49.0±12.3 years, 57% female) of the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, a longitudinal population-based study. Dairy intake was measured at baseline using a food frequency questionnaire. Prediabetes at 5-year and 12-year follow-up was defined according to WHO criteria as fasting plasma glucose levels of 110-125 mg/dl or 2-hour plasma glucose levels of 140-199 mg/dl. Associations were analyzed using Poisson regression, adjusted for social demographics, lifestyle behaviors, family history of diabetes, and food group intake.

RESULTS

765 (15.6%) incident cases of prediabetes were observed. The mean intake of dairy foods was 2.4±1.2 servings/day, mostly consisting of low-fat milk (0.70±0.78) and high-fat milk (0.47±0.72). A higher intake of high-fat dairy (RR_servings/day, 0.92, 95%CI 0.85-1.00), high-fat milk (0.89, 0.80-0.99), and total cheese (0.74, 0.56-0.96)was associated with lower prediabetes risk. Low-fat milk intake was associated non-linearly with prediabetes risk. Low-fat dairy foods, total milk, yogurt, low-fat cheese, and ice cream were not associated with prediabetes risk.

CONCLUSION

In this large Australian cohort, protective associations were found for high-fat dairy types, while neutral associations were seen for low-fat dairy. Studies with more detail on sugar content of types of dairy foods and products eaten with dairy foods (e.g., cereals or jam), as well as studies into potential causal mechanisms of the health effects of dairy intake are required.

Mechanisms of gut microbiota-immune-host interaction on glucose regulation in type 2 diabetes

Intestinal absorption of food is one of the sources of glucose. Insulin resistance and impaired glucose tolerance caused by lifestyle and diet are the precursors of type 2 diabetes. Patients with type 2 diabetes have trouble controlling their blood sugar levels. For long-term health, strict glycemic management is necessary. Although it is thought to be well correlated with metabolic diseases like obesity, insulin resistance, and diabetes, its molecular mechanism is still not completely understood. Disturbed microbiota triggers the gut immune response to reshape the gut homeostasis. This interaction not only maintains the dynamic changes of intestinal flora, but also preserves the integrity of the intestinal barrier. Meanwhile, the microbiota establishes a systemic multiorgan dialog on the gut-brain and gut-liver axes, intestinal absorption of a high-fat diet affects the host's feeding preference and systemic metabolism. Intervention in the gut microbiota can combat the decreased glucose tolerance and insulin sensitivity linked to metabolic diseases both centrally and peripherally. Moreover, the pharmacokinetics of oral hypoglycemic medications are also influenced by gut microbiota. The accumulation of drugs in the gut microbiota not only affects the drug efficacy, but also changes the composition and function of them, thus may help to explain individual therapeutic variances in pharmacological efficacy. Regulating gut microbiota through healthy dietary patterns or supplementing pro/prebiotics can provide guidance for lifestyle interventions in people with poor glycemic control. Traditional Chinese medicine can also be used as complementary medicine to effectively regulate intestinal homeostasis. Intestinal microbiota is becoming a new target against metabolic diseases, so more evidence is needed to elucidate the intricate microbiota-immune-host relationship, and explore the therapeutic potential of targeting intestinal microbiota.

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.

Association between dairy consumption and the risk of diabetes: A prospective cohort study from the China Health and Nutrition Survey

Diet is closely related to the risk of diabetes; yet the relationship between dairy consumption and the risk of diabetes is unclear with conflicting evidence from previous studies. This study used data from the Chinese Health and Nutrition Survey to investigate the association between dairy consumption and diabetes. A total of 15,512 adults were included; dairy consumption at each survey was assessed by the 3-day 24-h recall and weighed food record methods, and diabetes occurrence was derived from self-reported information. The association between dairy consumption and diabetes was explored using Cox regression and further stratified with BMI and energy intake. Results indicated that 12,368 (79.7%) participants had no dairy consumption, while 2,179 (14.0%) and 947 (6.1%) consumed dairy at 0.1-100 and >100 g/day, respectively. After adjusting for potential confounders, dairy consumption of 0.1-100 g/day was associated with lower risk of diabetes in all participants (HR 0.53, 95% CI:0.38 -0.74; P < 0.001) and males (HR 0.50, 95% CI: 0.31-0.80; P = 0.004). According to the restricted cubic splines (RCS), the protective effect on diabetes was significant in the total population with dairy consumption ranging from 25 to 65 g/day (HR <1, P = 0.025). In the stratified analysis, consuming 30-80 g/day was associated with reduced diabetes risk among the ≤ 2,000 kcal/day energy intake group (HR <1, P = 0.023). In conclusion, dairy consumption was inversely associated with a reduced diabetes risk in Chinese population. Further studies are required to examine the optimal level of dairy consumption for preventing diabetes in the Chinese population.

Determination of factors associated with serum cholesterol response to dairy fat consumption in overweight adults: Secondary analysis from an RCT

Elevated intakes of saturated fatty acids (SFA) can adversely affect serum cholesterol levels. Dairy fat contains ~60% SFA, prompting healthy eating guidelines to recommend low-fat dairy. Physiological, and environmental factors influence inter-individual variance in response to food consumption. Evidence exploring the dairy matrix has differing effects of dairy fat consumption on serum cholesterol levels when consumed in the form of cheese. The extent of this variability and determinants of response to dairy fat are currently unknown. The objective of this study was to determine factors associated with lipid metabolism response to a dairy fat intervention, with a focus on serum cholesterol. A 6-week randomized parallel intervention trial was carried out in healthy volunteers (≥50 years, BMI ≥25 kg/m²). Participants (n = 104) consumed ~40 g dairy fat daily in addition to their usual diet, in 1 of 3 forms: butter, cheese, or reduced-fat cheese and butter. For this analysis, “response” was based on the percentage (%) change in serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) from pre- to post-intervention. Participants were divided into tertiles for each lipid response. The upper and lower tertiles were used to categorize participants as “responders” and “non-responders.” For TC and LDL-c, response was classified as a decrease, whereas “response” was defined as an increase for HDL-c. Clinical response was also considered, by calculating pre- and post-intervention prevalence of those meeting target levels of cholesterol recommendations. Participants demonstrating the largest % decrease (Tertile 1; “responders”) in TC had significantly higher levels of TC and HDL-c, at baseline, and lower levels of triglycerides (TAGs) compared to those in tertile 3 (i.e., TC non-responders). Those with the largest % decrease in LDL-c (Tertile 1: LDL-c responders) had higher baseline levels of LDL-c and lower levels of TAGs. Multiple regression analysis revealed that the % change in TC and LDL-c was associated with baseline TC, TAG, body weight and high-sensitivity C-reactive protein (hsCRP; P < 0.05). Previous work has demonstrated the dairy food matrix affects lipid response to dairy consumption. This study suggests that phenotypic differences may also influence response to dairy fat in overweight individuals.

Leveraging Observational Cohorts to Study Diet and Nutrition in Older Adults: Opportunities and Obstacles

By 2060, the number of adults aged ≥65 y is expected to double, and the ≥85 y segment of the population is expected to triple in the United States. US federal nutrition guidance is based on the premise that healthy diets contribute to delaying the onset and progression of many age-related diseases and disability. Yet, little is known about the dietary intakes or nutritional needs across the older adulthood age span. This review aims to identify community-based cohorts that collected information on dietary intake of adults ≥65 y in the United States. Thirty-two cohorts met all inclusion criteria. We summarized information on the cohorts' design, demographics, and diet assessment. We also identified key gaps in the existing databases that, if filled, could enhance their utility to address certain research questions. This review serves as a valuable inventory of cohorts that can be leveraged to answer key questions about the diet and nutritional needs of the oldest old, who represent the fastest growing segment of the population in the United States.

Gut microbiota and fermentation-derived branched chain hydroxy acids mediate health benefits of yogurt consumption in obese mice

Meta-analyses suggest that yogurt consumption reduces type 2 diabetes incidence in humans, but the molecular basis of these observations remains unknown. Here we show that dietary yogurt intake preserves whole-body glucose homeostasis and prevents hepatic insulin resistance and liver steatosis in a dietary mouse model of obesity-linked type 2 diabetes. Fecal microbiota transplantation studies reveal that these effects are partly linked to the gut microbiota. We further show that yogurt intake impacts the hepatic metabolome, notably maintaining the levels of branched chain hydroxy acids (BCHA) which correlate with improved metabolic parameters. These metabolites are generated upon milk fermentation and concentrated in yogurt. Remarkably, diet-induced obesity reduces plasma and tissue BCHA levels, and this is partly prevented by dietary yogurt intake. We further show that BCHA improve insulin action on glucose metabolism in liver and muscle cells, identifying BCHA as cell-autonomous metabolic regulators and potential mediators of yogurt's health effects.

A food-level substitution analysis assessing the impact of replacing regular-fat dairy with lower fat dairy on saturated fat intake at a population level in Canada

BACKGROUND

The 2019 Canada's Food Guide recommends the consumption of lower fat dairy products to reduce saturated fat (SFA) intakes.

OBJECTIVES

The objective of this study was to assess the impact of such recommendation on SFA intake at a population level in Canada.

METHODS

Analyses were conducted based on dietary intakes from the nationally representative 2015 Canadian Community Health Survey-Nutrition (unweighted n = 20,103). Dietary intake was assessed using 24-h dietary recalls. Food-based substitution modeling analyses were conducted by replacing all regular-fat dairy products reported by an equal amount of a corresponding lower fat dairy product. Regular-fat dairy products included milks ≥2% fat, cheeses >25% fat, and yogurts ≥2% fat. Corresponding lower fat replacement products were 1% fat milks, 10-25% fat cheeses, and <2% fat yogurts. The National Cancer Institute method was used to account for within-person variation in dietary intakes.

RESULTS

Replacing all regular-fat dairy products consumed by Canadians (ages ≥2 y) by a corresponding lower fat product reduced the population's SFA intake from 10.8% of total energy intake (%E; 95% CI: 10.7%, 11.0%) to 10.0%E (95% CI: 9.8%, 10.2%). This reduction was mostly attributable to the milk and cheese substitutions (mean SFA reductions of -0.3%E each). The proportion of the population with an SFA intake <10%E was 34.7% (95% CI: 31.2%, 38.2%) before substitution and 51.5% (95% CI: 47.5%, 55.5%) after substitution.

CONCLUSIONS

This food-based substitution modeling analysis suggests that SFA intakes at a population level are slightly reduced if all regular-fat dairy products consumed by Canadians were replaced by a lower fat dairy product. Approximately half of the population would still consume SFAs in excess of 10%E even if all regular-fat dairy consumed were replaced by lower fat dairy.

Changes in dairy product consumption and subsequent type 2 diabetes among individuals with prediabetes: Tehran Lipid and Glucose Study

Background

People with prediabetes can postpone or even reverse progression to type 2 diabetes (T2D) by making dietary changes. This study aimed to examine the association of changes in consumption of total and specific types of dairy products with the subsequent risk of incident T2D among individuals with prediabetes.

Method

This cohort study included 639 individuals (50% female, mean age 47.3 years) of the Tehran Lipid and Glucose Study (TLGS) who had prediabetes at baseline. We assessed 3-year changes in the consumption of dairy products using a food frequency questionnaire. Using multivariable logistic regression, odds ratios (OR) and 95% confidence intervals (CI) were calculated for the association of changes in intake of total and subtypes of dairy products during a 3-year interval with the risk of incident T2D in the subsequent 3 years.

Results

After almost 9 years of follow-up, the incidence of T2D was 25.2%. Compared with individuals whose intake remained relatively stable over 3 years, those who decreased consumption of total dairy (> 0.5 servings/day) had a higher T2D risk (OR = 1.56; 95% CI: 1.02 to 2.41). Increasing low-fat dairy consumption by 0.50 serving/d was associated with a lower risk of T2D (OR = 0.56; 95% CI: 0.35 to 0.90) compared with stable consumption. Those who increased consumption of low-fat milk (OR = 0.59; 95% CI: 0.37 to 0.92) and low-fat yogurt (OR = 0.55; 95% CI: 0.33 to 0.93) had a lower risk of T2D than those who were relatively stable in their consumption. Replacing low-fat milk and yogurt with regular cheese was associated with 66 and 47% higher risk of T2D, respectively.

Conclusion

In individuals with prediabetes, increasing consumption of low-fat dairy, low-fat milk, and low-fat yogurt had reduced risk of subsequent T2D. These data suggest a role of low-fat dairy products in the prevention of T2D among prediabetes patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00745-x.

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.

Dairy Product Consumption and Cardiovascular Health: a Systematic Review and Meta-Analysis of Prospective Cohort Studies

The association between dairy product consumption and cardiovascular health remains highly debated. We quantitatively synthesized prospective cohort evidence on the associations between dairy consumption and risk of hypertension (HTN), coronary heart disease (CHD) and stroke. We systematically searched PubMed, Embase, and Web of Science through August 1st, 2020 to retrieve prospective cohort studies that reported on dairy consumption and risk of HTN, CHD or stroke. We used random-effects models to calculate the pooled relative risk (RR) and 95% confidence interval (CI) for the highest vs the lowest category of intake and for 1 serving/day increase in consumption. We rated the quality of evidence using NutriGrade. Fifty-five studies were included. Total dairy consumption was associated with a lower risk of HTN (RR for highest vs lowest level of intake: 0.91, 95% CI: 0.86-0.95, I2 = 73.5%; RR for 1 serving/day increase: 0.96, 95% CI: 0.94-0.97, I2 = 66.5%), CHD (highest vs lowest level of intake: 0.96, 95% CI: 0.92-1.00, I2 = 46.6%; 1 serving/day increase: 0.98, 95% CI: 0.95-1.00, I2 = 56.7%), and stroke (highest vs lowest level of intake: 0.90, 95% CI: 0.85-0.96, I2 = 60.8%; 1 serving/day increase: 0.96, 95% CI: 0.93-0.99, I2 = 74.7%). Despite moderate to considerable heterogeneity, these associations remained consistent across multiple subgroups. Evidence on the relationship between total dairy and risk of HTN and CHD were of moderate quality and of low quality for stroke. Low-fat dairy consumption was associated with lower risk of HTN and stroke, and high-fat dairy with a lower risk of stroke. Milk, cheese, or yogurt consumption showed inconsistent associations with the cardiovascular outcomes in high vs. low intake and dose-response meta-analyses. Total dairy consumption was associated with a modestly lower risk of hypertension, CHD and stroke. Moderate to considerable heterogeneity was observed in the estimates and the overall quality of the evidence was low to moderate.

Dairy Consumption and 3-Year Risk of Type 2 Diabetes after Myocardial Infarction: A Prospective Analysis in the Alpha Omega Cohort

Population-based studies suggest a role for dairy, especially yogurt, in the prevention of type 2 diabetes (T2D). Whether dairy affects T2D risk after myocardial infarction (MI) is unknown. We examined associations of (types of) dairy with T2D incidence in drug-treated, post-MI patients from the Alpha Omega Cohort. The analysis included 3401 patients (80% men) aged 60-80 y who were free of T2D at baseline (2002-2006). Dairy intakes were assessed using a validated food-frequency questionnaire. Incident T2D was ascertained through self-reported physician diagnosis and/or medication use. Multivariable Cox models were used to calculate Hazard ratios (HRs) and 95% confidence intervals (CI) for T2D with dairy intake in categories and per 1-standard deviation (SD) increment. Most patients consumed dairy, and median intakes were 264 g/d for total dairy, 82 g/d for milk and 41 g/d for yogurt. During 40 months of follow-up (10,714 person-years), 186 patients developed T2D. After adjustment for confounders, including diet, HRs per 1-SD were 1.06 (95% CI 0.91-1.22) for total dairy, 1.02 (0.88-1.18) for milk and 1.04 (0.90-1.20) for yogurt. Associations were also absent for other dairy types and in dairy categories (all p-trend > 0.05). Our findings suggest no major role for dairy consumption in T2D prevention after MI.

Dairy Product Intake and Long-Term Risk for Frailty among French Elderly Community Dwellers

Dairy products (DP) are part of a food group that may contribute to the prevention of physical frailty. We aimed to investigate DP exposure, including total DP, milk, fresh DP and cheese, and their cross-sectional and prospective associations with physical frailty in community-dwelling older adults. The cross-sectional analysis was carried out on 1490 participants from the Three-City Bordeaux cohort. The 10-year frailty risk was examined in 823 initially non-frail participants. A food frequency questionnaire was used to assess DP exposure. Physical frailty was defined as the presence of at least 3 out of 5 criteria of the frailty phenotype: weight loss, exhaustion, slowness, weakness, and low physical activity. Among others, diet quality and protein intake were considered as confounders. The baseline mean age of participants was 74.1 y and 61% were females. Frailty prevalence and incidence were 4.2% and 18.2%, respectively. No significant associations were observed between consumption of total DP or DP sub-types and frailty prevalence or incidence (OR = 1.40, 95%CI 0.65–3.01 and OR = 1.75, 95%CI 0.42–1.32, for a total DP consumption >4 times/d, respectively). Despite the absence of beneficial associations of higher DP consumption on frailty, older adults are encouraged to follow the national recommendations regarding DP.

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.

Dairy consumption and hepatocellular carcinoma risk

This review provides epidemiological and translational evidence for milk and dairy intake as critical risk factors in the pathogenesis of hepatocellular carcinoma (HCC). Large epidemiological studies in the United States and Europe identified total dairy, milk and butter intake with the exception of yogurt as independent risk factors of HCC. Enhanced activity of mechanistic target of rapamycin complex 1 (mTORC1) is a hallmark of HCC promoted by hepatitis B virus (HBV) and hepatitis C virus (HCV). mTORC1 is also activated by milk protein-induced synthesis of hepatic insulin-like growth factor 1 (IGF-1) and branched-chain amino acids (BCAAs), abundant constituents of milk proteins. Over the last decades, annual milk protein-derived BCAA intake increased 3 to 5 times in Western countries. In synergy with HBV- and HCV-induced secretion of hepatocyte-derived exosomes enriched in microRNA-21 (miR-21) and miR-155, exosomes of pasteurized milk as well deliver these oncogenic miRs to the human liver. Thus, milk exosomes operate in a comparable fashion to HBV- or HCV- induced exosomes. Milk-derived miRs synergistically enhance IGF-1-AKT-mTORC1 signaling and promote mTORC1-dependent translation, a meaningful mechanism during the postnatal growth phase, but a long-term adverse effect promoting the development of HCC. Both, dietary BCAA abundance combined with oncogenic milk exosome exposure persistently overstimulate hepatic mTORC1. Chronic alcohol consumption as well as type 2 diabetes mellitus (T2DM), two HCC-related conditions, increase BCAA plasma levels. In HCC, mTORC1 is further hyperactivated due to RAB1 mutations as well as impaired hepatic BCAA catabolism, a metabolic hallmark of T2DM. The potential HCC-preventive effect of yogurt may be caused by lactobacilli-mediated degradation of BCAAs, inhibition of branched-chain α-ketoacid dehydrogenase kinase via production of intestinal medium-chain fatty acids as well as degradation of milk exosomes including their oncogenic miRs. A restriction of total animal protein intake realized by a vegetable-based diet is recommended for the prevention of HCC.

Multi-omics analyses reveal relationships among dairy consumption, gut microbiota and cardiometabolic health

BACKGROUND

Little is known about the interplay among dairy intake, gut microbiota and cardiometabolic health in human prospective cohort studies.

METHODS

The present study included 1780 participants from the Guangzhou Nutrition and Health Study. We examined the prospective association between habitual dairy consumption (total dairy, milk, yogurt) and gut microbial composition using linear regression after adjusting for socio-demographic, lifestyle and dietary factors. The cross-sectional association of dairy-associated microbial features with cardiometabolic risk factors was examined with a linear regression model, adjusting for potential confounders. Serum metabolomic profiles were analyzed by partial correlation analysis.

FINDINGS

There was a significant overall difference in gut microbial community structure (β-diversity) comparing the highest with the lowest category for each of total dairy, milk and yogurt (P < 0.05). We observed that dairy-associated microbes and α-diversity indices were inversely associated with blood triglycerides, while positively associated with high-density lipoprotein cholesterol. A follow-up metabolomics analysis revealed the association of targeted serum metabolites with dairy-microbial features and cardiometabolic traits. Specifically, 2-hydroxy-3-methylbutyric acid, 2-hydroxybutyric acid and L-alanine were inversely associated with dairy-microbial score, while positively associated with triglycerides (FDR-corrected P < 0.1).

INTERPRETATION

Dairy consumption is associated with the gut microbial composition and a higher α-diversity, which provides new insights into the understanding of dairy-gut microbiota interactions and their relationship with cardiometabolic health.

FUNDING

This work was supported by the National Natural Science Foundation of China, Zhejiang Ten-thousand Talents Program, Westlake University and the 5010 Program for Clinical Researches of the Sun Yat-sen University.

Dairy consumption, plasma metabolites, and risk of type 2 diabetes

BACKGROUND

Epidemiologic studies have reported a modest inverse association between dairy consumption and the risk of type 2 diabetes (T2D). Whether plasma metabolite profiles associated with dairy consumption reflect this relationship remains unknown.

OBJECTIVES

We aimed to identify the plasma metabolites associated with total and specific dairy consumption, and to evaluate the association between the identified multi-metabolite profiles and T2D.

METHODS

The discovery population included 1833 participants from the Prevención con Dieta Mediterránea (PREDIMED) trial. The confirmatory cohorts included 1522 PREDIMED participants at year 1 of the trial and 4932 participants from the Nurses' Health Studies (NHS), Nurses' Health Study II (NHSII), and Health Professionals Follow-Up Study US-based cohorts. Dairy consumption was assessed using validated FFQs. Plasma metabolites (n = 385) were profiled using LC-MS. We identified the dairy-related metabolite profiles using elastic net regularized regressions with a 10-fold cross-validation procedure. We evaluated the associations between the metabolite profiles and incident T2D in the discovery and the confirmatory cohorts.

RESULTS

Total dairy intake was associated with 38 metabolites. C14:0 sphingomyelin (positive coefficient), C34:0 phosphatidylethanolamine (positive coefficient), and γ-butyrobetaine (negative coefficient) were associated in a directionally similar fashion with total and specific (milk, yogurt, cheese) dairy consumption. The Pearson correlation coefficients between self-reported total dairy intake and predicted total dairy intake based on the corresponding multi-metabolite profile were 0.37 (95% CI, 0.33-0.40) in the discovery cohort and 0.16 (95% CI, 0.13-0.19) in the US confirmatory cohort. After adjusting for T2D risk factors, a higher total dairy intake-related metabolite profile score was associated with a lower T2D risk [HR per 1 SD; discovery cohort: 0.76 (95% CI, 0.63-0.90); US confirmatory cohort: 0.88 (95% CI, 0.78-0.99)].

CONCLUSIONS

Total dairy intake was associated with 38 metabolites, including 3 consistently associated with dairy subtypes (C14:0 sphingomyelin, C34:0 phosphatidylethanolamine, γ-butyrobetaine). A score based on the 38 identified metabolites showed an inverse association with T2D risk in Spanish and US populations.

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.

Dairy consumption and risk of type-2 diabetes: the untold story

The role of dairy products in human health has been extensively studied for decades; however, evidence regarding dairy consumption and risk of type 2 diabetes (T2D) remains controversial and uncertain. Furthermore, study results are misinterpreted to a remarkable extent. The aim of this review is to critically appraise the association between intake of dairy foods and risk of T2D. A thorough search was conducted using electronic databases of PubMed, Scopus, and Web of Science. Related studies that addressed this research question between 2004 to 2019 were considered. Although most of the existing evidence suggests a beneficial role of dairy consumption on risk of T2D, only low-fat dairy foods and yogurt have shown a significant and consistent role, while other dairy products showed no association with prevention of T2D. Researchers, readers, and the public should maintain caution when reporting and interpreting findings and consider aspects such as heterogeneity, generalizability, and clinical and statistical significance.

Changes in Plant-Based Diet Indices and Subsequent Risk of Type 2 Diabetes in Women and Men: Three U.S. Prospective Cohorts

OBJECTIVE

We evaluated the associations between changes in plant-based diets and subsequent risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS

We prospectively followed 76,530 women in the Nurses' Health Study (NHS) (1986-2012), 81,569 women in NHS II (1991-2017), and 34,468 men in the Health Professionals Follow-up Study (1986-2016). Adherence to plant-based diets was assessed every 4 years with the overall plant-based diet index (PDI), healthful PDI (hPDI), and unhealthful PDI (uPDI). We used multivariable Cox proportional hazards models to estimate hazard ratios (HRs). We pooled results of the three cohorts using meta-analysis.

RESULTS

We documented 12,627 cases of type 2 diabetes during 2,955,350 person-years of follow-up. After adjustment for initial BMI and initial and 4-year changes in alcohol intake, smoking, physical activity, and other factors, compared with participants whose indices remained relatively stable (±3%), participants with the largest decrease (>10%) in PDI and hPDI over 4 years had a 12-23% higher diabetes risk in the subsequent 4 years (pooled HR, PDI 1.12 [95% CI 1.05, 1.20], hPDI 1.23 [1.16, 1.31]). Each 10% increment in PDI and hPDI over 4 years was associated with a 7-9% lower risk (PDI 0.93 [0.91, 0.95], hPDI 0.91 [0.87, 0.95]). Changes in uPDI were not associated with diabetes risk. Weight changes accounted for 6.0-35.6% of the associations between changes in PDI and hPDI and diabetes risk.

CONCLUSIONS

Improving adherence to overall and healthful plant-based diets was associated with a lower risk of type 2 diabetes, whereas decreased adherence to such diets was associated with a higher risk.

Socio-Demographic Characteristics, Dietary, and Nutritional Intakes of French Elderly Community Dwellers According to Their Dairy Product Consumption: Data from the Three-City Cohort

Few data are available regarding dietary habits of the elderly, especially about dairy products (DPs) (total DP and milk, fresh DP, and cheese), whereas these are part of healthy habits. The aim was to describe the socio-demographic characteristics, food, and nutritional intakes of elderly DP consumers. The sample consisted of 1584 participants from the Three-City-Bordeaux cohort (France), who answered a food frequency questionnaire and a 24-h dietary recall. Socio-demographic characteristics, practice of physical activity, Body Mass Index, and polymedication were registered. The sample was 76.2 years (SD 5.0 years) on average, 35% were in line with the French dietary guidelines for DP (3 or 4 servings of DP/day), while 49% were below, and 16% above. Women were significantly more likely to declare the highest total DP (≥4 times/day), milk (>1 time/day), and fresh DP (>1.5 times/day) frequency consumption. The highest cheese frequency consumers (>1.5 times/day) were more likely men, married, and ex-smokers. The highest frequency of fresh DP intake was significantly associated with the lowest energy and lipid intakes, and that of cheese with the highest consumption of charcuteries, meat, and alcohol. This cross-sectional analysis confirmed that the socio-demographics and dietary characteristics varied across DP sub-types consumed, which encourages individual consideration of these confounders in further analyses.

Dietary intake and cardiometabolic risk factors among Venezuelan adults: a nationally representative analysis

BACKGROUND

Increasing trends in global obesity have been attributed to a nutrition transition where healthy foods are replaced by ultra-processed foods. It remains unknown if this nutrition transition has occurred in Venezuela, a country undergoing a socio-political crisis with widespread food shortages.

METHODS

We described dietary intake of Venezuelans from a nationally representative study conducted between 2014 and 2017. We conducted a cross-sectional analysis of dietary, sociodemographic, and clinical data from Venezuelans ≥20 years of age (n = 3420). Dietary intake was assessed using a semi-quantitative food frequency questionnaire. Standardized clinical and anthropometric measurements estimated obesity, type 2 diabetes, and hypertension. A Dietary Diversity Score (DDS) was calculated using an amended Minimum Dietary Diversity for Women score where the range was 0 to 8 food groups, with 8 being the most diverse. Analyses accounted for complex survey design by estimating weighted frequencies of dietary intake and DDS across sociodemographic and cardiometabolic risk-based subgroups.

RESULTS

The prevalence of obesity was 24.6% (95% CI: 21.6-27.7), type 2 diabetes was 13.3% (11.2-15.7), and hypertension was 30.8% (27.7-34.0). Western foods were consumed infrequently. Most frequently consumed foods included coffee, arepas (a salted corn flour cake), and cheese. Mean DDS was 2.3 food groups (Range: 0-8, Standard Error: 0.07) and this score did not vary among subgroups. Men, younger individuals, and those with higher socioeconomic status were more likely to consume red meat and soft drinks once or more weekly. Women and those with higher socioeconomic status were more likely to consume vegetables and cheese once or more daily. Participants with obesity, type 2 diabetes, and hypertension had lower daily intake of red meat and arepas compared to participants without these risk factors.

CONCLUSIONS

Despite high prevalence of cardiometabolic risk factors, adults in Venezuela have not gone through a nutrition transition similar to that observed elsewhere in Latin America. Dietary diversity is low and widely consumed food groups that are considered unhealthy are part of the traditional diet. Future studies are needed in Venezuela using more comprehensive measurements of dietary intake to understand the effect of the socio-political crisis on dietary patterns and cardiometabolic risk factors.

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.

Distinct Effects of Milk-Derived and Fermented Dairy Protein on Gut Microbiota and Cardiometabolic Markers in Diet-Induced Obese Mice

BACKGROUND

Recent meta-analyses suggest that the consumption of fermented dairy products reduces type 2 diabetes and cardiovascular disease (CVD) risk, although the underlying mechanisms remain unclear.

OBJECTIVE

We evaluated whether dairy protein products modulated gut microbiota and cardiometabolic features in mouse models of diet-induced obesity and CVD.

METHODS

Eight-week-old C57BL/6J wild-type (WT) and LDLr-/-ApoB100/100 (LRKO) male mice were fed for 12 and 24 wk, respectively, with a high-fat/high-sucrose diet [66% kcal lipids, 22% kcal carbohydrates (100% sucrose), 12% kcal proteins]. The protein sources of the 4 diets were 100% nondairy protein (NDP), or 50% of the NDP energy replaced by milk (MP), milk fermented by Lactobacillus helveticus (FMP), or Greek-style yogurt (YP) protein. Fecal 16S rRNA gene-based amplicon sequencing, intestinal gene expression, and glucose tolerance test were conducted. Hepatic inflammation and circulating adhesion molecules were measured by multiplex assays.

RESULTS

Feeding WT mice for 12 wk led to a 74% increase in body weight, whereas after 24 wk the LRKO mice had a 101.5% increase compared with initial body weight. Compared with NDP and MP, the consumption of FMP and YP modulated the gut microbiota composition in a similar clustering pattern, upregulating the Streptococcus genus in both genotypes. In WT mice, feeding YP compared with NDP increased the expression of genes involved in jejunal (Reg3b, 7.3-fold, P = 0.049) and ileal (Ocln, 1.7-fold, P = 0.047; Il1-β,1.7-fold, P = 0.038; Nos2, 3.8-fold, P = 0.018) immunity and integrity. In LRKO mice, feeding YP compared with MP improved insulin sensitivity by 65% (P = 0.039). In LRKO mice, feeding with FMP versus NDP attenuated hepatic inflammation (monocyte chemoattractant protein 1, 2.1-fold, P ˂ 0.0001; IL1-β, 5.7-fold, P = 0.0003; INF-γ, 1.7-fold, P = 0.002) whereas both FMP [vascular adhesion molecule 1 (VCAM1), 1.3-fold, P = 0.0003] and YP (VCAM1, 1.04-fold, P = 0.013; intracellular adhesion molecule 1, 1.4-fold, P = 0.028) decreased circulating adhesion molecules.

CONCLUSION

Both fermented dairy protein products reduce cardiometabolic risk factors in diet-induced obese mice, possibly by modulating the gut microbiota.

A prospective study of yogurt and other dairy consumption in relation to incidence of type 2 diabetes among black women in the USA

BACKGROUND

Yogurt consumption and low-fat dairy consumption have been associated with reduced incidence of type 2 diabetes (T2D) in some studies.

OBJECTIVE

We assessed the relation of yogurt and other dairy consumption to incidence of T2D in black women, a population group with a disproportionately high incidence of T2D.

METHODS

The Black Women's Health Study has followed 59,000 US black women since 1995 through biennial questionnaires which update health information. Each questionnaire inquired about doctor-diagnosed diabetes in the previous 2 y. FFQs completed by participants in 1995 and 2001 provided information on yogurt and other dietary intake. HRs with 95% CIs for yogurt (nonfrozen or frozen) and other dairy consumption in relation to incident T2D (n = 8061 cases) were estimated with Cox proportional hazards regression, controlling for risk factors for T2D.

RESULTS

The HR for consumption of ≥1 serving of yogurt/d relative to <1 serving/mo was 0.99 (95% CI: 0.87, 1.13, P trend = 0.65) after control for dietary and nondietary risk factors for T2D. The multivariable HR was 0.97 (95% CI: 0.75, 1.27; P trend = 0.74) for 2 or more servings/d of low-fat dairy other than yogurt relative to <1 serving/mo and 1.06 (95% CI: 0.91, 1.25, P trend = 0.36) for 2 or more servings/d of regular dairy relative to <1 serving/mo.

CONCLUSION

Results from this study do not support an inverse association of yogurt consumption or other dairy consumption with T2D risk in black women.

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.

Dairy Consumption and Cardiometabolic Risk Factors in Patients with Type 2 Diabetes and Overweight or Obesity during Intensive Multidisciplinary Weight Management: A Prospective Observational Study

Dairy products are integral parts of healthy diets; however, their association with cardiometabolic (CM) health among patients with type 2 diabetes (T2D) undergoing weight management is debated. We examined the relationship between dairy consumption and CM biomarkers in 45 subjects with T2D and obesity (mean age 56 ± 9 yrs, 40% female) enrolled in a 12-week intensive multidisciplinary weight management (IMWM) program. After the IMWM program (intervention phase), subjects were followed for 12 weeks (maintenance phase). We stratified subjects based on initial average dairy consumption into infrequent (IFR), less-frequent (LFR), and frequent (FR) consumers. Outcomes were assessed at baseline, 12, and 24 weeks. There were no differences between tertiles at baseline except for higher total energy intake among FR compared with IFR. HbA1c changes showed no association with dairy consumption at 12 or 24 weeks. FR Females achieved greater weight loss at 12 weeks compared with IFR peers (-4.5 kg; 95%CI: -5.5, -3.5). There was a trend towards lower HDL-C with increasing dairy consumption during the intervention phase. In subjects with T2D and overweight or obesity, dairy consumption during weight management is not associated with HbA1c changes but with lower HDL-C and with higher magnitude of weight loss among females.

Metabolic Syndrome-Preventive Peptides Derived from Milk Proteins and Their Presence in Cheeses: A Review

The metabolic syndrome (MetS) is defined as the occurrence of diet-related diseases such as abdominal obesity, atherogenic dyslipidemia, hyperglycemia (insulin resistance) and hypertension. Milk-derived peptides are well-known agents acting against high blood pressure, blood glucose level, and lipoprotein disproportion. The aim of this review are metabolic syndrome-preventive peptides derived from milk proteins which were identified in cheeses. Special attention was paid to the sequences acting as angiotensin converting enzyme (ACE), dipeptidyl peptidase IV (DDP4), and α-glucosidase inhibitors, as well as antioxidative, hypocholesterolemic, antiobesity, and anti-inflammatory agents. Some results of meta-analyses concerning the consumption of cheese and the risk of MetS diseases were also presented.