Dairy consumption, type 2 diabetes, and changes in cardiometabolic traits: a prospective cohort study of middle-aged and older Chinese in Beijing and Shanghai

Dairy consumption has a partial inverse association with systolic blood pressure and hypertension in populations with high salt and low dairy diets: cross-sectional data analysis from the Iwaki Health Promotion Project

The prevalence of hypertension in Japan remains high, owing to the high salt content of the typical Japanese diet. Dairy-based foods may reduce blood pressure and hypertension risk. However, dairy consumption is low in Japan, and the relationships between dairy intake and blood pressure or the mechanisms by which dairy products affect blood pressure are not fully understood. This cross-sectional study was conducted as part of the Iwaki Health Promotion Project in Aomori, Japan. A total of 1071 participants were included from those who underwent annual medical checkups in June 2015. Adjusted multivariate linear and logistic regression analyses were performed to analyze the relationships between dairy consumption and blood pressure or hypertension risk. Comprehensive blood biomarker measurements were also performed. Whole- and high-fat dairy consumption was found to have significant inverse associations with systolic blood pressure (SBP) for all participants (β = -0.0213, P = 0.044) and with SBP and systolic hypertension risk for non-users of antihypertensive medicines (β = -0.0306, P = 0.011; and OR = 0.9927, P = 0.016; respectively). Three blood biomarkers related to phosphorus metabolism (inorganic phosphorus, intact parathyroid hormone, and interleukin-6) were associated with both dairy consumption and SBP. Dairy consumption had a partial inverse association with SBP and hypertension risk in a Japanese population with high salt and low dairy consumption. Analysis of blood biomarkers suggested that phosphorus metabolism is involved in the associations between dairy consumption and blood pressure.

The association between consumption of dairy products and risk of type 2 diabetes

Background

The effects of dairy products on type 2 diabetes mellitus (T2DM) are unclear. Some studies have revealed the beneficial effects, whereas others found harmful effects of dairy products on the risk of T2DM. The objective of the present study was to investigate the association of different types of dairy products with risk of T2DM in Iranian adults.

Methods

This cross-sectional study included a total of 4241 individuals. Among these participants, 1804 were diagnosed with T2DM or prediabetes, whereas the remaining 2437 individuals were without T2DM. A validated food frequency questionnaire was used to assess the consumption of different types of dairy products.

Results

A positive association was found between T2DM with dietary intake of milk [odds ratio (OR): 1.16, 95% confidence interval (CI): 1.11-1.23, P = 0.008] and cheese (OR: 1.90, 95% CI: 1.41-2.29, P = 0.001) after adjustment for age, sex, physical activity, BMI, education level, energy, and fat intake. There was no significant association between T2DM and dietary intake of total dairy, yogurt, ayran (yogurt drink), and curd.

Conclusion

A positive association was found between the consumption of some dairy products including milk and cheese and the risk of T2DM. Further longitudinal studies are warranted to approve this finding.

Skimmed milk intake reduces the risk of ER- breast cancer: a Mendelian randomization analysis

BACKGROUND

In prior observational investigations, it has been demonstrated that the consumption of milk is associated with the incidence of breast cancer (BC). Despite the existence of a two-sample Mendelian randomization (MR) that suggests a causal relationship between milk intake and breast cancer risk, the outcomes still lack a definitive conclusion. This ambiguity may be attributed to variables such as the variety of milk ingested, estrogen levels, the specific type of BC, and potential confounding factors. Therefore, our principal objective is to establish the causal association between the consumption of skimmed milk and full cream milk and the risk of different types of BC through the utilization of two-sample and two-step MR analyses.

METHODS

In this study, we analyzed single nucleotide polymorphisms associated with skimmed and full-cream milk consumption in a cohort of 360,806 individuals from European populations through genome-wide association studies. We conducted a two-sample MR analysis using three different methods: inverse variance weighting (IVW) was used as the main analysis, and MR-Egger and Weighted median were used as supplementary analyses to IVW. We also performed sensitivity analysis, which included leave-one-out analysis, Cochran's Q test to detect heterogeneity, and MR-Egger intercept analysis to detect potential biases caused by pleiotropy. We used two-step MR analysis to evaluate potential mediators of associations.

RESULTS

In the two-sample MR analysis, IVW analysis suggests a potential inverse causal relationship between skimmed milk and BC [OR 0.34, 95% CI (0.12-1.00), P = 0.05]. Subgroup analysis revealed that skimmed milk reduces the risk of estrogen receptor-negative (ER-) breast cancer [OR 0.18, 95% CI (0.04-0.90), P = 0.04], but not estrogen receptor-positive (ER+) breast cancer [OR 0.42, 95% CI (0.15-1.22), P = 0.11]. MR Egger reached similar results, that is, skimmed milk reduces the risk of ER- breast cancer [OR 0.006, 95% CI (0.00-0.70), P = 0.04], but not BC [OR 0.16, 95% CI (0.01-4.66), P = 0.30] and ER+ breast cancer [OR 0.50, 95% CI (0.02-12.61), P = 0.65]. Additionally, we found no causal relationship between full cream milk and BC (P > 0.05). In two-step MR analysis, we found evidence for a mediating role of BMI in the relationship between skimmed milk intake and ER-breast cancer risk.

CONCLUSION

Our findings strengthen the evidence for a protective effect of skimmed milk consumption on ER-breast cancer risk. Further two-step MR analyses suggest that this protective effect may partly result from body mass index (BMI). There is no evidence that full cream milk consumption affects the risk of BC.

Effect of Dietary Approaches to Stop Hypertension (DASH) on Patients with Metabolic Syndrome and Its Potential Mechanisms

Metabolic syndrome (MS) is more prevalent in chronic diseases and, if left untreated, can lead to serious consequences, such as cardiovascular disease (CVD), cerebrovascular disease and type 2 diabetes, which have become significant public health issues globally. Metabolic syndrome is significantly influenced by the daily diet of patients. The dietary approaches to stop hypertension (DASH) diet, originally designed to prevent or control hypertension, offers additional metabolic benefits due to its nutrient composition. The DASH diet recommends the intake of potassium, magnesium, calcium and fibre while limiting total fat, saturated fat and sodium, which is beneficial for patients with MS. Due to its limited fat content and high levels of fibre and calcium, individuals following the DASH diet are less prone to being overweight and obese and have lower concentrations of total and low-density lipoprotein cholesterol. Moreover, the DASH diet can reduce blood pressure and is effective in correcting glucose and insulin abnormalities. This review comprehensively summarises the health benefits of the DASH diet on the risk factors of MS and describes the potential mechanisms based on available evidence.

Associations of Plasma Lipidomic Profiles with Uric Acid and Hyperuricemia Risk in Middle-Aged and Elderly Chinese

Little is known about the links of disturbed lipid metabolism with hyperuricemia (HUA). We aimed to investigate the associations of lipidomic profiles with uric acid (UA)/HUA and their modifying factors in middle-aged and elderly Chinese. A total of 350 lipids were quantified in 2247 community-based Chinese aged 50-70 years by high-coverage targeted lipidomics. HUA was defined by plasma UA > 420 μmol/L in men or > 360 μmol/L in women. The prevalence of HUA in this population was 10.4%. After multivariable adjustment including BMI and lifestyle, 123 lipids were significantly associated with UA, predominantly glycerolipids (GLs) and glycerophospholipids (GPs). Specifically, diacylglycerol [DAG (16:0/22:5), DAG (16:0/22:6), DAG (18:1/20:5), DAG (18:1/22:6)], phosphatidylcholine [PC (16:0/20:5)), and triacylglycerol (TAG (53:0)] were the most significant lipid signatures positively associated with HUA risk, while lysophosphatidylcholine (LPC (20:2)) was inversely associated with HUA risk (p < 0.05). Network analysis also showed a positive association between TAGs/PCs/DAGs contained module and HUA risk (p < 0.01). Notably, HUA-related lipids were associated with de novo lipogenesis fatty acids, especially 16:1n-7 (Spearman correlation coefficients = 0.32-0.41, p < 0.001). Reduced rank regression showed that increased aquatic products intake was correlated to elevated HUA risk and HUA-associated lipids; while high dairy consumption was correlated with low level of HUA-associated lipids (|factor loadings| ≥ 0.2). Moreover, mediation analyses suggested that the lipid-HUA associations were partially mediated by retinol-binding protein 4 (RBP4, mediation proportion 5-14%), an adipokine linked with dyslipidemia and insulin resistance. In conclusion, disturbed specific metabolisms of GLs and GPs were associated with high prevalent HUA, partially mediated by RBP4 and/or influenced by certain dietary factors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-024-00157-x.

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 consumption in adults in China: a systematic review

BACKGROUND

Research on dairy consumption in China is lacking, however, some evidence has demonstrated significant changes in recent years, with a reported increase in the overall consumption of dairy products. To fully understand these changes, a systematic review was conducted to examine reported dairy intakes and differences between dairy consumption in different population groups in China.

METHODS

Web of Science, Embase, and PubMed databases were searched for studies published from January 2000 to September 2022. The China National Knowledge Infrastructure (CNKI) was used to retrieve papers available in Chinese. Papers reporting dietary intakes of dairy consumption across age, sex, and geographical location sub-groups were considered for inclusion in this review. In addition, this review includes the consumption of different types of dairy foods and changes in dairy intake over time.

RESULTS

Forty-seven papers were included in the present study. Twelve papers examined dairy consumption across age groups, showing that middle-aged adults tend to consume less dairy than other age groups. Studies comparing across location-specific cohorts reported dairy intakes among urban populations were higher than rural, as well as being higher than the national average. Coastal, Northern and Eastern residents consumed more dairy products than those living in other regions of China, and people in larger cities had higher reported intakes than smaller cities. Milk was the primary dairy product reportedly consumed by Chinese population, followed by yogurt. Concerning sex, evidence showed that females generally reported a greater daily dairy intake than males.

CONCLUSIONS

This review shows that, in China, several different population groups displayed significant differences in the amount and type of dairy consumed. When considering the incorporation of dairy products into healthy eating guidelines or positioning specific dairy products on the market, it is important to consider the differences and variations in consumption patterns within population groups.

Diet-Related Lipidomic Signatures and Changed Type 2 Diabetes Risk in a Randomized Controlled Feeding Study With Mediterranean Diet and Traditional Chinese or Transitional Diets

OBJECTIVE

Few trials studied the links of food components in different diets with their induced lipidomic changes and related metabolic outcomes. Thus, we investigated specific lipidomic signatures with habitual diets and modified diabetes risk by using a trial and a cohort.

RESEARCH DESIGN AND METHODS

We included 231 Chinese with overweight and prediabetes in a randomized feeding trial with Mediterranean, traditional, or transitional diets (control diet) from February to September 2019. Plasma lipidomic profiles were measured at baseline, third month, and sixth month by high-throughput targeted liquid chromatography-mass spectrometry. Associations of the identified lipids with habitual dietary intakes were examined in another lipidomic database of a Chinese cohort (n = 1,117). The relationships between diet-induced changes of lipidomic species and diabetes risk factors were further investigated through both individual lipids and relevant modules in the trial.

RESULTS

Out of 364 lipidomic species, 26 altered across groups, including 12 triglyceride (TAG) fractions, nine plasmalogens, four phosphatidylcholines (PCs), and one phosphatidylethanolamine. TAG fractions and PCs were associated with habitual fish intake while plasmalogens were associated with red meat intake in the cohort. Of the diet-related lipidomic metabolites, 10 TAG fractions and PC(16:0/22:6) were associated with improved Matsuda index (β = 0.12 to 0.42; PFDR < 0.030). Two plasmalogens were associated with deteriorated fasting glucose (β = 0.29 to 0.31; PFDR < 0.014). Similar results were observed for TAG and plasmalogen related modules.

CONCLUSIONS

These fish- and red meat-related lipidomic signatures sensitively reflected different diets and modified type 2 diabetes risk factors, critical for optimizing dietary patterns.

The relationship between the intake of fruits, vegetables, and dairy products with hypertension: findings from the STEPS study

BACKGROUND

The current research aimed to evaluate the relationship between fruit, vegetable (FV), and dairy consumption with the odds of developing hypertension based on nationwide Stepwise approach to surveillance (STEPS) data in Iran.

METHODS

This cross-sectional study was accomplished by the research center of non-communicable diseases (NCDs) in Tehran. In total, 29,378 individuals' data were analyzed. Participants were classified into normal, elevated BP, stage I, and stage II hypertension according to systolic blood pressure (SBP) and diastolic blood pressure (DBP) examinations. Based on the STEPS questionnaire, the consumption of FVs and dairy products was evaluated. Multinomial logistic regression was applied to assess the relationship between the consumption of FVs and dairy products with hypertension.

RESULTS

The findings revealed that only fruit consumption (≥ 2 servings/day) was negatively related to stage I hypertension (odds ratio (OR) = 0.81; 95% confidence interval (CI): 0.69-0.95) in two servings per day and OR = 0.81; 95% CI: 0.68-0.96 in > two servings per day) in the adjusted model. There was no significant relationship between consuming vegetables and dairy products with elevated BP and hypertension.

CONCLUSION

Our study showed that increasing fruit consumption was related to reducing hypertension odds. Regarding the consumption of dairy products and vegetables, no significant relationship was found with the odds of hypertension. More studies, especially cohorts, are needed to evaluate the impacts of FV and dairy products on the risk of hypertension.

Associations between dairy consumption, physical activity, and blood pressure in Chinese young women

Introduction

The prevalence of hypertension (HTN) has been increasing in young adults. A healthy dietary pattern and increasing physical activity (PA) are commonly recommended as lifestyle modifications needed to manage blood pressure (BP). However, little is known about the relationship between dairy intake, PA, and BP in Chinese young women. The aim of this study was to examine whether BP was associated with dairy intake, moderate-to-vigorous intensity physical activity (MVPA) and total physical activity (TPA) in a sample of Chinese young women.

Methods

A total of 122 women (20.4 ± 1.4) who had complete data sets from the Physical Fitness in Campus (PFIC) study were included in this cross-sectional analysis. Data related to dairy intake and PA was collected using a food frequency questionnaire and an accelerometer. BP was measured following standardized procedures. The association between BP with dairy intake and PA was examined using multivariable linear regression models.

Results

After controlling for potential covariables, we observed a significant and independent relationship only between systolic BP with dairy intake [standardized beta (b) = -0.275, p < 0.001], MVPA (b = -0.167, p = 0.027), and TPA (b = -0.233, p = 0.002). Furthermore, we found a decrease of 5.82 ± 2.94, 1.13 ± 1.01, and 1.10 ± 0.60 mm Hg in systolic BP for daily additional servings of dairy, 10 min of MVPA, and 100 counts per minute of TPA, respectively.

Conclusion

Our results suggested that the higher amount of dairy consumption or PA was associated with lower level of SBP in Chinese young women.

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 of dietary patterns with obesity and metabolically healthy obesity phenotype in Chinese population: a cross-sectional analysis of China Multi-Ethnic Cohort Study

Metabolically healthy obesity (MHO) might be an alternative valuable target in obesity treatment. We aimed to assess whether alternative Mediterranean (aMED) diet and Dietary Approaches to Stop Hypertension (DASH) diet were favourably associated with obesity and MHO phenotype in a Chinese multi-ethnic population. We conducted this cross-sectional analysis using the baseline data of the China Multi-Ethnic Cohort study that enrolled 99 556 participants from seven diverse ethnic groups. Participants with self-reported cardiometabolic diseases were excluded to eliminate possible reverse causality. Marginal structural logistic models were used to estimate the associations, with confounders determined by directed acyclic graph (DAG). Among 65 699 included participants, 11·2 % were with obesity. MHO phenotype was present in 5·7 % of total population and 52·7 % of population with obesity. Compared with the lowest quintile, the highest quintile of DASH diet score had 23 % decreased odds of obesity (OR = 0·77, 95 % CI 0·71, 0·83, P_trend < 0·001) and 27 % increased odds of MHO (OR = 1·27, 95 % CI 1·10, 1·48, P_trend = 0·001) in population with obesity. However, aMED diet showed no obvious favourable associations. Further adjusting for BMI did not change the associations between diet scores and MHO. Results were robust to various sensitivity analyses. In conclusion, DASH diet rather than aMED diet is associated with reduced risk of obesity and presents BMI-independent metabolic benefits in this large population-based study. Recommendation for adhering to DASH diet may benefit the prevention of obesity and related metabolic disorders in Chinese population.

Association between frequency of dairy product consumption and hypertension: a cross-sectional study in Zhejiang Province, China

BACKGROUND

Hypertension, a well-known risk factor, contributes to millions of deaths from cardiovascular and renal diseases worldwide. However, evidence on the association between frequency of dairy product consumption and hypertension is inconsistent.

METHODS

The data for the present study are from the Tongxiang baseline dataset of the China Kadoorie Biobank prospective study. A total of 53,916 participants aged 30-79 years were included in the final analysis. Multivariable logistic regression was utilized to evaluate the association of dairy product consumption with hypertension, and multiple linear regression was conducted to assess the association of dairy product consumption with systolic and diastolic blood pressure.

RESULTS

Of the 53,916 participants, 2.6% reported consuming dairy products weekly, and 44.4% had prevalent hypertension. After adjusting for socio-demographic status, lifestyle factors, BMI, waist circumference, sleep duration and snoring, when compared with participants who never consumed dairy products, the odds ratios (95% CI) for hypertension among those consuming dairy products less than once per week, and ≥ 1 time per week were 0.85 (0.77-0.95) and 0.74 (0.65-0.84), respectively. The corresponding odds ratios (95% CI) for men were 0.85 (0.71-1.02) and 0.75 (0.61-0.92), respectively (P_trend = 0.001), and for women were 0.88 (0.76-1.01) and 0.77 (0.65-0.91), respectively. (P_trend < 0.001).

CONCLUSIONS

In this large epidemiological study, higher frequency of dairy product consumption is associated with significantly lower odds of hypertension among Chinese adults.

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

BACKGROUND

Omics data may provide a unique opportunity to discover dairy-related biomarkers and their linked cardiovascular health.

METHODS

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.

RESULTS

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).

CONCLUSIONS

The beneficial effects of dairy products on cardiovascular health might be mediated through specific sphingomyelins among Chinese with overall low dairy consumption.

Dairy consumption and risks of total and site-specific cancers in Chinese adults: an 11-year prospective study of 0.5 million people

BACKGROUND

Previous studies of primarily Western populations have reported contrasting associations of dairy consumption with certain cancers, including a positive association with prostate cancer and inverse associations with colorectal and premenopausal breast cancers. However, there are limited data from China where cancer rates and levels of dairy consumption differ importantly from those in Western populations.

METHODS

The prospective China Kadoorie Biobank study recruited ~0.5 million adults from ten diverse (five urban, five rural) areas across China during 2004-2008. Consumption frequency of major food groups, including dairy products, was collected at baseline and subsequent resurveys, using a validated interviewer-administered laptop-based food frequency questionnaire. To quantify the linear association of dairy intake and cancer risk and to account for regression dilution bias, the mean usual consumption amount for each baseline group was estimated via combining the consumption level at both baseline and the second resurvey. During a mean follow-up of 10.8 (SD 2.0) years, 29,277 incident cancer cases were recorded among the 510,146 participants who were free of cancer at baseline. Cox regression analyses for incident cancers associated with usual dairy intake were stratified by age-at-risk, sex and region and adjusted for cancer family history, education, income, alcohol intake, smoking, physical activity, soy and fresh fruit intake, and body mass index.

RESULTS

Overall, 20.4% of participants reported consuming dairy products (mainly milk) regularly (i.e. ≥1 day/week), with the estimated mean consumption of 80.8 g/day among regular consumers and of 37.9 g/day among all participants. There were significant positive associations of dairy consumption with risks of total and certain site-specific cancers, with adjusted HRs per 50 g/day usual consumption being 1.07 (95% CI 1.04-1.10), 1.12 (1.02-1.22), 1.19 (1.01-1.41) and 1.17 (1.07-1.29) for total cancer, liver cancer (n = 3191), female breast cancer (n = 2582) and lymphoma (n=915), respectively. However, the association with lymphoma was not statistically significant after correcting for multiple testing. No significant associations were observed for colorectal cancer (n = 3350, 1.08 [1.00-1.17]) or other site-specific cancers.

CONCLUSION

Among Chinese adults who had relatively lower dairy consumption than Western populations, higher dairy intake was associated with higher risks of liver cancer, female breast cancer and, possibly, lymphoma.

Plasma Industrial and Ruminant Trans Fatty Acids and Incident Type 2 Diabetes in the EPIC-Potsdam Cohort

OBJECTIVE

Although dietary intake of trans fatty acid (TFA) is a major public health concern because of the associated increase in the risk of cardiovascular events, it remains unclear whether TFAs also influence risk of type 2 diabetes (T2D) and whether industrial TFAs (iTFAs) and ruminant TFAs (rTFAs) exert the same effect on health.

RESEARCH DESIGN AND METHODS

To investigate the relationship of 7 rTFAs and iTFAs, including 2 conjugated linoleic acids (CLAs), plasma phospholipid TFAs were measured in a case-cohort study nested within the European Prospective Investigation Into Cancer and Nutrition-Potsdam cohort. The analytical sample was a random subsample (n = 1,248) and incident cases of T2D (n = 801) over a median follow-up of 6.5 years. Using multivariable Cox regression models, we examined associations of TFAs with incident T2D.

RESULTS

The TFA subtypes were intercorrelated with each other, with other fatty acids, and with different food sources. After controlling for other TFAs, the iTFAs (18:1n-6t, 18:1n-9t, 18:2n-6,9t) were not associated with diabetes risk. Some rTFA subtypes were inversely associated with diabetes risk: vaccenic acid (18:1n-7t; hazard ratio [HR] per SD 0.72; 95% CI 0.58-0.89) and t10c12-CLA (HR per SD 0.81; 95% CI 0.70-0.94), whereas c9t11-CLA was positively associated (HR per SD 1.39; 95% CI 1.19-1.62). Trans-palmitoleic acid (16:1n-7t) was not associated with diabetes risk when adjusting for the other TFAs (HR per SD 1.08; 95% CI 0.88-1.31).

CONCLUSIONS

The TFAs' conformation plays an essential role in their relationship to diabetes risk. rTFA subtypes may have opposing relationships to diabetes risk. Previous observations for reduced diabetes risk with higher levels of circulating trans-palmitoleic acid are likely due to confounding.

Healthy dietary patterns and metabolic dysfunction-associated fatty liver disease in less-developed ethnic minority regions: a large cross-sectional study

BACKGROUND

Little is known about the associations between healthy dietary patterns and metabolic dysfunction-associated fatty liver disease (MAFLD) in less-developed ethnic minority regions (LEMRs), where the prevalence of MAFLD is increasing rapidly and dietary habits are quite different from those in developed countries. Moreover, a significant subset of MAFLD individuals in LEMRs are nonobese, but the efficacy of dietary patterns on MAFLD individuals with different obese statuses is also unclear. We aimed to test the associations of two wildly recommended a priori dietary patterns-Alternate Mediterranean diet (AMED) and Dietary Approaches to Stop Hypertension (DASH)-with the risk of MAFLD in the total population, and further in nonobese and obese individuals.

METHODS

We recruited 99,556 participants in the China Multi-Ethnic Cohort Study, an ongoing cohort study in less-developed southwest China. Using validated food frequency questionnaire, each participant was assigned an AMED score and a DASH score. MAFLD was ascertained as hepatic steatosis on ultrasound together with diabetes, overweight/obesity, or two other metabolic risk factors. We performed logistic regression with inverse probability of exposure weighting (IPEW) to examine associations between two dietary patterns and MAFLD, adjusting for potential confounders under the guidance of directed acyclic graphs. Further, analyses were stratified by body mass index.

RESULTS

We included 66,526 participants (age 49.5±11.0; 62.6% women), and the prevalence of MAFLD was 16.1%. Participants in the highest quintile of DASH score showed strong inverse associations with risks of MAFLD (OR = 0.85; 95% CI, 0.80-0.91; Ptrend < 0.001) compared with participants in the lowest quintile. The association between DASH and nonobese MAFLD (OR = 0.69; 95% CI, 0.61-0.78; Ptrend < 0.001) was stronger (I2 = 78.5 % ; Pheterogeneity = 0.001) than that with obese MAFLD (OR = 0.90; 95% CI, 0.83-0.98; Ptrend = 0.002). There was a null association between AMED and MAFLD risk.

CONCLUSIONS

In LEMRs, a DASH diet but not AMED was associated with MAFLD. The relationship appeared to be more pronounced in nonobese MAFLD individuals than in obese MAFLD individuals.

Dose-response relationships between dairy intake and non-communicable chronic diseases: an NHANES-based cross-sectional study

The purpose of this study was to explore the possible association between dairy and NCDs and identify possible dairy types that could lower the odds of NCDs. Data were from the 2003-2016 NHANES, a cross-sectional study with 20,297 adults. Multivariable logistic regression analyses and restricted cubic spline (RCS) models were conducted. In the highest intake group (>250 g/d, 1 daily serving), yogurt and milk were inversely associated with the odds of general obesity and central obesity [OR (95% CI), general obesity, 0.74 (0.60-0.91) and 0.75 (0.68-0.83); central obesity, 0.70 (0.56-0.87), and 0.77 (0.70-0.86), respectively, p < 0.05]. Higher milk intake is inversely associated with diabetes, and higher cream intake is associated with a lower likelihood of hyperlipidaemia. The intake of yogurt, milk, cheese, and butter was 0-308 g/d (0-1.2 daily servings), 0-887 g/d (0-3.5 daily servings), <75 g/d (1.7 daily servings), and <15 g/d (0.5 daily servings), respectively.

Nutritional Metabolomics and the Classification of Dietary Biomarker Candidates: A Critical Review

Recent advances in metabolomics allow for more objective assessment of contemporary food exposures, which have been proposed as an alternative or complement to self-reporting of food intake. However, the quality of evidence supporting the utility of dietary biomarkers as valid measures of habitual intake of foods or complex dietary patterns in diverse populations has not been systematically evaluated. We reviewed nutritional metabolomics studies reporting metabolites associated with specific foods or food groups; evaluated the interstudy repeatability of dietary biomarker candidates; and reported study design, metabolomic approach, analytical technique(s), and type of biofluid analyzed. A comprehensive literature search of 5 databases (PubMed, EMBASE, Web of Science, BIOSIS, and CINAHL) was conducted from inception through December 2020. This review included 244 studies, 169 (69%) of which were interventional studies (9 of these were replicated in free-living participants) and 151 (62%) of which measured the metabolomic profile of serum and/or plasma. Food-based metabolites identified in ≥1 study and/or biofluid were associated with 11 food-specific categories or dietary patterns: 1) fruits; 2) vegetables; 3) high-fiber foods (grain-rich); 4) meats; 5) seafood; 6) pulses, legumes, and nuts; 7) alcohol; 8) caffeinated beverages, teas, and cocoas; 9) dairy and soya; 10) sweet and sugary foods; and 11) complex dietary patterns and other foods. We conclude that 69 metabolites represent good candidate biomarkers of food intake. Quantitative measurement of these metabolites will advance our understanding of the relation between diet and chronic disease risk and support evidence-based dietary guidelines for global health.

Quantity and variety of food groups consumption and the risk of diabetes in adults: A prospective cohort study

BACKGROUND

Evidence remains inconsistent regarding the association between quantity of food groups and diabetes, and remains scarce regarding the relation of dietary diversity with diabetes.

OBJECTIVE

We aimed to evaluate the prospective relation of variety and quantity of 12 major food groups with new-onset diabetes.

METHODS

A total of 16,117 participants who were free of diabetes at baseline from China Health and Nutrition Survey were included. Dietary intake and variety score were measured by three consecutive 24-h dietary recalls combined with a household food inventory in each survey round. The study outcome was new-onset diabetes, defined as self-reported physician-diagnosed diabetes during the follow-up period. Cox proportional hazards models and restricted cubic spline analysis were used to estimate hazard ratios (HR) and dose-response relation, respectively.

RESULTS

During a median follow-up duration of 9.0 years, a total of 1088 (6.7%) participants developed new-onset diabetes. Overall, there was a significant inverse association between dietary variety score and the risk of new-onset diabetes (per one point increment; HR, 0.85; 95% CI, 0.80-0.90). In addition, there were U-shaped associations of refined grains, whole grains, nuts, red meat, poultry, processed meat, dairy products, and aquatic products intake with diabetes, and L-shaped associations of legumes, vegetables, fruits, and eggs intake with diabetes (all P values for nonlinearity <0.001).

CONCLUSION

Our results suggested that greater variety of food groups consumption was associated with significantly lower risk of new-onset diabetes. Furthermore, when the quantity of food groups intakes was relatively low, there was a negative correlation between the quantity of each different food group consumption and diabetes risk; however, when intake exceeded certain thresholds, the risks of new-onset diabetes increased or reached a plateau.

The relationship between dairy products intake and breast cancer incidence: a meta-analysis of observational studies

BACKGROUND

The effect of dairy products intake on breast cancer (BC) is highly controversial. This study aims to investigate the relationship between dairy intake and BC incidence.

METHODS

A search was carried out in PubMed, EBSCO, Web of Science, and Cochrane Library databases before January 2021. The primary objective was the risk of BC and intake of dairy products were exposure variables.

RESULTS

The meta-analysis comprised 36 articles with 1,019,232 participants. Total dairy products have a protective effect on female population (hazard ratio (HR) =0.95, 95% confidence interval (CI) =0.91-0.99, p = 0.019), especially for estrogen receptor-positive (ER+) (HR = 0.79, p = 0.002) and progesterone receptor-positive (PR+) BC (HR = 0.75, p = 0.027). For ER+/PR+ BC, there is a trend of protection, but it has not reached statistical significance (HR = 0.92, p = 0.075). Fermented dairy products can reduce BC risk in postmenopausal population (HR = 0.96, 95%CI = 0.93-0.99, p = 0.021), but have no protective effect on premenopausal population (HR = 0.98, 95%CI = 0.94-1.03, p = 0.52). Non-fermented dairy products have no significant effect on BC occurrence (p > 0.05). High-fat dairy products are harmful to women, without statistical difference (HR = 1.06, 95%CI = 1.00-1.13, p = 0.066). On the contrary, low-fat dairy products can protect the premenopausal population (HR = 0.94, 95%CI = 0.89-1.00, p = 0.048).

CONCLUSION

The intake of dairy products can overall reduce BC risk in the female population, but different dairy products have varying effects on different BC subtypes and menopausal status.

Dietary patterns and cardiometabolic risks in diverse less-developed ethnic minority regions: results from the China Multi-Ethnic Cohort (CMEC) Study

Background In Western developed countries, food-based dietary patterns have been associated with the risk of cardiometabolic diseases, but little is known about such associations in less developed ethnic minority regions (LEMRs), where the cardiometabolic disease burden is growing rapidly and food patterns differ substantially.

Methods Between May 2018 and September 2019, we recruited 99556 participants aged 30-79 years from the China Multi-Ethnic Cohort (CMEC) Study. We measured habitual dietary intake with validated food frequency questionnaire (FFQ) and then calculated dietary pattern scores for two of the most studied a priori dietary patterns, i.e., Dietary Approaches to Stop Hypertension (DASH) and alternative Mediterranean (aMED) style diets, and three a posteriori dietary patterns. Four cardiometabolic risks, including hypertension, diabetes, dyslipidaemia and metabolic syndrome (MetS), were newly diagnosed by medical examination and blood tests. We estimated adjusted odds ratios (OR) relating various dietary pattern scores to cardiometabolic risks using marginal structural models under the guidance of directed acyclic graphs. For the above associations, we further calculated the proportion mediated by overweight (PM) using regression-based mediation analysis for better public health implications.

Findings The final study sample consisted of 68834 participants. Among them, we newly diagnosed 12803 hypertension, 3527 diabetes, 16342 hyperlipidaemia, and 8198 MetS cases. Overall, all 5 dietary patterns showed considerable associations with risks of hypertension and MetS. Comparing the highest with the lowest quintiles, the DASH score showed the strongest inverse associations with risks of hypertension (OR=0.74, 95% CI:0.70-0.79; PM=10%) and MetS (OR=0.79, 95% CI:0.74-0.85; PM=35%); conversely, scores of the localized a posteriori Yunnan-Guizhou plateau dietary pattern in LEMRs showed the strongest positive associations with risks of hypertension (OR=1.44, 95% CI:1.35-1.52; PM=10%) and MetS (OR=1.35, 95% CI:1.26-1.46; PM=33%), with all P values for trend <0.001. These associations were consistent in various subgroups defined by sex, age, smoking and physical activity, but with magnitudes that differed substantially across different ethnic regions and urbanicity. By investigating the single-component effects of dietary patterns, the dairy intake component contributed a major proportion to the beneficial effects of DASH (41.9% for hypertension and 100.5% for MetS).

Interpretation Substantial socioeconomic status and ethnic disparities in diet quality and related cardiometabolic risks were seen in LEMRs, with hypertension being the top diet-related cardiometabolic risk. Our findings support that DASH provides superior dietary guidance compared to aMED for reducing cardiometabolic risks in LEMRs. In particular, the dairy intake encouraged by DASH may produce considerable beneficial effects.

Funding This study was funded by the National Key R&D Program of China; full funding sources listed in the acknowledgements.

Circulating Glycerolipids, Fatty Liver Index, and Incidence of Type 2 Diabetes: A Prospective Study Among Chinese

CONTEXT

Few lipidomic studies have specifically investigated the association of circulating glycerolipids and type 2 diabetes (T2D) risk, especially among Asian populations. It remains unknown whether or to what degree fatty liver could explain the associations between glycerolipids and T2D.

OBJECTIVE

We aimed to assess associations between plasma glycerolipids and incident T2D and to explore a potential role of liver fat accumulation in the associations.

METHODS

This was a prospective cohort study with 6 years of follow-up. The study population included 1781 Chinese participants aged 50 to 70 years. The main outcome measure was incident T2D.

RESULTS

At the 6-year resurvey, 463 participants had developed T2D. At the false discovery rate (FDR) of 5%, 43 of 104 glycerolipids were significantly associated with incident T2D risk after multivariate adjustment for conventional risk factors. After further controlling for glycated hemoglobin (HbA1c), 9 of the 43 glycerolipids remained significant, including 2 diacylglycerols (DAGs) (16:1/20:4, 18:2/20:5) and 7 triacylglycerols (TAGs) (46:1, 48:0, 48:1, 50:0, 50:1, 50:2, and 52:2), with relative risks (RRs) (95% CIs) ranging from 1.16 (1.05-1.27) to 1.23 (1.11-1.36) per SD increment of glycerolipids. However, additional adjustment for fatty liver index largely attenuated these findings (RR [95% CI] 0.88 [0.81 to 0.95] to 1.10 [1.01 to 1.21]). Mediation analyses suggested that the fatty liver index explained 12% to 28% of the glycerolipids-T2D associations (all P < 0.01).

CONCLUSION

Higher plasma levels of DAGs and TAGs were associated with increased incident T2D risk in this Chinese population, which might be partially explained by liver fat accumulation.

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 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.

The Sum of Plasma Fatty Acids iso16:0, iso17:0, trans11-18:1, cis9, trans11-CLA, and cis6-18:1 as Biomarker of Dairy Intake Established in an Intervention Study and Validated in the EPIC Cohort of Gipuzkoa

The questioned reliability of 15:0, 17:0, and trans9-16:1 acids as biomarkers of dairy fat intake also questions the relationship between the intake of these products and their health effects. Two studies were conducted in the same geographical region. In an intervention study, volunteers followed a diet rich in dairy products followed by a diet without dairy products. Plasma and erythrocyte fatty acids (FA) were analyzed, and their correlations with dairy product intakes were tested. The FA biomarkers selected were validated in the Gipuzkoa cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) observational study. The correlation coefficients between plasma concentrations of iso16:0, iso17:0, trans11-18:1, cis9, trans11-18:2, and cis6-18:1 and the dairy fat ingested are similar in both studies, indicating that their concentration increases by 0.8 µmol/L per gram of dairy fat ingested. The biomarkers are positively related to plasma triglycerides (r = 0.324 and 0.204 in the intervention and observational studies, respectively) and total cholesterol (r = 0.459 and 0.382), but no correlation was found between the biomarkers and atherogenicity indexes. In conclusion, the sum of the plasma concentration of the selected FAs can be used as biomarkers of dairy product consumption. A linear relationship exists between their plasma concentrations and ruminant product intake. These biomarkers allow for obtaining consistent relationships between dairy intake and plasma biochemical parameters.

Evidence for a causal association between milk intake and cardiometabolic disease outcomes using a two-sample Mendelian Randomization analysis in up to 1,904,220 individuals

BACKGROUND

High milk intake has been associated with cardio-metabolic risk. We conducted a Mendelian Randomization (MR) study to obtain evidence for the causal relationship between milk consumption and cardio-metabolic traits using the lactase persistence (LCT-13910 C > T, rs4988235) variant as an instrumental variable.

METHODS

We tested the association of LCT genotype with milk consumption (for validation) and with cardio-metabolic traits (for a possible causal association) in a meta-analysis of the data from three large-scale population-based studies (1958 British Birth Cohort, Health and Retirement study, and UK Biobank) with up to 417,236 participants and using summary statistics from consortia meta-analyses on intermediate traits (N = 123,665-697,307) and extended to cover disease endpoints (N = 86,995-149,821).

RESULTS

In the UK Biobank, carriers of 'T' allele of LCT variant were more likely to consume milk (P = 7.02 × 10^-14). In meta-analysis including UK Biobank, the 1958BC, the HRS, and consortia-based studies, under an additive model, 'T' allele was associated with higher body mass index (BMI) (P_{meta-analysis} = 4.68 × 10^-12) and lower total cholesterol (TC) (P = 2.40 × 10^-36), low-density lipoprotein cholesterol (LDL-C) (P = 2.08 × 10^-26) and high-density lipoprotein cholesterol (HDL-C) (P = 9.40 × 10^-13). In consortia meta-analyses, 'T' allele was associated with a lower risk of coronary artery disease (OR:0.86, 95% CI:0.75-0.99) but not with type 2 diabetes (OR:1.06, 95% CI:0.97-1.16). Furthermore, the two-sample MR analysis showed a causal association between genetically instrumented milk intake and higher BMI (P = 3.60 × 10^-5) and body fat (total body fat, leg fat, arm fat and trunk fat; P < 1.37 × 10^-6) and lower LDL-C (P = 3.60 × 10^-6), TC (P = 1.90 × 10^-6) and HDL-C (P = 3.00 × 10^-5).

CONCLUSIONS

Our large-scale MR study provides genetic evidence for the association of milk consumption with higher BMI but lower serum cholesterol levels. These data suggest no need to limit milk intakes with respect to cardiovascular disease risk, with the suggested benefits requiring confirmation in further studies.

Consumption of Dairy Products in Relation to Type 2 Diabetes Mellitus in Chinese People: The Henan Rural Cohort Study and an Updated Meta-Analysis

Recent studies on whether dairy consumption is associated with type 2 diabetes mellitus (T2DM) have yielded inconsistent results, so we explored the relationship between dairy consumption and T2DM through a large-sample, cross-sectional study and a meta-analysis. In the meta-analysis, summary relative risks (RRs) of 23 articles were compiled with a random effects model, and a restricted cubic spline regression model was used to explore whether there is a nonlinear relationship between dairy intake and T2DM risk. This cross-sectional study used baseline data from 38,735 participants of the Henan Rural Cohort study and the association between dairy consumption and T2DM was analyzed by a logistic regression model. The meta-analysis revealed a borderline negative significant association between total dairy intake and risk of T2DM, the RR and 95% confidence interval (CI) was 0.94; (0.89, 1.00), and the risk was lowest at 270 g daily dairy intake. In the cross-sectional study, there were 3654 T2DM patients and 68.3 percent of the respondents had no dairy intake. The average intake of dairy in the total population was 12 g per day. Fully adjusted analyses suggested positive associations, with an odds ratio (OR) comparing the highest with the zero intake of 1.34 (95% CI: 1.22, 1.48) for all participants, which was unaffected by sex. Dairy intake in rural areas of Henan province is low, and we found, in the context of overall low dairy intake, that a high intake was positively associated with T2DM, which is inconsistent with the meta-analysis results suggesting that dairy has marginal protective effects against T2DM.

Adaptation and validity assessment of a diet quality index for patients with type 2 diabetes

PURPOSE

As diet quality indices (DQI) are likely to be influenced by disease background, adapting the existing indices for each disease is crucial. No study has been adapted a DQI for patients with type 2 diabetes. We aimed to adapt healthy eating index and assess its validity for Iranian patients with type 2 diabetes mellitus (T2DM).

METHODS

In this cross-sectional study, the analysis was conducted on 489 adults with T2DM. We adapted HEI and assessed its validity using construct validity. Construct validity was assessed using a 168-item semi-quantitative food-frequency questionnaire (FFQ). General linear model was used to assess associations between adapted HEI scores and demographic characteristics, anthropometric indices, physical activity and food and nutrient intakes.

RESULTS

Adapted HEI were examined on 489 subjects (163 men and 326 women). Findings showed that in older subjects the mean adapted HEI score was greater than the younger ones. However, it was significant only in women (p = 0.01). Women with higher education level obtained the greater score (p < 0.001). The greatest mean score of the adapted HEI score in men was related to non-smokers. The mean score in both genders were raised following the increase in physical activity level (p < 0.05). Moreover, a reduction in the mean score of adapted HEI was observed in men with higher BMI compared to those with the lower one (p = 0.001).

CONCLUSION

Adapted HEI could successfully discriminate diet quality in patients with T2DM. Older and high-educated women were adhered greatly to high quality diets. The adapted DQI linked with greater physical activity level and non-smokers diabetic men with lower BMI.

Fatty acids and cardiometabolic health: a review of studies in Chinese populations

Rapid nutrition transition from plant-based traditional diet to westernized diet has led to dramatically heightening burdens of cardiometabolic diseases in China in past decades. Recently, national surveys reported that poor dietary quality including low marine n-3 fatty acids and high intakes of red meat and processed meat was associated with considerably elevated cardiometabolic deaths. Previous studies mainly from Western population-based cohorts have indicated that not only fat quantity but also quality linked with different cardiometabolic outcomes. Compared with Western peoples, Asian peoples, including Chinese, are known to have different dietary patterns and lifestyle, as well as genetic heterogeneities, which may modify fatty acid metabolism and disease susceptibility in certain degree. To date, there were limited prospective studies investigating the relationships between fatty acids and cardiometabolic disease outcomes in Chinese, and most existing studies were cross-sectional nature and within one or two region(s). Notably, shifting dietary patterns could change not only amount, types, and ratio of fatty acids accounting for overall energy intake, but also their food sources and ratio to other macronutrients. Moreover, large geographic and urban-rural variations in prevalence of cardiometabolic diseases among Chinese may also reflect the effects of socioeconomic development and local diets on health status. Therefore, current review will summarize available literatures with more focus on the Chinese-based studies which may extend current knowledge about the roles of fatty acids in pathogenesis of cardiometabolic diseases for Asian populations and also provide useful information for trans-ethnic comparisons with other populations.

Fatty acids as biomarkers of total dairy and dairy fat intakes: a systematic review and meta-analysis

Context

Dairy intake in humans is commonly assessed using questionnaires, but the data collected are often biased. As a result, there is increasing interest in biomarkers of dairy fat. To date, there has been no overview of the fatty acids suitable for use as biomarkers of dairy fat intake.

Objective

This systematic review and meta-analysis of observational studies was performed to identify circulating fatty acids as biomarkers of total dairy and dairy fat intakes in the general population.

Data Sources

MEDLINE, Embase, and Web of Knowledge databases were searched for eligible studies published until June 2017.

Study Selection

Articles were included when a correlation between circulating dairy fatty acids and intakes of total dairy and dairy fat was found, as measured by dietary assessment tools.

Data Extraction

Two authors extracted data independently and assessed the risk of bias. An adapted form of the Newcastle-Ottawa Scale was used for quality assessment.

Results

Data were pooled using the random-effects model. Meta-analysis revealed that the fatty acids in plasma/serum were significantly correlated with intakes of total dairy (C14:0 [r = 0.15; 95%CI, 0.11 - 0.18], C15:0 [r = 0.20; 95%CI, 0.13 - 0.27], and C17:0 [r = 0.10; 95%CI, 0.03 - 0.16] and dairy fat (C14:0 [r = 0.16; 95%CI, 0.10 - 0.22], C15:0 [r = 0.33; 95%CI, 0.27 - 0.39], C17:0 [r = 0.19; 95%CI, 0.14 - 0.25], and trans-C16:1n-7 [r = 0.21; 95%CI, 0.14 - 0.29).

Conclusions

C14:0, C15:0, C17:0, and trans-C16:1n-7 were identified as biomarkers of total dairy and dairy fat intakes in the general population. In light of the suboptimal measurement techniques used in some studies, correlations with trans-C18:1n-7 and conjugated linoleic acid require further investigation.

The association between milk consumption and the metabolic syndrome: a cross-sectional study of the residents of Suzhou, China and a meta-analysis

The association between milk consumption and the metabolic syndrome remains inconclusive, and data from Chinese populations are scarce. We conducted a cross-sectional study to investigate the association between milk consumption and the metabolic syndrome and its components among the residents of Suzhou Industrial Park, Suzhou, China. A total of 5149 participants were included in the final analysis. A logistic regression model was applied to estimate the OR and 95 % CI for the prevalence of the metabolic syndrome and its components according to milk consumption. In addition, the results of our study were further meta-analysed with other published observational studies to quantify the association between the highest v. lowest categories of milk consumption and the metabolic syndrome and its components. There was no significant difference in the odds of having the metabolic syndrome between milk consumers and non-milk consumers (OR 0·86, 95 % CI 0·73, 1·01). However, milk consumers had lower odds of having elevated waist circumference (OR 0·78, 95 % CI 0·67, 0·92), elevated TAG (OR 0·83, 95 % CI 0·70, 0·99) and elevated blood pressure (OR 0·85, 95 % CI 0·73, 0·99). When the results were pooled together with other published studies, higher milk consumption was inversely associated with the risk of the metabolic syndrome (relative risk 0·80, 95 % CI 0·72, 0·88) and its components (except elevated fasting blood glucose); however, these results should be treated with caution as high heterogeneity was observed. In summary, the currently available evidence from observational studies suggests that higher milk consumption may be inversely associated with the metabolic syndrome.

Dietary Protein Consumption and the Risk of Type 2 Diabetes: ADose-Response Meta-Analysis of Prospective Studies

The relationship between dietary protein consumption and the risk of type 2 diabetes (T2D) has been inconsistent. The aim of this meta-analysis was to explore the relations between dietary protein consumption and the risk of T2D. We conducted systematic retrieval of prospective studies in PubMed, Embase, and Web of Science. Summary relative risks were compiled with a fixed effects model or a random effects model, and a restricted cubic spline regression model and generalized least squares analysis were used to evaluate the diet–T2D incidence relationship. T2D risk increased with increasing consumption of total protein and animal protein, red meat, processed meat, milk, and eggs, respectively, while plant protein and yogurt had an inverse relationship. A non-linear association with the risk for T2D was found for the consumption of plant protein, processed meat, milk, yogurt, and soy. This meta-analysis suggests that substitution of plant protein and yogurt for animal protein, especially red meat and processed meat, can reduce the risk for T2D.

Dose-response relationships between dairy intake and chronic metabolic diseases in a Chinese population

BACKGROUND

This study investigated associations between dairy intake and chronic metabolic diseases (CMDs), and evaluated possible dose-response relationships in Chinese.

METHODS

This cross-sectional study included 6073 adults aged ≥18 years from China. General characteristics were gathered using a validated dietary questionnaire. Multivariable logistic regression analyses investigated associations between dairy intake and chronic metabolic diseases (CMDs) (overweight/obesity, obesity, central obesity, and hyperlipidemia). Restricted cubic spline models explored dose-response relationships between dairy intake and CMDs, and possible dairy intake in the prevention of CMDs. Structural equation modeling explored the potential mechanisms of the effects of dairy intake on CMDs.

RESULTS

Significant inverse associations were found between dairy intake and overweight/obesity, obesity, central obesity, and hyperlipidemia, with odds ratios (ORs) of 0.66 (95% confidence interval [CI] 0.56-0.79), 0.63 (95% CI 0.47-0.85), 0.71 (95% CI 0.60-0.85), and 0.81 (95% CI 0.56-1.17), respectively (P < 0.05 for all). The intake of yogurt, milk, and total dairy to prevent CMDs differed according to age group (16-74, 29-187, and 159-269 mL/d, respectively, in the entire group; 69-110, 59-152, and 138-167 mL/d, respectively, in the young group, ≤ 44 years; 9-58, 57-149, and 117-145 mL/d, respectively, in the middle-aged group, 45-59 years; and 23-59 mL/d yogurt only in the old group, ≥ 60 years). Structural equation modeling showed that dairy intake could reduce body mass index and waist circumference by regulating carbohydrate, fat, protein, and total energy.

CONCLUSIONS

Dairy intake was inversely associated with the prevalence of overweight, obesity, central obesity, and hyperlipidemia, and the optimal range of dairy intake differed with age. The beneficial effects of dairy intake in preventing CMDs could involve regulation of carbohydrate, fat, protein, and total energy.

The Association of Maternal Protein Intake during Pregnancy in Humans with Maternal and Offspring Insulin Sensitivity Measures

The purpose of this review is to critically evaluate the studies assessing the relations between protein intake during human pregnancy and insulin sensitivity measures in the mother and offspring, and to get a better understanding of the knowledge gaps that still exist. Overall, there is insufficient evidence to conclude about implications of higher amounts of protein intake during pregnancy on maternal or offspring insulin sensitivity. However, studies show a relation between protein quality and insulin sensitivity, such that animal protein may be associated with negative outcomes and plant protein may be associated with positive insulin sensitivity outcomes. There is an urgent need for standardized studies using comparable terminology to evaluate any potential relations between insulin sensitivity in mothers and offspring and truly low and high maternal protein intake while maintaining eucaloric balance to better inform about optimal protein dosage and quality during this period.

Association between dairy intake and the risk of contracting type 2 diabetes and cardiovascular diseases: a systematic review and meta-analysis with subgroup analysis of men versus women

CONTEXT

The association between dairy product intake and the risk of developing type 2 diabetes (T2D) or cardiovascular disease (CVD) has been investigated in several studies, but little attention was given to the role of sex as a moderator of these associations. (In this article, the term "sex" is used to denote the biologically-based differences between males and females.).

OBJECTIVE

This meta-analysis examines whether dairy consumption has different effects on T2D and CVD in men and women.

DATA SOURCES

The PubMed database and previous reviews were searched for cohort studies published between 2006 and 2016.

DATA EXTRACTION AND ANALYSIS

Reported risk ratios (RRs) for T2D/CVD with high versus low dairy intake were extracted. A random-effects model has been used to calculate the pooled RR. A subgroup analysis was conducted to compare the results for men and women.

RESULTS

The present meta-analysis of 201 studies found that T2D (n = 16 studies) and CVD (n = 13 studies) are inversely associated with dairy intake. Subgroup analysis for sex showed that the association between dairy intake and T2D and between dairy intake and CVD are significant in women (RR for T2D = 0.868; 95%CI, 0.82-0.92; P < 0.001; RR for CVD = 0.837; 95%CI, 0.75-0.93; P < 0.001) but not in men.

CONCLUSIONS

There is an inverse association between high dairy intake and the risk of developing T2D and CVD in women.

Dairy foods and positive impact on the consumer's health

The objective of the present chapter was to demonstrate the state of the art in the recent advances in nutritional and functional components of dairy products research. In this chapter, the main mechanisms responsible and essential for a better understanding of nutritional and functional values of the components of milk and dairy products are highlighted. It also includes a discussion about the positive impacts of fermented milk, cheese, butter, ice cream, and dairy desserts components on the consumer's health.

Linking of metabolomic biomarkers with cardiometabolic health in Chinese population

Due to rapid nutrition transitions, the prevalence of cardiometabolic diseases, such as metabolic syndrome, type 2 diabetes, and cardiovascular diseases, has been increasing at an alarming rate in the Chinese population. Moreover, Asians, including Chinese, have been hypothesized to have a higher susceptibility to cardiometabolic diseases than Caucasians. Early prediction and prevention are key to controlling this epidemic trend; to this end, the identification of novel biomarkers is critical to reflect environmental exposure, as well as to reveal endogenous metabolic and pathophysiologic mechanisms. The emerging "omics" technologies, especially metabolomics, offer a unique opportunity to provide novel signatures or fingerprints to understand the effects of genetic and non-genetic factors on cardiometabolic health. During the past two decades, metabolomic approaches have been increasingly used in various epidemiological studies, primarily in Western populations. Although the field is still in its early stages, some studies have tried to identify novel compounds or confirm their metabolites and associations with cardiometabolic diseases in Chinese populations, including amino acids, fatty acids, acylcarnitines and other metabolites. Despite major efforts to discover novel biomarkers for disease prediction or intervention, the limits in current study design, analytical platforms, and data processing approaches are challenges in metabolomic research worldwide. Therefore, future research with more advanced technologies, rigorous study designs, standardized detection and analytic approaches, and integrated data from multiomics approaches are essential to evaluate the feasibility of using metabolomics in clinical settings. Finally, the functional roles and underlying biological mechanisms of metabolomic biomarkers should be elucidated by future mechanistic research.

Circulating fatty acids as biomarkers of dairy fat intake: data from the lifelines biobank and cohort study

Background: C14:0, C15:0, C17:0 and trans-C16:1(n-7) are often used as biomarkers for dairy fat intake. Trans-C18:1(n-7) and CLA, two fatty acids which are also present in dairy, have hardly been explored. We investigated whether trans-C18:1(n-7) and CLA can enrich the existing biomarker portfolio. Methods: Data were obtained from Lifelines (n = 769). Dairy fat intake was determined by FFQ. Fatty acids were measured in fasting plasma triglycerides (TG), phospholipids (PL) and cholesterol esters (CE). Results: Median (25th-75th percentile) intakes of dairy and dairy fat were 322(209-447) and 12.3(8.4-17.4) g/d respectively. A pilot study showed that trans-C18:1(n-7) and CLA were only detectable in TG and PL. Of the established markers, TG C15:0 was most strongly associated with dairy fat intake (standardized β (std.β) = 0.286, R² = 0.111). Of the less established markers, TG trans-C18:1(n-7) was most strongly associated with dairy fat intake (Std.β = 0.292, R² = 0.115), followed by PL CLA (Std.β = 0.272, R² = 0.103) and PL trans-C18:1(n-7) (Std.β = 0.269, R² = 0.099). In TG, a combination of C15:0 and trans-C18:1(n-7) performed best (R² = 0.128). In PL, a combination of C14:0, C15:0, trans-C18:1(n-7) and CLA performed best (R² = 0.143). Conclusion: Trans-C18:1(n-7) and CLA can be used as biomarkers of dairy fat intake. Additionally, combining established with less established markers allowed even stronger predictions for dairy fat intake.

Dairy product consumption is associated with pre-diabetes and newly diagnosed type 2 diabetes in the Lifelines Cohort Study

Previous studies show associations between dairy product consumption and type 2 diabetes, but only a few studies conducted detailed analyses for a variety of dairy subgroups. Therefore, we examined cross-sectional associations of a broad variety of dairy subgroups with pre-diabetes and newly diagnosed type 2 diabetes (ND-T2DM) among Dutch adults. In total, 112 086 adults without diabetes completed a semi-quantitative FFQ and donated blood. Pre-diabetes was defined as fasting plasma glucose (FPG) between 5·6 and 6·9 mmol/l or HbA1c% of 5·7-6·4 %. ND-T2DM was defined as FPG ≥7·0 mmol/l or HbA1c ≥6·5 %. Logistic regression analyses were conducted by 100 g or serving increase and dairy tertiles (T1ref), while adjusting for demographic, lifestyle and dietary covariates. Median dairy product intake was 324 (interquartile range 227) g/d; 25 549 (23 %) participants had pre-diabetes; and 1305 (1 %) had ND-T2DM. After full adjustment, inverse associations were observed of skimmed dairy (OR100 g 0·98; 95 % CI 0·97, 1·00), fermented dairy (OR100 g 0·98; 95 % CI 0·97, 0·99) and buttermilk (OR150 g 0·97; 95 % CI 0·94, 1·00) with pre-diabetes. Positive associations were observed for full-fat dairy (OR100 g 1·003; 95 % CI 1·01, 1·06), non-fermented dairy products (OR100 g 1·01; 95 % CI 1·00, 1·02) and custard (ORserving/150 g 1·13; 95 % CI 1·03, 1·24) with pre-diabetes. Moreover, full-fat dairy products (ORT3 1·16; 95 % CI 0·99, 1·35), non-fermented dairy products (OR100 g 1·05; 95 % CI 1·01, 1·09) and milk (ORserving/150 g 1·08; 95 % CI 1·02, 1·15) were positively associated with ND-T2DM. In conclusion, our data showed inverse associations of skimmed and fermented dairy products with pre-diabetes. Positive associations were observed for full-fat and non-fermented dairy products with pre-diabetes and ND-T2DM.

Erythrocyte PUFAs, circulating acylcarnitines, and metabolic syndrome risk: a prospective study in Chinese

The effects of PUFAs on metabolic syndrome (MetS) remain to be characterized, particularly in Asians. We aimed to investigate the prospective associations of PUFAs with MetS and the role of acylcarnitines in these associations in Chinese individuals. Among 1,245 Chinese men and women aged 50-70 years who completed a 6 year follow-up, baseline erythrocyte FAs and plasma acylcarnitines were profiled using gas chromatography coupled with positive chemical ionization and liquid chromatography-tandem mass spectrometry, respectively. Total n-6 PUFAs and three 22-carbon n-6 PUFAs were significantly associated with lower MetS risk comparing extreme quartiles: relative risks (RRs) (95% CIs) were 0.75 (0.57, 0.97) for total n-6 PUFAs, 0.69 (0.56, 0.85) for 22:2n-6, 0.76 (0.59, 0.99) for 22:4n-6, and 0.74 (0.58, 0.94) for 22:5n-6, while 18:3n-3 and 18:3n-6 were positively associated with MetS risk. In a network analysis, a module mostly consisting of long-chain n-6 PUFAs and very-long-chain saturated FAs was inversely associated with incident MetS (RR per SD: 0.84; 95% CI: 0.76, 0.92), and this module was more strongly associated with lower MetS risk when a short- to medium-chain acylcarnitine (C5-C10) module score was lower (P _interaction = 0.03). Our data suggested inverse associations of total n-6 and certain long-chain n-6 PUFAs with cardiometabolic disorders, and this association might be modified by certain acy-l-carnitines.

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

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

Association between plasma trans-fatty acid concentrations and diabetes in a nationally representative sample of US adults

BACKGROUND

A diet high in trans-fatty acids (TFA) induces insulin resistance in rodent models and primates. However, previous epidemiological studies on the association between TFAs, based primarily on self-reported intake from the diet, and diabetes in humans have yielded conflicting results. Herein we examined the associations of objectively measured plasma TFA concentrations with diabetes in a large population-based study among US adults.

METHODS

We included 3801 participants aged ≥20 years from the National Health and Nutrition Examination Survey 1999-2000 and 2009-10. Four major TFAs, namely palmitelaidic acid (C16:1 n-7t), elaidic acid (C18:1 n-9t), vaccenic acid (C18:1 n-7t), and linolelaidic acid (C18:2 n-6t, 9t), were measured in fasting plasma using gas chromatography-mass spectrometry. Diabetes was defined by self-reported physician diagnosis, plasma fasting glucose ≥126 mg/dL, or HbA1c ≥6.5%.

RESULTS

After adjustment for other major risk factors, the odds ratios (95% confidence intervals) of diabetes comparing the highest with lowest quintile of plasma TFAs was 2.19 (1.27-3.79) for total TFAs (P_trend  = 0.01), 2.34 (1.48-3.72) for elaidic acid (P_trend  = 0.0004), 1.33 (0.82-2.15) for linolelaidic acid (P_trend  = 0.18), 1.58 (0.97-2.58) for palmitelaidic acid (P_trend  = 0.02), and 1.64 (0.95-2.84) for vaccenic acid (P_trend  = 0.08). In addition, total TFAs, elaidic acid, palmitelaidic acid, and vaccenic acid were significantly associated with fasting glucose, fasting insulin, the insulin resistance index, and HbA1c.

CONCLUSIONS

In a nationally representative population, plasma TFAs, in particular elaidic acid, were positively associated with diabetes and biomarkers of glucose metabolism.

Associations of Dairy Intake with Arterial Stiffness in Brazilian Adults: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Recent studies have suggested the possible effect of dairy product intake on cardiovascular risk markers, including arterial stiffness. Our aim was to investigate whether dairy food intake is associated with arterial stiffness, which we assessed by carotid-femoral pulse wave velocity (cfPWV) and pulse pressure (PP) in a cross-sectional analysis of baseline data (2008–2010; n = 12,892) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Dairy consumption was evaluated with a validated food-frequency questionnaire (FFQ) by computing servings per day for total and subgroups of dairy products. Dairy consumption was described in four categories (≤1 serving/day to >4 servings/day). Covariance analysis (ANCOVA) was used to compare cfPWV across increasing intake of dairy food, adjusting for confounding factors, including non-dairy food groups. The intake of total dairy was inversely associated with cfPWV and PP (−0.13 m/s and −1.3 mmHg, from the lowest and to the highest category of dairy intake). Low-fat dairy, fermented dairy and cheese showed an inverse relationship with cfPWV and PP. These findings suggest a beneficial effect of dairy consumption to reduce arterial stiffness. However, further evidence from longitudinal studies or long-term intervention is needed to support reduction of cfPWV and PP mediating the beneficial effects of dairy products on cardiovascular health.

Association between Milk Consumption and Metabolic Syndrome among Korean Adults: Results from the Health Examinees Study

It has been suggested that a greater dairy consumption, particularly of milk, may have contributed in lowering the prevalence of metabolic syndrome (MetS). A cross-sectional analysis was conducted to examine the association between milk consumption and MetS, and its components among Korean adults aged 40–69. A total of 130,420 subjects (43,682 men and 86,738 women) from the Health Examinees Study were selected for the final analysis. Milk consumption was estimated using a validated 106-item food frequency questionnaire. MetS was defined using the National Cholesterol Education Program, Adult Treatment Panel III (NCEP III). Logistic regression analyses were performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) between milk consumption and MetS after adjusting for potential confounders. In this study, the average milk consumption was 77.9 g/day, with the overall prevalence of MetS being 26.1% (29.1% in men and 24.6% in women). We found that the prevalence of the MetS was significantly lower in subjects with higher milk consumption (p < 0.0001). Adjusted OR for MetS was significantly lower in the highest milk consumption category (≥1 serving/day among men; ≥2 serving/day among women) than those in the lowest milk consumption category (OR: 0.92 95%CI: 0.86–0.99, p trend = 0.0160 in men; OR: 0.68, 95%CI: 0.60–0.76, p trend < 0.0001 in women). Overall, higher milk consumption was inversely associated with the MetS components: elevated waist circumference, elevated triglyceride, and reduced high-density lipoprotein cholesterol (HDL-C) (all p trend < 0.05). This study concludes that higher milk consumption is associated with the lower odds of MetS in Korean adults.

The Consumption of Dairy Products Is Associated with Reduced Risks of Obesity and Metabolic Syndrome in Korean Women but not in Men

We aimed to investigate the association between dairy product consumption and the risk of obesity and metabolic syndrome (MetS) in Korean adults. Data from 13,692 Korean adults aged ≥19 years from the KNHANES 2010–2013 were used. The study participants were divided into three groups according to the serving size of dairy products they consumed based on a single 24-h recall. About 58% of the Korean adults did not consume any dairy products in one day. In both the sexes, only those who adhered to the recommendation for dairy products (≥1 serving/day) achieved the daily requirement of calcium. Women who consumed ≥1 serving/day of dairy products had lower risks of obesity (body mass index ≥ 25 kg/m²) (adjusted odds ratio (AOR), 0.77; 95% confidence interval (CI), 0.66–0.89; p for trend < 0.01) and MetS (AOR, 0.67; 95% CI, 0.56–0.80; p for trend < 0.01) than women who did not consume dairy products. However, these significant associations were not observed in men. In conclusion, consuming ≥ 1 serving/day of dairy products could be an easy and efficient strategy for meeting daily calcium requirement as well as lowering risks of obesity and MetS among Korean women.

Higher Maternal Dietary Protein Intake Is Associated with a Higher Risk of Gestational Diabetes Mellitus in a Multiethnic Asian Cohort

Background: Dietary protein may affect glucose metabolism through several mechanisms, but results from studies on dietary protein intake and risk of gestational diabetes mellitus (GDM) have been inconsistent.Objective: We examined the cross-sectional associations of dietary protein intake from different food sources during pregnancy with the risk of GDM in a multiethnic Asian population.Methods: We included 980 participants with singleton pregnancies from the Growing Up in Singapore Toward healthy Outcomes (GUSTO) cohort. Protein intake was ascertained from 24-h dietary recall and 3-d food diaries at 26-28 wk gestation. GDM was defined as fasting glucose ≥7.0 mmol/L and/or 2-h postload glucose ≥7.8 mmol/L at 26-28 wk gestation. We evaluated the association of dietary protein intake with GDM risk by substituting carbohydrate with protein in an isocaloric model with the use of multivariable logistic regression analysis.Results: The prevalence of GDM was 17.9% among our participants. After adjustment for potential confounders, a higher total dietary protein intake was associated with a higher risk of GDM; the OR comparing the highest with the lowest quartile of intake was 2.15 (95% CI: 1.27, 3.62; P-trend = 0.016). Higher intake levels of both animal protein (OR: 2.87; 95% CI: 1.58, 5.20; P-trend = 0.001) and vegetable protein (OR: 1.78; 95% CI: 0.99, 3.20; P-trend = 0.009) were associated with a higher risk of GDM. Among the animal protein sources, higher intake levels of seafood protein (OR: 2.17; 95% CI: 1.26, 3.72; P-trend = 0.023) and dairy protein (OR: 1.87; 95% CI: 1.11, 3.15; P-trend = 0.017) were significantly associated with a higher GDM risk.Conclusion: Higher intake levels of both animal and vegetable protein were associated with a higher risk of GDM in Asian women. This trial was registered at clinicaltrials.gov as NCT01174875.

Dairy consumption, systolic blood pressure, and risk of hypertension: Mendelian randomization study

Objective To examine whether previous observed inverse associations of dairy intake with systolic blood pressure and risk of hypertension were causal.Design Mendelian randomization study using the single nucleotide polymorphism rs4988235 related to lactase persistence as an instrumental variable.Setting CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium.Participants Data from 22 studies with 171 213 participants, and an additional 10 published prospective studies with 26 119 participants included in the observational analysis.Main outcome measures The instrumental variable estimation was conducted using the ratio of coefficients approach. Using meta-analysis, an additional eight published randomized clinical trials on the association of dairy consumption with systolic blood pressure were summarized.Results Compared with the CC genotype (CC is associated with complete lactase deficiency), the CT/TT genotype (TT is associated with lactose persistence, and CT is associated with certain lactase deficiency) of LCT-13910 (lactase persistence gene) rs4988235 was associated with higher dairy consumption (0.23 (about 55 g/day), 95% confidence interval 0.17 to 0.29) serving/day; P<0.001) and was not associated with systolic blood pressure (0.31, 95% confidence interval -0.05 to 0.68 mm Hg; P=0.09) or risk of hypertension (odds ratio 1.01, 95% confidence interval 0.97 to 1.05; P=0.27). Using LCT-13910 rs4988235 as the instrumental variable, genetically determined dairy consumption was not associated with systolic blood pressure (β=1.35, 95% confidence interval -0.28 to 2.97 mm Hg for each serving/day) or risk of hypertension (odds ratio 1.04, 0.88 to 1.24). Moreover, meta-analysis of the published clinical trials showed that higher dairy intake has no significant effect on change in systolic blood pressure for interventions over one month to 12 months (intervention compared with control groups: β=-0.21, 95% confidence interval -0.98 to 0.57 mm Hg). In observational analysis, each serving/day increase in dairy consumption was associated with -0.11 (95% confidence interval -0.20 to -0.02 mm Hg; P=0.02) lower systolic blood pressure but not risk of hypertension (odds ratio 0.98, 0.97 to 1.00; P=0.11).Conclusion The weak inverse association between dairy intake and systolic blood pressure in observational studies was not supported by a comprehensive instrumental variable analysis and systematic review of existing clinical trials.