Higher Intake of Total Dietary Essential Amino Acids Is Associated with a Lower Prevalence of Metabolic Syndrome among Korean Adults

Protein source associated with risk of metabolic syndrome in adults with low and adequate protein intake: A prospective cohort study of middle-aged and older adults

OBJECTIVES

Metabolic syndrome is associated with an increased risk of diabetes, cardiovascular disease, and all-cause mortality. Some evidence suggests that the cardiometabolic health benefits of protein intake may vary by the source (animal or plant); however, the evidence is inconsistent. This study aimed to assess the risk of developing metabolic syndrome according to the protein source.

PARTICIPANTS

Among a total of 3,310 participants aged 40 years or older in the Ansan and Ansung population based prospective cohort, 1,543 incident cases of metabolic syndrome were identified between 2007 and 2018.

MEASUREMENTS

Dietary intake was assessed using a validated food frequency questionnaire. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) by quintile (Q), adjusting for demographics and health-related lifestyle factors.

RESULTS

Higher intake of animal protein (HRquintile5 (Q5) vs quintile1 (Q1) [95% CIs]: 0.76 [0.59-0.96], P-trend ≤ 0.0307) and a higher relative intake of animal protein (HRQ5 vs.Q1: 0.78 [0.64-0.95], P-trend ≤ 0.0017) were associated with a significantly decreased risk of developing metabolic syndrome. In subgroup analyses, associations between the risk of metabolic syndrome and the relative intake of animal and plant protein differed according to whether the total protein intake was within the recommended nutrient intake (RNI). Specifically, significant associations were observed only among those with a total protein consumption below the RNI (HRQ5vs Q1 [95% CIs]: 0.72 [0.56-0.93] for the relative intake of animal protein), but not among those consuming above the RNI. This association was more significant in women than in men.

CONCLUSION

A higher absolute and relative intake of animal protein were associated with a significantly decreased risk of metabolic syndrome, particularly among those who consumed less than the RNI of protein.

The inverse associations of glycine and histidine in diet with hyperlipidemia and hypertension

BACKGROUND

Amino acids are crucial for nutrition and metabolism, regulating metabolic pathways and activities vital to organismal health and stability. Glycine and histidine act as potent antioxidants and anti-inflammatory agents; however, limited knowledge exists regarding the associations between these amino acids and hyperlipidemia and hypertension. The purpose of this study is to investigate the relationship between dietary glycine and histidine, and hyperlipidemia and hypertension.

METHODS

This population-based cross-sectional study evaluated the influence of dietary glycine and histidine, as well as their combined effect, on hyperlipidemia and hypertension in Chinese adults participating in the Nutrition Health Atlas Project (NHAP). General characteristics were acquired using a verified Internet-based Dietary Questionnaire for the Chinese. Binary logistic regression, along with gender, age groups, and median energy intake subgroup analyses, was employed to investigate the associations between dietary glycine and histidine and hyperlipidemia and hypertension. A sensitivity analysis was conducted to assess the impact of excluding individuals who smoke and consume alcohol on the results.

RESULTS

Based on the study's findings, 418 out of 1091 cases had hyperlipidemia, whereas 673 had hypertension. A significant inverse relationship was found between dietary glycine, histidine, and glycine + histidine and hyperlipidemia and hypertension. Compared with the 1st and 2nd tertiles, the multivariable-adjusted odd ratios (ORs) (95% confidence intervals) (CIs) of the 3rd tertile of dietary glycine for hyperlipidemia and hypertension were 0.64 (0.49-0.84) (p < 0.01) and 0.70 (0.56-0.88) (p < 0.001); histidine was 0.63 (0.49-0.82) (p < 0.01) and 0.80 (0.64-0.99) (p < 0.01); and glycine + histidine was 0.64 (0.49-0.83) (p < 0.01) and 0.74 (0.59-0.92) (p < 0.001), respectively. High glycine and high histidine (HGHH) intake were negatively associated with hyperlipidemia and hypertension OR (95% CIs) were: 0.71 (0.58-0.88) (p < 0.01) and 0.73 (0.61-0.87) (p < 0.01), respectively.

CONCLUSIONS

Dietary glycine and histidine, as well as their HGHH group, revealed an inverse relationship with hyperlipidemia and hypertension. Further investigations are needed to validate these findings.

Dietary serine intake is associated with cognitive function among US adults

Aims: Diet can modify the risk of cognitive decline. However, research on the relationship between dietary intake of serine and cognitive decline remains limited and this study aims to reveal the relationship between them. Methods: Data from the National Health and Nutrition Examination Survey (NHANES) 1988-1994 (n = 1837) were used to explore the relationship between dietary intakes of serine and cognitive function through quantile multiple linear analysis and restricted cubic splines (RCS) regression. We also investigated 9 food groups for serine intake according to the USDA food code to determine which food sources of serine are beneficial for cognitive function. Results: The top three serine intakes were attributed to meat/poultry/fish, grain products, and milk or milk products. Multivariable linear regression analysis showed that a significant negative linear trend was observed between serine intake and SDLT. RCS results showed a non-linear relationship between serine intake and SDLT or SDST. Among the 9 food group intakes, milk or milk products sourced serine intake was good for memory ability. Conclusion: serine, particularly serine from milk or milk products, has a beneficial impact on memory ability in adults.

Dietary branched-chain amino acids intake, glycemic markers, metabolic profile, and anthropometric features in a community-based sample of overweight and obese adults

BACKGROUND

Existing research provides conflicting evidence regarding the relationship between estimated branched-chain amino acid (BCAA) intake and metabolic, glycemic markers, and anthropometric characteristics. This research seeks to examine the association between estimated dietary BCAA consumption and glycemic, and metabolic markers, as well as anthropometric parameters in adults classified as overweight or obese.

METHODS

In this cross-sectional analysis, we gathered data from 465 overweight and obese individuals aged between 18 and 37 years. To evaluate dietary data, we employed the food frequency questionnaire, and the BCAA content in foods was determined via the United States Department of Agriculture website. We utilized ELISA kits to measure fasting blood glucose (FBS) and lipid profile markers, and additionally calculated low-density lipoprotein (LDL) and insulin sensitivity markers. We assessed sociodemographic status, physical activity (PA), and anthropometric attributes through a method recognized as both valid and reliable. For statistical analysis, we conducted analyses of covariance (ANCOVA), making adjustments for variables including sex, PA, age, energy, and body mass index (BMI).

RESULTS

Upon adjusting for confounders, those in the highest tertiles of BCAA intake exhibited an increase in weight, BMI, waist circumference (WC), waist-to-hip ratio (WHR), and fat-free mass (FFM). Conversely, they demonstrated reduced fat mass (FM) (%) and FM (kg) compared to their counterparts in the lowest tertiles (P < 0.05). Additionally, there was a noted association between greater estimated BCAA intake and reduced LDL levels. Nonetheless, our findings did not reveal a significant relationship between dietary BCAA and glycemic indices.

CONCLUSIONS

From our findings, an increased estimated intake of BCAA seems to correlate with diminished serum LDL concentrations. To gain a more comprehensive understanding of this association, it is imperative that further experimental and longitudinal studies be conducted.

Protein Quality, Glycemic and Metabolic Indices and Anthropometric Features Among Overweight and Obese Adults

Background

Various studies have shown an inverse relationship between the quality of protein intake based on essential amino acids (EAAs) with obesity and its complications. We assumed that increasing EAAs-based protein intake quality improves glycemic and metabolic markers and anthropometric measurements in obese and overweight people.

Methods

This cross-sectional study included 180 obese and overweight participants aged 18 to 35. Dietary information was obtained using an 80-item food frequency questionnaire. The total intake of EAAs was calculated using the United States department of agriculture (USDA) database. Quality protein was defined as the ratio of EAAs (gr) to total dietary protein (gr). Sociodemographic status, physical activity (PA), and anthropometric characteristics were evaluated using a valid and reliable method. Analysis of covariance (ANCOVA) tests adjusted for sex, PA, age, energy, and body mass index (BMI) were used to measure this association.

Results

Protein quality intake was highest among the group with the lowest weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), and fat mass (FM); and on the other hand, the fat-free mass (FFM) has increased; also Increasing the quality of protein intake improved the lipid profile and some glycemic indices and insulin sensitivity, although this association was not significant.

Conclusions

Increasing the quality of protein intake significantly improved anthropometric measurements, and also improved some glycemic and metabolic indices although, their relationship was not significant.