Dietary sodium intake and prevalence of overweight in adults

Estimation of 24-hour urinary sodium and potassium excretion among Chinese adults: a cross-sectional study from the China National Nutrition Survey

BACKGROUND

High-sodium intake is one of the most important risk factors for hypertension and cardiovascular disease, yet reliable national estimates of sodium intake in Chinese adults have not been reported.

OBJECTIVES

We estimated 24-h urinary sodium and potassium excretion and population daily sodium and potassium intake of Chinese adults for the first time at a national level.

METHODS

A nationally representative cross-sectional survey was conducted to collect 24-h urine specimens from Chinese adults aged ≥18 y as part of the China National Nutrition Survey 2015. Finally, 10,114 participants (4932 males and 5182 females) with complete 24-h urine specimens were included in the analysis. Estimates of mean urinary electrolyte excretion and demographic, socioeconomic, and health characteristics were used with weighted coefficients that accounted for sample selection probabilities, poststratification weighting, and nonresponse rates.

RESULTS

The estimation of overall weighted mean 24-h urinary sodium excretion was 4121 mg (95% confidence interval [CI]: 3993, 4250), 4155 mg (95% CI: 3993, 4317) in males and 4081 mg (95% CI: 3953, 4209) in females (P for sex difference = 0.36). Overall mean 24-h urinary potassium excretion was 1534 mg (95% CI: 1492, 1577), 1468 mg (95% CI: 1424, 1513) in males and 1614 mg (95% CI: 1569-1660) in females (P for sex difference <0.001). Mean 24-h urinary sodium excretion was significantly higher in rural adults (4350 mg; 95% CI: 4217, 4483) than in urban residents (3909 mg; 95% CI: 3739, 4080; P < 0.001), and in northern residents (4388 mg; 95% CI: 4237, 4539) than in southern residents (3998 mg; 95% CI: 3832, 4163; P = 0.002).

CONCLUSIONS

The first nationwide survey with 24-h urine collection confirmed that mean sodium intake in Chinese adults was more than twice the upper limit, whereas mean potassium intake was <60% of the lower limit, recommended by the World Health Organization. Urgent measures should be taken to reduce sodium intake and increase potassium intake in China.

Comparison between 24-hour diet recall and 24-hour urine collection for estimating sodium and potassium intakes and their ratio among Korean adults

BACKGROUND/OBJECTIVES

This study aimed to compare 24-h diet recall (DR) and 24-h urine collection (UC) for estimating sodium and potassium intakes and their ratio (Na/K), identifying factors associated with sodium and potassium intakes and Na/K, and identifying those who were likely to underestimate sodium and potassium intakes by DR.

SUBJECTS/METHODS

A total of 640 healthy adults aged 19-69 yrs completed a questionnaire survey, salty taste assessment, anthropometric measurement, two 24-h DRs, and two 24-h UCs.

RESULTS

The mean sodium and potassium intakes and Na/K were 3,755 mg/d, 2,737 mg/d, and 1.45 according to DR, and 4,145 mg/d, 2,812 mg/d, and 1.57 according to UC, with percentage differences of -9.4%, -2.7%, and -7.6% in the values between the two methods, respectively. Men, older adults, smokers, obese individuals, those who consumed all the liquid in the soup, and those who were found to be salty in the salty taste assessment consumed significantly more sodium; older adults, the heavy- activity group, and obese individuals consumed more potassium; and men, younger adults, smokers, and obese individuals had a significantly higher Na/K, according to UC. Compared with UC, DR was more likely to underestimate sodium intake in older adults, smokers, obese individuals, those who consumed all the liquid in the soup, and those who consumed eating-out/delivery food at least once a day, and potassium intake in older adults, the heavy-activity group, and obese individuals.

CONCLUSIONS

The mean sodium and potassium intakes and Na/K estimated by DR were comparable to those measured by UC. However, the association of sodium and potassium intakes with sociodemographic and health-related factors showed inconsistent results when estimated by DR and UC. Factors influencing the underestimation of sodium intake by DR compared to UC should be further investigated.

The association between dietary sodium intake and obesity in adults by sodium intake assessment methods: a review of systematic reviews and re-meta-analysis

BACKGROUND/OBJECTIVES

The scientific evidence of a sodium-obesity association is limited by sodium intake assessments. Our specific aim is to synthesize the association between dietary sodium intake and obesity across the sodium intake assessments as evidenced by systematic reviews in adults.

SUBJECTS/METHODS

A systematic search identified systematic reviews comparing the association of dietary sodium intakes with obesity-related outcomes such as body mass index (BMI), body weight, waist circumference, and risk of (abdominal) obesity. We searched PubMed on October 24, 2022. To assess the Risk of Bias in Systematic Reviews (ROBIS), we employed the ROBIS tool.

RESULTS

This review included 3 systematic reviews, consisting of 39 unique observational studies (35 cross-sectional studies and 4 longitudinal studies) and 15 randomized controlled trials (RCTs). We found consistently positive associations between dietary sodium intake and obesity-related outcomes in cross-sectional studies. Studies that used 24-h urine collection indicated a greater BMI for those with higher sodium intake (mean difference = 2.27 kg/m2; 95% confidence interval [CI], 1.59-2.51; P < 0.001; I2 = 77%) compared to studies that used spot urine (mean difference = 1.34 kg/m2; 95% CI, 1.13-1.55; P < 0.001; I2 = 95%) and dietary methods (mean difference = 0.85 kg/m2; 95% CI, 0.1-1.51; P < 0.05; I2 = 95%).

CONCLUSIONS

Quantitative synthesis of the systematic reviews has shown that cross-sectional associations between dietary sodium intake and obesity outcomes were substantially different across the sodium intake assessments. We need more high-quality prospective cohort studies and RCTs using 24-h urine collection to examine the causal effects of sodium intake on obesity.

Urinary Sodium Excretion and Obesity Markers among Bangladeshi Adult Population: Pooled Data from Three Cohort Studies

We evaluated the relationship of urinary sodium excretion with a conditional mean, 10th and 90th percentiles of body mass index (BMI), and waist circumference among 10,034 person-visits of Bangladeshi population. We fitted linear mixed models with participant-level random intercept and restricted maximum likelihood estimation for conditional mean models; and quantile mixed-effect models with participant-level random intercept and Laplace estimation for 10th and 90th percentiles models. For each 100 mmol/24 h increase in urinary sodium excretion, participants had a 0.10 kg/m2 (95% CI: 0.00, 0.10) increase in the mean; a 0.39 kg/m2 (95% CI: 0.23, 0.54) increase in the 10th percentile; and a 0.59 kg/m2 (95% CI: 0.39, 0.78) increase in the 90th percentile of BMI. For each 100 mmol/24 h increase in urinary sodium excretion, participants had a 0.20 cm (95% CI: 0.10, 0.30) increase in mean; a 0.18 cm (95% CI: -0.03, 0.40) change in the 10th percentile; and a 0.23 cm (95% CI: 0.03, 0.43) increase in the 90th percentile of waist circumference. We found a modest association between urine sodium and conditional mean of BMI and waist circumference. The magnitude of associations between urine sodium and the 10th and 90th percentile BMI distributions were higher compared to the conditional mean models, suggesting high sodium intake could be more detrimental to underweight and obese participants.

Identifying Excessive Intake of Oil and Salt to Prevent and Control Hypertension: A Latent Class Analysis

Introduction

To identify health hazard behaviors and provide a basis for targeted management and intervention for patients with hypertension, we classified their health-related behaviors.

Methods

A multi-stage random sampling method was used to conduct an on-site questionnaire survey among residents aged ≥15 years in a certain urban area of Taiyuan City, Shanxi Province, China. A latent class analysis was used to classify the lifestyle behaviors of patients with hypertension. The lifestyle behavior characteristics of different types of patients with hypertension and their awareness of hypertension were assessed.

Results

The prevalence of hypertension in Taiyuan City was 19.5%. Patients with hypertension were classified into three clusters according to their lifestyle patterns: smoking and drinking (13.35%), excessive edible oil and salt intake (68.27%), and healthy behavior (18.38%). Comparing the three latent classes of lifestyle, the distribution of age, sex, marital status, and education level was different (P < 0.05). The awareness of hypertension and the rate of control among the three classes were also different (P < 0.05).

Conclusion

The lifestyle behaviors of patients with hypertension have evident classification characteristics. Approximately two-thirds of the patients with hypertension have an excessive intake of oil and salt. Therefore, targeted and precise intervention measures should be taken to control the intake of oil and salt in this cohort.

High-fat and high-sodium diet induces metabolic dysfunction in the absence of obesity

OBJECTIVE

Excess dietary fat and sodium (NaCl) are both associated with obesity and metabolic dysfunction. In mice, high NaCl has been shown to block high-fat (HF) diet-induced weight gain. Here, the impact of an HF/NaCl diet on metabolic function in the absence of obesity was investigated.

METHODS

Wild-type mice were administered chow, NaCl (4%), HF, and HF/NaCl diets. Metabolic analysis was performed by measuring fasted blood glucose and insulin levels and by glucose tolerance test and insulin tolerance test.

RESULTS

After 10 weeks on diets, male and female mice on the HF diet gained weight, and HF/NaCl mice had significantly reduced weight gain similar to chow-fed mice. In the absence of obesity, HF/NaCl mice had significantly elevated fasting blood glucose and impaired glucose control during glucose tolerance tests. Both NaCl and HF/NaCl mice had decreased pancreas and β-cell mass. Administration of NaCl in drinking water did not protect mice from HF-diet-induced weight gain and obesity. Further analysis revealed that longer administration of HF/NaCl diets for 20 weeks resulted in significant weight gain and insulin resistance.

CONCLUSIONS

The data demonstrate that despite early inhibitory effects on fat deposition and weight gain, an HF/NaCl diet does not prevent the metabolic consequences of HF diet consumption.

Associations of Urine Specific Gravity With Body Mass Index and Lean Body Mass at the Population Level: Implications for Hydration Monitoring

Urine specific gravity (USG) thresholds are used in practice and research to determine hypohydration. However, some limited research has found that body size and body composition may impact USG, suggesting that fixed cutoffs may be insensitive. Cross-sectional data from 3,634 participants of the 2007-2008 National Health and Nutrition Examination Survey were analyzed. Along with USG, body mass index (BMI), estimated lean body mass (LBM), and dietary intake were quantified. Logistic regression models were used to evaluate whether higher quintiles of BMI and LBM were associated with elevated USG (USG ≥ 1.020 and ≥1.025) after accounting for dietary moisture and sodium. The USG (1.018 ± 0.0003 vs. 1.015 ± 0.0004); BMI (28.4 ± 0.2 vs. 28.0 ± 0.2 kg/m2); LBM (60.9 ± 0.3 vs. 42.2 ± 0.2 kg); dietary moisture (3,401 ± 92 vs. 2,759 ± 49 g/day); and dietary sodium (4,171 ± 85 vs. 2,959 ± 50) were greater in men than in women (p < .05). Men and women in the fifth quintiles of BMI or LBM (vs. Quintile 1) had greater odds (2.00-3.68, p < .05) of elevated USG. (The only exception was for the association between BMI and USG ≥ 1.025 in men.) Being in Quintile 4 of LBM or BMI (vs. Quintile 1) also tended to be associated with higher odds of elevated of USG, though this pattern was more consistent when using USG ≥ 1.020 than USG ≥ 1.025. In summary, BMI and LBM are associated with USG at the population level. These results affirm that USG depends on body size and composition and raise questions about using fixed USG thresholds for determining hypohydration, particularly for people in the upper quintiles of BMI and LBM.

Characteristics of urinary sodium excretion in patients with chronic kidney disease in Jiangsu, China

The current study aimed to assess the dietary salt intake in patients with CKD in Jiangsu province and investigate the relationship of urinary sodium excretion with blood pressure. A total of 800 patients with CKD stages 1-4 were recruited. All enrolled patients were asked to collect complete 24-h urine specimen. At the same time, patient's demographic and laboratory data were recorded. The mean age was 47.45 ± 15.25 years old, including 423 men and 377 women. There was no significant difference in urinary sodium excretion among different stages of CKD (p = .748). This study revealed that the median urinary sodium excretion of all patients was 127.20 mmol/d (IQR 91.03-172.06), corresponding to a salt intake of 7.4 g/d. Among them, only 167 (20.9%) cases had salt intake <5 g/d. Moreover, urinary sodium excretion in overweight group and obese group was higher than that in normal weight group (p = .001, p ˂ .001). Likewise, urinary sodium excretion in men was higher than that in women (p ˂ .001). Spearman correlation analysis indicated that urinary sodium excretion positively correlated with urinary protein excretion (r = .178, p ˂ .001), SBP (r = .109, p = .002), and DBP (r = .086, p = .015). After adjusting for age, gender, BMI, eGFR, urinary protein excretion, and history of taking antihypertensive drug, multivariate linear regression demonstrated that higher level of urinary sodium excretion associated with increased level of SBP, DBP, and MAP (β = 0.020, p = .049; β = 0.015, p = .040; β = 0.016, p = .025, respectively). In conclusion, the dietary salt intake in CKD patients, especially in male, overweight and obese subjects, remains high in Jiangsu province. It is vital to decline salt intake to control blood pressure in Jiangsu patients with CKD.

Relationship of Sodium Intake with Overweight/Obesity among Chinese Children and Adolescents: Data from the CNNHS 2010-2012

This study aims to examine association between sodium intake and overweight/obesity among Chinese children and adolescents. Data were obtained from China National Nutrition and Health Surveillance (CNNHS), 2010–2012. All participants recruited in this study aged 7–18 years old and provided complete dietary data on three-day consecutive 24 h dietary recalls combining with the household weighing method. Body Mass Index (BMI) was used to define overweight/obesity, and waist-to-height ratio (WHtR) was used to define abdominal obesity. Sodium intake showed association with risk of overweight/obesity assessed by BMI in the highest tertile group with OR of 1.48 (95%CI 1.13–1.94) and 1.89 (95%CI 1.33–2.67) for WHtR. After adjusted for gender, age, household income, area, energy, carbohydrates, protein, fat, saturated fatty acids, and fiber intake, the relationship between sodium intake and overweight/obesity and abdominal obesity are not changed. The same results were founded in subjects aged 10–18 years old. Our results reveal a positive association between sodium intake and overweight/obesity in Chinese children and adolescents, independent of energy consumption.

Assessing the Impact of Salt Reduction Initiatives on the Chronic Disease Burden of Singapore

Globally, many countries are facing an increasing burden of chronic disease due to ageing populations, of which cardiovascular disease forms a large proportion. Excess dietary sodium contributes to cardiovascular disease risk and requires intervention at a population level. This study aimed to quantify the impact of several salt reduction initiatives on population health over a 30-year horizon using GeoDEMOS, a population model from Singapore. Four interventions were modelled in four demographic groups in 2020 for a total of 16 intervention scenarios. The effect of 0.5, 2.0, and 4.0 g/day reductions in daily salt consumption, along with adherence to the World Health Organization guidelines of a maximum of 5.0 g of salt each day, was modelled in the entire population, including the overweight and obese, the elderly, and diabetics. In each scenario, the number of averted incident cases of acute myocardial infarction and stroke, along with the disability-adjusted life years up to 2050, was monitored. We found 4.0 g/day reductions in salt consumption were the most effective when implemented across the entire population, resulting in 24,000 averted incident cases of cardiovascular disease and 215,000 disability-adjusted life years over 30 years. This is a large figure when compared with the 29,200 projected annual incident cases of cardiovascular disease in 2050. When targeted at specific high-risk demographic groups, the largest effects were observed in the overweight and obese, with the same intervention yielding 10,500 averted incident cases of cardiovascular disease and 91,500 disability-adjusted life years. Quantifying the benefits of salt reduction initiatives revealed a significant impact when administered across the entire population or the overweight and obese. Health promotion efforts directed toward sustainably reducing salt consumption will help to lower the chronic disease burden on the healthcare system in years to come.

Estimated dietary sodium intake in Thailand: A nationwide population survey with 24-hour urine collections

Thailand has committed to reducing population sodium intake by 30% by 2025. However, reliable nationally representative data are unavailable for monitoring progress toward the goal. We estimated dietary sodium consumption using 24‐hour urinary analyses in a nationally representative, cross‐sectional population‐based survey. We selected 2388 adults (aged ≥ 18 years) from the North, South, North‐east, Central Regions, and Bangkok, using multi‐stage cluster sampling. Mean sodium excretion was inflated by 10% to adjust for non‐urinary sources. Multivariate logistic regression was performed to assess factors associated with sodium consumption ≥ 2000 mg. Among 1599 (67%) who completed urine collection, mean age was 43 years, 53% were female, and 30% had hypertension. Mean dietary sodium intake (mg/day) was 3636 (±1722), highest in South (4108 ± 1677), and lowest in North‐east (3316 ± 1608). Higher sodium consumption was independently associated with younger age (Adjusted Odds Ratio (AOR) 2.81; 95% Confidence interval (CI): 1.53‐5.17; p = .001); higher education (AOR 1.79; 95% CI: 1.19‐2.67; p = .005), BMI ≥ 25 (AOR 1.55; 95% CI: 1.09‐2.21; p=.016), and hypertension (AOR 1.58; 95% CI: 1.02‐2.44; p = .038). Urine potassium excretion was 1221 mg/day with little variation across Regions. Estimated dietary sodium consumption in Thai adults is nearly twice as high as recommended levels. These data provide a benchmark for future monitoring.

Salt added to food and body mass index: A bidirectional Mendelian randomisation study

AIM

This study aimed to determine the causal association between salt added to food and body mass index (BMI) by integrating a summary-level genome-wide association study (GWAS) data.

METHODS

We performed two-sample Mendelian randomisation (MR) analyses using summary statistics of GWAS. Inverse-variance weighted (IVW), maximum likelihood estimation, and random effect model were used to analyse the effect of salt added to food on BMI. A bidirectional MR analysis with BMI as the exposure and salt added to food as the outcome was also performed.

RESULTS

The single nucleotide polymorphisms (SNPs) were selected from the UK Biobank (n = 462 630) and a meta-analysis of 322 154 European-descent individuals. The IVW method estimate indicated that salt added to food was positively associated with BMI (β = 0.1416, SE = 0.0576, P = .0139). Results from maximum likelihood estimation (β = 0.1476, SE = 0.0363, P < .0001) and the random effect model (β = 0.1411, SE = 0.0572, P = .0137) were consistent with the IVW. Bidirectional MR analysis suggested that BMI did not causally affect salt added to food.

CONCLUSION

Our results provided qualitative evidence supporting a causal relationship between salt intake and BMI.

Dietary Sodium Intake is Predicted by Antihypertensive Medication Regimen in Patients With Heart Failure

BACKGROUND

Low-sodium diet adherence is foundational to heart failure (HF) self-management. Altered salt taste perception caused by angiotensin-converting enzyme (ACE) inhibitors commonly prescribed to patients with HF may increase sodium consumption. We hypothesized sodium intake, indicated by dietary sodium density, would be significantly higher among patients with HF prescribed ACE inhibitors compared with those not prescribed the drug.

OBJECTIVE

The aim of this study was to assess the association between prescribed ACE inhibitors and dietary sodium density in patients with HF.

METHODS

We conducted a secondary analysis of baseline data from patients with HF in an observational longitudinal study. Sodium density was derived by dividing averaged daily sodium intake from 4-day food diaries by averaged kilocalories consumed. Medical chart review was conducted to ascertain prescribed medications. Patients were categorized as prescribed and not prescribed an ACE inhibitor. t Tests were conducted to compare sodium intake between groups, and linear regression was conducted to examine whether prescribed ACE inhibitors independently predicted sodium density controlling for age, gender, New York Heart Association class, prescribed diuretics, and β-blockers.

RESULTS

Analyses included 255 patients with HF aged 61 ± 12 years, with 67% male, 44% New York Heart Association class III/IV, and 68% prescribed an ACE inhibitor. Compared with those not prescribed an ACE inhibitor, 13% more sodium per kilocalorie was consumed by patients prescribed an ACE inhibitor. Prescribed ACE inhibitor independently predicted dietary sodium density (β = 0.238, P = .009).

CONCLUSIONS

Sodium intake was higher among patients prescribed ACE inhibitors. Interventions to assist patients with HF with dietary sodium adherence can be informed by assessing medication regimens.

The association between dietary sodium intake, adiposity and sugar-sweetened beverages in children and adults: a systematic review and meta-analysis

Higher intakes of Na may contribute to weight gain. The primary aim of this systematic review and meta-analysis was to examine the relationship between dietary Na intake and measures of adiposity in children and adults. Given the previous link between Na intake and the consumption of sugar-sweetened beverages (SSB), which are a known risk factor for obesity, a secondary aim examining the relationship between Na intake and SSB consumption was assessed. A systematic literature search identified cross-sectional and longitudinal studies and randomised controlled trials (RCT) which reduced dietary Na (≥3 months). Meta-analysis was performed for outcomes with ≥3 studies. Cross-sectionally higher Na intakes were associated with overweight/obesity in adults (five studies; n 11 067; OR 1·74; 95 % CI 1·43, 2·13) and in children (three studies; n 3625, OR 3·29; 95 % CI 2·25, 4·80), and abdominal obesity (five studies; n 19 744; OR 2·04; 95 % CI 1·72, 2·42) in adults. Overall, associations remained in sensitivity analyses which adjusted for energy. Findings from longitudinal studies were inconsistent. RCT in adults indicated a trend for lower body weight on reduced-Na compared with control diets (fifteen studies; n 5274; -0·29 kg; 95 % CI -0·59, 0·01; P = 0·06); however, it is unclear if energy intakes were also altered on reduced-Na diets. Among children higher Na intakes were associated with higher intake of SSB (four studies, n 10 329, b = 22, 16 and 26 g/d); no studies were retrieved for adults. Overall, there was a lack of high-quality studies retrieved. While cross-sectional evidence indicates Na intake was positively associated with adiposity, these findings have not been clearly confirmed by longitudinal studies or RCT.

Is urinary sodium excretion related to anthropometric indicators of adiposity in adults?

Background

Although increasing salt intake is associated with greater odds of obesity, little is known about its relationship with body fat. We investigated the relation of urinary sodium (UNa) with obesity indices, including Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE), a body shape index (ABSI), body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR).

Materials and Methods

A total of 508 free-living adults aged ≥ 19 years were selected through stratified multistage random method as a representative of general population from central parts of Iran and were included in this cross-sectional study. Dietary sodium intake was measured using 24-h UNa (24-UNa) excretion. Weight, height, and WC were measured using standard protocols and calibrated equipment and used to measure obesity indicators, including BMI, WHtR, ABSI, and CUN-BAE. Adjusted univariate multiple logistic regression was used to assess the risk of having greater obesity measures across the tertiles of 24-UNa.

Results

Individuals in the top tertile of 24-UNa in comparison with those in the first tertile had greater body weight (72.02 ± 1.00 vs. 66.02 ± 0.89 kg; P < 0.0001), BMI (26.14 ± 0.33 vs. 24.82 ± 0.29 kg/m²; P = 0.007), and CUN-BAE (29.89 ± 0.42 vs. 28.38 ± 0.78; P = 0.036). There was a trend toward an increment in WC by increasing sodium intake (P = 0.073). After controlling for potential confounders, individuals with greater sodium consumption had greater chance for overweight (odds ratio [OR]: 1.004, 95% confidence interval [CI]: 1.001-1.007; P = 0.015), abdominal obesity (OR: 1.004, 95% CI: 1.00-1.008; P = 0.031), and more body fat (OR: 1.007, 95% CI: 1.003-1.01; P = 0.001). No significant association was found for sodium and WHtR and ABSI.

Conclusion

Greater 24-UNa excretion was associated with greater means of body weight, BMI, WC, and CUN-BAE. Although changes in obesity indices per each additional 24-UNa excretion were small, our findings are relevant because of the rising obesity epidemic.

Higher Sodium Intake Assessed by 24 Hour Urinary Sodium Excretion Is Associated with Non-Alcoholic Fatty Liver Disease: The PREVEND Cohort Study

A higher sodium intake is conceivably associated with insulin resistant conditions like obesity, but associations of non-alcoholic fatty liver disease (NAFLD) with a higher sodium intake determined by 24 hours (24 h) urine collections are still unclear. Dietary sodium intake was measured by sodium excretion in two complete consecutive 24 h urine collections in 6132 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort. Fatty Liver Index (FLI) ≥60 and Hepatic Steatosis Index (HSI) >36 were used as proxies of suspected NAFLD. 1936 (31.6%) participants had an FLI ≥60, coinciding with the increased prevalence of type 2 diabetes (T2D), metabolic syndrome, hypertension and history of cardiovascular disease. Sodium intake was higher in participants with an FLI ≥60 (163.63 ± 61.81 mmol/24 h vs. 136.76 ± 50.90 mmol/24 h, p < 0.001), with increasing incidence in ascending quartile categories of sodium intake (p < 0.001). Multivariably, an FLI ≥60 was positively associated with a higher sodium intake when taking account for T2D, a positive cardiovascular history, hypertension, alcohol intake, smoking and medication use (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.44–1.64, p < 0.001). Additional adjustment for the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) diminished this association (OR 1.30, 95% CI 1.21–1.41, p < 0.001). HSI >36 showed similar results. Associations remained essentially unaltered after adjustment for body surface area or waist/hip ratio. In conclusion, suspected NAFLD is a feature of higher sodium intake. Insulin resistance-related processes may contribute to the association of NAFLD with sodium intake.

Relationship between 24-hour urinary sodium excretion and blood pressure in the adult population in Shandong, China

The main objective of this study was to determine baseline salt intake levels in a sample of the adult population of Shandong province and to establish the relationship between urinary sodium excretion and blood pressure. A total of 512 participants were recruited, and all the participants provided complete 24‐hour urine collections. Physical assessment and socioeconomic status of participants were collected at the same time. The mean 24‐hour urinary sodium excretion of all subjects was 228.0 ± 127.5 mmol/24 hours. Estimated salt intake was higher in obese subjects (17.6 ± 8.8 g/d) compared with overweight subjects (15.6 ± 8.0 g/d) and those with a normal BMI (13.9 ± 6.8 g/d). Likewise, urinary sodium excretion of hypertensive participants was dramatically higher than that of non‐hypertensive ones, the equivalent of 18.2 ± 9.1 g/d vs 13.3 ± 6.8 g/d. Urinary sodium was significantly associated with SBP (β = 1.08, P = .018) after adjustment for potential confounders. In summary, we found significantly high levels of salt intake in Shandong Province, particularly in obese and hypertension subjects. It is quite important to improve public education about reducing salt intake to control blood pressure among Shandong people.

Salt intake and prevalence of overweight/obesity in Japan, China, the United Kingdom, and the United States: the INTERMAP Study

BACKGROUND

Several studies have reported that dietary salt intake may be an independent risk factor for overweight/obesity, but results from previous studies are controversial, reflecting study limitations such as use of a single spot urine or dietary recall to estimate daily salt intake rather than 24-h urine collections, and population samples from only a single country or center.

OBJECTIVE

The aim of this study was to use data from the International Study of Macro-/Micro-nutrients and Blood Pressure (INTERMAP Study) to explore the relation between dietary salt intake estimated from 2 timed 24-h urine collections and body mass index (BMI; in kg/m2) as well as prevalence of overweight/obesity in Japan, China, the United Kingdom, and the United States.

METHODS

Data were from a cross-sectional study of 4680 men and women aged 40-59 y in Japan (n = 1145), China (n = 839), the United Kingdom (n = 501), and the United States (n = 2195). General linear models were used to obtain the regression coefficients (β) of salt intake associated with BMI. Multivariable logistic regression models were used to determine the ORs and 95% CIs of overweight/obesity associated with a 1-g/d higher dietary salt intake.

RESULTS

After adjustment for potential confounding factors including energy intake, salt intake 1 g/d higher was associated with BMI higher by 0.28 in Japan, 0.10 in China, 0.42 in the United Kingdom, and 0.52 in the United States, all P values < 0.001. Salt intake 1 g/d higher was associated with odds of overweight/obesity 21% higher in Japan, 4% higher in China, 29% higher in the United Kingdom, and 24% higher in the United States, all P values < 0.05.

CONCLUSIONS

Salt intake is positively associated with BMI and the prevalence of overweight/obesity in Japan, China, the United Kingdom, and the United States. This association needs to be further confirmed in well-designed prospective studies with repeated dietary and BMI measurements.This trial was registered at clinicaltrials.gov as NCT00005271.

Association of usual 24-h sodium excretion with measures of adiposity among adults in the United States: NHANES, 2014

Background

Both excessive sodium intake and obesity are risk factors for hypertension and cardiovascular disease. The association between sodium intake and obesity is unclear, with few studies assessing sodium intake using 24-h urine collection.

Objectives

Our objective was to assess the association between usual 24-h sodium excretion and measures of adiposity among US adults.

Methods

Cross-sectional data were analyzed from a sample of 730 nonpregnant participants aged 20-69 y who provided up to 2 complete 24-h urine specimens in the NHANES 2014 and had data on overweight or obesity [body mass index (kg/m2) ≥25] and central adiposity [waist circumference (WC): >88 cm for women, >102 cm for men]. Measurement error models were used to estimate usual sodium excretion, and multiple linear and logistic regression models were used to assess its associations with measures of adiposity, adjusting for sociodemographic, health, and dietary variables [i.e., energy intake or sugar-sweetened beverage (SSB) intake]. All analyses accounted for the complex survey sample design.

Results

Unadjusted mean ± SE usual sodium excretion was 3727 ± 43.5 mg/d and 3145 ± 55.0 mg/d among participants with and without overweight/obesity and 3653 ± 58.1 mg/d and 3443 ± 35.3 mg/d among participants with or without central adiposity, respectively. A 1000-mg/d higher sodium excretion was significantly associated with 3.8-units higher BMI (95% CI: 2.8, 4.8) and a 9.2-cm greater WC (95% CI: 6.9, 11.5 cm) adjusted for covariates. Compared with participants in the lowest quartile of sodium excretion, the adjusted prevalence ratios in the highest quartile were 1.93 (95% CI: 1.69, 2.20) for overweight/obesity and 2.07 (95% CI: 1.74, 2.46) for central adiposity. The associations also were significant when adjusting for SSBs, instead of energy, in models.

Conclusions

Higher usual sodium excretion is associated with overweight/obesity and central adiposity among US adults.

Dietary components modulate the risk of hepatocellular carcinoma in cirrhotic patients

Eighty percent of hepatocellular carcinoma (HCC) cases occur after cirrhosis from various etiologies. The association between diet and cancer is well accepted, but the links with cirrhosis progression and HCC risk have been poorly investigated. However, we hypothesized that diet could be a modifiable preventive factor for HCC. Thus, the aim of our study was to explore the relationships between dietary factors and the risk of HCC in a population of cirrhotic patients. A total of 582 cirrhotic patients were studied: 401 without HCC (controls) and 181 with HCC (cases). These patients were recruited between 2008 and 2012 for the "CiRCE" case-control study conducted in six French university hospitals. Information about the consumption of 208 food items and 23 nutrients were collected through a diet history questionnaire. Unconditional multivariate logistic regressions were performed for each residual food group and nutrients in tertiles. HCC patients were more often men, diabetic and older than controls. After adjustment, a significant positive association was found between HCC risk and carbonated beverages (OR_{Tertile3vsTertile1} = 2.44 [1.17-5.09] p-trend = 0.021), total cereals (OR_T3vsT1 = 1.87 [1.09-3.22] p-trend = 0.035), processed meat (OR_T3vsT1 = 1.97 [1.14-3.41] p-trend = 0.028) and sodium (OR_T3vsT1 = 2.00 [1.14-3.53] p-trend = 0.043). Conversely, the consumption of fiber (OR_T3vsT1 = 0.49 [0.28-0.86] p-trend = 0.012), vitamin E (OR_T3vsT1 = 0.52 [0.30-0.89] p-trend = 0.017), vitamin B9 (folate and folic acid) (OR_T3vsT1 = 0.56 [0.33-0.95] p-trend = 0.036), manganese (OR_T3vsT1 = 0.56 [0.32-0.97] p-trend = 0.038) and potassium (OR_T3vsT1 = 0.44 [0.25-0.76] p-trend = 0.004) were significantly lower in HCC patients compared with cirrhotic controls. Although these findings must be confirmed in prospective studies, using dietary patterns or biological parameters, they suggest that certain dietary components may modulate HCC risk in cirrhotic patients.

The relationship between diabetic risk factors, diabetic complications and salt intake

The relationship between salt and hypertension is the focus of a large amount of research, there are few reviews of the relationship between salt and diabetes, despite the increasing incidence of diabetes. By searching PubMed and the Cochrane Library, we summarized the relationships between diabetic risk factors, diabetic complications and salt intake. The pathophysiological mechanisms underlying the effects of salt on diabetes risk factors and diabetic complications are also discussed. Our findings should assist experts and scholars to understand the current research of salt intake and to pay more attention to the prevention and treatment of related diseases caused by excessive salt intake; guide treatment for patients with diabetes mellitus; and provide a reference for government departments to formulate a reasonable salt restriction policy. We also recommend future research directions.

Sodium and potassium urinary excretion and their ratio in the elderly: results from the Nutrition UP 65 study

BACKGROUND

We aimed to describe urinary sodium and potassium excretion and their ratio in a representative sample of Portuguese elderly population, according to sociodemographic characteristics and weight status.

METHODS

A cluster sampling approach was used, representing older Portuguese adults (≥65 years) according to age, sex, education level, and regional area within the Nutrition UP 65 study. This cross-sectional evaluation was conducted in 2015 and 2016. From a sample size of 1,500 participants, 1,318 were eligible for the present analysis, 57.3% were women, and 23.5% were aged ≥80 years. Sodium and potassium consumption was evaluated through one 24 h urinary excretion. Inadequate sodium intake was defined as ≥2,000 mg/day, inadequate potassium intake was considered as <3,510 mg/day, and inadequate sodium-to-potassium ratio was defined as >1, according to the World Health Organization cutoffs.

RESULTS

The proportion of the participants with an inadequate intake was 80.0% in women and 91.5% in men (sodium), 96.2% of women and 79.4% of men (potassium), and 98.4% of women and 99.1% of men (sodium-to-potassium ratio). Higher sodium adequacy was observed among the older elderly, unmarried, with lower household income, and underweight/normal weight. Higher potassium adequacy was observed in the younger elderly, married, and with higher income.

CONCLUSION

The majority of the Portuguese elderly population was classified as having inadequate sodium, potassium, and sodium-to-potassium ratio urinary excretion. Therefore, strategies for reducing sodium and increasing potassium intake are priorities in the Portuguese elderly population.

Low salt and low calorie diet does not reduce more body fat than same calorie diet: a randomized controlled study

Background

Recent several observational studies have reported that high salt intake is associated with obesity. But it is unclear whether salt intake itself induce obesity or low salt diet can reduce body fat mass. We investigated whether a low salt diet can reduce body weight and fat amount.

Matrials and Methods

The randomized, open-label pilot trial was conducted at a single institution. A total of 85 obese people were enrolled. All participants were served meals three times a day, and provided either a low salt diet or control diet with same calorie. Visceral fat was measured with abdominal computer tomography, while body fat mass and total body water was measured with bio-impedance.

Results

Reductions in body weight (–6.3% vs. –5.0%, p = 0.05) and BMI (–6.6% vs. –5.1%, p = 0.03) were greater in the low salt group than in the control group. Extracellular water and total body water were significantly reduced in the low salt group compared to the control group. However, changes in body fat mass, visceral fat area, and skeletal muscle mass did not differ between the two groups. Changes in lipid profile, fasting glucose, and HOMA-IR did not differ between the two groups.

Conclusions

A two-month low salt diet was accompanied by reduction of body mass index. However, the observed decrease of body weight was caused by reduction of total body water, not by reduction of body fat mass or visceral fat mass.

Associations of Sodium and Potassium with Obesity Measures Among Diverse US Hispanic/Latino Adults: Results from the Hispanic Community Health Study/Study of Latinos

OBJECTIVE

The objective of this study was to evaluate cross-sectional associations of sodium and potassium with BMI, waist circumference (WC), and body fat and to determine whether the nativity and/or duration of United States (US) residence modified these associations.

METHODS

Sodium and potassium were derived from 24-hour diet recalls from 16,156 US participants of the 2008 to 2011 Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and from 24-hour urine in 447 HCHS/SOL participants. BMI, WC, and body fat were measured.

RESULTS

Dietary sodium that was 500 mg/d higher was cross-sectionally associated with a 0.07-kg/m2 higher BMI (P < 0.05) and a 0.18-cm larger WC (P = 0.04). Dietary potassium that was 500 mg/d higher was only associated with lower BMI and smaller WC among those who were foreign-born with 10 + years in the US (-0.13 kg/m2 , P < 0.01 and -0.36 cm, P = 0.01, respectively) and among those who were US-born (-0.62 kg/m2 , P < 0.01 and -1.42 cm, P < 0.01, respectively). Urinary sodium that was 500 mg/d higher was associated with a 0.27-kg/m2 higher BMI (P < 0.01) and 0.54 kg more body fat (P < 0.01).

CONCLUSIONS

Sodium intake was associated with higher BMI, WC, and body fat. Potassium intake was associated with lower BMI and smaller WC among US-born participants and participants with a longer duration of US residence.

A high salt diet inhibits obesity and delays puberty in the female rat

BACKGROUND/OBJECTIVES

Processed foods are considered major contributors to the worldwide obesity epidemic. In addition to high sugar and fat contents, processed foods contain large amounts of salt. Owing to the correlations with rising adiposity, salt has recently been proposed to be obesogenic. This study investigated three hypotheses: (i) high salt contributes to weight gain and adiposity in juvenile female rats, (ii) puberty onset would be altered because salt is known to affect neuronal systems involved in activating the reproductive system, and (iii) enhanced adiposity will act synergistically with salt to drive early puberty onset.

DESIGN

Female weanling rats (post-natal day 21, n=105) were fed a low fat/low salt diet, low fat/high salt diet, high fat/low salt diet or a high salt/high fat diet for 24 days. Metabolic measures, including weight gain, food intake, fecal output, activity and temperature were recorded in subsets of animals.

RESULTS

Body weight, retroperitoneal and perirenal fat pad weight, and adipocyte size were all lower in animals fed high fat/high salt compared with animals fed high fat alone. Leptin levels were reduced in high fat/high salt fed animals compared with high fat/low salt-fed animals. Daily calorie intake was higher initially but declined with adjusted food intake and was not different among groups after 5 days. Osmolality and corticosterone were not different among groups. Fecal analysis showed excess fat excretion and a decreased digestive efficiency in animals fed high fat/low salt but not in animals fed high fat/high salt. Although respiratory exchange ratio was reduced by high dietary fat or salt, aerobic-resting metabolic rate was not affected by the diet. High salt delayed puberty onset, regardless of dietary fat content.

CONCLUSIONS

Salt delays puberty and prevents the obesogenic effect of a high fat diet. The reduced weight gain evident in high salt-fed animals is not due to differences in food intake or digestive efficiency.

Obesity and Weight Loss in Idiopathic Intracranial Hypertension: A Narrative Review

BACKGROUND

Most patients with idiopathic intracranial hypertension (IIH) are obese. Weight loss is felt to be an important factor in improving IIH. The mechanism by which weight loss leads to a reduction in elevated intracranial pressure is unclear. Evidence from prospective studies evaluating the role of weight loss in IIH is lacking.

EVIDENCE ACQUISITION

We performed a detailed review of the published literature regarding the association of IIH and obesity, including proposed pathogenetic mechanisms, and the effect of weight loss and weight-loss interventions in IIH. References were identified by searching PubMed with the terms idiopathic intracranial hypertension and weight loss. Additional citations were found in the identified references.

RESULTS

Over 90% of IIH patients are obese or overweight. The risk of IIH increases as a function of body mass index (BMI) and weight gain over the preceding year. The risk of IIH-induced vision loss also increases with increasing BMI, especially with BMI >40 kg/m. Several mechanisms have been proposed linking obesity to the development of IIH but the pathophysiology remains unknown. Published studies and clinical observations strongly support weight loss as an effective treatment, although there are no prospective controlled trials. Weight loss in the range of 6%-10% often leads to IIH remission. Weight loss of ≥5% at 1 year is achieved in roughly 50%-70% of patients if they are enrolled in a high-intensity lifestyle modification program and in 20%-35% of patients if they direct their own weight loss. Weight is typically regained over 1-3 years but about a third of patients maintain ≥5% weight loss over the long term. Patients treated initially with lifestyle modification therapy show a modest persisting benefit over self-directed patients. Selected commercial weight loss programs also may improve long-term maintenance of weight loss. New antiobesity drugs significantly improve the proportion of obese patients who have ≥5% loss of weight at 1 year.

CONCLUSIONS

Obesity is an important contributing factor for the development of IIH, although the pathophysiological mechanism linking obesity to IIH is unknown. The risk of developing IIH and associated visual loss increases with increasing BMI. Weight loss is an effective treatment for IIH. Long-term maintenance of initial weight loss is helped modestly by lifestyle modification programs and possibly by selected commercial weight loss programs. New antiobesity drugs may provide further options for IIH therapy in the future.

The impacts of the interaction of genetic variation, CYP11β2 and NEDD4L, with sodium intake on pediatric obesity with gender difference: a 3-year panel study

Backgrounds/Objectives:This panel study was to predict the incidences of pediatric obesity by the interaction of sodium (Na) intake and nine single-nucleotide polymorphisms (SNPs) of salt-sensitive genes (SSGs), ACE(angiotensin-converting enzyme), ADD1 G460W,AGT M235T,CYP11β2 (cytochrome P450 family 11-subfamily β-2, -aldosterone synthase),GNB3 C285T,GRK4(A142V)(G-protein-coupled receptor kinases type 4),GRK4 (A486V),NEDD4L (neural precursor cell expressed developmentally downregulated 4 like; rs2288774) and SLC12A3 (solute carrier family 12 (Na/Cl transporters)-member 3), selected from genome-wide association study.

SUBJECTS/METHODS

Non-obese (non-OB) Korean children of 9 years old were recruited from eight elementary schools in Seoul in 2007 and 2009, each. Follow-up subjects (total=798) in 2010 and 2012 were final participants. Participants were classified as OB group for those whose body mass index were over the 85th percentile using the 'Korean National Growth Charts', and others were classified as non-OB. With nine SNPs typing, the genetic interaction with the variation of Na intake for 3 years was evaluated as an obesity risk.

RESULTS

The obesity incidence rate for non-OB children at baseline after 3 years was 10.31%. Na intake in non-OB after 3 years was significantly decreased compared with the baseline, whereas Na intake reduction was undetectable in OB. We found gender differences on association between the changes of Na intake and the obesity incidence for 3 years by the SSG variation. Odds ratio for the obesity risk was 5.75 times higher in girls having hetero/mutant types of NEDD4L with higher Na intakes (Q2+Q3+Q4 in quartiles) compared with that in the wild type with the lowest Na intake (Q1). Girls with hetero/mutant of CYP11β2 tended to increase the obesity incidence as Na intake increased (Q1<Q2<Q3<Q4, P-value trend=0.047). The other seven SNPs of SSGs had no significance over Na intake.

CONCLUSIONS

From this panel study and the previous cross-sectional study, we found CYP11β2 as the common gene, powerful to explain the interaction between obesity incidence and Na intake, in particular, among girls. Girls with hetero/mutant allele of this gene should reduce their daily Na intake to prevent obesity.

Associations of Obesity and Dyslipidemia with Intake of Sodium, Fat, and Sugar among Koreans: a Qualitative Systematic Review

A qualitative systematic review was performed to identify associations of obesity and dyslipidemia with intake of sodium, fat, and sugar among Koreans. We reviewed 6 Korean research databases (KMbase, KoreaMed, NDSL, DBpia, RISS, KISS) with the keywords “sodium intake,” “fat intake,” and “sugar intake.” Total of 11 studies were investigated in this present study. Of these articles, 7 studies were related to sodium intake, 2 studies had a relation to fat intake, and 2 studies were associated with sugar intake. We indicated general characteristics, concentration of serum lipids, nutrition intake, and statistically significant results. High sodium intake contributed to increased etiology of hypertriglyceridemia, high-density lipoprotein (HDL) hypocholesterolemia, and a risk of being overweight. Fat intake was significantly associated with body fat, low-density lipoprotein (LDL) hypercholesterolemia, and HDL hypocholesterolemia. Sugar intake from coffee drinks and sugar-sweetened beverages contributed to increased HDL hypocholesterolemia and continuous metabolic syndrome score. This qualitative review among Koreans represented that intake of sodium, fat, and sugar has a positive relationship with cause of obesity-related diseases. Especially, this present study has a great significance in terms of considered study that intake of the potentially hazardous nutrients among Koreans has an association with obesity and dyslipidemia. However, further studies such as randomized controlled trials on associations between sodium, fat, and sugar and obesity and dyslipidemia need to be continuously required in order to conduct quantitative systematic reviews and a meta-analysis for Koreans.

Does the Theory of Planned Behavior Predict Dietary Sodium Intake in Patients With Heart Failure?

Sodium intake in heart failure (HF) is a crucial but poorly understood phenomenon. Theoretical models promote understanding and provide a context for rational appraisal of complex situations. The purpose of this study was to determine which factors were associated with sodium intake in HF patients using theory of planned behavior (TPB). In this study, patients’ ( N = 244) attitudes, subjective norms, and perceived behavioral control (tenets of the TPB) were assessed using the Dietary Sodium Restriction Questionnaire. Sodium intake was estimated objectively by 24-hr urinary sodium excretion (UNa). The average UNa was 3,811 mg. Subjective norms, gender, and New York Heart Association functional class were associated with sodium intake ( p < .001). Thus, it is important for health care providers to clearly express their approval of following low-sodium diet to their HF patients, and include significant others in interventions to help patients develop/maintain a positive subjective norm to decrease sodium intake and reduce HF exacerbations.

Dietary sodium and potassium intake in relation to non-alcoholic fatty liver disease

A few epidemiological data are available assessing the associations of intakes of sodium (Na) and potassium (K) with non-alcoholic fatty liver disease (NAFLD). We aimed to examine the associations of dietary intake of Na and K with the prevalence of ultrasound-diagnosed NAFLD. We performed a cross-sectional study of 100 177 participants (46 596 men and 53 581 women) who underwent a health screening examination and completed a FFQ at the Kangbuk Samsung Hospital Total Healthcare Centers, South Korea, between 2011 and 2013. NAFLD was defined by ultrasonographic detection of fatty liver in the absence of excessive alcohol intake or other known causes of liver disease. The proportion of NAFLD was 35·6 % for men and 9·8 % for women. Increasing prevalence of NAFLD was observed with increasing Na intake. The multivariable-adjusted prevalence ratios (PR) of NAFLD comparing the highest with the lowest quintile of energy-adjusted Na intake were 1·25 (95 % CI 1·18, 1·32; P trend<0·001) in men and 1·32 (95 % CI 1·18, 1·47; P trend <0·001) in women. However, when we additionally adjusted for body fat percentage, the association became attenuated; the corresponding PR of NAFLD were 1·15 (95 % CI 1·09, 1·21) in men and 1·06 (95 % CI 0·95, 1·17) in women. No inverse association was observed for energy-adjusted K intake. Our findings suggest that higher Na intake is associated with a greater prevalence of NAFLD in young and middle-aged asymptomatic adults, which might be partly mediated by adiposity.

Distinct Adipose Depots from Mice Differentially Respond to a High-Fat, High-Salt Diet

BACKGROUND

Dietary factors such as high-sodium or high-fat (HF) diets have been shown to induce a proinflammatory phenotype. However, there is limited information with respect to how microenvironments of distinct intra-abdominal adipose depots respond to the combination of a high-salt, HF diet.

OBJECTIVE

We tested the hypothesis that HF feeding would cause changes in distinct adipose depots, which would be further amplified by the addition of high salt to the diet.

METHODS

Twenty-seven male C57BL6 mice were fed an HF diet (60% of kcal from fat), an HF + high-salt diet (4% wt:wt), a control diet [low-fat (LF);10% of kcal from fat], or an LF + high-salt diet for 12 wk. The main sources of fat in the diets were corn oil and lard. Adipokines in serum and released from adipose tissue organ cultures were measured by immunoassays. QIAGEN's Ingenuity Pathway Analysis was used to perform functional analysis of the RNA-sequencing data from distinct adipose depots.

RESULTS

Diet-induced obesity resulted in a classical inflammatory phenotype characterized by increased concentrations of circulating inflammatory mediators (38-56%) and reduced adiponectin concentrations (27%). However, high-salt feeding did not exacerbate the HF diet-induced changes in adipokines and cytokines. Leptin and interleukin-6 were differentially released from adipose depots and HF feeding impaired adiponectin and resistin secretion across all 3 depots (34-48% and 45-83%, respectively). The addition of high salt to the HF diet did not further modulate secretion in cultured adipose tissue experiments. Although gene expression data from RNA sequencing indicated a >4.3-fold upregulation of integrin αX (Itgax) with HF feeding in all 3 depots, markers of cellular function were differentially expressed in response to diet across depots.

CONCLUSION

Collectively, these findings highlight the role of distinct adipose depots in mice in the development of obesity and emphasize the importance of selecting specific depots to study the effects of therapeutic interventions on adipose tissue function.

24-h urinary sodium excretion is associated with obesity in a cross-sectional sample of Australian schoolchildren

Emerging evidence indicates that dietary Na may be linked to obesity; however it is unclear whether this relationship is independent of energy intake (EI). The aim of this study was to assess the association between Na intake and measures of adiposity, including BMI z score, weight category and waist:height ratio (WHtR), in a sample of Australian schoolchildren. This was a cross-sectional study of schoolchildren aged 4-12 years. Na intake was assessed via one 24-h urine collection. BMI was converted to age- and sex-specific z scores, and WHtR was used to define abdominal obesity. In children aged ≥8 years, EI was determined via one 24-h dietary recall. Of the 666 children with valid urine samples 55 % were male (average age 9·3 (sd 1·8) years). In adjusted models an additional 17 mmol/d of Na was associated with a 0·10 higher BMI z score (95 % CI 0·07, 0·13), a 23 % (OR 1·23; 95 % CI 1·16, 1·31) greater risk of being overweight/obese and a 15 % (OR 1·15; 95 % CI 1·09, 1·23) greater risk of being centrally obese. In the subsample of 8-12-year-old children (n 458), adjustment for EI did not markedly alter the associations between Na and adiposity outcomes. Using a robust measure of daily Na intake we found a positive association between Na intake and obesity risk in Australian schoolchildren, which could not be explained by total energy consumption. To determine whether this is a causal relationship, longitudinal studies, with high-quality measures of Na and EI, are required.

Relationship of sodium intake with obesity among Korean children and adolescents: Korea National Health and Nutrition Examination Survey

We investigated whether dietary and urinary Na is associated with adiposity in Korean children and adolescents (10-18 years), a population with a high salt intake. Study subjects were Korean children and adolescents who participated in the cross-sectional nationally representative Korea National Health and Nutrition Examination Survey (2010-2011). This study used measures of dietary (24-h dietary recall) and urinary Na (Na:creatinine ratio) and three methods to determine obesity (BMI, waist circumference (WC) and total body per cent fat (TBPF)). Higher Na intake was significantly associated with obesity, adjusting for the covariates. Subjects in the highest tertile of urinary Na excretion had a significantly higher OR for higher adiposity compared with those in the lowest tertile (multivariate-adjusted OR 3·13 (95% CI 1·81, 5·50) for BMI, 2·15 (95% CI 1·27, 3·66) for WC and 1·92 (95% CI 1·29, 2·86) for TBPF, respectively). Na intake estimated by the 24-h recall method also showed significant association with adiposity (multivariate-adjusted OR 2·79 (95% CI 1·66, 4·68) for BMI and 2·14 (95% CI 1·25, 3·67) for WC, respectively). The significant associations between Na and adiposity remained significant after additionally adjusting for sugar-sweetened beverage (SSB) consumption. Our results revealed a significant positive association between urinary and dietary Na and adiposity in Korean children and adolescents, independent of SSB consumption.

Does salt have a permissive role in the induction of puberty?

Puberty is starting earlier than ever before and there are serious physiological and sociological implications as a result of this development. Current research has focused on the potential role of high caloric, and commensurate high adiposity, contributions to early puberty. However, girls with normal BMI also appear to be initiating puberty earlier. Westernized diets, in addition to being high in fat and sugar, are also high in salt. To date, no research has investigated a link between elevated salt and the reproductive axis. We hypothesize that a high salt diet can result in an earlier onset of puberty through three mechanisms that are not mutually exclusive. (1) High salt activates neurokinin B, a hormone that is involved in both the reproductive axis and salt regulation, and this induces kisspeptin release and ultimate activation of the reproductive axis. (2) Vasopressin released in response to high salt acts on vasopressin receptors expressed on kisspeptin neurons in the anteroventral periventricular nucleus, thereby stimulating gonadotropin releasing hormone and subsequently luteinizing hormone secretion. (3) Salt induces metabolic changes that affect the reproductive axis. Specifically, salt acts indirectly to modulate adiposity, ties in with the obesity epidemic, and further compounds the pathologic effects of obesity. Our overall hypothesis offers an additional cause behind the induction of puberty and provides testable postulates to determine the mechanism of potential salt-mediated affects on puberty.

Importance of imaging and recent developments in diagnosis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease and is a major public health problem worldwide. It is a spectrum that includes simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Recently, NAFLD prevalence in children and adolescents has increased too. The increasing prevalence has resulted in NASH-related chronic liver disease. Therefore, early diagnosis and treatment is quite important. Although liver biopsy is still the gold standard for diagnosis and staging of NAFLD, particularly for the diagnosis of NASH, imaging methods such as ultrasonography, computed tomography, magnetic resonance imaging with chemical shift imaging and especially magnetic resonance spectroscopy and elastography have been increasingly approved as noninvasive alternative methods. The aim of this review is to analyze the diagnostic accuracy and limitations of the imaging methods and recent developments in the diagnosis of NAFLD.

High sodium intake is associated with short leukocyte telomere length in overweight and obese adolescents

Background/Objectives

Telomere shortening plays an important role in cellular aging. However, the impact of high sodium intake, an important risk factor of age-related diseases, on telomere shortening remains unknown. Therefore, we examined the relationship between high dietary sodium intake and leukocyte telomere length, particularly in the context of obesity since obesity increases salt sensitivity.

Subjects/Methods

Leukocyte telomere length (LTL) was determined by a quantitative polymerase chain reaction method in 766 adolescents aged 14–18 years (50% female, 49% African Americans). Dietary sodium intake was assessed by seven independent 24-h dietary recalls. We divided the sample into low sodium (mean 2388 ± 522 mg/day) or high sodium groups (mean 4142 ± 882 mg/day) based on the median value (3280.9 mg/day).

Results

In the entire cohort, there was no significant association between sodium intake and LTL (r = −0.05, p = 0.24). However, there was a significant interaction between sodium intake and obesity status (p = 0.049). Further multiple linear regression analyses revealed that higher dietary sodium intake was associated with shorter LTL in the overweight/obese group (BMI ≥ 85^th percentile, β = −0.37, p = 0.04), but not in the normal weight group (β = 0.01, p= 0.93) after adjusting for multiple confounding factors. In the overweight/obese group, LTL was significantly shorter in the high sodium intake subjects vs. low sodium intake subjects (1.24 ± 0.22 vs. 1.32 ± 0.20, p = 0.02), but not the normal weight group (1.29 ± 0.24 vs. 1.30 ± 0.24, p = 0.69).

Conclusions

Higher dietary sodium intake is associated with shorter telomere length in overweight and obese adolescents.

New research developments and insights from Metabolism

In a field of great importance to daily life and clinical care, metabolic-related research covers a wealth of information and knowledge. This broad field encompasses a number of physical states that are increasingly critical to study, including obesity, type 2 diabetes, metabolic syndrome, and cardiovascular disease. Additionally, the impacts of diet, nutrition, and exercise on these physical states are an area of ever-important and expanding research. With the latest advances in metabolic research, much knowledge has been gained. Here, we present the newest findings from research published in Metabolism. We hope that these results provide not only critical knowledge needed for clinical care and daily life, but also a platform for the continuing expansion of research into metabolic-related issues.

Independent associations of sodium intake with measures of body size and predictive body fatness

OBJECTIVE

Observational studies highlight a possible relationship between sodium intake and obesity. This investigation explores the cross-sectional relationships between sodium intake and measures of body size and fatness (body mass index [BMI], weight, waist circumference, predictive body fatness).

METHODS

Analyses were performed using data from participants in the National Health and Nutrition Examination Survey (NHANES) 2009-10 with two 24-h dietary recalls and measures of body size and fatness (n = 4,613). Regression analyses assessed the relationships of sodium (1,000 mg/day) with outcomes, adjusting for caloric intake. Analyses are presented overall and by sex; data were weighted to be representative of the non-institutionalized US adult population.

RESULTS

Positive associations between sodium intake and measures of body size and predictive body fatness were observed, and the magnitude of association was larger in women than in men. For each 1,000 mg/day higher sodium intake, BMI was 1.03 kg/m(2) higher; weight was 2.75 kg higher; waist circumference was 2.15 cm higher; and predictive body fatness was 1.18% higher after adjustment for energy intake.

CONCLUSIONS

Longitudinal analyses examining associations between sodium intake and measures of body size and body fatness are needed.

Identifying predictors of high sodium excretion in patients with heart failure: a mixed effect analysis of longitudinal data

BACKGROUND

A low-sodium diet is a core component of heart failure self-care but patients have difficulty following the diet.

AIM

The aim of this study was to identify predictors of higher than recommended sodium excretion among patients with heart failure.

METHODS

The World Health Organization Five Dimensions of Adherence model was used to guide analysis of existing data collected from a prospective, longitudinal study of 280 community-dwelling adults with previously or currently symptomatic heart failure. Sodium excretion was measured objectively using 24-hour urine sodium measured at three time points over six months. A mixed effect logistic model identified predictors of higher than recommended sodium excretion.

RESULTS

The adjusted odds of higher sodium excretion were 2.90, (95% confidence interval (CI): 1.15-4.25, p<0.001) for patients who were obese; 2.80 (95% CI: 1.33-5.89, p=0.007) for patients with diabetes; and 2.22 (95% CI: 1.09-4.53, p=0.028) for patients who were cognitively intact.

CONCLUSION

Three factors were associated with excess sodium excretion and two factors, obesity and diabetes, are modifiable by changing dietary food patterns.

Effect of NaCl/Monosodium Glutamate (MSG) Mixture on the Sensorial Properties and Quality Characteristics of Model Meat Products

Sodium chloride is an important ingredient added to most of foods which contributes to flavor enhancement and food preservation but excess intake of sodium chloride may also cause various diseases such as heart diseases, osteoporosis and so on. Therefore, this study was carried out to investigate the effect of monosodium glutamate (MSG) as a salty flavor enhancer on the quality and sensorial properties of the NaCl/MSG complex and actual food system. For characterizing the spray-dried NaCl/MSG complex, surface dimension, morphology, rheology, and saltiness intensity were estimated by increasing MSG (0-2.0%) levels at a fixed NaCl concentration (2.0%). MSG levels had no effect of the characteristics of the NaCl/MSG complex, although the addition of MSG increased the surface dimension of the NaCl/MSG complex significantly (p<0.05). Furthermore, the effect of MSG on enhancing the salty flavor was not observed in the solution of the NaCl/MSG complex. In the case of an actual food system, model meat products (pork patties) were prepared by replacing NaCl with MSG. MSG enhanced the salty flavor, thereby increasing overall acceptability of pork patties. Replacement of NaCl with MSG (<1.0%) did not result in negative sensorial properties of pork patties, although quality deterioration such as high cooking loss was found. Nevertheless, MSG had a potential application in meat product formulation as a salty flavor enhancer or a partial NaCl replacer when meat products were supplemented with binding agents.

Estimated daily salt intake in relation to blood pressure and blood lipids: the role of obesity

BACKGROUND

Excessive salt intake causes increased blood pressure which is considered the leading risk for premature death. One major challenge when evaluating associations between daily salt intake and markers of non-communicable diseases is that a high daily salt intake correlates with obesity, which is also a well described risk factor for poor cardiometabolic outcome. The aim of this study was to evaluate the relationship of estimated daily salt intake with blood pressure and blood lipids and to investigate the effect of taking different measures of obesity into account.

METHODS

We included 3294 men and women aged 18-69 years from a general population based study in Copenhagen, Denmark. Estimated 24-hour sodium excretion was calculated by measurements of creatinine and sodium concentration in spot urine in combination with information of sex, age, height and weight. The relations of estimated 24-hour sodium excretion with blood pressure and blood lipids were evaluated by linear regression models.

RESULTS

The daily mean estimated intake of salt was 10.80 g and 7.52 g among men and women, respectively. Daily salt intake was significantly associated with blood pressure (β-estimates 1.18 mm Hg/g salt (systolic) and 0.74 mm Hg/g salt (diastolic), p < 0.0001) - however this association was markedly affected by adjustment for obesity (β-estimates around 0.60 mm Hg/g salt (systolic) and around 0.25 mm Hg/g salt (diastolic), p < 0.05). Also associations between daily salt intake and blood lipids were highly affected by adjustment for obesity.

CONCLUSIONS

Associations of estimated daily salt intake with blood pressure and blood lipids were highly affected by adjustment for obesity.