Report of the Working Group for Dietary Salt Reduction of the Japanese Society of Hypertension: (1) Rationale for Salt Restriction and Salt-Restriction Target Level for the Management of Hypertension

Aversion to a High Salt Taste is Disturbed in Patients With CKD

Introduction

A reduced salt intake is a vital lifestyle modification in the management of hypertension. Initiatives aimed at decreasing the intake of salt are based on the preference by humans for a salt taste. Salt intake behavior appears to be affected by the balance between attraction to a low salt taste and aversion to a high salt taste. However, aversion to a high salt taste has not yet been quantitively investigated in both healthy individuals and patients with chronic kidney disease (CKD).

Methods

Assessments of gustatory and aversion thresholds for salt, bitter, sour, and sweet tastes were performed using a stimulant-impregnated test strip in healthy subjects and patients with CKD.

Results

In a pilot taste test of 125 healthy subjects, the number of participants with an aversive reaction increased at higher salt concentrations. The threshold for normal taste perception was arbitrarily defined as 10% NaCl, with 47.2% of healthy subjects displaying an aversive reaction. In taste tests performed by 70 patients with CKD, 10% were unable to recognize a salt taste, even at the highest concentration (20% NaCl), suggesting a significant impairment in taste perception in patients with CKD. Only 15.7% of patients with CKD exhibited a normal aversion to NaCl, whereas 78.6% showed the complete loss of aversion to salt.

Conclusion

The present results confirmed the anticipated aversive response to a high salt taste in humans and demonstrated its impairment in patients with CKD, implying that patients with CKD have reduced resistance to a high salt intake.

Research trends and hotpots on the relationship between high salt and hypertension: A bibliometric and visualized analysis

INTRODUCTION

A high salt diet is a significant risk factor for hypertension, and scholarly investigations into this relationship have garnered considerable attention worldwide. However, bibliometric analyses in this field remain underdeveloped. This study aimed to conduct a bibliometric and visual analysis of research progress on the link between high salt and hypertension from 2011 to 2022 with the goal of identifying future research trends and providing valuable insights for this field.

METHODS

High salt and hypertension data were obtained from the Web of Science Core Collection database. Microsoft Excel, Scimago Graphica, CiteSpace, and VOSviewer software were employed to analyze publication output trends, the most productive countries or regions, journals, authors, co-cited references, and keywords.

RESULTS

After screening, 1470 papers met the inclusion criteria. Relevant publications increased annually by 3.66% from 2011 to 2022. The United States led in research productivity, with The Journal of Hypertension publishing the most papers, and David L. Mattson as the most prolific author. Oxidative stress has emerged as a prominent research topic, and extensive investigations have been conducted on related mechanisms. "Oxidative stress," "gut microbiota," and "kidney injury" are recent hotspots that are expected to remain so, and this study carefully characterizes the mechanism of high salt-induced hypertension based on these hotspots.

CONCLUSION

This study utilized bibliometric and visualization analysis to identify the development trends and hotspots of publications related to high salt and hypertension. The findings of this study offer valuable insights into the forefront of emerging trends and future directions in this field.

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.

Stress Condition on a Restricted Sodium Diet Using Umami Substance (L-Glutamate) in a Pilot Randomized Cross-Over Study

Hypertensive patients who adopt a sodium-restricted diet have difficulty maintaining this change, and this could increase stress. On the other hand, soup rich in umami substances (dashi) was reported to reduce indexes of anxiety and stress. The objective of this study was to measure mood and physiological stress indexes during administration of a sodium-restricted diet with and without an umami substance (free L-glutamate) by a cross-over randomized, single-blind, placebo-controlled trial in Japanese female university students. The baseline was measured for 5 days followed by a sodium-restricted diet intervention phase that lasted for 10 days. The Profile of Mood States questionnaire was administered, a stress marker in saliva (chromogranin-A) was measured, and the amount of sodium intake was confirmed from 24 h urine collection samples. Results showed that the sodium reduction was verified by 24 h urine excretion. The percentage of change in the stress marker from the baseline showed that the stress level in group without the umami substance was significantly higher than that in the group with the umami substance (p = 0.013) after receiving a sodium-reduced diet for 6 or more days, indicating that stress was alleviated. This study suggested that umami substances might help to ameliorate stress during a sodium-reduced diet, especially in the initial phase.

The role of dietary salt and alcohol use reduction in the management of hypertension

Introduction: Despite the improved treatment protocol of hypertension, the magnitude of the disease and its related burden remains raised. Hypertension makes up the leading cause of stroke, kidney disease, arterial disease, eye disease, and cardiovascular disease (CVD) growth. Areas covered: This review provides the overview of the role of dietary salt and alcohol use reduction in the management of hypertension, a brief history of alcohol, the vascular endothelium functions, the effects of alcohol use on blood pressure (BP), the mechanisms of alcohol, brief history of salt, the effects of dietary salt intake on BP, and the mechanisms of salt. Expert opinion: Studies found that high dietary salt intake and heavy alcohol consumption have a major and huge impact on BP while both of them have been identified to increase BP. Also, they raise the risk of hypertension-related morbidity and mortality in advance. On the other way, the dietary salt and alcohol use reduction in the management of hypertension are significant in the control of BP and its related morbidity and mortality. Further, studies suggested that the dietary salt and alcohol use reductions are the cornerstone in the management of hypertension due to their significance as part of comprehensive lifestyle modifications.

Biochemical interaction of salt sensitivity: a key player for the development of essential hypertension

Worldwide, more than 1 billion people have elevated blood pressure, with up to 45% of adults affected by the disease. In 2016 the global health study report on patients from 67 countries was released in Lancet, which identified hypertension as the world's leading cause for death and disability-adjusted years since 1990. This paper aims to analyze the pathophysiological connection between hemodynamic inflammatory reactions through sodium balance, salt sensitivity, and potential pathophysiological reactions. Besides, we explore how sodium consumption enhances the expression of transient receptor potential channel 3 (TrpC3) mRNA and facilitates the release of calcium inside immune cell groups, together with elevated blood pressure in essential hypertensive patients.

The Nutritional Characteristics of the Hypotensive WASHOKU-modified DASH Diet: A Sub-analysis of the DASH-JUMP Study

Background

We developed a WASHOKU-modified DASH diet named DASH-JUMP. We previously reported the hypotensive effect of the DASH-JUMP diet in Japanese participants with untreated high-normal Blood Pressure (BP) or stage 1 hypertension.

Objective

We aim to introduce the DASH-JUMP diet worldwide as a new lifestyle medicine. Accordingly, we prospectively assessed the nutritional characteristics of the DASH-JUMP diet.

Methods

Participants were treated with the DASH-JUMP diet for 2 months. Then, for 4 months after the intervention, they consumed their usual diets. We conducted a nutritional survey using the FFQg nutrient questionnaire at baseline and after 1, 2, 3, and 6 months. We received completed questionnaires from 55 participants (28 men and 27 women; mean age 54.2 ± 8.0 years) and analyzed them.

Results

The DASH-JUMP diet is rich in green-yellow vegetables, seaweed, milk, and mushrooms, while it has low contents of meat, eggs, confectionery, oils and fats, pickles, shellfish boiled in sweetened soy sauce, and fruits. Nutrients significantly associated with the observed change in systolic BP were niacin (P = 0.005) and carbohydrate (P = 0.033). The results of the FFQg questionnaire revealed that participants who had an increased BP at 1 month after ceasing the intervention had eating habits that broadly imitated the DASH-JUMP diet at 4 months after ceasing the intervention. Therefore, the systolic and diastolic BP values at 4 months after ceasing the intervention decreased significantly compared to those at baseline.

Conclusion

The DASH-JUMP diet may represent a new lifestyle medicine for reducing hypertension.

Functional foods for augmenting nitric oxide activity and reducing the risk for salt-induced hypertension and cardiovascular disease in Japan

High salt intake is one of the major dietary determinants of hypertension and cardiovascular disease in Japan and throughout the world. Although dietary salt restriction may be of clinical benefit in salt-sensitive individuals, many individuals may not wish, or be able to, reduce their intake of salt. Thus, identification of functional foods that can help protect against mechanistic abnormalities mediating salt-induced hypertension is an issue of considerable medical and scientific interest. According to the "vasodysfunction" theory of salt-induced hypertension, the hemodynamic abnormality initiating salt-induced increases in blood pressure usually involves subnormal vasodilation and abnormally increased vascular resistance in response to increased salt intake. Because disturbances in nitric oxide activity can contribute to subnormal vasodilator responses to increased salt intake that often mediate blood pressure salt sensitivity, increased intake of functional foods that support nitric oxide activity may help to reduce the risk for salt-induced hypertension. Mounting evidence indicates that increased consumption of traditional Japanese vegetables and other vegetables with high nitrate content such as table beets and kale can promote the formation of nitric oxide through an endothelial independent pathway that involves reduction of dietary nitrate to nitrite and nitric oxide. In addition, recent studies in animal models have demonstrated that modest increases in nitrate intake can protect against the initiation of salt-induced hypertension. These observations are: (1) consistent with the view that increased intake of many traditional Japanese vegetables and other nitrate rich vegetables, and of functional foods derived from such vegetables, may help maintain healthy blood pressure despite a high salt diet; (2) support government recommendations to increase vegetable intake in the Japanese population.

The SONG (Salt intake and OrigiN from General foods) Study - A Large-scale Survey of the Eating Habits and Dietary Salt Intake in the Working-age Population

Objective Dietary salt reduction is important for the prevention and treatment of lifestyle-related diseases, including hypertension. Thus, in order to follow a strict low-salt diet, it is necessary to assess one's salt intake and to become aware of the importance of salt reduction. Methods More than 2,000 employees of a company, who received a periodic health checkup, participated in the present study. They assessed their day-to-day diet-related lifestyle, using the Salt Check Sheet, and we analyzed the correlations among the Salt Check Sheet scores, the daily salt intake (as estimated by a spot urine sample), and the results of the periodic health checkup. Results In the overall survey population, we only found a weak correlation between the salt check scores and the salt intake. In a subgroup analysis, significant correlations between these two variables were observed among untreated hypertensive participants, but not among treated hypertensive participants. We examined the association between 13 individual questionnaire items and the estimated daily salt intake using a multivariate linear regression model and found that only 5 of the 13 questionnaire items were correlated with the daily salt intake. Conclusion We found that a Salt Check Sheet composed of the 5 items that showed a strong correlation with the salt intake might be more useful for periodic health checks of the working-age population.

Comparison of telmisartan/amlodipine and telmisartan/hydrochlorothiazide in the treatment of Japanese patients with uncontrolled hypertension: the TAT-Kobe study

OBJECTIVE

The aim of this study was to compare the efficacy and safety of telmisartan plus amlodipine with telmisartan plus hydrochlorothiazide for the treatment of uncontrolled hypertension.

METHODS

Japanese hypertensive patients with uncontrolled hypertension, despite taking angiotensin II receptor blockers, were assigned randomly to either a fixed-dose combination of telmisartan/amlodipine (n=36) or telmisartan/hydrochlorothiazide (n=39). The primary endpoint was the change in office blood pressure from the baseline value at 12 weeks.

RESULTS

Both telmisartan/amlodipine and telmisaratan/hydrochlorothiazide reduced the office blood pressure efficiently (systole: -25.5±12.1 vs. -24.3±15.0 mmHg, P=0.705; diastole: -10.8±13.8 vs. -11.4±12.3 mmHg, P=0.832). Treatment with telmisartan/hydrochlorothiazide resulted in the quicker onset of blood pressure-lowering effects compared with telmisartan/amlodipine. The target therapeutic blood pressure was similar in both groups at the 12-week visit. Home blood pressure measurements taken in the mornings and evenings were also similar in both groups. Compared with the telmisartan/amlodipine group, serum potassium and brain natriuretic peptide levels decreased and uric acid and hemoglobin A1c levels increased significantly in the telmisartan/hydrochlorothiazide group. Both treatment groups showed a significant reduction in urine albumin. However, the estimated glomerular filtration rate decreased slightly but significantly in the telmisartan/hydrochlorothiazide group alone. Severe adverse effects were not observed in both groups.

CONCLUSION

Combination therapy with telmisartan/amlodipine or telmisartan/hydrochlorothiazide led to efficient blood pressure reduction among Japanese patients with previously uncontrolled hypertension with angiotensin II receptor blocker monotherapy.

Sodium Excretion and Cardiovascular Structure and Function in the Nonhypertensive Population: The Korean Genome and Epidemiology Study

BACKGROUND

The effect of sodium intake on the cardiovascular system remains controversial. The purpose of this study is to investigate the relation between sodium intake and cardiovascular structure and function in the nonhypertensive population.

METHODS

We performed a cross-sectional analysis in 1,586 nonhypertensive subjects who participated in the Korean Genome Epidemiology Study (2007-2008). Sodium intake was assessed by estimating the 24-hour urinary sodium excretion from a spot urine sample. Changes in cardiovascular structure and function were assessed by using tissue Doppler echocardiography, the carotid intima-media thickness (CIMT), and the brachial-ankle pulse wave velocity (baPWV).

RESULTS

Systolic and diastolic blood pressures increased with increasing tertiles of estimated 24-hour urinary sodium excretion. In multivariate analyses adjusting for covariates, there were stepwise decreases in the baPWV (P = 0.003) and CIMT (P = 0.001) values as the estimated 24-hour urinary sodium excretion increased, whereas no significant differences in left ventricular (LV) structural and functional parameters were observed across the tertiles of estimated 24-hour urinary sodium excretion. Multiple linear regression analyses revealed that the estimated 24-hour urinary sodium excretion was independently and inversely associated with baPWV (P < 0.001) and CIMT (P = 0.001), but not with LV parameters.

CONCLUSIONS

In the nonhypertensive population, urinary sodium excretion was inversely related to baPWV and CIMT. However, there were no associations between urinary sodium excretion and LV structure or function.

Relationship between white blood cells and hypertension in Chinese adults: the Cardiometabolic Risk in Chinese (CRC) study

Increased blood pressure was associated with increased white blood cell count (adjusted p < 0.001) in a community-based health examination survey of adults in China (n = 39 282; aged 18-93 years). Adjusted odds ratios (95% confidence intervals) for hypertension across white blood cell count quintiles were 1.00, 0.99 (0.89-1.09), 1.11 (1.01-1.22), 1.09 (0.99-1.20), and 1.19 (1.08-1.31) (p for trend < 0.001). Body mass index and white blood cell count had an additive effect on systolic blood pressure (p for interaction = 0.047). Therefore, white blood cell count could independently predict hypertension in Chinese adults.

Systolic hypertension: an increasing clinical challenge in Asia

Systolic hypertension, the predominant form of hypertension in patients aged over 50-60 years, is a growing health issue as the Asian population ages. Elevated systolic blood pressure is mainly caused by arterial stiffening, resulting from age-related vascular changes. Elevated systolic pressure increases the risk of cardiovascular disease, mortality and renal function decline, and this risk may increase at lower systolic pressure levels in Asian than Western subjects. Hence, effective systolic pressure lowering is particularly important in Asians yet blood pressure control remains inadequate despite the availability of numerous antihypertensive medications. Reasons for poor blood pressure control include low awareness of hypertension among health-care professionals and patients, under-treatment, and tolerability problems with antihypertensive drugs. Current antihypertensive treatments also lack effects on the underlying vascular pathology of systolic hypertension, so novel drugs that address the pathophysiology of arterial stiffening are needed for optimal management of systolic hypertension and its cardiovascular complications.

Current dietary salt intake of Japanese individuals assessed during health check-up

Excess salt intake is a risk factor for increased blood pressure (BP) and hypertension. To prevent hypertension, the reduction of salt intake is promoted in many countries. For people with hypertension or cardiovascular disease (CVD), a more severe restriction of salt intake is indispensable. Japanese individuals consume high quantities of salt, and it is thus important to determine the degree to which the salt intake of these individuals has been restricted. Here, we investigated the current level of salt consumption of Japanese individuals using data obtained during annual health check-ups. A total of 10 762 individuals were assessed who underwent annual health check-ups at our institution in 2011. The estimated daily salt intake (EDSI) was calculated using spot urine samples. The average EDSI was 7.83±2.02 g per day. BP increased in proportion to the EDSI, and multivariate logistic regression analysis showed that the EDSI was a significant and independent risk factor for hypertension. The average EDSI of the subjects with hypertension or a history of CVD was higher than that of the subjects without these diseases. The subjects who drank more heavily showed higher EDSIs. This study demonstrated that the average EDSI of the subjects needing to restrict their salt intake because of past or present illnesses was high. To achieve adherence to the recommended reduction of salt intake, more efforts are required.

Healthy aging diets other than the Mediterranean: a focus on the Okinawan diet

The traditional diet in Okinawa is anchored by root vegetables (principally sweet potatoes), green and yellow vegetables, soybean-based foods, and medicinal plants. Marine foods, lean meats, fruit, medicinal garnishes and spices, tea, alcohol are also moderately consumed. Many characteristics of the traditional Okinawan diet are shared with other healthy dietary patterns, including the traditional Mediterranean diet, DASH diet, and Portfolio diet. All these dietary patterns are associated with reduced risk for cardiovascular disease, among other age-associated diseases. Overall, the important shared features of these healthy dietary patterns include: high intake of unrefined carbohydrates, moderate protein intake with emphasis on vegetables/legumes, fish, and lean meats as sources, and a healthy fat profile (higher in mono/polyunsaturated fats, lower in saturated fat; rich in omega-3). The healthy fat intake is likely one mechanism for reducing inflammation, optimizing cholesterol, and other risk factors. Additionally, the lower caloric density of plant-rich diets results in lower caloric intake with concomitant high intake of phytonutrients and antioxidants. Other shared features include low glycemic load, less inflammation and oxidative stress, and potential modulation of aging-related biological pathways. This may reduce risk for chronic age-associated diseases and promote healthy aging and longevity.

Understanding of sodium content labeled on food packages by Japanese people

Salt reduction is one of the most important lifestyle modifications for the prevention of hypertension. The health promotion law regulates the labeling of the nutrient content of food in Japan and, the level of sodium, not salt (sodium chloride), has to be printed on the labels of manufactured foods. In order to control their salt intake, consumers need to apply a conversion factor to the sodium levels listed on the labels to obtain the salt equivalent. However, it is not known whether people have the knowledge appropriate for making the conversion. We carried out a questionnaire survey at the 7th National Shokuiku (food education) Conference in 2012, asking subjects to determine the salt equivalent of 1000 mg of sodium on food labels. We also asked about the target values of salt reduction in grams in the Dietary Reference Intakes for Japanese 2010 (DRI2010) and the Guidelines for Management of Hypertension 2009 by the Japanese Society of Hypertension (JSH2009). We analyzed the data from 683 respondents (169 men and 514 women); only 13.3% of respondents gave a correct answer for the salt equivalent of 1000 mg of sodium (2.50-2.60 g), whereas 61.8 and 40.4% of respondents chose the correct target values for salt reduction according to DRI2010 and JSH2009, respectively. In conclusion, few people could convert sodium content to salt, which suggested difficulty in using food labels to control their salt intake. Salt content in grams, not sodium content, should be labeled on food packages for effective salt reduction and prevention of hypertension.

Risk factors for primary prevention of cardiovascular disease and risk reduction by lipid control: the OMEGA study risk factor sub-analysis

To identify risk factors for cardiovascular disease (CVD) in hypertensive patients with no history of CVD being treated with antihypertensive drugs, we examined subgroup data (n = 13 052) from the prospective, observational Olmesartan Mega Study to Determine the Relationship between Cardiovascular Endpoints and Blood Pressure Goal Achievement (OMEGA) study. Risk factors for CVD, stroke and coronary heart disease (CHD) were examined using a Cox proportional hazards model. In addition, the effect of statin therapy at baseline on CHD prevention was analyzed in dyslipidemic patients. The factors significantly related to CVD were female (hazard ratio [HR] = 0.637, 95% confidence interval [CI] 0.428-0.948), older age (65-69 years: HR = 2.165, 95% CI 1.214-3.861; 70-74 years: HR = 2.324, 95% CI 1.294-4.174; ≥75 years: HR = 2.448, 95% CI 1.309-4.578), family history of CHD (HR = 1.993, 95% CI 1.249-3.179), diabetes (HR = 2.287, 95% CI 1.700-3.078), current smoking (HR = 2.289, 95% CI 1.512-3.466) and alcohol drinking socially (HR = 0.589, 95% CI 0.379-0.913). Diabetes was a risk factor for both stroke and CHD, while age, family history of CHD, and sodium intake score were risk factors for stroke alone. Sex, dyslipidemia, smoking and exercise habits were risk factors for CHD alone. The risk of CHD in dyslipidemic patients on statin treatment was comparable to the risk in patients without dyslipidemia (HR = 1.134, 95% CI 0.604-2.126). However, in dyslipidemic patients not on statin treatment, the HR increased to 1.807 (95% CI 1.156-2.825). In conclusion, some risk factors for CVD in hypertensive patients being treated with antihypertensive drugs with no history of CVD differed between CHD and stroke. These results suggest the importance of managing dyslipidemia with a statin for primary prevention of CHD, as well as the importance of hypertension therapy.

Effects of disclosing hypothetical genetic test results for salt sensitivity on salt restriction behavior

BACKGROUND

A few studies have explored the effects of disclosure of genetic testing results on chronic disease predisposition. However, these effects remain unclear in cases of hypertension. Reducing salt intake is an important nonpharmacological intervention for hypertension. We investigated the effects of genetic testing for salt sensitivity on salt restriction behavior using hypothetical genetic testing results.

METHODS

We conducted a cross-sectional study using a self-completed questionnaire. We enrolled consecutive outpatients who visited primary care clinics and small hospitals between September and December 2009 in Japan. We recorded the patients' baseline characteristics and data regarding their salt restriction behavior, defined as reducing salt intake before and after disclosure of hypothetical salt sensitivity genetic test results. Behavioral stage was assessed according to the five-stage transtheoretical model. After dividing subjects into salt restriction and no salt restriction groups, we compared their behavioral changes following positive and negative test results and analyzed the association between the respondents' characteristics and their behavioral changes.

RESULTS

We analyzed 1562 participants with a mean age of 58 years. In the no salt restriction group, which included patients at the precontemplation, contemplation, and preparation stages, 58.7% stated that their behavioral stage progressed after a positive test result, although 29.8% reported progression after a negative result (P < 0.001). Conversely, in the salt restriction group, which included patients at the active and maintenance stages, 9.2% stated that they would quit restricting salt intake following a negative test result, and 2.2% reported they would quit following a positive result (P < 0.001). Age < 65 years (adjusted odds ratio [OR] 1.74; 95% confidence interval [CI] 1.12-2.71), female gender (adjusted OR 1.84; CI 1.29-2.62), graduation from college or university (adjusted OR 1.66; CI 1.11-2.49), and desire for genetic testing (adjusted OR 4.53; CI 3.13-6.57) were associated with progression of behavioral stage in the no salt restriction group. Conversely, salt preference (adjusted OR 2.13; CI 1.31-3.49) was associated with quitting salt restriction in the salt restriction group.

CONCLUSION

Patients in the no salt restriction group show the possibility of progression from the behavioral stage to the action stage after testing positive for salt sensitivity. Conversely, patients in the salt restriction group, particularly those with a salt preference, would quit salt restriction after testing negative.

Cerebral aqueduct block attenuates cardio-renal injuries in post-DOCA-NaCl-hypertensive Dahl R rats

The systemic and/or local effects of the hydrocephalic brain were investigated in DOCA-NaCl-hypertensive Dahl R rats induced by 250 mg kg(-1) DOCA in silicone and 1% saline water. After a 1-week recovery with 0.3% NaCl chow and tap water, one group had the aqueduct of Sylvius blocked with silicone and epoxy materials with a control sham group matching mean blood pressure (BP) and body weight. The 4-week-postsurgery BP on the 0.3% NaCl diet averaged 161±3.2 in the sham group and 146±2.3 mm Hg in the blocked group (P<0.0001). Both groups were then given an 8% NaCl diet and after 4 weeks, the sham group's BP was increased further with markedly increased mortality: 186 mm Hg vs. 154 mm Hg (P<0.0001); 12 sham rats died after 11 weeks, while all the blocked rats survived (P<0.0001). A transient change in plasma Na levels was observed in the blocked group after 48 h on the 8% NaCl diet. At 14 weeks, 0 sham rats survived, compared with 10 out of 16 blocked rats (P<0.0001). After 11 weeks on 8% NaCl, the average tail venous pressure in the sham group was significantly higher than that of the blocked rats (P<0.0001) indicating the end stage of renal and heart failure. The hearts and kidneys weighed significantly more in the sham vs. the blocked rats (P<0.0001 for both groups). These results indicate that the aqueduct block prevents post-DOCA hypertension and cardio-renal injuries, suggesting that centralized third ventricular brain signaling has a role in salt-genetic hypertension.

Dietary intervention with cooking instructions and self-monitoring of the diet in free-living hypertensive men

The control of blood pressure (BP) is important in the prevention of cardiovascular diseases. This study was conducted to evaluate the effect of a dietary educational program for free-living, high-normal, and stage 1 or 2 hypertensive men. The participants were volunteers aged 40-75 years who agreed to the intervention. They were divided into two groups: 39 men for the intervention group and 32 men for the control group. BP, urinary sodium and potassium excretion, dietary and lifestyle data, and nonfasting venous blood sample were collected at baseline and after the intervention period. The intervention was designed to decrease sodium level with an emphasis on a decrease in the consumption of salted foods and to increase potassium level with an emphasis on an increase in the consumption of fruit and vegetables through cooking instructions and self-monitoring of the diet. At the baseline, there were no significant differences observed between the groups, except the diastolic BP. In the intervention group, a greater decrease in the urinary sodium-to-potassium excretion ratio was observed, compared with the control group (net difference 0.6, P = .029). The systolic and diastolic BP (mm Hg) decreased in the intervention group (149.0-143.0, P = .073; 93.0-87.0, P = .002), but no changes were observed in the control group (145.0-143.0, P = .231; 84.9-85.3, P = .381). In the intervention group, the urinary sodium-to-potassium excretion ratio was significantly improved by focusing on cooking instructions and self-monitoring of the diet.

Comparison of medium-dose losartan/hydrochlorothiazide and maximal-dose angiotensin II receptor blockers in the treatment of Japanese patients with uncontrolled hypertension: the Kobe-CONNECT Study

The objective of this study is to examine the effects of thiazide diuretics, plus medium-dose losartan versus maximal-dose angiotensin II receptor blockers (ARBs) on blood pressure (BP) in Japanese patients with uncontrolled hypertension despite the use of medium-dose ARBs. Hypertensive patients in whom BP was inadequately controlled by treatment with medium-dose ARBs alone or with calcium-channel blockers were enrolled. Patients were randomly assigned to a fixed-dose combination of 50 mg per day losartan and 12.5 mg per day hydrochlorothiazide (HCTZ; n=98), or to a maximal dose of current ARBs (n=95). The reduction in office BP from baseline was significantly larger in the losartan/HCTZ group than in the maximal-dose ARB group (systolic BP -22.7±13.7 vs. -11.7±13.0 mm Hg, diastolic BP -9.6±10.9 vs. -4.5±11.0 mm Hg; P<0.01, respectively). The proportion of patients in whom the therapeutic target BP was achieved was greater in the losartan/HCTZ group than in the maximal-dose ARB group (59.2 vs. 26.3%; P<0.001). Both early-morning and evening BP were controlled more effectively over 1 year of treatment in the losartan/HCTZ group than in the maximal-dose ARB group (the mean BP difference between the groups, early-morning: 5.6 mm Hg (P=0.001), evening: 3.8 mm Hg (P=0.049)). Adverse changes in serum potassium and uric acid were observed in the losartan/HCTZ group; however, both changes were very slight, and the values were still within the normal range. The concomitant usage of losartan and HCTZ had no influence on glucose metabolism and lipid profiles. Declines in plasma N-terminal pro-brain natriuretic peptide levels and urinary albumin excretion were observed in the losartan/HCTZ group, but not in the maximal-dose ARB group. Switching from medium-dose ARBs to losartan plus HCTZ reduced both office and home BP efficiently in patients with uncontrolled hypertension.

Guidelines on nutritional management in Japanese patients with liver cirrhosis from the perspective of preventing hepatocellular carcinoma

AIM

  The Japanese Nutritional Study Group for Liver Cirrhosis (JNUS) was assembled in 2008 with the support of a Health Labor Sciences Research Grant from the Ministry of Health, Labor and Welfare of Japan. The goal of the study group was to propose new nutritional guidelines for Japanese patients with liver cirrhosis (LC), with the aim of preventing hepatocellular carcinoma.

METHODS

  Between 2008 and 2010, the member investigators of JNUS conducted various clinical and experimental studies on nutrition on LC. These included anthropometric studies, a questionnaire study on daily nutrient intake, clinical trials, experimental studies using animal models, re-evaluation of previous publications and patient education. Over this 3-year period, the group members regularly discussed the nutritional issues related to LC, and a proposal was finally produced.

RESULTS

  Based on the results of JNUS projects and discussions among the members, general recommendations were made on how Japanese patients with LC should be managed nutritionally. These recommendations were proposed with a specific regard to the prevention of hepatocarcinogenesis.

CONCLUSION

  The new JNUS guidelines on nutritional management for Japanese patients with LC will be useful for the actual nutritional management of patients with LC. The JNUS members hope that these guidelines will form the basis for future discussions and provide some direction in nutritional studies in the field of hepatology.

Reactive oxygen species and the central nervous system in salt-sensitive hypertension: possible relationship with obesity-induced hypertension

1. There are multiple and complex mechanisms of salt-induced hypertension; however, central sympathoexcitation plays an important role. In addition, the production of reactive oxygen species (ROS) is increased in salt-sensitive hypertensive humans and animals. Thus, we hypothesized that brain ROS overproduction may increase blood pressure (BP) by central sympathostimulation. 2. Recently, we demonstrated that ROS levels were elevated in the hypothalamus of salt-sensitive hypertensive animals. Moreover, intracerebroventricular anti-oxidants suppressed BP and renal sympathetic nerve activity more in salt-sensitive than non-salt-sensitive hypertensive rats. Thus, brain ROS overproduction increased BP through central sympathoexcitation in salt-sensitive hypertension. 3. Salt sensitivity of BP is enhanced in obesity and metabolic syndrome. Interestingly, it is also suggested that, in obesity-induced hypertension models, increases in BP are caused by brain ROS-induced central sympathoexcitation. 4. Recent studies suggest that increased ROS production in the brain and central sympathoexcitation may share a common pathway that increases BP in both salt- and obesity-induced hypertension.

Sodium intake in men and potassium intake in women determine the prevalence of metabolic syndrome in Japanese hypertensive patients: OMEGA Study

Dietary intake affects hypertension and metabolic syndrome (MS) and their management. In Japanese hypertensive patients, little evidence exists regarding the relation between diet and MS. A self-administered lifestyle questionnaire was completed by each patient at the baseline. Three dietary scores were calculated for each patient: sodium intake, potassium intake and soybean/fish intake. The relationships between dietary scores and systolic blood pressure (SBP) and diastolic blood pressure (DBP) were analyzed by multiple regression analysis. The relation between dietary intake of sodium, potassium and soybean/fish, and the presence of MS was evaluated by the Mantel–Haenszel test. A total of 9585 hypertensive patients (mean age, 64.9 years; women, 51.4%) were included in this sub-analysis. High sodium intake was significantly related to increased SBP (P=0.0003) and DBP (P=0.0130). Low potassium intake was significantly related to increased SBP (P=0.0057) and DBP (P=0.0005). Low soybean/fish intake was significantly related to increased SBP (P=0.0133). A significantly higher prevalence of MS was found in men in the highest quartile of sodium intake compared with the lower quartiles (P=0.0026) and in women in the lowest quartile of potassium intake compared with the higher quartiles (P=0.0038). A clear relation between dietary habits and blood pressure was found in Japanese hypertensive patients using a patient-administered questionnaire. Sodium and potassium intake affect MS prevalence. Dietary changes are warranted within hypertension treatment strategies.

Long-term compliance of salt restriction and blood pressure control status in hypertensive outpatients

The purpose of the present study was to investigate the long-term compliance with salt restriction and blood pressure (BP) control status in Japanese hypertensive outpatients. Subjects included 103 patients, 59 women and 44 men, mean age 67 +/- 9 years, who underwent successful 24-h home urine collection more than 10 times over an interval of 5 years. Urinary salt, potassium, and creatinine were measured. During the follow-up period (average 8.6 years), participants underwent urine collection 11.4 times in average. Urinary salt excretion at the last visit was significantly lower than that of the first visit (8.2 +/- 3.1 vs. 9.6 +/- 3.7 g/day; p < 0.01). The achievement of urinary salt excretion <6 g/day increased from 18.5% at the first visit to 26.2% at the last visit. Similarly, BP at the last visit was significantly lower than that of the first visit (130 +/- 14/69 +/- 11 vs. 145 +/- 17/86 +/- 12 mmHg; p < 0.01). The achievement rate of BP <140/90 mmHg and <130/85 mmHg also increased significantly during this period (39.2% to 70.8% and 13.7% to 39.6%, respectively, p < 0.01). Results suggest that urinary salt excretion decreased by repeated measurements using 24-h home urine collection. Lifestyle modification including weight loss as well as the intensive antihypertensive treatment contributed to the improved BP control during this period.

Hypertension is a major risk factor for future atherosclerotic changes in the Japanese population

Background

Great differences in age-standardized mortality rates by cardiovascular disease exist among countries. We prospectively assessed determinants of future cardiovascular changes in a Japanese cohort.

Methods

In 1996, 1011 men and 1153 women from a Japanese community participated in a study on cardiovascular risk factors at a local health centre. Of these, the 896 subjects who visited the centre both in 1996 and 2001 were selected for the analysis. The presence of cardiovascular changes was defined as the appearance of one or more of the following in five years: positive electrocardiographic findings, intima–media thickness of the carotid artery ≥0.8 mm and retinal vascular changes ≥Keith–Wegener–Barker classification stage I.

Results

Of the 607 subjects who had no history of cardiovascular disease in 1996, 421 showed changes in 2001. Both the age-adjusted and multivariate models showed that the risk of the cardiovascular changes increased as systolic blood pressure (SBP) increased to ≥135 mmHg (multivariate odds ratio = 1.739, 95% confidence interval = 1.076–2.810, P < 0.05) compared with those with an SBP of 110–134 mmHg. When we made the analyses only for laboratory test results by excluding SBP, body mass index, alcohol intake and current smoking from the regression model, high-density lipoprotein cholesterol and fasting plasma glucose were significant variables.

Conclusion

The risk of future cardiovascular changes is significantly greater with higher SBP in the Japanese population.

Compound ion salt, a novel low-sodium salt substitute: from animal study to community-based population trial

BACKGROUND

Salt restriction, an important approach for primary and secondary prevention of hypertension, is undermined by unsatisfactory adherence. A salt-restriction study tested the efficacy and safety of a compound ion salt (CISalt) with low sodium content in an animal model and in a community-based population.

METHODS

In part 1, 8-week-old male spontaneously hypertensive rats (SHRs) were fed 1% CISalt in the study group and 8% or 1% normal salt (NSalt) in controls (n = 10 each) for 12 weeks. Blood pressure (BP) and urinary electrolytes were measured every 3 weeks. After 12 weeks, collagen deposition in the heart and kidney and the levels of angiotensin II (Ang II) and nitric oxide (NO) in plasma and renal cortex were measured. In part 2, a single-blind, randomized, 6-month controlled trial with CISalt was conducted in 248 persons (age >or=65 years) in 10 rural communities. Plasma renin activity and Ang II were included in blood and urinary measures at baseline and 6 months.

RESULTS

Reduced BP urinary protein excretion and reduced collagen in the heart and kidneys were significantly different in animals fed CISalt compared to controls. In human studies, at 6 months, mean systolic BP (SBP) was decreased by 9.6 mm Hg (95% confidence interval (CI): 13.1 to 6.1, P < 0.001) and diastolic BP (DBP) by 5.3 mm Hg (95% CI: 7.9 to 2.6, P < 0.001), respectively, compared to controls; urinary sodium excretion also decreased by 67.4 mmol/24 h (95% CI: 84.8 to 50.0, P < 0.001), and plasma renin activity was slightly increased by 0.19 ng/ml/h (95% CI: 0.04-0.33, P = 0.013). No adverse cardiovascular events were reported.

CONCLUSIONS

In these studies, CISalt lowered BP and showed end-organ protection in hypertensive animals and BP reduction in humans. CISalt appears to be a safe and acceptable strategy to reduce BP.

Metabolic syndrome and oxidative stress

Metabolic syndrome is an obesity-associated collection of disorders, each of which contributes to cardiovascular risk. Metabolic syndrome is also associated with overproduction of reactive oxygen species (ROS). ROS contribute to the interrelationship between metabolic syndrome and salt-sensitive hypertension, which are both caused by obesity and excess salt consumption and are major threats to health in developed countries. ROS can induce insulin resistance, which is indispensable for the progression of metabolic syndrome, and salt-sensitive hypertension stimulates ROS production, thereby promoting the development of metabolic syndrome. Moreover, ROS activate mineralocorticoid receptors (MRs) and the sympathetic nervous system, which can contribute to the development of metabolic syndrome and salt-sensitive hypertension. Salt-induced progression of cardiovascular disease (CVD) is also accelerated in animal models with metabolic syndrome, probably owing to further stimulation of ROS overproduction and subsequent ROS-induced MR activation and sympathetic excitation. Therefore, ROS contribute to the progression of the metabolic syndrome itself and to the CVD accompanying it, particularly in conjunction with excessive salt consumption.

União interétnica de nipo-brasileiros associada a hábitos alimentares menos saudáveis e ao pior perfil de risco cardiometabólico

OBJETIVO: Casamento interétnico entre brasileiros nikkeis e não nikkeis pode favorecer a ocidentalização da dieta. Compararam-se consumo alimentar, dados clínico-laboratoriais e frequências de doenças metabólicas em população nipo-brasileira, com casamento intraétnico ou interétnico. MÉTODOS: Empregaram-se teste t, Mann-Whitney, qui-quadrado e coeficiente de Pearson. RESULTADOS: Em 1009 nipo-brasileiros havia 18,9% de casamentos interétnicos, mais frequentes entre homens nikkeis. Estes apresentaram maiores médias de IMC, cintura, pressão arterial, glicemia e triglicérides que mulheres. As frequências de obesidade, hipertrigliceridemia e síndrome metabólica foram 47,7%, 68,1% e 45,2%, sendo maiores nos casamentos interétnicos comparados aos intraétnicos. Comparando-se indivíduos com casamento interétnico, hipertrigliceridemia foi mais frequente nos homens e HDL-c baixo nas mulheres. O consumo de calorias, gorduras e dos grupos de álcool, doces e óleos foram maiores nos casamentos interétnicos. Indivíduos casados intraetnicamente consumiam mais carboidratos, proteínas, fibras, vitaminas, minerais, hortaliças, frutas/sucos, cereais e missoshiru. Comparando-se indivíduos com casamento interétnico, homens nikkeis apresentavam padrão mais ocidental que mulheres nikkeis. CONCLUSÃO: Casamento interétnico associa-se a hábitos alimentares menos saudáveis e pior perfil de risco cardiometabólico.

A randomized trial of the effect of an angiotensin II receptor blocker SR47436 (irbesartan) on 24-hour blood pressure in patients with essential hypertension

The aim of this placebo-controlled, double-blind randomized study was to evaluate the duration of the effect of once-daily administration of irbesartan in patients with essential hypertension. After a placebo run-in baseline period (of 2-4 weeks), 79 patients were randomized to either irbesartan (one 100 mg tablet per day) or placebo, for 6 weeks. The primary outcome was the reduction in the mean 24-h blood pressure (BP) as assessed by ambulatory BP monitoring under standardized conditions. Seventy-six patients completed the study protocol. In the irbesartan group, the average reductions in 24-h systolic and diastolic BPs were 5.8 and 3.4 mmHg, respectively (95% confidence interval: 3.2-8.4/1.6-5.1 mmHg), and in the placebo group, they were -1.7 and -0.5 mmHg, respectively (95% confidence interval: -4.3 to 1.0/-1.8 to 0.7 mmHg). There were statistically significant differences in the average reductions of 24-h BP (7.5/3.9 mmHg, p<0.001), daytime BP (8.6/4.0 mmHg, p<0.001) and nighttime BP (6.1/3.4 mmHg, p<0.05) as well as casual BP (9.0/5.0 mmHg, p<0.001). The trough/peak (T/P) ratios for the systolic and diastolic BPs were 0.84 and 0.78, respectively, in the irbesartan group. The incidence of adverse events was similar in both groups. The results showed that irbesartan administered 100 mg once daily was well tolerated in the treatment of essential hypertension and was effective in producing sustained 24-h BP control.

Effect of low vs. high dietary sodium on blood pressure levels in a normotensive Indo-Asian population

BACKGROUND

Hypertension is a major modifiable risk factor, and while sodium restriction in hypertensive patients appears effective, its role in normotensive individuals remains unclear. We assessed the effect of a low vs. high-sodium diet on blood pressure in normotensive Indo-Asian adults.

METHODS

A randomized, controlled, crossover trial was conducted on 200 normotensive subjects randomly selected from the general population in Karachi, Pakistan. Participants were randomized to either a low (20 mEq/day) or a high-sodium diet (220 mEq/day) for 1 week, followed by 1 week of washout, then the alternate diet for 1 week. The primary outcome was difference in systolic blood pressure (SBP) measured at the end of each phase in the overall population.

RESULTS

Mean (95% confidence interval) decline in 24-h urinary sodium excretion was 81.0 (69.6-92.4) mEq/day (P < 0.001), and in SBP was 1 (0-3)mm Hg (P = 0.17) between high and low-sodium phase. A significant interaction was detected (P = 0.001) between dietary sodium and baseline SBP with a greater adjusted mean (95% confidence interval) decline in SBP (6 (2-9)mm Hg) among participants with high-normal SBP (130-139 mm Hg) and no significant change (-1(-2 to 1)) in those with normal baseline SBP (<130 mm Hg), respectively.

CONCLUSIONS

Reducing sodium intake has a beneficial effect on blood pressure in Indo-Asians with high-normal SBP, at least in the short term. Given the ubiquity of high-normal blood pressure (BP), and frank hypertension in this population, we argue that primary prevention strategies, targeted at use of discretionary sodium, should now be designed and evaluated.