Risk of metabolic syndrome and metabolic phenotypes in relation to biomarker-calibrated estimates of energy and protein intakes: an investigation from the Women's Health Initiative

Blood pressure impact of dietary practices using the DASH method: a systematic review and meta-analysis

Background

In order to ascertain the impact of the Dietary Approach to Stop Hypertension (DASH) diet on blood pressure (BP), a systematic review and meta-analysis of randomized controlled trials were carried out. DASH is advised for lowering BP.

Methods

Scopus databases were searched from the beginning of 2024. A total of 579 articles from 2019 to 2023 from PubMed: 15, Scopus: 164 and Crossref: 400. There were 8 articles included in the meta-analysis.

Results

Systolic BP (1.29 mmHg to 4.6 mmHg, 95% CI, -2.17, -0.41; P < 0.005) and diastolic BP (0.76 mmHg to 1.1 mmHg, 95% CI, -1.39, -0.13; P < 0.005) were found to be significantly reduced by the DASH diet, while total cholesterol concentrations (5.2 mmol/L; P < 0.005), low-density lipoprotein (8.2 mmol/L; P = 0.03), and high-density lipoprotein increased by 8.2% (P < 0.005) were lowered by 0.9 points.

Conclusions

When followed consistently, the DASH diet can reduce BP's systolic and diastolic readings.

Trial Registration

PROSPERO Identifier: CRD42023494005.

Association between the C-reactive protein-albumin-lymphocyte index and metabolic syndrome: evidence from the 2003-2010 national health and nutrition examination survey

BACKGROUND

Metabolic syndrome (MetS) is a global public health problem that significantly impacts human health and quality of life. The relationship between MetS and the C-reactive protein-albumin-lymphocyte (CALLY) index is uncertain.

METHODS

This study analyzed the data of 7,534 individuals from the National Health and Nutrition Examination Survey cycles (2003-2010 cycles). Weighted logistic regression and weighted restricted cubic spline (RCS) curve analyses were used to identify the relationships between the CALLY index and MetS, as well as its components.

RESULTS

Of the 7,534 participants, 2,086 were diagnosed with MetS. The estimated prevalence of MetS decreased with an increase in the CALLY index (P < 0.001). Multivariable logistic regression analysis showed that the odds ratio of MetS was 0.25 (95% confidence interval 0.20-0.32, P < 0.001) in the highest CALLY index quartile compared with the lowest quartile after adjusting for confounding variables. The RCS curve analysis revealed non-linear relationships between the CALLY index and MetS or its components.

CONCLUSIONS

This study revealed an inverse relationship between the CALLY index and MetS risk. The CALLY index might be valuable for identifying individuals who are at a high risk of MetS.

CLINICAL TRIAL NUMBER

Not applicable.

Lifestyle Factors Influencing Metabolic Syndrome after Adjusting for Socioeconomic Status and Female Reproductive Health Indicators: A National Representative Survey in Korean Pre- and Postmenopausal Women

Metabolic syndrome (MetS) is increasing markedly among postmenopausal women. Although studies suggest multiple risk factors for its development, few have investigated changes in socioeconomic status (SES), female reproductive health indicators (menarche age, experience of pregnancy, delivery, breastfeeding, and postmenopausal status), and lifestyle factors. This study investigated lifestyle factors affecting MetS prevalence among pre- and post-menopausal women after adjusting for SES and female reproductive health indicators. Data from the Korea National Health and Nutrition Examination Survey VII (2016-2018) on 2856 pre- and postmenopausal women aged 40-59 years were analyzed. Differences in SES (e.g., age, education, and household income), female reproductive health indicators (e.g., age of menarche and menopause), and lifestyle (e.g., total calorie intake, fats, and proteins, percentage of energy from carbohydrates, fats, and proteins, smoking, physical activity, and obesity) between MetS and non-MetS groups were calculated by performing χ2 or t-tests. Consequently, current smoking, physical inactivity, overweight, and obesity were significantly associated with increased MetS after adjusting for SES and female reproductive health indicators using logistic regression analysis. Hence, health policies and programs focusing on modifiable MetS risk factors-encouraging healthy eating habits, smoking cessation, and regular exercise-must be formulated to prevent the development of MetS in pre- and postmenopausal women.

L-theanine regulates the immune function of SD rats fed high-protein diets through the FABP5/IL-6/STAT3/PPARα pathway

The protein levels in a diet are correlated with immunity but the long-term intake of excessive protein can compromise various aspects of health. L-theanine regulates immunity and protein metabolism; however, how its regulatory immunity effects under a high-protein diet are unclear. We used proteomics, metabonomics, and western blotting to analyze the effects of diets with different protein levels on immune function in rats to determine the role of L-theanine in immunity under a high-protein diet. The long-term intake of high-protein diets (≥40% protein) promoted oxidative imbalance and inflammation. These were alleviated by L-theanine. High-protein diets inhibited peroxisome proliferator-activated receptor (PPAR)α expression through the interleukin (IL)-6/signal transducer and activator of transcription (STAT)3 pathway and mediated inflammation. L-theanine downregulated anti-fatty acid-binding protein 5 (FABP5), inhibited the IL-6/STAT3 axis, and reduced high-protein diet-induced PPARα inhibition. Therefore, L-theanine alleviates the adverse effects of high-protein diets via the FABP5/IL-6/STAT3/PPARα pathway and regulates the immunity of normally fed rats through the epoxide hydrolase (EPHX)2/nuclear factor-kappa B inhibitor (IκB)α/triggering receptor expressed on myeloid cells (TREM)1 axis.

Carbon Isotope Ratios of Plasma and RBC Fatty Acids Identify Meat Consumers in a 12-Week Inpatient Feeding Study of 32 Men

BACKGROUND

Molecular stable isotope ratios are a novel type of dietary biomarker with high sensitivity and specificity for certain foods. Among these, fatty acid carbon isotope ratios (CIRs) have strong potential but have not been investigated as dietary biomarkers.

OBJECTIVES

We evaluated whether fatty acid CIRs and mass proportions were associated with meat, fish, and sugar-sweetened beverage (SSB) intake.

METHODS

Thirty-two men [aged 46.2 ± 10.5 y; BMI (kg/m2): 27.2 ± 4.0] underwent a 12-wk inpatient dietary intervention at the National Institute of Diabetes and Digestive and Kidney Diseases in Phoenix, Arizona. Men were randomly assigned to 1 of 8 dietary treatments varying the presence/absence of dietary meat, fish, and SSBs in all combinations. Fatty acid CIRs and mass proportions were measured in fasting blood samples and adipose tissue biopsies that were collected pre- and postintervention. Dietary effects were analyzed using multivariable regression and receiver operating characteristic AUCs were calculated using logistic regression.

RESULTS

CIRs of the several abundant SFAs, MUFAs and arachidonic acid (20:4n-6) in plasma were strongly associated with meat, as were a subset of these fatty acids in RBCs. Effect sizes in plasma ranged from 1.01‰ to 1.93‰ and were similar but attenuated in RBCs. Mass proportions of those fatty acids were not associated with diet. CIRs of plasma dihomo-γ-linolenic acid (20:3n-6) and adipose palmitic acid (16:0) were weakly associated with SSBs. Mass proportions of plasma odd-chain fatty acids were associated with meat, and mass proportions of plasma EPA and DHA (20:5n-3 and 22:6n-3) were associated with fish.

CONCLUSIONS

CIRs of plasma and RBC fatty acids show promise as sensitive and specific measures of dietary meat. These provide different information from that provided by fatty acid mass proportions, and are informative where mass proportion is not. This trial is registered at www.clinicaltrials.gov as NCT01237093.

Pyropia yezoensis porphyran alleviates metabolic disorders via modulating gut microbiota in high-sucrose-fed Drosophila melanogaster

BACKGROUND

Prebiotics, such as algal polysaccharides, can be used to manage metabolic diseases by modulating gut microbiota. However, the effect of Pyropia yezoensis porphyran (PYP), a red algal polysaccharide, on gut microbiota has not been reported. Thus, the objective of this study was to determine effects of PYP on metabolic disorders caused by high sucrose (HS) and underlying mechanisms involved in such effects.

RESULTS

Biochemical analysis demonstrated that an HS diet increased triglyceride and circulating sugar contents (metabolic abnormalities) in Drosophila larvae. It also increased the relative abundance of harmful microbiota within the larvae as identified by 16S ribosomal DNA analysis. PYP supplementation at 25 and 50 g kg^-1 equivalently reduced metabolic abnormalities in the HS group. Therefore, 25 g kg^-1 PYP was selected to investigate its effects on the metabolic pathway and gut microbiota of larvae in the HS group. The activity of PYP in ameliorating metabolic abnormalities by reverse transcription quantitative real-time polymerase chain reaction analysis was consistent with the expression trend of key factors involved in metabolism regulation. PYP reduced the relative abundance of bacteria causing metabolic abnormalities, such as Escherichia-Shigella and Fusobacterium, but increased the relative abundance of beneficial bacteria such as Bacillus and Akkermansia. However, PYP had no effect on triglyceride and circulating sugar contents in HS-fed larvae treated with a mixture of antibiotics designed to remove gut microbiota.

CONCLUSION

PYP exhibits anti-metabolic disorder activity by modulating gut microbiota, thereby supporting the development of PYP as a functional prebiotic derived from red algae food. Copyright © 2022 John Wiley & Sons, Ltd. © 2022 Society of Chemical Industry.

Dietary total, plant and animal protein intake in relation to metabolic health status in overweight and obese adolescents

Few studies have investigated dietary total protein intake and its subtypes in relation to metabolic health status. We explored the relation between dietary total, plant and animal protein intake with metabolic health status in Iranian overweight/obese adolescents. Overweight/obese adolescents (n = 203) were selected for this cross-sectional study by multistage cluster random-sampling method. A validated food frequency questionnaire was used to evaluate dietary intakes. Total, plant and animal protein intake were considered as percentage of energy intake. Anthropometric indices, blood pressure, lipid and glycemic profiles were collected. Participants were classified as metabolically healthy obese (MHO) or unhealthy obese (MUO) based on International Diabetes Federation (IDF) and IDF/Homeostasis Model Assessment Insulin Resistance (HOMA-IR) definitions. Subjects had a mean age of 13.98 years, and 50.2% of them were girls. Based on IDF criteria, adolescents in the top tertile of total (OR = 0.32; 95% CI 0.13–0.77), plant (OR = 0.30; 95% CI 0.10–0.91), and animal (OR = 0.20; 95% CI 0.08–0.54) protein intake had lower odds of being MUO compared to the reference category. Considering IDF/HOMA-IR criteria, subjects in the highest tertile of total (OR = 0.31; 95% CI 0.12–0.79) and animal (OR = 0.17; 95% CI 0.06–0.49) protein intake were less likely to be MUO. However, no substantial association was observed with plant protein intake. Also, an inverse association was observed between each SD increase in total and animal protein with MUO odds. We found inverse association between total, plant and animal protein intake and chance of being MUO in adolescents. Further prospective studies are needed to confirm the findings.

An evaluation of the serum carbon isotope ratio as a candidate predictive biomarker of the dietary animal protein ratio (animal protein/total protein) in a 15-day controlled feeding study of US adults

BACKGROUND

The serum natural abundance carbon isotope ratio (CIR) was recently identified as a candidate biomarker of animal protein intake in postmenopausal women. Such a biomarker would help clarify the relation between dietary protein source (plant or animal) and chronic disease risk.

OBJECTIVES

We aimed to evaluate the performance of the serum CIR as a biomarker of dietary protein source in a controlled feeding study of men and women of diverse age and BMI.

METHODS

We conducted a 15-d feeding study of 100 adults (age: 18-70 y, 55% women) in Phoenix, AZ. Participants were provided individualized diets that approximated habitual food intakes. Serum was collected at the end of the feeding period for biomarker measurements.

RESULTS

Median [IQR] animal protein intake was 67 g/d [55-88 g/d], which was 64% of total protein. The serum CIR was positively correlated with animal protein and inversely correlated with plant protein intake, leading to a strong correlation (r2 = 0.76) with the dietary animal protein ratio (APR; animal/total protein). Regressing serum CIR on the APR, serum nitrogen isotope ratio (NIR), gender, age, and body weight generated an R2 of 0.78. Following the measurement error model for predictive biomarkers, the resulting regression equation was then inverted to develop a calibrated biomarker equation for APR. Added sugars ratio (added/total sugars intake) and corn intakes also influenced the serum CIR but to a much lesser degree than the APR; variations in these intakes had only small effects on biomarker-estimated APR.

CONCLUSIONS

Based on our findings in this US cohort of mixed sex and age, we propose the serum CIR alongside NIR as a predictive dietary biomarker of the APR. We anticipate using this biomarker to generate calibrated estimates based on self-reported intake and ultimately to obtain more precise disease risk estimates according to dietary protein source.

Macronutrient Intake in Adults Diagnosed with Metabolic Syndrome: Using the Health Examinee (HEXA) Cohort

Macronutrient intake is important in the prevention and management of metabolic syndrome (MetS). This study aimed to evaluate total energy and macronutrient intake of participants diagnosed with MetS at recruitment of the health examinees (HEXA) cohort, considering the plant and animal sources of each macronutrient. We included 130,423 participants aged 40-69 years for analysis. Odds ratios (OR) and 95% confidence intervals (CI) were estimated to evaluate the intake of macronutrients stratified by gender. Energy and macronutrient intake were estimated by linking food frequency questionnaire data to the Korean food composition database, and were calculated separately for plant and animal foods. Low energy (men: OR = 0.95, 95% CI: 0.92-0.98; women: OR = 0.97, 95% CI: 0.95-0.99), and fat intake (men: OR = 0.93, 95% CI: 0.90-0.96; women: OR = 0.80, 95% CI: 0.77-0.83) were observed. Only postmenopausal women had lower intake of total energy (OR = 0.95, 95% CI: 0.92-0.97), whereas low fat intake was observed in all women (OR = 0.80, 95% CI: 0.77-0.83). For carbohydrate intake, the OR were 1.14 (95% CI: 1.08-1.22) and 1.17 (95% CI: 1.08-1.27) among women in their 50s and 60s, respectively. Protein intake was low (OR = 0.90, 95% CI: 0.86-0.95; and OR = 0.88, 95% CI: 0.82-0.94) among women in their 50s and 60s, respectively. High intake of plant carbohydrates in women (OR = 1.16, 95% CI: 1.12-1.20), and plant protein in both genders (OR = 1.09, 95% CI: 1.05-1.13) were observed, but low intake of total energy, fat, and animal-source carbohydrates in both genders was also observed. Fat intake was low regardless of food source. In conclusion, high consumption of plant-source macronutrients, and low consumption of animal-source macronutrients was observed in Korean adults diagnosed with MetS. Attention should be directed to plant sources of carbohydrates and proteins when designing population interventions for metabolic syndrome reduction in Korea.