Elevation of Fasting Ghrelin in Healthy Human Subjects Consuming a High-Salt Diet: A Novel Mechanism of Obesity?

Association between minerals intake and childhood obesity: A cross-sectional study of the NHANES database in 2007-2014

BACKGROUND

The roles of minerals in obesity received increasing attention recently due to its oxidant or antioxidant functions and effects on insulin and glucose metabolism that may be associated with obesity. Herein, this study aims to explore the association between minerals and obesity and body mass index (BMI) in children with different ages, and hope to provide some references for prevention and management in children with high-risk of obesity.

METHODS

Data of children aged 2-17 years old were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 2007-2014 in this cross-sectional study. Weighted univariate and multivariate logistic regression and liner regression analyses were used to screen covariates, and explore the association between minerals [including calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), sodium (Na), potassium (K) and selenium (Se)] and childhood obesity and BMI. The evaluation indexes were β, odds ratios (ORs) and 95% confidence intervals (CIs). These relationships were also investigated in age subgroups.

RESULTS

Among 10,450 eligible children, 1,988 (19.02%) had obesity. After adjusting for covariates, we found the highest quartile of dietary Fe [OR = 0.74, 95%CI: (0.58, 0.95)] and Zn [OR = 0.70, 95%CI: (0.54, 0.92)] intakes were associated with low odds of childhood obesity, while that of dietary Na intake seemed to be positively linked to childhood obesity [OR = 1.35, 95%CI: (1.05, 1.74)]. High dietary intakes of Ca, Na and K were positively associated with children's BMI, on the contrary, dietary Fe and Zn consumptions had a negative one (all P<0.05). Additionally, these associations were also found in children with different age (all P<0.05).

CONCLUSION

Dietary Fe and Zn intakes played positive roles in reducing childhood obesity or BMI, while the intakes of Na should be controlled suitably.

Sodium and potassium consumption in Jamaica: National estimates and associated factors from the Jamaica Health and Lifestyle Survey 2016-2017

This study aimed to estimate dietary sodium and potassium consumption among Jamaicans and evaluate associations with sociodemographic and clinical characteristics. A cross-sectional study was conducted using data from the Jamaica Health and Lifestyle Survey 2016-2017. Participants were noninstitutionalized Jamaicans aged ≥15 years. Trained staff collected sociodemographic and health data via interviewer-administered questionnaires and spot urine samples. The Pan American Health Organization formula was used to estimate 24-hour urine sodium and potassium excretion. High sodium level was defined as ≥2000 mg/day, and low potassium levels as <3510 mg/day (World Health Organization criteria). Associations between these outcomes and sociodemographic and clinical characteristics were explored using multivariable ANOVA models using log-transformed 24-hour urine sodium and potassium as outcome variables. Analyses included 1009 participants (368 males, 641 females; mean age 48.5 years). The mean sodium excretion was 3582 mg/day (males 3943 mg/day, females 3245 mg/day, P < .001). The mean potassium excretion was 2052 mg/day (males, 2210 mg/day; females, 1904 mg/day; P = .001). The prevalence of high sodium consumption was 66.6% (males 72.8%, females 60.7%, P < .001) and that of low potassium intake was 88.8% (85.1% males, 92.3% females, P < .001). Sodium consumption was inversely associated with older age, higher education, and low glomerular filtration rate but was directly associated with being male, current smoking, and obesity. Overall, males had higher sodium consumption than women, with the effect being larger among hypertensive men. Women with hypertension had lower sodium consumption than nonhypertensive women; however, hypertensive men had higher sodium consumption than nonhypertensive men. Potassium consumption was higher among men, persons with obesity, and those with high total cholesterol but was lower among men with "more than high school" education compared to men with "less than high school" education. We conclude that most Jamaican adults have diets high in sodium and low in potassium. In this study, sodium consumption was directly associated with male sex, obesity, and current smoking but was inversely associated with older age and higher education. High potassium consumption was associated with obesity and high cholesterol levels. These associations should be further explored in longitudinal studies and population-based strategies should be developed to address these cardiovascular risk factors.

The role of dietary salt in metabolism and energy balance: Insights beyond cardiovascular disease

Dietary salt (NaCl) is essential to an organism's survival. However, today's diets are dominated by excessive salt intake, which significantly impacts individual and population health. High salt intake is closely linked to cardiovascular disease (CVD), especially hypertension, through a number of well-studied mechanisms. Emerging evidence indicates that salt overconsumption may also be associated with metabolic disorders. In this review, we first summarize recent updates on the mechanisms of salt-induced CVD, the effects of salt reduction and the use of salt substitution as a therapy. Next, we focus on how high salt intake can impact metabolism and energy balance, describing the mechanisms through which this occurs, including leptin resistance, the overproduction of fructose and ghrelin, insulin resistance and altered hormonal factors. A further influence on metabolism worth noting is the reported role of salt in inducing thermogenesis and increasing body temperature, leading to an increase in energy expenditure. While this result could be viewed as a positive metabolic effect because it promotes a negative energy balance to combat obesity, caution must be taken with this frame of thinking given the deleterious consequences of chronic high salt intake on cardiovascular health. Nevertheless, this review highlights the importance of salt as a noncaloric nutrient in regulating whole-body energy homeostasis. Through this review, we hope to provide a scientific framework for future studies to systematically address the metabolic impacts of dietary salt and salt replacement treatments. In addition, we hope to form a foundation for future clinical trials to explore how these salt-induced metabolic changes impact obesity development and progression, and to elucidate the regulatory mechanisms that drive these changes, with the aim of developing novel therapeutics for obesity and CVD.

Hepatic Transcriptomics Reveals Reduced Lipogenesis in High-Salt Diet Mice

It has been demonstrated that a high salt diet (HSD) increases the risk of cardiovascular disease and metabolic dysfunction. In particular, the impact and molecular mechanisms of long-term HSD on hepatic metabolism remain largely unknown. To identify differentially expressed genes (DEGs) affecting the metabolism of liver tissues from HSD and control groups, a transcriptome analysis of liver tissues was performed in this study. As a result of the transcriptome analysis, the expression of genes related to lipid and steroid biosynthesis (such as Fasn, Scd1, and Cyp7a1) was significantly reduced in the livers of HSD mice. Additionally, several gene ontology (GO) terms have been identified as associated with metabolic processes in the liver, including the lipid metabolic process (GO: 0006629) and the steroid metabolic process (GO: 0008202). An additional quantitative RT-qPCR analysis was conducted to confirm six down-regulated genes and two up-regulated genes. Our findings provide a theoretical basis for further investigation of HSD-induced metabolic disorders.

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.

Dietary Sodium and Nonalcoholic Fatty Liver Disease: A Systematic Review

(1) Introduction: Restriction in sodium intake is an important strategy for reducing cardiovascular morbidity and mortality, considering the direct influence of high-sodium diet consumption on the development of hypertension and cardiovascular diseases. There are only a few studies dealing with the influence of dietary sodium on the development of nonalcoholic fatty liver disease (NAFLD). In this systematic review, evidence in humans and animal models was compiled in a critical view of the influence of dietary sodium intake patterns on NAFLD markers; (2) Methods: Systematic review of PubMed data. Clinical outcomes included the prevalence/incidence of NAFLD for human studies, and NAFLD markers (hepatic lipogenesis, and markers of steatosis, fibrosis, and inflammation) for animal studies. The protocol was registered at the International Prospective Register of Systematic Review (PROSPERO; CRD42023390447); (3) Results and Conclusion: Seven studies in humans and eight in animals were included. All studies in humans were observational and associated high-sodium intake with NAFLD. However, in animals, both the increased and reduced consumption of sodium negatively influenced markers of liver steatosis, inflammation, and fibrosis.

Role of high-salt diet in non-alcoholic fatty liver disease: a mini-review of the evidence

With the rising incidence of both obesity and diabetes, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. However, lifestyle intervention remains to be an effective approach for NAFLD due to lack of therapeutic medication. Recently, salt, an essential micronutrient free of calories, has raised a global concern owing to its wide-range healthy relevance. Accumulated evidence has suggested that a long-term high-salt diet (HSD) independently increases the risk of NAFLD. In the past decades, a number of studies have been reported regarding the mechanism of much investigation concerning HSD-induced NAFLD. Here, we review the updates in epidemiology and molecular mechanism of HSD-induced NAFLD and provide a novel insight into the role of HSD in the regulation of lipid metabolism.

Food-seeking behavior is triggered by skin ultraviolet exposure in males

Sexual dimorphisms are responsible for profound metabolic differences in health and behavior. Whether males and females react differently to environmental cues, such as solar ultraviolet (UV) exposure, is unknown. Here we show that solar exposure induces food-seeking behavior, food intake, and food-seeking behavior and food intake in men, but not in women, through epidemiological evidence of approximately 3,000 individuals throughout the year. In mice, UVB exposure leads to increased food-seeking behavior, food intake and weight gain, with a sexual dimorphism towards males. In both mice and human males, increased appetite is correlated with elevated levels of circulating ghrelin. Specifically, UVB irradiation leads to p53 transcriptional activation of ghrelin in skin adipocytes, while a conditional p53-knockout in mice abolishes UVB-induced ghrelin expression and food-seeking behavior. In females, estrogen interferes with the p53-chromatin interaction on the ghrelin promoter, thus blocking ghrelin and food-seeking behavior in response to UVB exposure. These results identify the skin as a major mediator of energy homeostasis and may lead to therapeutic opportunities for sex-based treatments of endocrine-related diseases.

The role of caloric intake in the association of high salt intake with high blood pressure

Since current recommendations call for a substantial reduction in overall sodium consumption, we tested whether or not these recommendations are implemented in common large subpopulations such as those with abnormal weight or hypertension in the current high sodium, high-calorie nutritional environment. In a national representative cross-sectional survey of the community-dwelling subjects aged 25-65 years conducted in Israel between 2015 and 2017, 582 randomly selected subjects completed health and dietary questionnaires, underwent blood pressure and anthropometric measurements and collected 24-h urine specimens, to assess dietary sodium intake. Overall mean 24-h sodium excretion was 3834 mg, more than double the recommended upper intake for adults < 1500 mg/day. Sodium excretion was directly related to caloric intake and blood pressure and linked to the presence of hypertension and overweight/obesity. The highest sodium excretion was seen in overweight/obese hypertensive subjects. This recent national survey shows a high consumption of sodium in the Israeli population and a dose-response association between caloric intake and urinary sodium excretion, independent of BMI and hypertension. Nevertheless, overweight/obese subjects with hypertension consume (excrete) more sodium than other BMI/ blood pressure-related phenotypes and may thus comprise a target subpopulation for future efforts to reduce sodium intake.

Association of Usual Sodium Intake with Obesity Among US Children and Adolescents, NHANES 2009-2016

OBJECTIVE

The purpose of this study was to investigate the association of sodium intake with obesity in US children and adolescents.

METHODS

Cross-sectional data were analyzed for 9,026 children and adolescents in the National Health and Nutrition Examination Survey (NHANES) 2009-2016. Usual sodium intake was estimated from 24-hour dietary recalls using a measurement error model. Logistic regression was used to assess the association of sodium intake with overweight/obesity, obesity, and central obesity (waist to height ratio [WtHR] ≥ 0.5; waist circumferences (WC) ≥ age- and sex-specific 90th percentile).

RESULTS

Mean (SE) sodium intake was 3,010  (9) and 3,404  (20) mg/d for children and adolescents, respectively. The adjusted odds ratio (AOR) comparing Q4 versus Q1 (87.5th vs. 12.5th percentile of sodium intake) among children was 1.98 (95% CI: 1.19-3.28) for overweight/obesity, 2.20 (1.30-3.73) for obesity, 2.10 (1.12-3.95) for WC ≥ 90th percentile, and 1.68 (0.95-2.97) for WtHR ≥ 0.5, adjusting for demographics, energy, and sugar-sweetened beverage intake. Among adolescents, AOR was 1.81 (0.98-3.37) for overweight/obesity, 1.71 (0.82-3.56) for obesity, 1.62 (0.71-3.66) for WC ≥ 90th percentile, and 1.73 (0.85-3.50) for WtHR ≥ 0.5.

CONCLUSIONS

Sodium intake was positively associated with overweight/obesity, obesity, and central obesity among US children independent of energy and SSB intake, but the association did not reach significance among adolescents.

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.

Dietary Sodium Intake and Health Indicators: A Systematic Review of Published Literature between January 2015 and December 2019

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.

Alteration Pattern of Taste Perception After Bariatric Surgery: a Systematic Review of Four Taste Domains

BACKGROUND

Efforts continue to understand the underlying mechanism of weight loss after bariatric surgery. Taste perception has shown to be a contributing factor. However, the alteration pattern in different taste domains and among bariatric procedures has not been sufficiently investigated.

OBJECTIVES

To study the alteration pattern in the perception of four taste domains after different bariatric procedures.

SETTINGS

Private Research Institute, USA.

METHODS

A systematic review was conducted to pool available data in the literature on post-operative changes in the perception of sensitivity to four taste domains after Roux-en-Y gastric bypass (RYGB), laparoscopic sleeve gastrectomy (LSG), and adjustable gastric banding (AGB).

RESULTS

Our study showed that bariatric surgery is associated with significant change in sensitivity to all four taste domains especially salt taste, sweetness, and sourness. LSG patients showed an increased sensitivity to all four taste domains. However, RYGB patients had a variable alteration pattern of taste perception but more commonly a decreased sensitivity to sweetness and an increased sensitivity to salt taste and sourness. Additionally, AGB patients had a decreased sensitivity to sweetness, salt taste, and sourness.

CONCLUSION

Bariatric surgery is associated with taste change in a way which results in less preference for high-calorie food and possibly reduced calorie intake. This may explain one of the mechanisms by which bariatric surgery produces weight loss. However, data are heterogeneous, the potential effect dilutes over time, and the alteration varies significantly between different procedures.

Salt consumption and the risk of chronic diseases among Chinese adults in Ningbo city

Background

Chronic diseases have become one of essential public health concerns, leading causes of mortality in China. It is related to the changes in dietary pattern and dietary behavior. The objectives are to assess daily salt intake in Chinese people living in Ningbo and to examine its relationship with health outcomes.

Methods

Our study used data from health and nutrition survey in 2017. This study included 2811 adults aged 18–79 years (48% males) from urban and rural areas in Ningbo. A food frequency questionnaire together with demographic, physical and medical questionnaires was used to collect dietary intake, demographic, lifestyle and medical information. Ordinal logistic regression was used in the statistical analysis.

Results

The mean daily salt intake (13.0 g/day) of the participants was higher than the Chinese dietary reference intake (DRI, 6 g/d), which was related to higher risk of pre-hypertension and hypertension. Stratified by gender, education and lifestyle factors, daily salt intake was only significant in the blood pressure category (male: P = 0.048; less education: P = 0.003; urban: P = 0.006; no regular physical activity: P = 0.005, no regular smoking: P = 0.006). Ordinal logistic regression model shows that daily salt intake was significantly associated with higher odds of developing hypertension.

Conclusion

The daily salt intake of the majority of citizens living in Ningbo exceeded Chinese DRI and may increase the risk of hypertension. Moreover, public health intervention of salt restriction is necessarily needed for the prevention and control the ongoing epidemic of chronic diseases.

Association between salt taste sensitivity threshold and blood pressure in healthy individuals: a cross-sectional study

BACKGROUND

Hypertension is an important public health problem. Overweight and high salt intake are risk factors for its development.

OBJECTIVE

To evaluate the association between salt taste sensitivity threshold (STST) and blood pressure (BP) in healthy adults.

DESIGN AND SETTING

Cross-sectional study conducted in a private institution.

METHODS

104 healthy adults (aged 18-59 years) were evaluated. Sociodemographic, clinical and dietary data were collected. Nutritional status and BP were assessed using body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP) and diastolic blood pressure (DBP). STST was assessed using graded saline solutions with sodium chloride concentrations ranging from 0.228 to 58.44 g/l. Identification of salty taste in solutions ≥ 3.652 g/l was used as the cutoff point for high STST.

RESULTS

Participants with high STST presented higher daily average intakes for energy (2017.4 ± 641.5 versus 1650.5 ± 357.7 kcal/day; P = 0.01) and sodium (3070.2 ± 1195.1 versus 2435.2 ± 963.6 mg/day; P = 0.01) and higher BMI (P = 0.008) and WC (P = 0.002). After adjustment for age, sex, sodium and potassium intake, WC and family history of hypertension, the averages for SBP and DBP in subjects with high STST were higher than in those with normal STST (SBP: 138.2 ± 1.7 versus 119.7 ± 0.9 mmHg; P < 0.001; DBP: 81.2 ± 1.9 versus 75.1 ± 1.0 mmHg; P = 0.008).

CONCLUSION

High STST was associated with elevated blood pressure in healthy adults, regardless of other risk factors for hypertension.

Twenty-Four-Hour Urinary Sodium and Potassium Excretion in China: A Systematic Review and Meta-Analysis

Background

In China, high sodium and low potassium intakes result in elevated blood pressure, a major cause of cardiovascular disease, yet the intake estimates lack accuracy and nutritional strategies remain limited.

Methods and Results

We aimed to determine sodium and potassium intake by systematically searching for and quantitatively summarizing all published 24‐hour urinary sodium and potassium data (ie, the most accurate method). MEDLINE, EMBASE, Scopus, China National Knowledge Infrastructure, and Wanfang were searched up to February 2019. All studies reporting 24‐hour urinary sodium or potassium in China were included; hospitalized patients were excluded. Data were pooled using random‐effects meta‐analysis and heterogeneity was explored with meta‐regression. Sodium data were reported in 70 studies (n=26 767), 59 of which also reported potassium (n=24 738). Mean sodium and potassium excretions were 86.99 mmol/24 h (95% CI, 69.88–104.10) and 14.65 mmol/24 h (95% CI, 11.10–18.20) in children aged 3 to 6 years, 151.09 mmol/24 h (95% CI, 131.55–170.63) and 25.23 mmol/24 h (95% CI, 22.37–28.10) in children aged 6 to 16 years, and 189.07 mmol/24 h (95% CI, 182.14–195.99) and 36.35 mmol/24 h (95% CI, 35.11–37.59) in adults aged >16 years. Compared with southern China, sodium intake was higher in northern China (P<0.0001) but is declining (P=0.0066).

Conclusions

Average sodium intake in all age groups across China is approximately double the recommended maximum limits, and potassium intake is less than half that recommended. Despite a decline, sodium intake in northern China is still among the highest in the world, and the North–South divide persists. Urgent action is needed to simultaneously reduce sodium and increase potassium intake across China.

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.

The Influence of Dietary Salt Beyond Blood Pressure

PURPOSE OF REVIEW

Excess sodium from dietary salt (NaCl) is linked to elevations in blood pressure (BP). However, salt sensitivity of BP varies widely between individuals and there are data suggesting that salt adversely affects target organs, irrespective of BP.

RECENT FINDINGS

High dietary salt has been shown to adversely affect the vasculature, heart, kidneys, skin, brain, and bone. Common mediators of the target organ dysfunction include heightened inflammation and oxidative stress. These physiological alterations may contribute to disease development over time. Despite the adverse effects of salt on BP and several organ systems, there is controversy surrounding lower salt intakes and cardiovascular outcomes. Our goal here is to review the physiology contributing to BP-independent effects of salt and address the controversy around lower salt intakes and cardiovascular outcomes. We will also address the importance of background diet in modulating the effects of dietary salt.

How Much Intake of Sodium Is Good for Frailty?: The Korean Frailty and Aging Cohort Study (KFACS)

OBJECTIVE

The aim of this study was to determine how sodium intake can affect frailty, but not anorexia, in community-dwelling older adults in Korea.

DESIGN

This was a cross-sectional study.

SETTING

The study used data from the Korean Frailty and Aging Cohort Survey (KFACS), a multi-center longitudinal study addressing 10 centers across urban, rural, and suburban communities in Korea, between 2016 and 2017.

PARTICIPANTS

A total of 954 older adults who underwent both 24-hour dietary recall assessment and physical function test during the first-year baseline investigation of the KFACS.

MEASUREMENTS

Frailty was determined according to the Fried frailty index (FFI).

RESULTS

Of the 954 participants, 461 (48.3%) were male and the mean age was 76.3 years old. The average daily sodium intake was 3857 mg. The frailty prevalence in first to third quartiles was 21.8%, 7.5%, and 5.4%, respectively, and increased in the fourth quartile of sodium intake to 8.9%. Using the second quartile of sodium intake (2504-3575 mg) as reference, the odds ratios of frailty were 1.64 (95% confidence interval: 0.84-3.22), 1.33 (0.57-3.06), and 4.00 (1.72-9.27) for the first (<2504 mg), third (3575-4873 mg), and fourth (≥4873 mg) quartiles, respectively, in a multivariate-adjusted analysis.

CONCLUSION

Low sodium intake (<2504 mg) is related to frailty in older people, but it seems to be a less important factor than other nutritional factors. The prevalence of frailty did not increase up to a daily sodium intake of 3575 mg, but it increased upon a daily sodium intake higher than 3575 mg.

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.

The Twin White Herrings: Salt and Sugar

India has the dubious distinction of being a hotspot for both diabetes and hypertension. Increased salt and sugar consumption is believed to fuel these two epidemics. This review is an in-depth analysis of current medical literature on salt and sugar being the two white troublemakers of modern society. The PubMed, Medline, and Embase search for articles published in January 2018, using the terms "salt" [MeSH Terms] OR "sodium chloride" [All Fields] OR "sugar" [All Fields]. India is world's highest consumer of sugar with one of the highest salt consumption per day. Increased salt intake is associated with increased risk of hypertension, left ventricular hypertrophy and fibrosis, cardiovascular events, renal stones, proteinuria, and renal failure. Increased sugar intake is directly linked to increased risk of obesity, fatty liver disease, and metabolic syndrome. Also, increased sugar intake may be indirectly related to the increased risk of type 2 diabetes. Both salt and sugar intake is directly linked to increased systemic and hypothalamic inflammation, endothelial dysfunction, microangiopathy, cardiovascular remodelling, cancers, and death. High fructose corn is especially damaging. There is no safe limit of sugar consumption, as the human body can produce its own glucose. Being nature's gift to mankind, there is no harm in moderate consumption of salt and sugar, however, modest reduction in the consumption of both can substantially reduce the burden of non-communicable diseases. Public health interventions to facilitate this behavioural change must be instituted and encouraged.

Ghrelin produces antidepressant-like effect in the estrogen deficient mice

Recent evidence shows that ghrelin plays an important role in depression. However, it was little known whether ghrelin produces antidepressant-like effect in the ovariectomized mice. The present study was aimed to investigate the antidepressant-like effects of the ghrelin in ovariectomized mice. In the forced swim test, ghrelin significantly decreased immobility time, reversing the “depressive-like” effect observed in ovariectomized mice, and this effect was reversed by the tamoxifen. In addition, immunohistochemical study indicated that ghrelin treatment reversed the reductions in c-Fos expression induced by ovariectomy. An estrogen antagonist tamoxifen also antagonized the effect of ghrelin on the c-Fos expression. Furthermore, the western blotting indicated that brain-derived neurotrophic factor (BDNF) in the hippocampus, but not phosphorylated cAMP response element-binding protein (pCREB)/CREB in the frontal cortex, were affected by ghrelin treatment. Ghrelin treatment significantly increased BrdU expression. Therefore, these findings suggest that ghrelin produces antidepressant-like effects in ovariectomized mice, and estrogen receptor may be involved in the antidepressant-like effects of the ghrelin.