Total Dairy Consumption Research Articles

Effectiveness of dairy products to protect against cognitive decline in later life: a narrative review.

As the world's population ages the prevalence of age-related health concerns is increasing, including neurodegeneration disorders such as mild cognitive impairment, vascular dementia and Alzheimer's disease. Diet is a key modifiable risk factor for the development of neurodegeneration, likely due to gut-brain axis interactions related to neuroinflammation. Analyses of dietary patterns identified dairy as being part of a cognitively healthy diet; however, its contribution to cognitive outcomes is difficult to discern. This narrative review evaluates the literature to determine whether there is sufficient evidence that the consumption of dairy products helps to maintain cognitive function in later life. A search using the terms (dairy OR milk OR cheese OR yogurt OR yogurt) AND ("mild cognitive impairment" OR dementia OR "Alzheimer's disease") identified 796 articles. After screening and sorting, 23 observational studies and 6 intervention studies were identified. The results of the observational studies implied that the relationship between total dairy consumption and cognitive outcomes is inverse U-shaped, with moderate consumption (1-2 servings per day) being the most beneficial. The analysis of the intake of different types of dairy products indicated that fermented products, particularly cheese, were most likely responsible for the observed benefits. The experimental studies all used dairy-derived peptides produced during fermentation as the dietary intervention, and the results indicated that these could be an effective treatment for early-stage cognitive impairment. Further experimental studies with whole dairy products, particularly fermented dairy, are needed to determine whether the regular consumption of these foods should be recommended to maximize the likelihood of healthy cognitive aging.

Dairy intake in association with asthma symptoms among a large sample of children and adolescents: a cross-sectional study.

Dairy products may be associated with an increased risk of asthma, although there is little scientific evidence to support this association. The goal of this study was to explore the association between dairy consumption and asthma symptoms. This cross-sectional study was conducted on children and adolescents aged 6-8 and 13-14 years living in central Iran. Dietary food consumption was assessed using a multiple-choice questionnaire. Logistic regression was used to obtain odds ratios for the association between milk, other dairy products, and total dairy consumption with the risk of asthma symptoms. In total, 7,667 participants (3,414 boys and 4,253 girls) were included in the current study. Milk intake and total dairy consumption were not associated with the likelihood of wheezing, asthma confirmed by a doctor, current asthma, and asthma medication use. In addition, there was no association between other dairy product intake and the odds of wheezing in the past 12 months in the crude model. However, after adjusting for several confounders, those in the top category had lower odds of wheezing in the past 12 months than those in the bottom category (OR: 0.58; 95% CI: 0.40-0.85). The consumption of dairy products other than milk, including cheese and yogurt, might reduce the likelihood of wheezing in children and adolescents.

A 30-year trend of dairy consumption and its determinants among income groups in Iranian households.

Milk and dairy products provide essential nutrients and have the potential to prevent chronic diseases, thus reducing healthcare costs. However, there is a lack of consistent and updated data on dairy consumption trends in Iran. This study aims to analyze the trends in dairy consumption among Iranian households from 1991 to 2021, focusing on household-level determinants across different expense groups. The study uses data from the Iranian Household Expenditure and Income Survey conducted annually from 1991 to 2021 to analyze households' dairy consumption. The data includes values and expenses of food and non-food items purchased in the previous month, as well as demographic characteristics of household members. The households were categorized into 10 deciles based on their gross expense. The econometric model used weighted mean per capita milk, yogurt, cheese, and total dairy consumption based on milk equivalent for each decile. The model takes into account changes in income, prices, household composition, education level, occupation, and residency area using panel data. Data preparation and model estimation were performed using RStudio and STATA17 software. Based on the findings, in 1991, per capita milk, yogurt, and cheese consumption were 26.77 kg, 16.63 kg, and 2.42 kg, respectively. By 2021, these figures changed to 22.68 kg, 11.06 kg, and 3.79 kg, reflecting a decrease in milk and yogurt consumption but an increase in cheese consumption. Family size was positively correlated with yogurt consumption and head of the household spouse's job score were positively correlated with milk, yogurt and cheese consumption. Also, the presence of under five-year-old children and older adults members (over the age of 60) in the household was inversely related with yogurt and cheese consumption. Female-headed households tended to purchase more cheese, while their milk purchase level was significantly lower. Residing in urban areas was negatively related to milk, while cheese and total dairy consumption was higher in urban areas. The findings highlight the importance of targeted dairy subsidy interventions and educational programs to improve dairy consumption in Iranian households, especially among vulnerable groups. This will require urging policymakers and food system stakeholders for effective strategies that address macro-level factors to promote dairy consumption.

Association of Estimated Daily Lactose Consumption, Lactase Persistence Genotype (rs4988235), and Gut Microbiota in Healthy Adults in the United States

BackgroundLactase persistence (LP) is a heritable trait in which lactose can be digested throughout adulthood. Lactase nonpersistent (LNP) individuals who consume lactose may experience microbial adaptations in response to undigested lactose. ObjectivesThe objective of the study was to estimate lactose from foods reported in the Automated Self-Administered 24-Hour Dietary Assessment Tool (ASA24) and determine the interaction between lactose consumption, LP genotype, and gut microbiome in an observational cross-sectional study of healthy adults in the United States (US). MethodsAverage daily lactose consumption was estimated for 279 healthy US adults, genotyped for the lactase gene −13910G>A polymorphism (rs4988235) by matching ASA24-reported foods to foods in the Nutrition Coordinating Center Food and Nutrient Database. Analysis of covariance was used to identify whether the A genotype (LP) influenced lactose and total dairy consumption, with total energy intake and weight as covariates. The 16S rRNA V4/V5 region, amplified from bacterial DNA extracted from each frozen stool sample, was sequenced using Illumina MiSeq (300 bp paired-end) and analyzed using Quantitative Insights Into Microbial Ecology (QIIME)2 (version 2019.10). Differential abundances of bacterial taxa were analyzed using DESeq2 likelihood ratio tests. ResultsAcross a diverse set of ethnicities, LP subjects consumed more lactose than LNP subjects. Lactobacillaceae abundance was highest in LNP subjects who consumed more than 12.46 g/d (upper tercile). Within Caucasians and Hispanics, family Lachnospiraceae was significantly enriched in the gut microbiota of LNP individuals consuming the upper tercile of lactose across both sexes. ConclusionsElevated lactose consumption in individuals with the LNP genotype is associated with increased abundance of family Lactobacillaceae and Lachnospriaceae, taxa that contain multiple genera capable of utilizing lactose.This trial was registered on clinicaltrials.gov as NCT02367287.

Associations between dairy intake and mortality due to all-cause and cardiovascular disease: the Japan Public Health Center-based prospective study

BackgroundSome studies have investigated the relation between dairy products and mortality, but with inconsistent results.ObjectiveWe examined the association between the consumption of dairy products and the risk of all-cause, cancer-related, and cardiovascular disease (CVD)-related mortality.MethodsFrom the Japan Public Health Center-based Prospective (JPHC) study, 43,117 males and 50,193 females with no history of cancer or CVD finished the food frequency questionnaire (FFQ) and were included in the study. Intake of dairy products was assessed using the FFQ and adjusted for total energy by using the residual method. We used multivariate Cox proportional hazard models to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for mortality risk in males and females.Results14,211 deaths in males and 9547 deaths in females from all causes were identified during an average follow-up of 19.3 years. For males, total dairy consumption was nonlinearly and significantly associated with lower risk of mortality from all causes [the third quartile, HR = 0.87 (0.83, 0.91), the fourth quartile, HR = 0.89 (0.85, 0.94), P for nonlinearity < 0.001] and CVD [the third quartile, HR = 0.77 (0.70, 0.85), the fourth quartile, HR = 0.78 (0.70, 0.86), P for nonlinearity < 0.001]. Milk and fermented milk intake were inversely associated with all-cause and CVD-related mortality in males. Cheese consumption was inversely associated with CVD-related mortality among males. There was no association between total dairy intake and mortality risk among females.ConclusionFor Japanese people, consumption of dairy products was associated with a decreased risk of mortality from all-cause and cardiovascular diseases among males.

Dairy Food Consumption Is Associated with Reduced Risk of Heart Disease Mortality, but Not All-Cause and Cancer Mortality in US Adults.

Previous evidence has linked animal protein intake, including dairy foods, with an increased risk in mortality from all-causes and certain chronic diseases, including cancer and heart disease. The objective of the current analysis was to examine associations between total dairy consumption with mortality from all-causes, cancer, and heart disease. Data for adults (≥19 y; n = 54,830) from the Third National Health and Nutrition Examination Survey (NHANES) and NHANES 1999-2014 were linked with mortality data through 2015. Individual usual intake for dairy foods were estimated using the National Cancer Institute method. Hazard ratio (HR) models were fit for mortality types (all cause, cancer, heart disease) and measures of usual intakes of dairy. Multivariable analysis further adjusted for age, gender, ethnicity, waist circumference, smoking status, education level, chronic condition status (i.e., based on cancer, myocardial infarct, and diabetes/diabetes medication reported), weight loss attempts, and % kcal from animal protein. No associations were seen between dairy food intake and mortality risk from all-causes [HR = 0.97; confidence intervals (CI): 0.85-1.11; p = 0.67], and cancer [HR = 0.95; CI: 0.75-1.20; p = 0.65] when comparing the lowest quartile to the highest quartile of consumption. Dairy food consumption was associated with a 26% reduced risk for heart disease mortality when comparing the lowest quartile to the highest quartile [HR = 0.74; CI: 0.54-1.01; p = 0.05]. Further analyses in different age groups showed that dairy food consumption was associated with 39% and 31% reduced risk for heart disease mortality in older adults 51-70 and ≥51 y, respectively [adults 51-70 y: HR = 0.61; CI: 0.41-0.91; p = 0.01; adults ≥51 y: HR = 0.69; CI: 0.54-0.89; p = 0.004]. These results contradict previous findings that have linked dairy foods to increased mortality risk. Further, dairy foods as part of a healthy dietary pattern, may help lower heart disease mortality risk.

Dairy production sustainability through a one-health lens

Dairy production provides high-quality, healthful nutrients to people on a planet soon to be inhabited by over 9 billion people. In doing so, it is ever more important to continuously improve the care of dairy animals, safeguard the environment we all share, and reliably produce nutritious food while maintaining the economic viability of the people working in dairy agriculture. In this paper, we review some associations between dairy consumption and human health along with the many interconnections between people, dairy animals, plants, and our shared environment. Understanding these relationships is an example of one health at work. In the US, total dairy consumption is at its highest point in the last 50 years, while many objective measures of cow health (eg, subclinical mastitis) have never been better since they have been recorded. Further, indications of food safety such as violative antibiotic residues in milk have never been lower. Dairy foods provide essential nutrients such as protein, vitamin B12, and calcium, while there is also evidence that they are protective against chronic conditions such as cardiovascular disease. Finally, the environmental footprint of dairy production in the US, as measured by metrics such as carbon dioxide–equivalent emissions intensity per unit of dairy nutrient, is the lowest it has ever been. The companion Currents in One Health by Nguyen et al, AJVR, January 2023, discusses some additional animal welfare and environmental impact implications of modern dairy production management in detail.

Dairy production sustainability through a one-health lens.

Dairy production provides high-quality, healthful nutrients to people on a planet soon to be inhabited by over 9 billion people. In doing so, it is ever more important to continuously improve the care of dairy animals, safeguard the environment we all share, and reliably produce nutritious food while maintaining the economic viability of the people working in dairy agriculture. In this paper, we review some associations between dairy consumption and human health along with the many interconnections between people, dairy animals, plants, and our shared environment. Understanding these relationships is an example of one health at work. In the US, total dairy consumption is at its highest point in the last 50 years, while many objective measures of cow health (eg, subclinical mastitis) have never been better since they have been recorded. Further, indications of food safety such as violative antibiotic residues in milk have never been lower. Dairy foods provide essential nutrients such as protein, vitamin B12, and calcium, while there is also evidence that they are protective against chronic conditions such as cardiovascular disease. Finally, the environmental footprint of dairy production in the US, as measured by metrics such as carbon dioxide-equivalent emissions intensity per unit of dairy nutrient, is the lowest it has ever been. The companion Currents in One Health by Nguyen et al, AJVR, January 2023, discusses some additional animal welfare and environmental impact implications of modern dairy production management in detail.

Theoretical attributable risk analysis and Disability Adjusted Life Years (DALYs) based on increased dairy consumption

BackgroundIdentification of modifiable risk factors that may impact chronic disease risk is critical to public health. Our study objective was to conduct a theoretical population attributable risk analysis to estimate the burden of disease from low dairy intake and to estimate the impact of increased dairy intake on United States (US)-based disability adjusted life years (DALYs).MethodsWe conducted a comprehensive literature review to identify statistically significant summary relative risk estimates (SRREs) from recent meta-analyses of dairy consumption and key chronic disease outcomes. The SRREs were applied to preventive fractions using a range of categories (low to high) for population consumption of dairy products. The preventive fraction estimates were then applied to the number of DALYs for each health outcome in the US based on 2019 WHO estimates. The population attributable risk proportion estimates were calculated using the inverse of the SRRE from each meta-analysis using the same range of categories of consumption. These values were subsequently applied to the DALYs estimates to estimate the theoretical burden of disease attributable to low dairy intake.ResultsStatistically significant SRREs were identified in recent meta-analyses of total dairy consumption in relation to breast cancer, colorectal cancer, cardiovascular disease (CVD), type 2 diabetes (T2D), stroke, and hypertension. In this theoretical analysis, nearly 850,000 DALYs (or 5.0% of estimated years of healthy life lost) due to CVD and 200,000 DALYs (4.5%) due to T2D may be prevented by increased dairy consumption. Approximately 100,000 DALYs due to breast cancer (7.5%) and approximately 120,000 DALYs (8.5%) due to colorectal cancer may be prevented by high dairy intake. The numbers of DALYs for stroke and hypertension that may be prevented by increased dairy consumption were approximately 210,000 (6.0%) and 74,000 (5.5%), respectively.ConclusionsConsumption of dairy products has been associated with decreased risk of multiple chronic diseases of significant public health importance. The burden of disease that may potentially be prevented by increasing dairy consumption is substantial, and population-wide improvement in meeting recommended daily dairy intake goals could have a notable public health impact. However, this analysis is theoretical, and thus additional studies providing empirical evidence are needed to further clarify potential relationships between dairy intake and various health outcomes.

Dairy consumption and incident risk of thyroid cancer in Japan: a pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study.

The impact of dairy consumption on thyroid cancer is unclear. The purpose of this study was to elucidate the association between dairy consumption and the risk of thyroid cancer in Japanese people. The association between dairy consumption and the risk of thyroid cancer in Japanese people was examined by conducting a pooled analysis of two prospective studies of residents in Miyagi Prefecture, Japan. Data from 64,340 men and women aged 40-79years registered in the Miyagi Cohort Study in 1990 and in the Ohsaki Cohort Study in 1994 were analyzed. Dairy consumption was assessed at baseline using a self-administered food frequency questionnaire and was divided into quartiles based on the weight (in grams) of total dairy consumption per day. During 1,075,018 person-years of follow-up, there were 190 incident cases of thyroid cancer (29 men and 161 women). The hazard ratios (HRs) and 95% confidence intervals (CIs) for thyroid cancer incidence in the highest quartile of dairy consumption compared with the lowest quartile were 0.83 (95% CIs 0.28-2.43, P-trend = 0.823) for men and 0.67 (95% CIs 0.42-1.06, P-trend = 0.056) for women. After stratification for BMI, a decreased risk was observed in women with BMI ≥ 25kg/m2 (HRs: 0.37, 95% CIs 0.18-0.79, P-trend = 0.010). Dairy consumption is inversely associated with the risk of thyroid cancer in women with BMI ≥ 25kg/m2.

Lipidomic Signatures of Dairy Consumption and Associated Changes in Blood Pressure and Other Cardiovascular Risk Factors Among Chinese Adults.

Omics data may provide a unique opportunity to discover dairy-related biomarkers and their linked cardiovascular health. Dairy-related lipidomic signatures were discovered in baseline data from a Chinese cohort study (n=2140) and replicated in another Chinese study (n=212). Dairy intake was estimated by a validated food-frequency questionnaire. Lipidomics was profiled by high-coverage liquid chromatography-tandem mass spectrometry. Associations of dairy-related lipids with 6-year changes in cardiovascular risk factors were examined in the discovery cohort, and their causalities were analyzed by 2-sample Mendelian randomization using available genome-wide summary data. Of 350 lipid metabolites, 4 sphingomyelins, namely sphingomyelin (OH) C32:2, sphingomyelin C32:1, sphingomyelin (2OH) C30:2, and sphingomyelin (OH) C38:2, were identified and replicated to be positively associated with total dairy consumption (β=0.130 to 0.148; P<1.43×10-4), but not or weakly with nondairy food items. The score of 4 sphingomyelins showed inverse associations with 6-year changes in systolic (-2.68 [95% CI, -4.92 to -0.43]; P=0.019), diastolic blood pressures (-1.86 [95% CI, -3.12 to -0.61]; P=0.004), and fasting glucose (-0.25 [95% CI, -0.41 to -0.08]; P=0.003). Mendelian randomization analyses further revealed that genetically inferred sphingomyelin (OH) C32:2 was inversely associated with systolic (-0.57 [95% CI, -0.85 to -0.28]; P=9.16×10-5) and diastolic blood pressures (-0.39 [95% CI, -0.59 to -0.20]; P=7.09×10-5). The beneficial effects of dairy products on cardiovascular health might be mediated through specific sphingomyelins among Chinese with overall low dairy consumption.

Total Dairy Consumption Is Not Associated With Likelihood of a First Clinical Diagnosis of Central Nervous System Demyelination.

BackgroundThe evidence associating consumption of dairy products and risk of MS is contradictory and inconclusive.ObjectiveTo test associations between dairy consumption and the likelihood of a first clinical diagnosis of central nervous system demyelination (FCD), a common precursor to MS.MethodsWe used data from the 2003–2006 Ausimmune Study, a population-based Australian, multicentre, matched case-control study (272 cases, 519 controls). Total dairy consumption (servings/day) was calculated by summing consumption of milk, cheese and yogurt. Covariate-adjusted treatment effects using augmented inverse probability weighting was used to test for associations with FCD. We conducted sensitivity analyses in the subset of participants who had had a classic first demyelinating event (FDE), defined as a single, first episode of symptoms suggestive of CNS demyelination.ResultsThere were no statistically significant associations between total dairy consumption (per one serving/day) and FCD (adjusted OR 1.00; 95% CI 0.93, 1.07; p = 0.979). However, yogurt consumption (vs. no yogurt consumption) was associated with an 11% decreased likelihood of FDE (adjusted OR 0.89; 95% CI 0.89, 0.79; p = 0.046).ConclusionWhile total dairy consumption was not associated with FCD in this Australian case-control study, yogurt consumption was associated with reduced likelihood of FDE.

Total dairy consumption in relation to overweight and obesity in children and adolescents: A systematic review and meta-analysis.

A systematic review and meta-analysis of cross-sectional and prospective cohort studies was conducted to assess the associations between total dairy consumption and its different subtypes with the prevalence and incidence of overweight, obesity, and overweight/obesity in children and adolescents. A literature search was conducted in Medline through PUBMED and Cochrane Library databases until October 18, 2021. Articles reporting the risk estimates as odd ratios (OR), risk ratios (RR), or hazard ratios and their corresponding 95% confidence interval (CI) for the association between dairy product consumption and the risk of overweight and/or obesity were included. In the meta-analysis from cross-sectional studies, results showed an inverse association between total dairy consumption and obesity prevalence (OR (95% CI): 0.66 (0.48-0.91). No significant associations were found between milk or yogurt and obesity prevalence risk. Regarding prospective studies, total milk consumption was positively associated with overweight prevalence (OR (95% CI): 1.13 (1.01-1.26)) and incidence (RR (95%CI): 1.17 (1.01-1.35)) risk. Evidence from pooled analysis of cross-sectional studies suggested an inverse association between total dairy consumption and obesity. However, there is limited and no conclusive evidence to confirm an inverse relationship from pooled analysis of prospective studies in children and adolescents.

Total, low-fat, and full-fat dairy consumption and risk of metabolic syndrome among workers.

Dairy products may play a beneficial role against metabolic syndrome; however, epidemiological evidence is scarce in Asian populations, who consume less dairy than Western populations. We prospectively investigated the association between dairy product intake, both overall and by fat content, and metabolic syndrome in a Japanese working population. Participants were 1014 workers (aged 19-68 years) without metabolic syndrome at baseline who completed a 3-year follow-up survey. Dietary intake was assessed using a validated self-administered diet history questionnaire. Metabolic syndrome was defined according to the Joint Interim Statement (JIS) criteria. Multiple logistic regression was used to estimate the odds ratio of metabolic syndrome according to tertile of total, low-fat, and full-fat dairy product intake with adjustment for covariates. At the 3-year follow-up, 66 (6.5%) workers were newly identified as having metabolic syndrome. A trend towards decreased odds of developing metabolic syndrome was observed among those in the highest tertile of total and full-fat dairy product intake: multivariable-adjusted odds ratio for the highest versus lowest tertile was 0.54 (95% CI 0.26-1.12; P for trend=0.094) for total dairy products and 0.50 (95% CI 0.24-1.05; P for trend=0.038) for full-fat dairy products. Low-fat dairy intake was not associated with metabolic syndrome. Our results suggest that higher intake of full-fat, but not low-fat, dairy products may be associated with a lower risk of metabolic syndrome among Japanese.

Guide and advances on childhood obesity determinants: Setting the research agenda.

Childhood obesity demands global solutions. Low birth weight and small for gestational age were associated with childhood obesity. Available data do not support prenatal exposure to antibiotics as risk factor for childhood obesity, and posology must be assessed. Prenatal exposure to persistent organic pollutants shows associations with childhood obesity. Gut microbiota composition influences obesity onset in childhood. Despite the unquestionable role of Mediterranean diet on healthy weight, there are only incomplete indications of metabolic benefits in childhood weight after following Mediterranean diet. Negative association between total dairy consumption and childhood obesity has been found, but inverse causality could not be discarded. Ultra-processed food intake is an adverse determinant of childhood obesity. Physical inactivity and sedentarism are critical risk factors of children adiposity; hence, built environment and environmental features will be determinants of childhood obesity. A consistent metabolic pattern of childhood obesity was observed; metabolomics research is needed to assess the role of specific molecules concerning childhood obesity. Epigenetic experiences support association with childhood obesity for DNA methylation of specific genes and miRNAs. Therefore, recent childhood obesity rates cannot only be explained by genetic predisposition and changes in lifestyle habits. It implies gene-environment interactions. It will be the next research.

Gut Microbiome Diversity and Composition Are Associated with Habitual Dairy Intakes: A Cross-Sectional Study in Men

BackgroundAt a population level, the relation between dairy consumption and gut microbiome composition is poorly understood. ObjectivesWe sought to study the cross-sectional associations between individual dairy foods (i.e., milk, yogurt, and cheese), as well as total dairy intake, and the gut microbiome composition in a large, representative sample of men living in south-eastern Australia. MethodsData on 474 men (mean ± SD: 64.5 ± 13.5 y old) from the Geelong Osteoporosis Study were used to assess the cross-sectional association between dairy consumption and gut microbiome. Information on dairy intake was self-reported. Men were categorized as consumers and nonconsumers of milk, yogurt, cheese, and high- and low-fat milk. Milk, yogurt, and cheese intakes were summed to calculate the total dairy consumed per day and categorized into either low (<2.5 servings/d) or high (≥2.5 servings/d) total dairy groups. Fecal samples were analyzed using bacterial 16S ribosomal RNA (rRNA) gene sequencing. After assessment of α and β diversity, differential abundance analysis was performed to identify bacterial taxa associated with each of milk, yogurt, and cheese consumption compared with nonconsumption, low compared with high total dairy, and low- compared with high-fat milk consumption. All analyses were adjusted for potential confounders. Resultsα Diversity was not associated with consumption of any of the dairy groups. Differences in β diversity were observed between milk and yogurt consumption compared with nonconsumption. Taxa belonging to the genera Ruminococcaceae UCG-010 and Bifidobacterium showed negative and weak positive associations with milk consumption, respectively. A taxon from the genus Streptococcus was positively associated with yogurt consumption, whereas a taxon from the genus Eisenbergiella was negatively associated with cheese consumption. No specific taxa were associated with low- compared with high-fat milk nor low compared with high total dairy consumption. ConclusionsIn men, community-level microbiome differences were observed between consumers and nonconsumers of milk and yogurt. Bacterial taxon-level associations were detected with milk, yogurt, and cheese consumption. Total dairy consumption was not associated with any microbiome measures, suggesting that individual dairy foods may have differential roles in shaping the gut microbiome in men.

Moderate partially skimmed milk consumption is associated with reduced mortality risk

Abstract Background Data on milk and other dairy products intake with health outcomes are inconsistent. We investigated the association of milk and total dairy consumption with the risk of all-cause and cause-specific mortality in a Mediterranean population. Methods We performed a longitudinal analysis on 22,889 men and women (mean age 55.4±11.7 y; 52.3% women), from the Moli-sani Study cohort (enrollment 2005-2010) followed-up for a median of 11 years. Dietary data were collected through a 188-item food frequency questionnaire. Total dairy consumption (g/d) was calculated as the sum of milk (whole and partially-skimmed, g/d), yogurt (whole and partially skimmed, g/d) and cheese (fresh and hard, g/d). Hazard ratio (HRs) with 95% confidence interval (CI) were calculated by multivariable Cox regression, modelled by spline curves. Results In multivariable-adjusted analysis controlled for sociodemographic, clinical and dietary factors, cheese, yogurt or whole milk intake were not associated with either all-cause or cause-specific mortality (p for overall association &amp;gt;0.38), as well as was total diary intake (p &amp;gt; 0.18). On the contrary, non-linear J-shaped curves were observed for the association of partially skimmed milk intake with all-cause and cancer mortality (p value for total and non-linear association=0.0072 and 0.035, and 0.097 and 0.049, respectively; magnitude of the relative reduction =16% and 18% at nadir of 128 and 114 g/d, respectively). A linear association between partially skimmed milk intake and CVD mortality was observed (p for association =0.047; p for non-linearity= 0.41), with HR = 0.82 (95%CI: 0.68-0.98) at 125 g/d and a window of statistically significant protection ranging from 100 to 250 g/d. Conclusions In a large Mediterranean population of adults, consumption of 1 standard cup of partially skimmed milk was associated with lower all-cause, cancer and CVD mortality. Other dairy sources were not associated with mortality. Key messages In a large Mediterranean population, total dairy intake did not predict mortality. Daily consumption of 1 standard cup of partially skimmed milk lowers the risk of all-cause, cardiovascular and cancer mortality.

The association between dairy products and psychological disorders in a large sample of Iranian adults

ABSTRACT Background Dairy products contain certain nutrients that are useful in mental disorders. This study aimed to assess the associations between dairy products and psychological disorders in a large sample of Iran, a Middle Eastern country. Methods This cross-sectional study was undertaken on 7387 adults. Data on dietary intakes were obtained using a validated Food Frequency Questionnaire. Psychological health was assessed by the Iranian validated version of depression, anxiety, and stress scale 21. Multivariable logistic regression analysis was performed to analyze the association between dairy intake and psychological disorders. Results After adjustment for potential confounders, total milk consumption (OR for the highest vs. lowest tertile: 0.73, 0.58-0.92) and total yogurt consumption (0.78, 0.62-0.97) were associated with decreased odds of depression. An inverse relationship was found between total dairy (0.73, 95% CI 0.590.91), total milk (0.72; 0.58-0.88), kashk (0.79, 0.65-0.96), and yogurt drink (0.80, 95% CI 0.65-0.98) consumption and anxiety symptoms. Higher intake of cheese was related to greater odds of stress (1.52, 1.02-2.26). No association was found between the consumption of high-fat dairy, low-fat dairy, low-fat milk, low-fat yogurt, high-fat yogurt, cheese, kashk, yogurt drink, and depression. Also, there is no association between dairy products and stress symptoms. This association was significant among men and women and high-fat and low-fat products in the total adjusted stratified analysis models. Conclusions Findings of this study revealed that both high-fat and low-fat dairy products are associated with a reduced prevalence of psychological disorders. Still, more prospective studies are required to confirm these associations.

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

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. 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. 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. 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)]. 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.

Serum metabolomics study of the association between dairy intake and the anti-m\xfcllerian hormone annual decline rate

BackgroundDairy intake has been implicated in later ovarian aging but mechanism underlying the association is unknown. This study aimed to investigate (1) associations between dairy intake and metabolites previously shown related to anti-müllerian hormone (AMH) decline rate; (2) mediating roles of these metabolites in the prospective association of total dairy consumption with odds of AMH fast decline rate.MethodsThe participants comprised 186 reproductive-aged women randomly selected from the Tehran Lipid and Glucose Study. AMH was measured at baseline (1999–2001) and the 5th follow-up (2014–2017), and dietary data was collected at the second follow-up (2005–2008) using a food frequency questionnaire. Untargeted metabolomics was performed by gas chromatography–mass spectrometry using fasting-serum samples of the second follow-up. We analyzed dairy intake in association with the eight metabolites linked to the higher odds of AMH fast decline rate using linear regression with the Benjamini–Hochberg false discovery correction. Mediatory roles of the metabolites were assessed by bootstrapping.ResultsMean age and BMI of the participants at metabolomics assessment were 44.7 ± 5.87 years and 28.8 ± 4.88 kg/m2, respectively. Phosphate, branched-chain amino acids (BCAAs), and proline decreased significantly from the first to the third tertile of total dairy intake. Total dairy as a continuous variable inversely associated with phosphate (beta = −0.166; p value = 0.018), valine (beta = −0.176; p value = 0.016), leucine (beta = −0.226; p value = 0.002), proline (beta = −0.219; p value = 0.003), and urea (beta = −0.156; p = 0.035) after accounting for all potential covariates and correction for multiplicity (q-value < 0.1). Fermented dairy showed similar results, but milk did not associate with any of the metabolites. Simple mediation showed significant indirect effects for phosphate, proline, and BCAAs but not urea. Entering the sum of phosphate, proline, and BCAAs as a mediator, the metabolites' total indirect effects were significant [β = −0.12 (95% CIs − 0.26, − 0.04)]. In contrast, the direct association of total dairy intake with the fast decline in AMH was non-significant [β = −0.28 (95% CIs − 0.67, 0.10)].ConclusionsTotal dairy was inversely associated with AMH decline rate-related metabolites. Inverse association of dairy intakes with the odds of AMH fast decline rate was indirectly mediated by lower phosphate, proline, and BCAAs.