Dietary salt intake in Japan - past, present, and future

Strategies for improving the treatment and control of hypertension in Japan

Despite the significant advancements in the diagnosis and treatment of hypertension, the burden of hypertension remains a major global health care concern. In Japan, estimates show that more than two-thirds of the population have uncontrolled hypertension, regardless of whether they were taking antihypertensive medication. To improve hypertension management, hypertension guidelines have been developed and updated regularly by hypertension societies across various countries and regions. The Japanese Society of Hypertension (JSH) updated the Guidelines for the Management of Hypertension in 2019 (JSH 2019). The JSH 2019 aims to establish a standard management strategy for hypertension and provide evidence to all health care providers. One of its updated main features is its proposal for multidisciplinary team-based care (TBC) involving physicians, pharmacists, nurses, dietitians, and other health care providers. The TBC will help initiate and intensify the management of hypertension, as well as combat clinical inertia, which is expected to contribute to uncontrolled blood pressure and subsequent development of cardiovascular diseases. This is consistent with the recommendations from recent major guidelines on hypertension management. Moreover, to reduce the evidence-practice gap in hypertension management, it is essential to disseminate the essence of the guidelines and provide hypertension education programs for all health care providers and patients. This review summarizes the points of the JSH 2019-based strategy for improving hypertension management and discusses guidelines for its implementation into actual clinical practice.

Misinformation surrounding sodium reduction for blood pressure: content analysis of Japanese posts on X

This content analysis aimed to assess misinformation themes regarding sodium reduction and blood pressure on X with the goal of providing strategies to address and debunk such misinformation. A total of 531 posts were manually coded into sodium-related misinformation themes, with inclusion criteria for posts asserting no association between sodium reduction and hypertension or claiming consuming sodium is beneficial for health. Numbers and post frequencies per misinformation theme were calculated. Post characteristics, including information sources, advertisements and narratives, were coded, and a correlation analysis was conducted to assess their association with each misinformation theme. Fourteen sodium-related misinformation themes were identified and consistently disseminated on X. The predominant theme, 'Natural Salt', accounted for 37.7% (n = 200), reaching 1.6 million followers, followed by 'Reducing salt could be bad for my health' theme, comprising 28.6% (n = 152) and reaching 1.5 million followers. There was a statistical correlation between the natural salt misinformation theme and advertisements. Many of the most frequent misinformation themes identified in this study have not been systematically debunked by organizations such as the World Health Organization and the American Heart Association. This study underscores the importance of continuous monitoring and analysis of sodium-related misinformation on social media platforms and their underlying commercial interests. Such monitoring has the potential to identify prevalent misinformation themes that may pose harm to the public and to inform public health organizations, enabling them to proactively address potential issues through debunking.

Achievement rate of target blood pressure in patients with hypertension treated by hypertension specialists and non-specialists in a real-world setting

Hypertension remains a major global healthcare issue. Considering that most Japanese patients with hypertension are managed by general practitioners, hypertension specialists should be involved in actual clinical practice. We investigated the blood pressure (BP), guidelines recommended for achievement rate of the target BP, and clinical variables of patients with hypertension treated by hypertension specialists and those treated by non-specialists in a real-world setting. Factors associated with the target BP achievement in this population were also investigated. Outpatients with hypertension from 12 medical facilities in Okinawa Prefecture were enrolled (n = 1469 [specialist group, 794; non-specialist group, 675]; mean age, 64.2 years; females, 45.8%). For all patients, BP and rate of the target BP achievement were 129.0 ± 15.5/74.6 ± 10.6 mmHg, and 51.8%, respectively. BP and the rate of target of BP achievement were 128.0 ± 15.1/73.4 ± 10.4 mmHg and 56.7% in the specialist group, and they were 130.1 ± 15.9/76.0 ± 10.8 mmHg and 46.1% in the non-specialist group. The urinary salt excretion and obesity rates were comparable between the specialist and non-specialist groups. Multivariable logistic analyses indicated that hypertension specialists and good medication adherence were positive factors, whereas obesity, chronic kidney disease, diabetes mellitus, and urinary salt excretion were inverse factors associated with target BP achievement in this population. Initiatives for salt reduction, medication adherence, and proper obesity management are crucial to improving BP management in patients with hypertension. Hypertension specialists are expected to play an essential role in them. For all patients, the target blood pressure (BP) achievement rate were 51.8%. Hypertension specialists and good medication adherence were positive factors in achieving target BP; conversely, obesity, diabetes mellitus, chronic kidney disease, and high urinary salt excretion were inverse factors in achieving target BP among patients with hypertension.

Reducing the Sodium Intake of Patients With Chronic Kidney Disease Through Education and Estimating Salt Excretion: A Propensity Score Matching Analysis

BACKGROUND

Japanese people traditionally consume high quantities of salt. This study aimed to investigate the effects of educating patients with chronic kidney disease (CKD) on simple methods for reducing their daily dietary salt intake.

METHODS

This single-center, retrospective observational study included 115 outpatients with CKD at Kawashima Hospital (Tokushima, Japan). One physician routinely recommended that patients should reduce their salt intake and provided tips for salt restriction. The physician estimated the patients' daily salt intake using spot urine samples at each medical examination (education group; n = 61). The other physicians' outpatients only received dietary guidance on recommended salt intake (control group; n = 54). The estimated 24-hour urinary sodium excretion (24hUNaV) and 24-hour potassium excretion (24hUKV) were calculated using Tanaka's equation.

RESULTS

Estimated 24hUNaV was positively correlated with body mass index (BMI), estimated 24hUKV, and urinary Na/K ratio. The patients in the education group were younger and had a lower BMI, higher estimated glomerular filtration rate, and lower systolic blood pressure (SBP). Using 38 pairs of patients obtained by propensity score matching with these variables, estimated 24hUNaV, estimated 24hUKV, and diastolic blood pressure (DBP) after one year were significantly reduced in the education group.

CONCLUSION

A simple salt reduction education may reduce salt intake in outpatients with CKD.

Sodium intake trend and current intake level by meal provision place among the citizens of Seoul

BACKGROUND/OBJECTIVES

The diversity of meal provision places has increased in recent years and sodium intake can vary depending on where meals are eaten, particularly in large cities. In this study, an analysis of the recent trends in sodium intake was performed and a comparison of sodium intake level according to meal provision place among citizens of Seoul was performed.

SUBJECTS/METHODS

Data from a 24-h recall dietary intake survey from the 2010-2019 Korea National Health and Nutrition Examination Survey (KNHANES) were used in order to determine the trends in sodium intake among citizens of Seoul, aged 3-74 years old. (n = 11,811). The trend of daily sodium intake was presented in absolute amount and proportion compared to the chronic disease risk reduction intake (CDRR) for each selected characteristic. A comparison of sodium intake level according to meal provision place by sex and age groups as a total amount per meal (mg), density per meal (mg/1,000 kcal), and proportion of the daily sodium intake was performed using the 2016-2019 KNHANES.

RESULTS

Sodium intake levels showed a downward trend from 2010-2019. The highest level of sodium intake was observed for subjects aged 30-49, and the level for males aged 30-49 was 202.8% higher than the CDRR. Results of the analysis of sodium intake per meal according to meal provision place showed that the highest sodium intake was in the order of restaurant meal (RM) > institutional foodservice (IF) > home meal (HM) > convenience food (CF). A higher sodium density (mg/1,000 kcal) was observed for IF compared with RM in most adults. Adults aged over 50 years old consumed more than half of the daily sodium in HM.

CONCLUSION

Significant variation in the level of sodium intake was observed according to sex and age groups, therefore, different approaches and nutrition policies based on meal provision place are needed.

Treatment of hypertension and obstructive sleep apnea counteracts cognitive decline in common neurocognitive disorders in diagnosis-related patterns

The aim of this study was to investigate the effect of arterial hypertension (AH) and of obstructive sleep apnea (OSA) on cognitive course in the neurocognitive disorder (NCD) cohort RIFADE which enrolled patients with NCD due to Alzheimer's disease (AD), vascular NCD (vNCD), and mixed NCD (AD + vNCD = mNCD). Multiple risk factors (RF), including AH and OSA, that contribute to the development of various kinds of dementia have been identified in previous studies. Studies that observed AH lacked investigation of long-term effects and did not isolate it from other RF. Studies involving OSA as a risk factor did not include participants with all stages of NCD. 126 subjects were screened for AH and OSA. Repeated cognitive measurements were performed with the DemTect as primary outcome and the clock drawing test as secondary outcome measure. 90 patients had AH (71.4%) and 40 patients had OSA (31.7%). RF-status had a significant effect on cognitive outcome in models with RF as single factors (AH p = 0.027, OSA p < 0.001), a 2-factor analysis with AH × OSA (AH as main factor p = 0.027) as well as a model including the 3 factors AH × OSA × diagnosis (p = 0.038). Similarly, a 3-factor model was significant for the clock-drawing test, whereas single factor-models remained insignificant. AH and OSA appear to be risk factors in common NCD and cognitive decline can be mitigated by treatment of these RF.

Nephrons, podocytes and chronic kidney disease: Strategic antihypertensive therapy for renoprotection

Chronic kidney disease (CKD) is one of the strongest risk factors for hypertension, and hypertension can exacerbate the progression of CKD. Thus, the management of CKD and antihypertensive therapy are inextricably linked. Research over the past decades has shown that the human kidney is more diverse than initially thought. Subjects with low nephron endowment are at increased risk of developing CKD and hypertension, which is consistent with the theory of the developmental origins of health and disease. Combined with other lifetime risks of CKD, hypertension may lead to a vicious cycle consisting of podocyte injury, glomerulosclerosis and further loss of nephrons. Of note, recent studies have shown that the number of nephrons correlates well with the number of podocytes, suggesting that these two components are intrinsically linked and may influence each other. Both nephrons and podocytes have no or very limited regenerative capacity and are destined to decrease throughout life. Therefore, one of the best strategies to slow the progression of CKD is to maintain the "numbers" of these essential components necessary to preserve renal function. To this end, both the achievement of an optimal blood pressure and a maximum reduction in urinary protein excretion are essential. Lifestyle modifications and antihypertensive drug therapy must be carefully individualized to address the potential diversity of the kidneys.

Chloride Ions, Vascular Function and Hypertension

Blood pressure is determined by cardiac output and systemic vascular resistance, and mediators that induce vasoconstriction will increase systemic vascular resistance and thus elevate blood pressure. While peripheral vascular resistance reflects a complex interaction of multiple factors, vascular ion channels and transporters play important roles in the regulation of vascular tone by modulating the membrane potential of vascular cells. In vascular smooth muscle cells, chloride ions (Cl⁻) are a type of anions accumulated by anion exchangers and the anion–proton cotransporter system, and efflux of Cl⁻ through Cl⁻ channels depolarizes the membrane and thereby triggers vasoconstriction. Among these Cl⁻ regulatory pathways, emerging evidence suggests that upregulation of the Ca²⁺-activated Cl⁻ channel TMEM16A in the vasculature contributes to the increased vascular contractility and elevated blood pressure in hypertension. A robust accumulation of intracellular Cl⁻ in vascular smooth muscle cells through the increased activity of Na⁺–K⁺–2Cl⁻ cotransporter 1 (NKCC1) during hypertension has also been reported. Thus, the enhanced activity of both TMEM16A and NKCC1 could act additively and sequentially to increase vascular contractility and hence blood pressure in hypertension. In this review, we discuss recent findings regarding the role of Cl⁻ in the regulation of vascular tone and arterial blood pressure and its association with hypertension, with a particular focus on TMEM16A and NKCC1.

Estimation of Sodium Availability and Food Sources from 2018 to 2019 and Its Trends during the 2004-2019 Period in Costa Rica

Sodium availability and food sources in 2018−2019 were estimated and trends analyzed for 15 years (2004−2019) in Costa Rica. Food purchase records from the National Household Income and Expenditure Survey (ENIGH) 2018−2019 were converted to energy and sodium using food composition tables measuring “apparent consumption”. Foods were classified by sodium content. ENIGH is a probabilistic, stratified, two-stage and replicated national survey, carried out regularly by the national statistics institution. Results from the 2004−2005 and 2012−2013 ENIGHs came from previous analysis. Differences between periods were determined through descriptive and inferential statistics. The available sodium adjusted to 2000 kcal/person/day was 3.40, 3.86, and 3.84 g/person/day (g/p/d) for periods 2004−2005, 2013−2014, and 2018−2019, respectively. In this last period, this was 3.94 urban and 3.60 g/p/d rural (p < 0.05), with a non-linear increase with income. During 2004−2019 sodium from salt and salt-based condiments increased from 69.5 to 75.5%; the contribution of common salt increased, from 60.2 to 64.8% and condiments without added salt from 9.3 to 10.7%. From 2012−2013 to 2018−2019, processed and ultra-processed foods with added sodium intake increased from 14.2 to 16.9% and decreased in prepared meals (7.2 to 2.8%). Costa Rica has been successful in reducing salt/sodium available for consumption; after a 12% increase of salt consumption between 2004−2005 and 2012−2013, to a level almost twice as high as recommended, it has stabilized in the last period.

Impact of Dietary Fructose and High Salt Diet: Are Preclinical Studies Relevant to Asian Societies?

Fructose consumption, especially in food additives and sugar-sweetened beverages, has gained increasing attention due to its potential association with obesity and metabolic syndrome. The relationship between fructose and a high-salt diet, leading to hypertension and other deleterious cardiovascular parameters, has also become more evident, especially in preclinical studies. However, these studies have been modeled primarily on Western diets. The purpose of this review is to evaluate the dietary habits of individuals from China, Japan, and Korea, in light of the existing preclinical studies, to assess the potential relevance of existing data to East Asian societies. This review is not intended to be exhaustive, but rather to highlight the similarities and differences that should be considered in future preclinical, clinical, and epidemiologic studies regarding the impact of dietary fructose and salt on blood pressure and cardiovascular health worldwide.