Associations of processed meat and unprocessed red meat intake with incident diabetes: the Strong Heart Family Study

Trends and Disparities in Diabetes Mellitus and Atrial fibrillation Related Mortality in the United States: 1999-2020

The co-occurrence of diabetes mellitus (DM) and atrial fibrillation (AF) poses growing health risks in the United States (U.S.), with diabetes patients having a 34 % higher risk of AF. This study examines trends in DM and AF related mortality among individuals aged ≥ 25 years in the U.S. from 1999 to 2020. Data from the CDC WONDER database were analyzed calculating age-adjusted mortality rates (AAMRs) per 100,000 and annual percent change (APC), stratified by age, sex, race/ethnicity, urbanization, and region. Between 1999 and 2020, 419,036 deaths were recorded among U.S. adults (≥25 years) with comorbid AF and DM. The AAMR rose from 4.83 in 1999 to 15.91 in 2020, with an APC increase of 15.01 from 2018 to 2020. Older adults (≥65) had higher AAMRs than younger adults (25-64). Men (11.23) had higher rates than women (7.16). NH American Indian/Alaskan Natives (9.54) and Whites (9.16) had the highest AAMRs, while NH Asian/Pacific Islanders (6.04) had the lowest. Non-metropolitan areas (10.32) exceeded metropolitan areas (8.53). The Western U.S. (9.87) had the highest regional AAMR. Rising DM and AF-related deaths highlight a growing burden, particularly in men, NH American Indian/Alaskan Natives and Whites, and rural populations, necessitating targeted interventions.

Geographic and dietary differences of urinary uranium levels in the Strong Heart Family Study

BACKGROUND

American Indian (AI) communities are affected by uranium exposure from abandoned mines and naturally contaminated drinking water. Few studies have evaluated geographical differences across AI communities and the role of dietary exposures.

OBJECTIVE

We evaluated differences in urinary uranium levels by diet and geographical area among AI participants from the Northern Plains, the Southern Plains, and the Southwest enrolled in the Strong Heart Family Study (SHFS).

METHODS

We used food frequency questionnaires to determine dietary sources related to urinary uranium levels for 1,682 SHFS participants in 2001-2003. We calculated adjusted geometric mean ratios (GMRs) of urinary uranium for an interquartile range (IQR) increase in self-reported food group consumption accounting for family clustering and adjusting for sociodemographic variables and other food groups. We determined the percentage of variability in urinary uranium explained by diet.

RESULTS

Median (IQR) urinary uranium levels were 0.027 (0.012, 0.057) μg/g creatinine. Urinary uranium levels were higher in Arizona (median 0.039 μg/g) and North Dakota and South Dakota (median 0.038 μg/g) and lower in Oklahoma (median 0.019 μg/g). The adjusted percent increase (95% confidence interval) of urinary uranium levels per IQR increase in reported food intake was 20% (5%, 36%) for organ meat, 11% (1%, 23%) for cereals, and 14% (1%, 29%) for alcoholic drinks. In analyses stratified by study center, the association with organ meat was specific to North Dakota and South Dakota participants. An IQR increase in consumption of fries and chips was inversely associated with urinary uranium levels -11% (-19%, -3%). Overall, we estimated that self-reported dietary exposures explained 1.71% of variability in urine uranium levels.

IMPACT

Our paper provides a novel assessment of self-reported food intake and urinary uranium levels in a cohort of American Indian participants. We identify foods (organ meat, cereals, and alcohol) positively associated with urinary uranium levels, find that organ meat consumption is only associated with urine uranium in North Dakota and South Dakota, and estimate that diet explains relatively little variation in total urinary uranium concentrations. Our findings contribute meaningful data toward a more comprehensive estimation of uranium exposure among Native American communities and support the need for high-quality assessments of water and dust uranium exposures in SHFS communities.

The Causal Relationship Between Dietary Factors and the Risk of Intracranial Aneurysms: A Mendelian Randomization Analysis

Background: Some studies have shown that dietary factors can influence the occurrence of intracranial aneurysms (IAs). This study aimed to investigate whether dietary factors and habits are associated with intracranial aneurysms using Mendelian randomization (MR) analysis. Methods: A two-sample MR study was conducted to evaluate the association of dietary factors with IAs. Heterogeneity was evaluated using Cochran's Q test, and horizontal pleiotropy was assessed through MR-Egger regression and MR-pleiotropy residual sum and outlier (MR-PRESSO). Results: Fresh fruit intake (OR: 0.28, 95% CI: [0.13, 0.59]) was related to a decreased risk of IAs. Lamb/mutton intake may be associated with IAs, although the meta-analysis results were not significant (OR: 1.43, 95% CI: [0.27, 7.67]). Furthermore, MR analyses based on two aneurysm databases showed that alcoholic intake was not associated with IAs (alcoholic drinks per week: OR: 1.057, 95% CI: [0.788, 1.42]; OR: 0.509, 95% CI: [0.1665, 1.56]; alcohol intake frequency: OR: 1.084, 95% CI: [0.909, 1.29]; OR: 1.307, 95% CI: [0.814, 2.1]). Our results showed no causal relationship between coffee intake and IAs (OR: 1.149, 95% CI: [0.575, 2.3]; OR: 0863, 95% CI: [0.2979, 2.5]). Other dietary intakes were also found to have no causal relationship with IAs. Conclusions: This study found that fresh fruit intake was associated with a reduced risk of IAs. Lamb/mutton intake may be associated with IAs. However, other dietary factors, including alcohol intake and coffee intake, were found not to be associated with IAs.

Depression and Incident Hypertension: The Strong Heart Family Study

Introduction

Compared with White Americans, American Indian adults have disproportionately high depression rates. Previous studies in non-American Indian populations report depression as common among people with uncontrolled hypertension, potentially interfering with blood pressure control. Few studies have examined the association of depressive symptoms with hypertension development among American Indians despite that population's high burden of depression and hypertension. We examined the association of depressive symptoms with incident hypertension in a large cohort of American Indians.

Methods

We studied 1,408 American Indian participants in the Strong Heart Family Study, a longitudinal, ongoing, epidemiologic study assessing cardiovascular disease and its risk factors among American Indian populations. Depressive symptoms were assessed by using the Center for Epidemiological Studies-Depression (CES-D) scale, 2001-2003. At each study examination in 2001-2003 and 2007-2009, blood pressure was measured 3 times. The average of the last 2 measurements taken at baseline and follow-up examinations was used for analyses. Incident hypertension was defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure of ≥90 mm Hg, or use of hypertension medications at follow-up. To account for within-family correlation, we used generalized estimating equations to examine the association of depressive symptoms with incident hypertension.

Results

During follow-up, 257 participants developed hypertension. Participants with symptoms consistent with depression (CES-D ≥16) at baseline had 54% higher odds of developing hypertension during follow-up (OR = 1.54; 95% CI, 1.06-2.23) compared with those without depression (CES-D <16) at baseline after adjustment for other risk factors.

Conclusion

These data suggest that participants who experienced symptoms consistent with depression were at increased odds of incident hypertension.

Charting Wellness in India: Piloting the iTHRIVE's Functional Nutrition Approach to Improve Glycaemic and Inflammatory Parameters in Prediabetes and Type 2 Diabetes Mellitus

Introduction Type 2 diabetes mellitus (T2DM) is characterized by elevation of blood glucose levels due to underlying insulin resistance and inflammation. Multiple modifiable risk factors such as unhealthy dietary habits, physical inactivity, obesity, smoking and psychological stress contribute to T2DM. We investigated the efficacy of a comprehensive functional nutrition approach aimed at mitigating T2DM using the iTHRIVE approach which encompassed anti-inflammatory and elimination diets, micronutrient supplements, physical activity, stress management and environmental modifications through a pre-post study design. The research assessed changes in blood glucose and inflammatory markers following the implementation of the functional nutrition program. Methods A prospective pre-post intervention pilot study was conducted at ThriveTribe Wellness Solutions Pvt Ltd. (iTHRIVE), where 50 study participants from urban areas of Pune city, India (n=25 each group) were recruited voluntarily in the age group of 20-60 years. The participants were subjected to 90 days of the iTHRIVE functional nutrition approach which consisted of eliminating certain inflammatory foods and adding a combination of nutritious organic foods, adding dietary supplements like magnesium, vitamin D, alpha lipoic acid, chromium picolinate, berberine and biogymnema, physical activities like resistance training, stress reduction techniques like meditation and deep breathing exercises along with environmental changes. The blood parameters like fasting blood glucose, postprandial blood glucose, glycated haemoglobin (HbA1C), fasting serum insulin, post-prandial serum insulin, high sensitivity C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), vitamin D, body weight and waist circumference were measured before and after the intervention. The changes were statistically analyzed using a paired t-test. Results The mean age of the participants was found to be 43.76±10.58 years. Around 68% of the participants were prediabetic (HbA1c: 5.7-6.4%) and 32% had T2DM (HbA1c ≥6.5%). A significant reduction was observed in the average HbA1c (13.75% reduction, p<0.0001), average post-prandial blood glucose levels (14.51% reduction, p<0.048), average post-prandial serum insulin (34.31% reduction, p<0.017) and average ESR levels (34.51% reduction, p<0.006). The hs-CRP levels were reduced by 6.6%, but not statistically significant. The average body weight of the participants dropped from 78.59±15.18 kg to 75.20±14.20 kg with a mean loss of 2.91 kg (p<0.05) whereas the waist circumference decreased from 37.54±5.09 to 35.97±4.74 inches with an average loss of 1.19 inches (p<0.0004). Conclusions Following the intervention, several health indicators indicated significant improvements. Particularly, there was a significant drop in HbA1c levels, suggesting better long-term blood glucose control. Blood glucose and serum insulin levels after a meal dropped significantly, indicating enhanced insulin sensitivity. There was a decrease in systemic inflammation as evidenced by the decrease in ESR levels. These results imply that the iTHRIVE functional nutrition approach used in this investigation might be beneficial for enhancing glycemic control and insulin sensitivity, along with reducing inflammatory markers in people with prediabetes and T2DM. Larger sample sizes and longer periods of monitoring would be useful in subsequent research to validate and build on these encouraging findings.

The protective association of dairy intake and the adverse impact of iron on gestational diabetes risk

Background: Gestational diabetes (GDM) is a pregnancy-related glucose intolerance with significant implications for maternal and fetal health. Calcium is essential for insulin secretion and metabolism, while iron intake may also impact GDM. This case-control study was conducted to investigate the relationship between calcium and iron intake with the risk of GDM. Methods: GDM was defined as Fasting Blood Sugar>92mg/dL or 75g Oral-Glucose-Tolerance-Test 120-minutes>153mg/dL. A 168-Item food-frequency-questionnaire was used to collect dietary calcium and iron intake from 24-40 weeks of gestation. The impact of total iron, red, processed/unprocessed meat consumption, calcium, and dairy intake on GDM were investigated. Results: A total of 229 GDM and 205 non-GDM women (18-45 years) participated. GDM group had higher pre-pregnancy weight, weight gain, and pre-pregnancy BMI. Across all models, GDM risk significantly increased in the third and fourth quartiles of iron intake. The fourth quartile had an Odds Ratio (OR) of 2.68 (CI 95%, 4.89-1.56; P<0.001) compared to the reference. Heme-iron consumption in the fourth quartiles increased GDM risk. In the second calcium intake model, ORs for the second, third, and fourth quartiles were 0.51 (CI 95%, 0.91-0.25), 0.43 (CI 95%, 0.77-0.24), and 0.35 (CI 95%, 0.63-0.19), respectively (P<0.001 all), reducing GDM risk by 50-65% compared to the first quartile. Dairy consumption in all quartiles of the first and second models was associated with lower GDM risk. Conclusions: Consumption of heme-iron through red and processed meat associated with an increased chance of developing GDM. Dairy intake reduces the chances of developing GDM in pregnant women.

Fasting plasma metabolites reflecting meat consumption and their associations with incident type 2 diabetes in two Swedish cohorts

BACKGROUND

Consumption of processed red meat has been associated with increased risk of developing type 2 diabetes (T2D), but challenges in dietary assessment call for objective intake biomarkers.

OBJECTIVES

This study aimed to investigate metabolite biomarkers of meat intake and their associations with T2D risk.

METHODS

Fasting plasma samples were collected from a case-control study nested within Västerbotten Intervention Program (VIP) (214 females and 189 males) who developed T2D after a median follow-up of 7 years. Panels of biomarker candidates reflecting the consumption of total, processed, and unprocessed red meat and poultry were selected from the untargeted metabolomics data collected on the controls. Observed associations were then replicated in Swedish Mammography clinical subcohort in Uppsala (SMCC) (n = 4457 females). Replicated metabolites were assessed for potential association with T2D risk using multivariable conditional logistic regression in the discovery and Cox regression in the replication cohorts.

RESULTS

In total, 15 metabolites were associated with ≥1 meat group in both cohorts. Acylcarnitines 8:1, 8:2, 10:3, reflecting higher processed meat intake [r > 0.22, false discovery rate (FDR) < 0.001 for VIP and r > 0.05; FDR < 0.001 for SMCC) were consistently associated with higher T2D risk in both data sets. Conversely, lysophosphatidylcholine 17:1 and phosphatidylcholine (PC) 15:0/18:2 were associated with lower processed meat intake (r < -0.12; FDR < 0.023, for VIP and r < -0.05; FDR < 0.001, for SMCC) and with lower T2D risk in both data sets, except for PC 15:0/18:2, which was significant only in the VIP cohort. All associations were attenuated after adjustment for BMI (kg/m2).

CONCLUSIONS

Consistent associations of biomarker candidates involved in lipid metabolism between higher processed red meat intake with higher T2D risk and between those reflecting lower intake with the lower risk may suggest a relationship between processed meat intake and higher T2D risk. However, attenuated associations after adjusting for BMI indicates that such a relationship may at least partly be mediated or confounded by BMI.

Plasma lipidomic markers of diet quality are associated with incident coronary heart disease in American Indian adults: the Strong Heart Family Study

BACKGROUND

Identifying lipidomic markers of diet quality is needed to inform the development of biomarkers of diet, and to understand the mechanisms driving the diet- coronary heart disease (CHD) association.

OBJECTIVES

This study aimed to identify lipidomic markers of diet quality and examine whether these lipids are associated with incident CHD.

METHODS

Using liquid chromatography-mass spectrometry, we measured 1542 lipid species from 1694 American Indian adults (aged 18-75 years, 62% female) in the Strong Heart Family Study. Participants were followed up for development of CHD through 2020. Information on the past year diet was collected using the Block Food Frequency Questionnaire, and diet quality was assessed using the Alternative Healthy Eating Index-2010 (AHEI). Mixed-effects linear regression was used to identify individual lipids cross-sectionally associated with AHEI. In prospective analysis, Cox frailty model was used to estimate the hazard ratio (HR) of each AHEI-related lipid for incident CHD. All models were adjusted for age, sex, center, education, body mass index, smoking, alcohol drinking, level of physical activity, energy intake, diabetes, hypertension, and use of lipid-lowering drugs. Multiple testing was controlled at a false discovery rate of <0.05.

RESULTS

Among 1542 lipid species measured, 71 lipid species (23 known), including acylcarnitine, cholesterol esters, glycerophospholipids, sphingomyelins and triacylglycerols, were associated with AHEI. Most of the identified lipids were associated with consumption of ω-3 (n-3) fatty acids. In total, 147 participants developed CHD during a mean follow-up of 17.8 years. Among the diet-related lipids, 10 lipids [5 known: cholesterol ester (CE)(22:5)B, phosphatidylcholine (PC)(p-14:0/22:1)/PC(o-14:0/22:1), PC(p-38:3)/PC(o-38:4)B, phosphatidylethanolamine (PE)(p-18:0/20:4)/PE(o-18:0/20:4), and sphingomyelin (d36:2)A] were associated with incident CHD. On average, each standard deviation increase in the baseline level of these 5 lipids was associated with 17%-23% increased risk of CHD (from HR: 1.17; 95% CI: 1, 1.36; to HR: 1.23; 95% CI: 1.05, 1.43).

CONCLUSIONS

In this study, lipidomic markers of diet quality in American Indian adults are found. Some diet-related lipids are associated with risk of CHD beyond established risk factors.

Dietary magnesium, C-reactive protein and interleukin-6: The Strong Heart Family Study

OBJECTIVES

To examine the associations of dietary Mg intake with inflammatory biomarkers (C-reactive protein (CRP) and interleukin 6 (IL-6)), and the interaction of dietary Mg intake with single nucleotide polymorphism (SNP) rs3740393, a SNP related to Mg metabolism and transport, on CRP and IL-6 among American Indians (AIs).

METHODS

This cross-sectional study included AI participants (n = 1,924) from the Strong Heart Family Study (SHFS). Mg intake from foods and dietary supplements was ascertained using a 119-item Block food frequency questionnaire, CRP and IL-6 were measured from blood, and SNP rs3740393 was genotyped using MetaboChip. Generalized estimating equations were used to examine associations of Mg intake, and the interaction between rs3740393 and dietary Mg, with CRP and IL-6.

RESULTS

Reported Mg intake was not associated with CRP or IL-6, irrespective of genotype. A significant interaction (p-interaction = 0.018) was observed between Mg intake and rs3740393 on IL-6. Among participants with the C/C genotype, for every 1 SD higher in log-Mg, log-IL-6 was 0.04 (95% CI: -0.10 to 0.17) pg/mL higher. Among participants with the C/G genotype, for every 1 SD higher in log-Mg, log-IL-6 was 0.08 (95% CI: -0.21 to 0.05) pg/mL lower, and among participants with the G/G genotype, for every 1 SD higher in log-Mg, log-IL-6 was 0.19 (95% CI: -0.38 to -0.01) pg/mL lower.

CONCLUSIONS

Mg intake may be associated with lower IL-6 with increasing dosage of the G allele at rs3740393. Future research is necessary to replicate this finding and examine other Mg-related genes that influence associations of Mg intake with inflammation.

Red meat consumption, cardiovascular diseases, and diabetes: a systematic review and meta-analysis

AIMS

Observational studies show inconsistent associations of red meat consumption with cardiovascular disease (CVD) and diabetes. Moreover, red meat consumption varies by sex and setting, however, whether the associations vary by sex and setting remains unclear.

METHODS AND RESULTS

This systematic review and meta-analysis was conducted to summarize the evidence concerning the associations of unprocessed and processed red meat consumption with CVD and its subtypes [coronary heart disease (CHD), stroke, and heart failure], type two diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM) and to assess differences by sex and setting (western vs. eastern, categorized based on dietary pattern and geographic region). Two researchers independently screened studies from PubMed, Web of Science, Embase, and the Cochrane Library for observational studies and randomized controlled trials (RCTs) published by 30 June 2022. Forty-three observational studies (N = 4 462 810, 61.7% women) for CVD and 27 observational studies (N = 1 760 774, 64.4% women) for diabetes were included. Red meat consumption was positively associated with CVD [hazard ratio (HR) 1.11, 95% confidence interval (CI) 1.05 to 1.16 for unprocessed red meat (per 100 g/day increment); 1.26, 95% CI 1.18 to 1.35 for processed red meat (per 50 g/day increment)], CVD subtypes, T2DM, and GDM. The associations with stroke and T2DM were higher in western settings, with no difference by sex.

CONCLUSION

Unprocessed and processed red meat consumption are both associated with higher risk of CVD, CVD subtypes, and diabetes, with a stronger association in western settings but no sex difference. Better understanding of the mechanisms is needed to facilitate improving cardiometabolic and planetary health.

Health effects associated with consumption of unprocessed red meat: a Burden of Proof study

Characterizing the potential health effects of exposure to risk factors such as red meat consumption is essential to inform health policy and practice. Previous meta-analyses evaluating the effects of red meat intake have generated mixed findings and do not formally assess evidence strength. Here, we conducted a systematic review and implemented a meta-regression-relaxing conventional log-linearity assumptions and incorporating between-study heterogeneity-to evaluate the relationships between unprocessed red meat consumption and six potential health outcomes. We found weak evidence of association between unprocessed red meat consumption and colorectal cancer, breast cancer, type 2 diabetes and ischemic heart disease. Moreover, we found no evidence of an association between unprocessed red meat and ischemic stroke or hemorrhagic stroke. We also found that while risk for the six outcomes in our analysis combined was minimized at 0 g unprocessed red meat intake per day, the 95% uncertainty interval that incorporated between-study heterogeneity was very wide: from 0-200 g d-1. While there is some evidence that eating unprocessed red meat is associated with increased risk of disease incidence and mortality, it is weak and insufficient to make stronger or more conclusive recommendations. More rigorous, well-powered research is needed to better understand and quantify the relationship between consumption of unprocessed red meat and chronic disease.

Arsenic Exposure, Blood DNA Methylation, and Cardiovascular Disease

BACKGROUND

Epigenetic dysregulation has been proposed as a key mechanism for arsenic-related cardiovascular disease (CVD). We evaluated differentially methylated positions (DMPs) as potential mediators on the association between arsenic and CVD.

METHODS

Blood DNA methylation was measured in 2321 participants (mean age 56.2, 58.6% women) of the Strong Heart Study, a prospective cohort of American Indians. Urinary arsenic species were measured using high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry. We identified DMPs that are potential mediators between arsenic and CVD. In a cross-species analysis, we compared those DMPs with differential liver DNA methylation following early-life arsenic exposure in the apoE knockout (apoE-/-) mouse model of atherosclerosis.

RESULTS

A total of 20 and 13 DMPs were potential mediators for CVD incidence and mortality, respectively, several of them annotated to genes related to diabetes. Eleven of these DMPs were similarly associated with incident CVD in 3 diverse prospective cohorts (Framingham Heart Study, Women's Health Initiative, and Multi-Ethnic Study of Atherosclerosis). In the mouse model, differentially methylated regions in 20 of those genes and DMPs in 10 genes were associated with arsenic.

CONCLUSIONS

Differential DNA methylation might be part of the biological link between arsenic and CVD. The gene functions suggest that diabetes might represent a relevant mechanism for arsenic-related cardiovascular risk in populations with a high burden of diabetes.

Association of Socioeconomic and Geographic Factors With Diet Quality in US Adults

IMPORTANCE

Poor diet quality is a key factor associated with obesity and chronic disease. Understanding associations of socioeconomic and geographic factors with diet quality can inform public health and policy efforts for advancing health equity.

OBJECTIVE

To identify socioeconomic and geographic factors associated with diet quality in a large US cohort study.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included adult men and women who enrolled in the Cancer Prevention Study-3 at American Cancer Society community events in 35 US states, the District of Columbia, and Puerto Rico between 2006 and 2013. Participants completed a validated food frequency questionnaire between 2015 and 2017. Data were analyzed from February to November 2021.

EXPOSURES

The main exposures included self-reported race and ethnicity, education, and household income. Geocoded addresses were used to classify urbanization level using Rural-Urban Commuting Area codes; US Department of Agriculture's Food Access Research Atlas database classified residence in food desert.

MAIN OUTCOMES AND MEASURES

Poor diet quality was defined as lowest quartile of dietary concordance with the 2020 American Cancer Society recommendations for cancer prevention score, based on sex-specific intake categories of vegetables and legumes, whole fruits, whole grains, red and processed meat, highly processed foods and refined grains, and sugar-sweetened beverages.

RESULTS

Among 155 331 adults, 123 115 were women (79.3%), and the mean (SD) age was 52 (9.7) years), and there were 1408 American Indian or Alaskan Native individuals (0.9%); 2721 Asian, Native Hawaiian, or Pacific Islander individuals (1.8%); 3829 Black individuals (2.5%); 7967 Hispanic individuals (5.1%); and 138 166 White individuals (88.9%). All key exposures assessed were statistically significantly and independently associated with poor diet quality. Compared with White participants, Black participants had a 16% (95% CI, 8%-25%) higher risk of poor diet quality, while Hispanic/Latino had 16% (95% CI, 12%-21%) lower risk and Asian, Native Hawaiian, and Pacific Islander participants had 33% (95% CI, 26%-40%) lower risk of poor diet quality. After controlling for other characteristics, rural residence was associated with a 61% (95% CI, 48%-75%) higher risk of poor diet quality, and living in a food desert was associated with a 17% (95% CI, 12%-22%) higher risk. Associations of income with diet quality and education with diet quality varied by race and ethnicity (income: P for interaction = .01; education: P for interaction < .001). All diet score components were associated with disparities observed.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that multiple individual-level socioeconomic and geographic variables were independently associated with poor diet quality among a large, racially and ethnically and geographically diverse US cohort. These findings could help to identify groups at highest risk of outcomes associated with poor diet to inform future approaches for advancing health equity.

Ultra-processed food and risk of type 2 diabetes: a systematic review and meta-analysis of longitudinal studies

BACKGROUND

The consumption of some food groups is associated with the risk of diabetes. However, there is no evidence from meta-analysis which evaluates the consumption of ultra-processed products in the risk of diabetes. This study aimed to review the literature assessing longitudinally the association between consumption of ultra-processed food and the risk of type 2 diabetes and to quantify this risk through a meta-analysis.

METHODS

We conducted a systematic review and meta-analysis with records from PubMed, Latin American and Caribbean Literature in Health Sciences (LILACS), Scielo, Scopus, Embase, and Web of Science. We included longitudinal studies assessing ultra-processed foods and the risk of type 2 diabetes. The review process was conducted independently by two reviewers. The Newcastle Ottawa scale assessed the quality of the studies. A meta-analysis was conducted to assess the effect of moderate and high consumption of ultra-processed food on the risk of diabetes.

RESULTS

In total 2272 records were screened, of which 18 studies, including almost 1.1 million individuals, were included in this review and 72% showed a positive association between ultra-processed foods and the risk of diabetes. According to the studies included in the meta-analysis, compared with non-consumption, moderate intake of ultra-processed food increased the risk of diabetes by 12% [relative risk (RR): 1.12; 95% confidence interval (CI): 1.06-1.17, I2 = 24%], whereas high intake increased risk by 31% (RR: 1.31; 95% CI: 1.21-1.42, I2 = 60%).

CONCLUSIONS

The consumption of ultra-processed foods increased the risk for type 2 diabetes as dose-response effect, with moderate to high credibility of evidence.

Processed and Unprocessed Red Meat Consumption and Risk for Type 2 Diabetes Mellitus: An Updated Meta-Analysis of Cohort Studies

Type II diabetes mellitus (T2DM) is a metabolic disorder that occurs in the body because of decreased insulin activity and/or insulin secretion. The incidence of T2DM has rapidly increased over recent decades. The relation between consumption of different types of red meats and risk of T2DM remains uncertain. This meta-analysis was conducted to quantitatively assess the associations of processed red meat (PRM) and unprocessed red meat (URM) consumption with T2DM. We searched PubMed, Embase, Web of Science and The Cochrane Library for English-language cohort studies published before January 2021. Summary relative risks (RR) with 95% confidence interval (CI) were estimated using fixed effects and random effects. Additionally, dose-response relationships were explored using meta-regression. Fifteen studies (n = 682,963 participants, cases = 50,675) were identified. Compared with the lowest intake group, high consumption of PRM and URM increased T2DM risk by 27% (95% CI 1.15-1.40) and 15% (95% CI 1.08-1.23), respectively. These relationships were consistently strongest for U.S-based studies, though the effects of sex are inconclusive. In conclusion, PRM and URM are both positively associated with T2DM incidence, and these relationships are strongest in the U.S. reduction of red meat consumption should be explored as a target for T2DM prevention initiatives.

Whole body metabolism is improved by hemin added to high fat diet while counteracted by nitrite: a mouse model of processed meat consumption

Nitrites and nitrates are traditional food additives used as curing agents in the food industry. They inhibit the growth of microorganisms and give a typical pink color to meat. Besides the positive effects of nitrite in foods, if present at high levels in the body, may induce hypoxia and contribute to the production of pro-carcinogenic secondary N-nitrosamines. This study investigated the whole-body metabolic effects of hemin and nitrite added to a high fat diet as red and processed red meat nutritional models. Mice were fed for 11 weeks with five different diets-(1) control diet (ND), (2) high fat diet (HFD) with 60% fat, (3) HFD with hemin (HFD + H, red meat model), (4) HFD with hemin and nitrite (HFD + HN, processed meat model), and (5) HFD with hemin, nitrite, and secondary amine (HFD + HNN, N-nitrosamine generating model)-and several metabolic parameters were determined and respiratory measurements were performed. Mice fed with the HFD + H or HFD + HNN diet had a lower epididymal white adipose tissue (eWAT) : body ratio and lower fasting glucose level than those fed the HFD alone. In addition, our results demonstrated a relief in hepatosteatosis grade among the HFD + H and HFD + HNN diet fed mice. Nitrite added to the HFD impaired the ability to use fat for energy, opposite to the effect of hemin. This study shows that nitrite in addition to pro-carcinogenesis and hypoxia can impact metabolic disease progression when added to meat.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Burden and management of type 2 diabetes in rural United States

In the United States, rural areas have a higher burden of type 2 diabetes (T2DM) compared to urban areas. However, there is limited information on risk factors and interventions that improve the primary prevention and management of T2DM in rural areas. To synthesize current knowledge on T2DM in rural areas and to guide healthcare providers and policy makers, we reviewed five scientific databases and the grey literature over the last decade (2010-2020). We described classification systems for rurality and the T2DM burden based on rurality and region (West, South, Midwest, and Northeast). We highlighted risk factors for T2DM in rural compared to urban areas, and summarized interventions to screen and manage T2DM based on opportunistic screening, T2DM self-management, community-based initiatives, as well as interventions targeting comorbidities and T2DM. Several studies identified the co-existence of T2DM and depression/psychological symptoms, which could reduce adherence to non-pharmacologic and pharmacologic management of T2DM. We highlighted the role of technology in education and counselling of patients with geographic and financial barriers to accessing care, which is exacerbated by the SARS-CoV-2 coronavirus disease-19 pandemic. We identified knowledge gaps and next steps in improving T2DM care in rural areas. There is an urgent need for interventions tailored to rural areas given that rural Americans currently experience a disproportionate burden of T2DM and are encumbered by its associated morbidity, mortality, and loss in economic productivity.

Moderate Consumption of Red Meat, Compared to Soy or Non-Soy Legume, Has No Adverse Effect on Cardio-Metabolic Factors in Patients with Type 2 Diabetes

BACKGROUND

Recently, it has been proposed that red meat consumption could enhance risk of diabetes and worsen lipid profile and glycemic status, in comparison with soy or non-soy legume, but the results of clinical trials are controversial.

OBJECTIVES

This study aimed to compare the effect of red meat, soy bean, and non-soy legume consumption on cardio-metabolic factors in patients with type 2 diabetes.

METHODS

This was a randomized controlled clinical trial which included 75 patients with diabetes, aged 40-65 years. Participants were randomly allocated to receive two servings of red meat (control group), soy bean, or non-soy legume, 3 days a week for 8 weeks. All groups also received a balanced-macronutrients weight maintenance diet. Body composition and cardio-metabolic factors including fasting blood glucose (FBG), fasting insulin, glycated hemoglobin (HbA1c), serum lipids, and blood pressure were measured at baseline and endpoint of the study. Quantitative insulin sensitivity check index (QUICKI) score and Framingham risk score (FRS) were also computed.

RESULTS

We found no significant differences in changes of FBG, fasting insulin, HbA1c, QUICKI score, serum lipids, FRS, and systolic and diastolic blood pressure among the 3 groups. Within group analysis showed that FRS reduced significantly in all groups (P<0.05). In addition, systolic (P=0.01) and diastolic (P=0.03) blood pressure reduced within red meat group.

CONCLUSIONS

Compared to soy bean or non-soy legume, moderate consumption of red meat had no adverse effect on cardio-metabolic factors including FBG, fasting insulin, HbA1C, QUICKI score, total cholesterol, low-density lipoprotein , high-density lipoprotein , and blood pressure in adults with type 2 diabetes.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity, and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis, the Spanish Diabetes Society, and the Spanish Society of Internal Medicine.

Executive summary: Updates to the dietary treatment of prediabetes and type 2 diabetes mellitus

Adequate lifestyle changes significantly reduce the cardiovascular risk factors associated with prediabetes and type 2 diabetes mellitus. Therefore, healthy eating habits, regular physical activity, abstaining from using tobacco, and good sleep hygiene are recommended for managing these conditions. There is solid evidence that diets that are plant-based; low in saturated fatty acids, cholesterol, and sodium; and high in fiber, potassium, and unsaturated fatty acids are beneficial and reduce the expression of cardiovascular risk factors in these subjects. In view of the foregoing, the Mediterranean diet, the DASH diet, a low-carbohydrate diet, and a vegan-vegetarian diet are of note. Additionally, the relationship between nutrition and these metabolic pathologies is fundamental in targeting efforts to prevent weight gain, reducing excess weight in the case of individuals with overweight or obesity; and personalizing treatment to promote patient empowerment. This document is the executive summary of an updated review that includes the main recommendations for improving dietary nutritional quality in people with prediabetes or type 2 diabetes mellitus. The full review is available on the webpages of the Spanish Society of Arteriosclerosis (SEA, for its initials in Spanish), the Spanish Diabetes Society (SED, for its initials in Spanish), and the Spanish Society of Internal Medicine (SEMI, for its initials in Spanish).

Long-Term Intake of Pork Meat Proteins Altered the Composition of Gut Microbiota and Host-Derived Proteins in the Gut Contents of Mice

SCOPE

This study is to investigate the effects of long-term intake of pork protein on the composition of gut microbiota and proteins in mice.

METHODS AND RESULTS

C57BL/6J mice are fed pork meat protein diets for 240 days, and the composition of gut microbiota and proteins in luminal contents from the duodenum to the colon are analyzed by 16S rRNA gene sequencing and LC-MS/MS. The stewed pork protein diet group has a highly similar microbiota composition to that of the cooked pork protein diet group, but different from the pork emulsion sausage or dry-cured pork protein diet groups. Lachnospiraceae NK4A136, Odoribacter, Defluviitaleaceae UCG-011, Ruminiclostridium 9, Blautia, Lachnoclostridium, and Ruminococcaceae UCG-010 play an important role in response to changes in gut luminal proteins. Specific microbes are significantly correlated with the Cela3b and Cpa1 that are derived from the host and involve protein digestion and absorption.

CONCLUSIONS

Pork meat protein diets alter the gut microbiota composition and specific gut microbes may have a great impact on protein digestion and absorption by regulating the secretion of digestive proteins from the host. These findings provide a new insight into the associations of long-term intake of meat protein diet with gut microbiota and host.

Associations of diet quality and blood serum lipoprotein levels in a population at high risk for diabetes: the Strong Heart Family Study

BACKGROUND/OBJECTIVES

Previous studies consistently report that diet quality is inversely associated with risk of cardiovascular disease (CVD) and type 2 diabetes. However, few studies have assessed the association of diet quality with serum lipoproteins, an intermediate marker of cardio-metabolic health, or assessed whether type 2 diabetes modifies these associations. This study assessed associations of diet quality (evaluated using the Alternative Healthy Eating Index (AHEI)), and the interaction of diet quality with diabetes, on total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), apolipoprotein A (apoA1), and apolipoprotein B (apoB) among American Indians (AIs).

SUBJECTS/METHODS

Participants comprised AIs who participated in the Strong Heart Family Study (SHFS)-a study of CVD and its risk factors in 12 AI communities. Generalized estimated equations (GEEs) were used to examine the following associations: (1) the cross-sectional associations of diet quality (as determined by AHEI) with serum lipoproteins (n = 2200); and (2) the prospective associations of the AHEI measured at baseline with serum lipoproteins (n = 1899).

RESULTS

In cross-sectional analyses, associations of AHEI with TC (p < 0.0001) LDL-C (p = 0.005), and ApoB (p = 0.002) differed according to diabetes status. In prospective analysis, AHEI was associated with more favorable levels of TC (p = 0.029) and LDL-C (p = 0.008) among participants with diabetes independent of other demographic, behavioral, and health factors; associations of diet quality with TC, LDL-C, and ApoB were much weaker among participants without diabetes. There was no association of diet quality with TG, HDL-C, or ApoA.

CONCLUSIONS

The associations of diet quality with TC, LDL-C, and ApoB differ according to diabetes status.

Effects of Aging and Diet on Cardioprotection and Cardiometabolic Risk Markers

The prevalence of several diseases increases by age, including cardiovascular diseases, which are the leading cause of morbidity and mortality worldwide. Aging, as a complex process characterized by senescence, triggers various pathways, such as oxidative stress, systemic inflammation, metabolism dysfunction, telomere shortening, mitochondrial dysfunction and deregulated autophagy. A better understanding of the mechanisms underlying senescence may lead to the development of new therapeutic targets and strategies for age-related pathologies and extend the healthy lifespan. Modulating lifestyle risk factors and adopting healthy dietary patterns remain significant tools in delaying the aging process, decreasing age-associated comorbidities and mortality, increasing life expectancy and consequently, preventing the development of cardiovascular disease. Furthermore, such a strategy represents the most cost-effective approach, and the quality of life of the subjects may be significantly improved. An integrated, personalized approach targeting cardiometabolic aging and frailty is suggested in daily clinical practice. However, it should be initiated from an early age. Moreover, there is a need for further well designed and controlled studies in order to elucidate a link between the time of feeding, longevity and cardiovascular prevention. In the future, it is expected that the pharmacological treatment in cardioprotective management will be necessary, accompanied by equally important lifestyle interventions and adjunctive exercise.

Meat and fish intake and type 2 diabetes: Dose-response meta-analysis of prospective cohort studies

AIMS

This meta-analysis aimed to quantitatively examine the possible associations between total meat, red meat, processed meat, poultry and fish intakes and type 2 diabetes (T2D).

METHODS

Relevant articles were identified in PubMed, Embase and Web of Science databases using a search time up to January 2019. Generalized least-squares trend estimations and restricted cubic spline regression models were used for analysis.

RESULTS

Twenty-eight articles were included in the analysis. When comparing the highest with the lowest category of meat intake, the summary relative risk of T2D was 1.33 (95% CI: 1.16-1.52) for total meat, 1.22 (95% CI: 1.16-1.28) for red meat, 1.25 (95% CI: 1.13-1.37) for processed meat, 1.00 (95% CI: 0.93-1.07) for poultry and 1.01 (95% CI: 0.93-1.10) for fish. In the dose-response analysis, each additional 100g/day of total and red meat, and 50g/day of processed meat, were found to be associated with a 36% (95% CI: 1.23-1.49), 31% (95% CI: 1.19-1.45) and 46% (95% CI: 1.26-1.69) increased risk of T2D, respectively. In addition, there was evidence of a non-linear dose-response association between processed meat and T2D (P=0.004), with the risk increasing by 30% with increasing intakes up to 30g/day.

CONCLUSION

Our meta-analysis has shown a linear dose-response relationship between total meat, red meat and processed meat intakes and T2D risk. In addition, a non-linear relationship of intake of processed meat with risk of T2D was detected.

Early-Life Arsenic Exposure, Nutritional Status, and Adult Diabetes Risk

PURPOSE OF REVIEW

In utero influences, including nutrition and environmental chemicals, may induce long-term metabolic changes and increase diabetes risk in adulthood. This review evaluates the experimental and epidemiological evidence on the association of early-life arsenic exposure on diabetes and diabetes-related outcomes, as well as the influence of maternal nutritional status on arsenic-related metabolic effects.

RECENT FINDINGS

Five studies in rodents have evaluated the role of in utero arsenic exposure with diabetes in the offspring. In four of the studies, elevated post-natal fasting glucose was observed when comparing in utero arsenic exposure with no exposure. Rodent offspring exposed to arsenic in utero also showed elevated insulin resistance in the 4 studies evaluating it as well as microRNA changes related to glycemic control in 2 studies. Birth cohorts of arsenic-exposed pregnant mothers in New Hampshire, Mexico, and Taiwan have shown that increased prenatal arsenic exposure is related to altered cord blood gene expression, microRNA, and DNA methylation profiles in diabetes-related pathways. Thus far, no epidemiologic studies have evaluated early-life arsenic exposure with diabetes risk. Supplementation trials have shown B vitamins can reduce blood arsenic levels in highly exposed, undernourished populations. Animal evidence supports that adequate B vitamin status can rescue early-life arsenic-induced diabetes risk, although human data is lacking. Experimental animal studies and human evidence on the association of in utero arsenic exposure with alterations in gene expression pathways related to diabetes in newborns, support the potential role of early-life arsenic exposure in diabetes development, possibly through increased insulin resistance. Given pervasive arsenic exposure and the challenges to eliminate arsenic from the environment, research is needed to evaluate prevention interventions, including the possibility of low-cost, low-risk nutritional interventions that can modify arsenic-related disease risk.

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.

Dietary determinants of inorganic arsenic exposure in the Strong Heart Family Study

BACKGROUND

Chronic exposure to inorganic arsenic (iAs) in the US occurs mainly through drinking water and diet. Although American Indian (AI) populations have elevated urinary arsenic concentrations compared to the general US population, dietary sources of arsenic exposure in AI populations are not well characterized.

METHODS

We evaluated food frequency questionnaires to determine the major dietary sources of urinary arsenic concentrations (measured as the sum of arsenite, arsenate, monomethylarsonate, and dimethylarsinate, ΣAs) for 1727 AI participants in the Strong Heart Family Study (SHFS). We compared geometric mean ratios (GMRs) of urinary ΣAs for an interquartile range (IQR) increase in reported food group consumption. Exploratory analyses were stratified by gender and study center.

RESULTS

In fully adjusted generalized estimating equation models, the percent increase (95% confidence interval) of urinary ΣAs per increase in reported food consumption corresponding to the IQR was 13% (5%, 21%) for organ meat, 8% (4%, 13%) for rice, 7% (2%, 13%) for processed meat, and 4% (1%, 7%) for non-alcoholic drinks. In analyses stratified by study center, the association with organ meat was only observed in North/South Dakota. Consumption of red meat [percent increase -7% (-11%, -3%)] and fries and chips [-6% (-10%, -2%)] was inversely associated with urinary ΣAs.

CONCLUSIONS

Organ meat, processed meat, rice, and non-alcoholic drinks contribute to ΣAs exposure in the SHFS population. Organ meat is a unique source of ΣAs exposure for North and South Dakota participants and may reflect local food consumption. Further studies should comprehensively evaluate drinking water arsenic in SHFS communities and determine the relative contribution of diet and drinking water to total arsenic exposure.

Full-Fat Dairy Food Intake is Associated with a Lower Risk of Incident Diabetes Among American Indians with Low Total Dairy Food Intake

BACKGROUND

Diet plays a key role in development of diabetes, and there has been recent interest in better understanding the association of dairy food intake with diabetes.

OBJECTIVE

This study examined the associations of full-fat and low-fat dairy food intake with incident diabetes among American Indians-a population with a high burden of diabetes.

METHODS

The study included participants from the Strong Heart Family Study (SHFS), a family-based study of cardiovascular disease in American Indians, free of diabetes at baseline (2001-2003) (n = 1623). Participants were 14-86-y-old at baseline and 60.8% were female. Dairy food intake was assessed using a Block food frequency questionnaire. Incident diabetes was defined using American Diabetes Association criteria. Parametric survival models with a Weibull distribution were used to evaluate the associations of full-fat and low-fat dairy food intake with incident diabetes. Serving sizes were defined as 250 mL for milk and 42.5 g for cheese.

RESULTS

We identified 277 cases of diabetes during a mean follow-up of 11 y. Reported intake of dairy foods was low [median full-fat dairy food intake: 0.11 serving/1000 kcal; median low-fat dairy food intake: 0.03 serving/1000 kcal]. Participants who reported the highest full-fat dairy food intake had a lower risk of diabetes compared to those who reported the lowest full-fat food dairy intake [HR (95% CI): 0.79 (0.59, 1.06); P-trend = 0.03, comparing extreme tertiles, after adjustment for age, sex, site, physical activity, education, smoking, diet quality, and low-fat dairy food intake]. Low-fat dairy food intake was not associated with diabetes.

CONCLUSIONS

American Indians who participated in the SHFS reported low dairy food intake. Participants who reported higher full-fat dairy food intake had a lower risk of diabetes than participants who reported lower intake. These findings may be of interest to populations with low dairy food intake.

Dietary Toll-Like Receptor Stimulants Promote Hepatic Inflammation and Impair Reverse Cholesterol Transport in Mice via Macrophage-Dependent Interleukin-1 Production

Background: The mechanisms connecting dietary intake of processed foods with systemic inflammatory markers and cardiovascular risk remain poorly defined. We sought to compare the abundance of pro-inflammatory stimulants of innate immune receptors in processed foods with those produced by the murine ileal and caecal microbiota, and to explore the impact of their ingestion on systemic inflammation and lipid metabolism in vivo. Methods and results: Calibrated receptor-dependent reporter assays revealed that many processed foods, particularly those based on minced meats, contain pro-inflammatory stimulants of Toll-like receptor (TLR)-2 and TLR4 at concentrations which greatly exceed those produced by the endogenous murine ileal microbiota. Chronic dietary supplementation with these stimulants, at concentrations relevant to those measured in the Western diet, promoted hepatic inflammation and reduced several markers of reverse cholesterol transport (RCT) in mice. Hepatocytes were found to be insensitive to TLR2- and TLR4-stimulants directly, but their secretion of functional cholesterol acceptors was impaired by interleukin (IL)-1β released by TLR-responsive hepatic macrophages. Hepatic macrophage priming by high-fat diet enhanced the impairment of RCT by ingested endotoxin, and this was reversed by macrophage depletion via clodronate liposome treatment, or genetic deficiency in the IL-1 receptor. Conclusion: These findings reveal an unexpected mechanism connecting processed food consumption with cardiovascular risk factors, and introduce the food microbiota as a potential target for therapeutic regulation of lipid metabolism.

Potential effects of reduced red meat compared with increased fiber intake on glucose metabolism and liver fat content: a randomized and controlled dietary intervention study

Background

Epidemiological studies suggest that an increased red meat intake is associated with a higher risk of type 2 diabetes, whereas an increased fiber intake is associated with a lower risk.

Objectives

We conducted an intervention study to investigate the effects of these nutritional factors on glucose and lipid metabolism, body-fat distribution, and liver fat content in subjects at increased risk of type 2 diabetes.

Methods

This prospective, randomized, and controlled dietary intervention study was performed over 6 mo. All groups decreased their daily caloric intake by 400 kcal. The "control" group (N = 40) only had this requirement. The "no red meat" group (N = 48) in addition aimed to avoid the intake of red meat, and the "fiber" group (N = 44) increased intake of fibers to 40 g/d. Anthropometric parameters and frequently sampled oral glucose tolerance tests were performed before and after intervention. Body-fat mass and distribution, liver fat, and liver iron content were assessed by MRI and single voxel proton magnetic resonance spectroscopy.

Results

Participants in all groups lost weight (mean 3.3 ± 0.5 kg, P < 0.0001). Glucose tolerance and insulin sensitivity improved (P < 0.001), and body and visceral fat mass decreased in all groups (P < 0.001). These changes did not differ between groups. Liver fat content decreased significantly (P < 0.001) with no differences between the groups. The decrease in liver fat correlated with the decrease in ferritin during intervention (r2 = 0.08, P = 0.0021). This association was confirmed in an independent lifestyle intervention study (Tuebingen Lifestyle Intervention Program, N = 229, P = 0.0084).

Conclusions

Our data indicate that caloric restriction leads to a marked improvement in glucose metabolism and body-fat composition, including liver-fat content. The marked reduction in liver fat might be mediated via changes in ferritin levels. In the context of caloric restriction, there seems to be no additional beneficial impact of reduced red meat intake and increased fiber intake on the improvement in cardiometabolic risk parameters. This trial was registered at clinicaltrials.gov as NCT03231839.

Targeted metabolomics to understand the association between arsenic metabolism and diabetes-related outcomes: Preliminary evidence from the Strong Heart Family Study

BACKGROUND

Inorganic arsenic exposure is ubiquitous and both exposure and inter-individual differences in its metabolism have been associated with cardiometabolic risk. A more efficient arsenic metabolism profile (lower MMA%, higher DMA%) has been associated with reduced risk for arsenic-related health outcomes. This profile, however, has also been associated with increased risk for diabetes-related outcomes.

OBJECTIVES

The mechanism behind these conflicting associations is unclear; we hypothesized the one-carbon metabolism (OCM) pathway may play a role.

METHODS

We evaluated the influence of OCM on the relationship between arsenic metabolism and diabetes-related outcomes (HOMA2-IR, waist circumference, fasting plasma glucose) using metabolomic data from an OCM-specific and P180 metabolite panel measured in plasma, arsenic metabolism measured in urine, and HOMA2-IR and FPG measured in fasting plasma. Samples were drawn from baseline visits (2001-2003) in 59 participants from the Strong Heart Family Study, a family-based cohort study of American Indians aged ≥14 years from Arizona, Oklahoma, and North/South Dakota.

RESULTS

In unadjusted analyses, a 5% increase in DMA% was associated with higher HOMA2-IR (geometric mean ratio (GMR)= 1.13 (95% CI: 1.03, 1.25)) and waist circumference (mean difference=3.66 (0.95, 6.38). MMA% was significantly associated with lower HOMA2-IR and waist circumference. After adjustment for OCM-related metabolites (SAM, SAH, cysteine, glutamate, lysophosphatidylcholine 18.2, and three phosphatidlycholines), associations were attenuated and no longer significant.

CONCLUSIONS

These preliminary results indicate that the association of lower MMA% and higher DMA% with diabetes-related outcomes may be influenced by OCM status, either through confounding, reverse causality, or mediation.

Arsenic, one carbon metabolism and diabetes-related outcomes in the Strong Heart Family Study

BACKGROUND

Inorganic arsenic exposure and inter-individual differences in its metabolism have been associated with cardiometabolic risk. A more efficient arsenic metabolism profile (lower MMA%, higher DMA%) has been associated with reduced risk for arsenic-related health outcomes; however, this profile has also been associated with increased risk for diabetes-related outcomes. The mechanism behind these contrasting associations is equivocal; we hypothesized one carbon metabolism (OCM) may play a role.

METHODS

We evaluated the association between OCM-related variables (nutrient intake and genetic variants) and both arsenic metabolism biomarkers (iAs%, MMA% and DMA%) and diabetes-related outcomes (metabolic syndrome, diabetes, HOMA2-IR and waist circumference) in 935 participants free of prevalent diabetes and metabolic syndrome from the Strong Heart Family Study, a family-based prospective cohort comprised of American Indian tribal members aged 14+ years.

RESULTS

Of the 935 participants free of both diabetes and metabolic syndrome at baseline, 279 (29.8%) developed metabolic syndrome over a median of 5.3 years of follow-up and of the 1458 participants free of diabetes at baseline, 167 (11.3%) developed diabetes over follow-up. OCM nutrients were not associated with arsenic metabolism, however, higher vitamin B₆ was associated with diabetes-related outcomes (higher HOMA2-IR and increased risk for diabetes and metabolic syndrome). A polymorphism in an OCM-related gene, methionine synthase (MTR), was associated with both higher MMA% (β = 2.57, 95% CI: 0.22, 4.92) and lower HOMA2-IR (GMR = 0.79, 95% CI = 0.66, 0.93 per 5 years of follow-up). Adjustment for OCM variables did not affect previously reported associations between arsenic metabolism and diabetes-related outcomes; however, the association between the MTR variant and diabetes-related outcomes were attenuated after adjustment for arsenic metabolism.

CONCLUSIONS

Our findings suggest MMA% may be a partial mediator in the association between OCM and diabetes-related outcomes. Additional mediation analyses with longer follow-up period are needed to confirm this finding. Further research is needed to determine whether excess B vitamin intake is associated with increased risk for diabetes-related outcomes.

The Association of Arsenic Exposure and Arsenic Metabolism With the Metabolic Syndrome and Its Individual Components: Prospective Evidence From the Strong Heart Family Study

Inorganic arsenic exposure is ubiquitous, and both exposure and interindividual differences in its metabolism have been associated with cardiometabolic risk. However, the associations of arsenic exposure and arsenic metabolism with the metabolic syndrome (MetS) and its individual components are relatively unknown. We used Poisson regression with robust variance to evaluate the associations of baseline arsenic exposure (urinary arsenic levels) and metabolism (relative percentage of arsenic species over their sum) with incident MetS and its individual components (elevated waist circumference, elevated triglycerides, reduced high-density lipoprotein cholesterol, hypertension, and elevated fasting plasma glucose) in 1,047 participants from the Strong Heart Family Study, a prospective family-based cohort study in American Indian communities (baseline visits were held in 1998-1999 and 2001-2003, follow-up visits in 2001-2003 and 2006-2009). Over the course of follow-up, 32% of participants developed MetS. An interquartile-range increase in arsenic exposure was associated with a 1.19-fold (95% confidence interval: 1.01, 1.41) greater risk of elevated fasting plasma glucose concentration but not with other individual components of the MetS or MetS overall. Arsenic metabolism, specifically lower percentage of monomethylarsonic acid and higher percentage of dimethylarsinic acid, was associated with higher risk of overall MetS and elevated waist circumference but not with any other MetS component. These findings support the hypothesis that there are contrasting and independent associations of arsenic exposure and arsenic metabolism with metabolic outcomes which may contribute to overall diabetes risk.

Modified Healthy Eating Index and Incidence of Metabolic Syndrome in Children and Adolescents: Tehran Lipid and Glucose Study

OBJECTIVE

To assess the relationship between modified healthy eating index (mHEI) with the development of metabolic syndrome (MetS) among children and adolescents.

STUDY DESIGN

Dietary data were collected using a food frequency questionnaire among 424 healthy subjects, aged 6-18 years. The components of mHEI were grains, vegetables and fruits, dairy, red to white meat ratio, butter, sweet snacks, sweetened beverages, salty snacks, and fast food. Multivariable logistic regression models were used to estimate the incidence of MetS after 3.6 years of follow-up in each quartile of the mHEI score, adjusted for baseline age, sex, total energy intake, physical activity, and body mass index.

RESULTS

The mean ± SD age and mHEI scores of participants were 13.6 ± 3.7 years and 55.9 ± 10.0, respectively, at baseline. MetS developed in 11% of the participants at the end of follow-up. After adjustment for confounders, the occurrences of MetS decreased in the highest quartile compared with the lowest quartile of the mHEI score (OR = 0.35, 95% CI 0.13-0.98, P for trend = .025). In addition, higher scores of mHEI components including fruits, salty snacks, and fast food were associated with lower risk of MetS.

CONCLUSIONS

Higher scores of mHEI as an indicator of diet quality may hinder the development of MetS among children and adolescents.

Association of Low-Moderate Arsenic Exposure and Arsenic Metabolism with Incident Diabetes and Insulin Resistance in the Strong Heart Family Study

BACKGROUND

High arsenic exposure has been related to diabetes, but at low-moderate levels the evidence is mixed. Arsenic metabolism, which is partly genetically controlled and may rely on certain B vitamins, plays a role in arsenic toxicity.

OBJECTIVE

We evaluated the prospective association of arsenic exposure and metabolism with type 2 diabetes and insulin resistance.

METHODS

We included 1,838 American Indian men and women free of diabetes (median age, 36 y). Arsenic exposure was assessed as the sum of inorganic arsenic (iAs), monomethylarsonate (MMA), and dimethylarsinate (DMA) urine concentrations (ΣAs). Arsenic metabolism was evaluated by the proportions of iAs, MMA, and DMA over their sum (iAs%, MMA%, and DMA%). Homeostasis model assessment for insulin resistance (HOMA2-IR) was measured at baseline and follow-up visits. Incident diabetes was evaluated at follow-up.

RESULTS

Median ΣAs, iAs%, MMA%, and DMA% was 4.4 μg/g creatinine, 9.5%, 14.4%, and 75.6%, respectively. Over 10,327 person-years of follow-up, 252 participants developed diabetes. Median HOMA2-IR at baseline was 1.5. The fully adjusted hazard ratio [95% confidence interval (CI)] for incident diabetes per an interquartile range increase in ΣAs was 1.57 (95% CI: 1.18, 2.08) in participants without prediabetes at baseline. Arsenic metabolism was not associated with incident diabetes. ΣAs was positively associated with HOMA2-IR at baseline but negatively with HOMA2-IR at follow-up. Increased MMA% was associated with lower HOMA2-IR when either iAs% or DMA% decreased. The association of arsenic metabolism with HOMA2-IR differed by B-vitamin intake and AS3MT genetics variants.

CONCLUSIONS

Among participants without baseline prediabetes, arsenic exposure was associated with incident diabetes. Low MMA% was cross-sectional and prospectively associated with higher HOMA2-IR. Research is needed to confirm possible interactions of arsenic metabolism with B vitamins and AS3MT variants on diabetes risk. https://doi.org/10.1289/EHP2566.

Diet Quality Is Linked to Insulin Resistance among Adults in China

Background: Little is known about the impact of Chinese diet quality changes on diabetes-related markers.Objective: The present study examined the association of changes in overall diet quality with various biomarkers of diabetes among adults in China.Methods: The current analysis used longitudinal diet data from 1991 to 2006 and fasting blood samples from 2009 for 4734 adults aged 18-65 y from the China Health and Nutrition Survey. Dietary intake was assessed by using 3 consecutive 24-h recalls and household food weighing. The tailored Alternative Healthy Eating Index (tAHEI) was adapted from the 2010 Harvard Alternative Healthy Eating Index to measure overall diet quality. We categorized baseline tAHEI scores into tertiles and annual changes in the scores into 5 levels (high decrease, low decrease, maintain, low increase, and high increase). We performed mixed-effects regressions to assess the associations between baseline scores and changes in the tAHEI scores and diabetes or insulin markers.Results: Adults with high baseline tAHEI scores tended to be male, older, of lower socioeconomic status, and with higher physical activity levels. After adjustment for all of the covariates, insulin and homeostasis model assessment of insulin resistance (HOMA-IR) values were 5.1% (95% CI: -0.100, -0.002) and 5.7% (95% CI: -0.113, -0.001) lower, respectively, for adults with high compared with low baseline tAHEI scores and 8.6% (95% CI: -0.155, -0.017) and 9.8% (95% CI: -0.177, -0.018) lower, respectively, for adults with a high increase in score compared with the "maintain" category. Null associations were observed between baseline scores and changes in the scores and fasting blood glucose, glycated hemoglobin (HbA1c), and diabetes prevalence.Conclusions: Baseline and changes in diet quality were independently associated with lower HOMA-IR and plasma insulin but not with fasting blood glucose and HbA1c in Chinese adults. Prospective studies on overall diet quality in relation to diabetes markers and risk of diabetes are needed.

Meat, Dietary Heme Iron, and Risk of Type 2 Diabetes Mellitus: The Singapore Chinese Health Study

We evaluated the relationships of red meat, poultry, fish, and shellfish intakes, as well as heme iron intake, with the risk of type 2 diabetes mellitus (T2D).The Singapore Chinese Health Study is a population-based cohort study that recruited 63,257 Chinese adults aged 45-74 years from 1993 to 1998. Usual diet was evaluated using a validated 165-item semiquantitative food frequency questionnaire at recruitment. Physician-diagnosed T2D was self-reported during 2 follow-up interviews in 1999-2004 and 2006-2010. During a mean follow-up of 10.9 years, 5,207 incident cases of T2D were reported. When comparing persons in the highest intake quartiles with those in the lowest, the multivariate-adjusted hazard ratio for T2D was 1.23 (95% confidence interval (CI): 1.14, 1.33) for red meat intake (P for trend < 0.001), 1.15 (95% CI: 1.06, 1.24) for poultry intake (P for trend = 0.004), and 1.07 (95% CI: 0.99, 1.16) for fish/shellfish intake (P for trend = 0.12). After additional adjustment for heme iron, only red meat intake remained significantly associated with T2D risk (multivariate-adjusted hazard ratio = 1.13, 95% CI: 1.01, 1.25; P for trend = 0.02). Heme iron was associated with a higher risk of T2D even after additional adjustment for red meat intake (multivariate-adjusted hazard ratio = 1.14, 95% CI: 1.02, 1.28; P for trend = 0.03). In conclusion, red meat and poultry intakes were associated with a higher risk of T2D. These associations were mediated completely for poultry and partially for red meat by heme iron intake.

Red meat consumption and cardiovascular target organ damage (from the Strong Heart Study)

OBJECTIVE

The aim of this study was to investigate whether red meat consumption is related to changes in left ventricular mass (LVM), left atrial diameter and carotid atherosclerosis in American Indians.

METHODS

We prospectively analyzed echocardiographic and carotid ultrasound data of 1090 adults aged 40 years and older enrolled in the Strong Heart Family Study who were free of cardiovascular disease at baseline - 535 (49%) were hypertensive and 555 (51%) participants were nonhypertensive. Processed and unprocessed red meat intake was ascertained by using a Block food-frequency questionnaire at baseline. Cardiac and vascular biomarkers were assessed at baseline and 4 years later. Marginal models with multivariate adjustment were used to assess the associations of red meat intake with LVM, left atrial diameter, intima-media thickness and presence and extent of carotid atherosclerosis.

RESULTS

Participants with hypertension were older, had a higher BMI, were more likely to be diabetic and less physically active. Processed and unprocessed red meat consumption was related to an increase in the presence of atherosclerotic plaques in male and female hypertensive individuals. In male hypertensive participants, processed meat intake was further observed to be associated with an increase in intima-media thickness, atrial diameter but not LVM. In nonhypertensive participants, neither unprocessed nor processed red meat intake was associated with changes in cardiac parameters or carotid atherosclerosis.

CONCLUSION

Over a 4-year period, red meat consumption was related to cardiovascular target organ damage in hypertensive American Indians. These findings emphasize the importance of dietary measures for cardiovascular disease prevention.

Health risk factors associated with meat, fruit and vegetable consumption in cohort studies: A comprehensive meta-analysis

The aim of this study was to perform a meta-analysis to test the association between red, processed, and total meat, as well as fruit and vegetable consumption, and selected health risk factors, including body weight status, smoking habit, physical activity level, level of education, and alcohol drinking in cohort studies on non-communicable disease. A systematic search of electronic databases was performed to identify relevant articles published up to March 2017. In a two-stage approach, frequency-weighted linear regression coefficients were first calculated for each variable, and then combined across studies through meta-regression. Ninety-eight studies including 20 on red meat, 6 on processed meat, 12 on total meat, 37 on fruit and vegetable combined, 21 on fruit and 24 on vegetable consumption were analyzed. Intake of red meat was positively associated with BMI, percentage of overweight and obese, low physical activity, and current and ever smoking and inversely associated with percentage of non-smokers and high physically active individuals. Similar associations were found for red meat were found, although based on fewer data. Intake of fruits and vegetables was positively associated with prevalence of non-smokers, high education and high physical activity, and similar results were found when examining fruit and vegetable consumption separately. Stratification by geographical area revealed that some associations were stronger in US rather than European or Asian cohorts. In conclusions, the distribution of health risk factors associated with high meat and fruit/vegetable consumption may differ from those of low-consumers. Some of these differences may mediate, confound, or modify the relation between diet and non-communicable disease risk.

Relative validation of a short questionnaire to assess the dietary habits of pregnant American Indian women

The objective of this study was to compare a short dietary screener developed to assess diet quality with interviewer‐administered telephone 24‐hour dietary recalls in a population of pregnant Northern Plains (NP) American Indian women. Participants were recruited from NP clinical sites of the Prenatal Alcohol and SIDS and Stillbirth (PASS) Network, as part of a large, prospective, multidisciplinary study. Prenatal PASS participants who enrolled prior to 24 weeks gestation were eligible to participate. Repeated 24‐hour dietary recalls were collected using the Nutrition Data System for Research (NDSR) software and a short dietary screener was administered intended to capture usual dietary intake during pregnancy. The available recalls were averaged across days for analysis. Items were grouped from the recalls to match the food group data estimates for the screener (e.g., total vegetables, total fruit, total dairy, total and whole grains). Deattenuated Pearson correlation coefficients were calculated between the two data sources after correcting for the within‐person variation in the 24‐hour recall data. A total of 164 eligible women completed the screener and at least two 24‐hour dietary recalls and were included in the analyses. Pearson deattenuated correlation coefficients between the diet screener and the dietary recalls for the majority of food groups were 0.40 or higher. This short diet screener to assess usual diet appears to be a valid instrument for use in evaluating diet quality among pregnant American Indian women.

Arsenic metabolism and one-carbon metabolism at low-moderate arsenic exposure: Evidence from the Strong Heart Study

B-vitamins involved in one-carbon metabolism (OCM) can affect arsenic metabolism efficiency in highly arsenic exposed, undernourished populations. We evaluated whether dietary intake of OCM nutrients (including vitamins B2, B6, folate (B9), and B12) was associated with arsenic metabolism in a more nourished population exposed to lower arsenic than previously studied. Dietary intake of OCM nutrients and urine arsenic was evaluated in 405 participants from the Strong Heart Study. Arsenic exposure was measured as the sum of iAs, monomethylarsonate (MMA) and dimethylarsenate (DMA) in urine. Arsenic metabolism was measured as the individual percentages of each metabolite over their sum (iAs%, MMA%, DMA%). In adjusted models, increasing intake of vitamins B2 and B6 was associated with modest but significant decreases in iAs% and MMA% and increases in DMA%. A significant interaction was found between high folate and B6 with enhanced arsenic metabolism efficiency. Our findings suggest OCM nutrients may influence arsenic metabolism in populations with moderate arsenic exposure. Stronger and independent associations were observed with B2 and B6, vitamins previously understudied in relation to arsenic. Research is needed to evaluate whether targeting B-vitamin intake can serve as a strategy for the prevention of arsenic-related health effects at low-moderate arsenic exposure.

Ratio of serum levels of AGEs to soluble RAGE is correlated with trimethylamine-N-oxide in non-diabetic subjects

Trimethylamine (TMA), an intestinal microflora-dependent metabolite formed from phosphatidylcholine- and L-carnitine-rich food, such as red meat, is further converted to trimethylamine-N-oxide (TMAO), which could play a role in cardiometabolic disease. Red meat-derived products are one of the major environmental sources of advanced glycation end products (AGEs) that may also contribute to the pathogenesis of cardiometabolic disorders through the interaction with receptor for AGEs (RAGE). However, the relationship among AGEs, soluble form of RAGE (sRAGE) and TMAO in humans remains unclear. Non-diabetic subjects underwent a physical examination, determination of blood chemistry and anthropometric variables, including AGEs, sRAGE, TMA and TMAO. Multiple regression analyses revealed that HbA1c, uric acid and AGEs were independently associated with log TMA, whereas log AGEs to sRAGE ratio and statin non-use were independently correlated with log TMAO. Our present findings indicated that AGEs to sRAGE ratio was correlated with log TMAO, a marker of cardiometabolic disorders.

Dietary determinants of cadmium exposure in the Strong Heart Family Study

Urinary cadmium (Cd) concentrations in the Strong Heart Family Study (SHFS) participants are higher than in the general US population. This difference is unlikely to be related to tobacco smoking. We evaluated the association of consumption of processed meats and other dietary products with urinary Cd concentrations in the SHFS, a family-based study conducted in American Indian communities. We included 1725 participants with urine Cd concentrations (standardized to urine creatinine) and food frequency questionnaire data grouped in 24 categories, including processed meat. Median (IQR) urinary Cd concentrations were 0.42 (0.20-0.85) μg/g creatinine. The age, sex, smoking, education, center, body mass index, and total kcal adjusted geometric mean ratio (GMR) (95%CI) of urinary cadmium concentrations per IQR increase in each dietary category was 1.16 (1.04-1.29) for processed meat, 1.10 (1.00-1.21) for fries and chips, 0.87 (0.80-0.95) for dairy products, and 0.89 (0.82-0.97) for fruit juices. The results remained similar after further adjustment for the dietary categories associated with urinary Cd in the previous model except for fries and chips, which was no longer statistically significant. These findings revealed the potential importance of processed meat products as a dietary source of cadmium.

Processed Meat, but Not Unprocessed Red Meat, Is Inversely Associated with Leukocyte Telomere Length in the Strong Heart Family Study

BACKGROUND

Telomeres are repetitive nucleotide sequences (TTAGGG) and their associated proteins at the end of eukaryote chromosomes. Telomere length shortens throughout the lifespan with each cell division, and leukocyte telomere length (LTL) is often used as a biomarker of cellular aging. LTL is related to many chronic diseases, including cardiovascular disease and diabetes. However, to our knowledge, the relation between LTL and risk factors for cardiovascular disease and diabetes, such as dietary intake of processed meat and unprocessed red meat, is largely unknown.

OBJECTIVE

We examined the associations of processed meat intake and unprocessed red meat intake with LTL.

METHODS

This cross-sectional study comprised 2846 American Indians from the Strong Heart Family Study who participated in the 2001-2003 examination. Dietary factors, including past-year consumption of processed meat and unprocessed red meat, were assessed with the use of a 119-item Block Food-Frequency Questionnaire. LTL was measured with the use of quantitative polymerase chain reaction. Generalized estimating equations were used to examine the associations of intake of processed meat and unprocessed red meat with LTL.

RESULTS

Consumption of processed meat was negatively associated with LTL after adjustment for age, sex, site, education, smoking, alcohol use, physical activity, and other dietary factors. For every additional daily serving of processed meat, LTL was 0.021 units (telomeric product-to-single-copy gene ratio) shorter (β ± SE = -0.021 ± 0.008, P = 0.009). No association was observed between the intake of unprocessed red meat and LTL (β ± SE = 0.008 ± 0.011, P = 0.46).

CONCLUSIONS

In the Strong Heart Family Study, consumption of processed meat, but not unprocessed red meat, was associated with shorter LTL, a potential mediator for several age-related diseases. Further studies are needed to better understand the biological mechanism by which processed meat intake influences cellular aging.

Diabetes mellitus associated with processed and unprocessed red meat: an overview

According to American Diabetes Association "as many as 1 in 3 American adults will have diabetes by 2050" imposing a serious burden on healthcare services and highlighting a substantial need to reduce "new-cases" incidence. Diabetes is inextricably linked to diet, in the prevention-spectrum. Red-meat-intake has been positively associated with reduced glycemic control. However, divergence exists among meat subtypes (i.e. fresh and processed) and the magnitude of their impact on diabetes development. The present overview attempted to summarize the latest data regarding red-meat subtypes on the examined association. Four meta-analysis and 10 prospective studies, focusing on the role of fresh and processed red meat in diabetes prevention, were selected. All of studies highlighted the aggravating role of processed meat-products in diabetes incidence, while fresh meat reached significance in only half of them. Therefore, the contribution of fresh red meat on diabetes remains inconclusive. Valid conclusions seem more robust concerning processed-meat-consumption.

Metal mixtures in urban and rural populations in the US: The Multi-Ethnic Study of Atherosclerosis and the Strong Heart Study

BACKGROUND

Natural and anthropogenic sources of metal exposure differ for urban and rural residents. We searched to identify patterns of metal mixtures which could suggest common environmental sources and/or metabolic pathways of different urinary metals, and compared metal-mixtures in two population-based studies from urban/sub-urban and rural/town areas in the US: the Multi-Ethnic Study of Atherosclerosis (MESA) and the Strong Heart Study (SHS).

METHODS

We studied a random sample of 308 White, Black, Chinese-American, and Hispanic participants in MESA (2000-2002) and 277 American Indian participants in SHS (1998-2003). We used principal component analysis (PCA), cluster analysis (CA), and linear discriminant analysis (LDA) to evaluate nine urinary metals (antimony [Sb], arsenic [As], cadmium [Cd], lead [Pb], molybdenum [Mo], selenium [Se], tungsten [W], uranium [U] and zinc [Zn]). For arsenic, we used the sum of inorganic and methylated species (∑As).

RESULTS

All nine urinary metals were higher in SHS compared to MESA participants. PCA and CA revealed the same patterns in SHS, suggesting 4 distinct principal components (PC) or clusters (∑As-U-W, Pb-Sb, Cd-Zn, Mo-Se). In MESA, CA showed 2 large clusters (∑As-Mo-Sb-U-W, Cd-Pb-Se-Zn), while PCA showed 4 PCs (Sb-U-W, Pb-Se-Zn, Cd-Mo, ∑As). LDA indicated that ∑As, U, W, and Zn were the most discriminant variables distinguishing MESA and SHS participants.

CONCLUSIONS

In SHS, the ∑As-U-W cluster and PC might reflect groundwater contamination in rural areas, and the Cd-Zn cluster and PC could reflect common sources from meat products or metabolic interactions. Among the metals assayed, ∑As, U, W and Zn differed the most between MESA and SHS, possibly reflecting disproportionate exposure from drinking water and perhaps food in rural Native communities compared to urban communities around the US.