Nutritional factors in the control of blood pressure and hypertension

Arterial hypertension-clinical trials update 2024

Arterial hypertension remains the most important modifiable cardiovascular risk factor for morbidity and mortality worldwide. This review summarizes and discusses major clinical trials published in 2023 and early 2024 in hypertension research. These trials include new epidemiological data, studies investigating the impact of blood pressure cuff size on blood pressure measurements, benefits of salt substitutes, and novel antihypertensive treatment options, including pharmacotherapy and bariatric surgery in patients with obesity. This summary reviews the major clinical trials published in 2023 and early 2024. AHT arterial hypertension, BP blood pressure, HR hazard ratio, OBP office blood pressure, PRA plasma renin activity, SBP systolic blood pressure.

Effects of chia seed (Salvia hispanica L.) supplementation on cardiometabolic health in overweight subjects: a systematic review and meta-analysis of RCTs

BACKGROUND

Obesity is a significant public health issue associated with various chronic diseases. Research has indicated that chia seeds have the potential to improve cardiometabolic health. However, due to the diversity of research and inconsistencies in study design, further investigation is needed to fully understand their clinical effects on overweight individuals. This review aims to comprehensively analyze the available evidence on the effects of chia seeds on cardiometabolic indices in overweight populations through a meta-analysis.

METHODS

A comprehensive literature search was performed across PubMed, Web of Science, Scopus, and Embase databases from their inception until 01-03-2024 to identify randomized controlled trials (RCTs) evaluating the effect of chia on cardiometabolic indices in overweight subjects. The search strategy incorporated both Medical Subject Headings (MeSH). Following the screening, ten RCTs were finally included. The data, including subject characteristics, study design, and changes in serum biomarkers, were extracted and analyzed using Stata software version 18.

RESULTS

The meta-analysis results reveal that chia supplementation no significant changes in lipid profile, including triglycerides (TG) (MD: - 5.80 mg/dL, p = 0.47), total cholesterol (TC) (MD: - 0.29 mg/dL, p = 0.95), high-density lipoprotein (HDL) (MD: 1.53 mg/dL, p = 0.33), and low-density lipoprotein (LDL) (MD: 0.63 mg/dL, p = 0.88). Similarity fasting blood glucose (FBG) (MD: - 0.03 mg/dL, p = 0.98), hemoglobin A1c (HbA1c) (MD: - 0.13%, p = 0.13), and insulin levels (MD: 0.45 µIU/mL, p = 0.78). However, chia seed supplementation was associated with a significant reduction in C-reactive protein (CRP) (MD: - 1.18 mg/L, p < 0.0001), but no significant changes were observed in interleukin-6 (IL-6) (MD: - 0.15, p = 0.70) or tumor necrosis factor-alpha (TNF-α) (MD: 0.03, p = 0.91). There was no significant effect on body mass index (BMI) (MD: 0.1 kg/m2, p = 0.91), but a significant reduction in waist circumference (WC) (MD: - 2.82 cm, p < 0.001) was noted. Additionally, chia seed supplementation resulted in a significant reduction in systolic blood pressure (BP) (MD: - 3.27 mmHg, p = 0.03), though diastolic BP changes were non-significant (MD: - 2.69 mmHg, p = 0.09). The studies showed low to moderate heterogeneity in outcome measures, with I2 < 50%.

CONCLUSION

Chia seed supplementation does not significantly impact most lipid profile parameters and glycemic markers. However, it shows potential benefits in reducing WC, BP, and CRP. While chia seeds can be a valuable addition to cardiometabolic health management, they should be part of a broader health strategy that includes a balanced diet, exercise, and lifestyle modifications for optimal results.

Chia seeds ameliorate cardiac disease risk factors via alleviating oxidative stress and inflammation in rats fed high-fat diet

Obesity upsurges the risk of developing cardiovascular disease, primarily heart failure and coronary heart disease. Chia seeds have a high concentration of dietary fiber and increased concentrations of anti-inflammatoryand antioxidant compounds. They are used for weight loss plus enhancing blood glucose and lipid profile. The current perspective was commenced to examine the protective influence of chia seeds ingestion on cardiovascular disease risk factors in high-fat diet-fed rats. Forty male albino rats (with an initial body weight of 180-200 g) were used in this study. Rats were randomly and equally divided into 4 groups: Group I was the control group and group II was a control group with chia seeds supplementation. Group III was a high-fat diet group (HFD) that received HFD for 10 weeks and group IV was fed on HFD plus chia seeds for 10 weeks. In all groups Echocardiographic measurements were performed, initial and final BMI, serum glucose, AC/TC ratio, lipid profile, insulin (with a computed HOMA-IR), creatinine phosphokinase-muscle/brain (CPK-MB), CRP, and cardiac troponin I (cTnI) and MAP were estimated. Whole heart weight (WHW) was calculated, and then WHW/body weight (BW) ratio was estimated. Eventually, a histopathological picture of cardiac tissues was performed to assess the changes in the structure of the heart under Haematoxylin and Eosin and Crossmon's trichrome stain. Ingestion of a high diet for 10 weeks induced a clear elevation in BMI, AC/ TC, insulin resistance, hyperlipidemia, CRP, CPK-MB, and cTnI in all HFD groups. Moreover, there was a significant increase in MAP, left ventricular end diastolic diameter (LVEDD), and left ventricular end systolic diameter (LVESD). Furthermore, histological cardiac examination showed structural alteration of the normal structure of the heart tissue with an increase in collagen deposition. Also, the Bcl-2 expression in the heart muscle was significantly lower, but Bax expression was significantly higher. Chia seeds ingestion combined with HFD noticeably ameliorated the previously-recorded biochemical biomarkers, hemodynamic and echocardiography measures, and histopathological changes. Outcomes of this report reveal that obesity is a hazard factor for cardiovascular disease and chia seeds could be a good candidate for cardiovascular system protection.

Lifestyle management of hypertension: International Society of Hypertension position paper endorsed by the World Hypertension League and European Society of Hypertension

Hypertension, defined as persistently elevated systolic blood pressure (SBP) >140 mmHg and/or diastolic blood pressure (DBP) at least 90 mmHg (International Society of Hypertension guidelines), affects over 1.5 billion people worldwide. Hypertension is associated with increased risk of cardiovascular disease (CVD) events (e.g. coronary heart disease, heart failure and stroke) and death. An international panel of experts convened by the International Society of Hypertension College of Experts compiled lifestyle management recommendations as first-line strategy to prevent and control hypertension in adulthood. We also recommend that lifestyle changes be continued even when blood pressure-lowering medications are prescribed. Specific recommendations based on literature evidence are summarized with advice to start these measures early in life, including maintaining a healthy body weight, increased levels of different types of physical activity, healthy eating and drinking, avoidance and cessation of smoking and alcohol use, management of stress and sleep levels. We also discuss the relevance of specific approaches including consumption of sodium, potassium, sugar, fibre, coffee, tea, intermittent fasting as well as integrated strategies to implement these recommendations using, for example, behaviour change-related technologies and digital tools.

Effect of Dietary Sodium on Blood Pressure: A Crossover Trial

Importance

Dietary sodium recommendations are debated partly due to variable blood pressure (BP) response to sodium intake. Furthermore, the BP effect of dietary sodium among individuals taking antihypertensive medications is understudied.

Objectives

To examine the distribution of within-individual BP response to dietary sodium, the difference in BP between individuals allocated to consume a high- or low-sodium diet first, and whether these varied according to baseline BP and antihypertensive medication use.

Design, Setting, and Participants

Prospectively allocated diet order with crossover in community-based participants enrolled between April 2021 and February 2023 in 2 US cities. A total of 213 individuals aged 50 to 75 years, including those with normotension (25%), controlled hypertension (20%), uncontrolled hypertension (31%), and untreated hypertension (25%), attended a baseline visit while consuming their usual diet, then completed 1-week high- and low-sodium diets.

Intervention

High-sodium (approximately 2200 mg sodium added daily to usual diet) and low-sodium (approximately 500 mg daily total) diets.

Main Outcomes and Measures

Average 24-hour ambulatory systolic and diastolic BP, mean arterial pressure, and pulse pressure.

Results

Among the 213 participants who completed both high- and low-sodium diet visits, the median age was 61 years, 65% were female and 64% were Black. While consuming usual, high-sodium, and low-sodium diets, participants' median systolic BP measures were 125, 126, and 119 mm Hg, respectively. The median within-individual change in mean arterial pressure between high- and low-sodium diets was 4 mm Hg (IQR, 0-8 mm Hg; P < .001), which did not significantly differ by hypertension status. Compared with the high-sodium diet, the low-sodium diet induced a decline in mean arterial pressure in 73.4% of individuals. The commonly used threshold of a 5 mm Hg or greater decline in mean arterial pressure between a high-sodium and a low-sodium diet classified 46% of individuals as "salt sensitive." At the end of the first dietary intervention week, the mean systolic BP difference between individuals allocated to a high-sodium vs a low-sodium diet was 8 mm Hg (95% CI, 4-11 mm Hg; P < .001), which was mostly similar across subgroups of age, sex, race, hypertension, baseline BP, diabetes, and body mass index. Adverse events were mild, reported by 9.9% and 8.0% of individuals while consuming the high- and low-sodium diets, respectively.

Conclusions and Relevance

Dietary sodium reduction significantly lowered BP in the majority of middle-aged to elderly adults. The decline in BP from a high- to low-sodium diet was independent of hypertension status and antihypertensive medication use, was generally consistent across subgroups, and did not result in excess adverse events.

Trial Registration

ClinicalTrials.gov Identifier: NCT04258332.

The benefit of vegetarian diets for reducing blood pressure in Taiwan: a historically prospective cohort study

OBJECTIVE

Past vegetarians research has often found that they have lower blood pressure (BP). Effects may include their lower BMI and higher intake levels of fruit and vegetables. Besides, the study pursues to extend this evidence in a diverse population containing vegans, lacto-ovo vegetarians and omnivores.

DESIGN

The study analyzed data on five hundred vigorous individuals aged 20 years or older from a standard medical screening program and provided validated questionnaire. Criteria were established for vegan, lacto-ovo vegetarian, partial vegetarian and omnivorous dietary patterns.

SETTING

Health screening programs were conducted at a standard medical screening program in Taiwan between 2006 and 2017. Dietary data were gathered by self-administered questionnaire.

SUBJECTS

Five hundred Taiwanese subjects representing the cohort.

RESULTS

Multiple regression analyses confirmed that the vegan vegetarians had lower systolic and diastolic BP (mmHg) than omnivorous Taiwanese (β =  - 6.8, p < 0.05 and β =  - 6.9, p < 0.001). Findings for lacto-ovo vegetarians (β =  - 9.1, p < 0.001 and β =  - 5.8, p < 0.001) were similar. The vegetarians were also less likely to be using antihypertensive medications. Defining hypertension as systolic BP > 139 mmHg or diastolic BP > 89 mmHg or routine of antihypertensive medications, the odds ratio of hypertension compared with omnivores was 0.37 (95% CI = 0.19-0.74), 0.57 (95% CI = 0.36-0.92) and 0.92 (95% CI = 0.50-1.70), respectively, for vegans, lacto-ovo vegetarians and partial vegetarians. Results were reduced after adjustment for BMI.

CONCLUSIONS

The study concludes from this relatively large study that vegetarians, especially vegans, with otherwise diverse characteristics but stable diets, do have lower systolic and diastolic BP and less hypertension than omnivores.

Differences in Nutritional and Psychological Habits in Hypertension Patients

Multifactorial factors such as psychological and nutritional habits are controlling factors in hypertension. The aim of the present study was to analyze differences in nutritional and psychological habits in humans with hypertension. Fifty participants with hypertension (HG) (57.5 ± 13.6 years) and 100 participants as control group (CG) with no hypertension disease (48.9 ± 7.9 years) were interviewed via online questionnaire. Multifactorial items in nutrition habits and psychological profile were analyzed by a compendium of questionnaires; psychological measures refer to personality, anxiety, depression, loneliness, perceived stress, and psychological inflexibility; and a nutritional questionnaire to analyze eating habits and nutrition behaviors of the participants. CG showed significantly higher week vitality (p = 0.001), juice weekly consumption (p = 0.011), coffee weekly consumption (p = 0.050), fermented milk weekly consumption (p = 0.004), and fruit weekly consumption (p = 0.022) than HG. Lower values of weekly coffee consumption and week vitality were found in HG. According to the psychological profile, significant differences were found only depression values, finding HG more depressed than CG (p = 0.002). In conclusion, our results showed that people with better nutrition and mental health would present lower levels of blood pressure. Therefore, the combination of psychological therapy and nutritional recommendations for reducing the risk of having hypertension and improving the blood pressure levels may be needed for patient with hypertension.

Vitamin C Lowers Blood Pressure in Spontaneously Hypertensive Rats by Targeting Angiotensin-Converting Enzyme I Production in a Frequency-Dependent Manner

The lowering blood pressure effect of vitamin C (VC) has been evaluated in various models. As VC has a fast degradation rate in the body after consumption, a study of the frequency-dependent manner of VC is essential for the sustained antihypertension effect of VC. In this study, we investigated the frequency and dose dependency of vitamin C (VC) on blood pressure reduction in spontaneously hypertensive rats (SHRs). Wistar–Kyoto rats (WKYs) and SHRs were orally administered tap water or VC (250, 500, 1000, and 2000 mg/60 kg/day). Blood pressures were measured using the tail-cuff method, and thoracic aortas, liver, and blood were harvested from sacrificed rats after 8 weeks to measure angiotensinogen, angiotensin-converting enzyme (ACE) I, endothelial nitric oxide synthase (eNOS), and total nitric oxide (NOx) concentration. VC decreased blood pressure from the fourth week with no significant differences between doses. The twice-a-day administration of VC decreased blood pressure from the second week, and the blood pressure in these groups was close to that of the WKY group in the eighth week. Treatment with once a day VC decreased ACE I production which was further significantly reduced in twice a day groups. Angiotensinogen and eNOS production were increased upon VC treatment but were not significant among groups. The NOx content was decreased by VC treatment. These results suggest that VC lowers blood pressure in SHRs by directly targeting ACE I production in a frequency-dependent manner and may improve endothelial function depending on the frequency of administration.

Quality of plant-based diets and risk of hypertension: a Korean genome and examination study

BACKGROUND AND AIMS

Plant-based diets have been suggested to have beneficial effects on various health outcomes. However, the evidence on the association of plant-based diet quality with health outcomes is very limited in Asian populations, who may have a different dietary pattern than western populations. This study explored the prospective association between different types of plant-based diets and risk of hypertension using recently established indices in South Koreans.

METHODS

Analyses were based on a community-based cohort of 5636 men and women (40-69 years of age at baseline, mean ± SD 50.6 ± 8.5 years) living in Ansan and Ansung, South Korea (2001-2016) without hypertension and related chronic diseases at baseline. Registration card and telephone registration number were used for the sampling. Dietary intakes were assessed using a validated food frequency questionnaire. Based on the questionnaire, scores of three plant-based diet indices [overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI)] were calculated.

RESULTS

Over a follow-up of 14 years, 2244 participants developed hypertension. Individuals in the highest vs. lowest quintile of hPDI had 35% lower incidence of hypertension [hazard ratio (HR) 0.65, 95% CI 0.57, 0.75] and uPDI had 44% higher incidence of hypertension (HR 1.44, 95% CI 1.24, 1.67), adjusting for demographic characteristics, and lifestyle factors (P trend ≤ 0.0001 for both indices). A similar inverse association of hPDI was observed with risk of hypertension by age, sex, residence area, and obesity. The PDI was not associated with hypertension.

CONCLUSIONS

Our results highlight the importance of considering the quality of plant foods (relatively higher healthy plant foods and relatively lower less healthy plant foods consumption) for the prevention of hypertension in a population with a long-term adherence to predominantly plant-based diets.

Chia seed (Salvia hispanica L.) supplementation to the diet of adults with type 2 diabetes improved systolic blood pressure: A randomized controlled trial

BACKGROUND

Functional food ingredients, such as dietary fiber, long-chain polyunsaturated fatty acids, and high-quality protein, have been shown to help control blood glucose concentration and lower high blood pressure (BP), as well as improving other cardiovascular disease risk factors. However, little research has assessed the impacts of consuming chia seeds, which are rich in these nutrients, on metabolic and physiological outcomes, and results are conflicting.

AIM

The study aimed to investigate the possible effects of chia seeds on fasting blood glucose, insulin, glycated hemoglobin, BP, lipid profile, body weight, and the inflammatory marker - high-sensitivity C-reactive protein - in people with type 2 diabetes (T2DM).

METHODS

Adults with T2DM (n = 42) were randomly assigned equally to the chia seed group, which consumed 40 g/day chia seeds for 12 weeks, or a control group, which did not consume any supplement. Blood samples were collected at baseline and after a 12-week intervention period to assess the study outcomes, such as glycemic control, BP, cardiovascular risk parameters including lipid profile, inflammatory marker, and body weight.

RESULTS

Adjusted for gender and baseline values, the chia seed group had systolic BP (SBP) significantly reduced compared to control [t (1) = 2.867, p = 0.007, η ² _p = 0.174]. No differences were observed in any other parameter tested in the chia seed or control group.

CONCLUSIONS

People with T2DM and hypertension, maintaining usual dietary consumption, physical activity pattern, and medications, had significantly reduced SBP compared to the control group when having consumed 40 g/d of chia seeds for 12 weeks.

Effect of nutrition education in reducing sodium intake and increasing potassium intake in hypertensive adults

BACKGROUND/OBJECTIVES

Hypertension is the major risk factor for cardiovascular disease, a leading cause of deaths in Korea. The objective of this study was to evaluate the effect of a nutrition education in reducing sodium intake and increasing potassium intake in hypertensive adults.

SUBJECTS/METHODS

Subjects who participated in this study were 88 adults (28 males and 60 females) who were pre-hypertension or untreated hypertensive patients aged ≥ 30 yrs in Gyeonggi Province, Korea. These subjects were divided into 2 groups: a low-sodium education (LS) group and a low-sodium high-potassium education (LSHP) group. Nutrition education of 3 sessions for 12 weeks was conducted. Blood pressure, blood and urine components, nutrient intake, and dietary behavior were compared between the two education groups.

RESULT

Blood pressure was decreased in both groups after the nutrition education (P < 0.05). In the LSHP group, levels of blood glucose (P < 0.05), total cholesterol (P < 0.01), and low-density lipoprotein-cholesterol (P < 0.05) were decreased after the program completion. Sodium intake was decreased in both groups after the nutrition education (P < 0.05). However, Na/K ratio was only decreased in the LS group (P < 0.05). Intake frequency of fish & shellfish was only significantly reduced in the LS group (P < 0.05), while intake frequencies of cooked rice, noodles & dumplings, breads & snacks, stew, kimchi, and fish & shellfish were reduced in the LSHP group (P < 0.05). Total score of dietary behavior appeared to be effectively decreased in both groups after the education program (P < 0.001).

CONCLUSIONS

This education for reducing sodium intake was effective in reducing blood pressure and sodium intake. The education for enhancing potassium intake resulted in positive changes in blood glucose and serum cholesterol levels.

Effects of Vegetarian Diets on Blood Pressure Lowering: A Systematic Review with Meta-Analysis and Trial Sequential Analysis

The beneficial effects of a vegetarian diet on blood pressure (BP) control have been reported in previous systematic reviews; however, so far, their relative effectiveness is not well established. Here, we performed a systematic review together with trial sequential analysis to determine the effect of a vegetarian diet on the reduction of blood pressure. We searched the randomized controlled trial (RCT) through Medline, PubMed and Cochrane Central Register. Fifteen eligible RCTs with 856 subjects were entered into the analysis. The pooled results demonstrated that vegetarian diet consumption significantly lowered the systolic blood pressure (weighted mean difference (WMD), −2.66 mmHg (95% confidence interval (CI) = −3.76, −1.55, p < 0.001) and diastolic BP was WMD, −1.69 95% CI = −2.97, −0.41, p < 0.001) as compared to an omnivorous diet. In subgroup analysis, a vegan diet demonstrated a greater reduction in systolic BP (WMD, −3.12 mmHg; 95% CI = −4.54, −1.70, p < 0.001) as compared with a lacto-ovo-vegetarian diet (WMD, −1.75 mmHg, 95% CI −5.38, 1.88, p = 0.05). The vegan diet has showed a similar trend in terms of diastolic blood pressure reduction (WMD, −1.92 mmHg (95% CI = −3.18, −0.66, p < 0.001) but those with a lacto-ovo-vegetarian diet showed no changes in diastolic BP reduction (WMD, 0.00, 95% CI = 0.00, 0.00), p = 0.432). In conclusion, vegetarian diets are associated with significant reductions in BP compared with omnivorous diets, suggesting that they may play a key role in the primary prevention and overall management of hypertension.

Heart Failure and a Plant-Based Diet. A Case-Report and Literature Review

A 54-year-old female with grade 3 obesity body mass index (BMI 45.2 kg/m2) and type II diabetes (hemoglobin A1c 8.1%) presented to her primary care physician in May 2017 with a chief complaint of left lower extremity edema. Work-up revealed heart failure with depressed left ventricular systolic function. Upon diagnosis, she substantially altered her lifestyle, changing her diet from a "healthy western" one to a whole food plant-based one. Guideline directed medical therapy for heart failure was also utilized. Over five and a half months, she lost 22.7 kg and reversed her diabetes without the use of diabetes medications. Her left ventricular systolic function normalized. Although causality cannot be determined, this case highlights the potential role of a plant-based diet in helping to reverse heart failure with reduced ejection fraction. This article will review how a minimally processed whole food plant-based dietary pattern and similar dietary patterns, such as the Dietary Approach to Stop Hypertension diet, may contribute to the reversal of left ventricular dysfunction.

Health Disparities in Lifestyle Choices Among Hypertensive Korean Americans, Non-Hispanic Whites, and Blacks

Purpose and Methods. To describe medication profile, diet, and exercise/physical activity in hypertensive Korean Americans, a convenience sample of 100 hypertensive Korean Americans (KAs) at two KA health clinics were interviewed by bilingual Korean nurses using questions from the 1988-1994 Third National Health and Nutrition Examination Survey (NHANES III). One hundred age- and gender-matched hypertensive non-Hispanic Whites and 100 Blacks were randomly selected from the NHANES III dataset, and results were compared to describe the health disparities in lifestyle choices among the three groups. Results. The medication profile among the three groups was similar. A majority of members of all three groups had been told by health professionals to exercise for hypertension. KAs made significantly less effort to reduce salt in their diets than did members of the other two groups (p < .05). Fewer KAs than non-Hispanic Whites or Blacks were following their health professionals’advice to control or lose weight for their high blood cholesterol levels. KAs had the lowest body mass index and were older and more educated than members of the other two groups. KAs’ primary reasons for using the KA clinic were the respect they received and the use of the Korean language. Implications. KA health professionals need to teach their patients more about the importance of health-promoting lifestyles for hypertension and its contributing factors. More KA hypertensive patients should follow the advice of health professionals on healthy lifestyles. Nurses should continue to treat patients with respect and provide care with sensitivity to language needs of patients.

Antihypertensive and Natriuretic Effects of Less-Sodium Soy Sauce Containing γ-Aminobutyric Acid in Spontaneously Hypertensive Rats

We investigated the mechanism of the antihypertensive effect of less-sodium soy sauce containing gamma-aminobutyric acid (GABA) in spontaneously hypertensive rats (SHRs). When SHRs were given a diet with less-sodium soy sauce containing GABA (GABA-rich soy sauce group) for 6 weeks, the systolic blood pressure decreased as compared with that in rats fed diets with less-sodium soy sauce or a solution of salt. Renal sympathetic nerve activity (RSNA) and positive Na balance were reduced, and the urinary Na excretion tended to increase in the GABA-rich soy sauce group. Vascular hypertrophy of the thoracic aorta and the coronary and renal interlobular arteries tended to reduce in the GABA-rich soy sauce group. These results suggest that inhibition of Na retention by natriuresis, as a result of inhibition of RSNA by the GABA in the soy sauce contributed to the antihypertensive effect of GABA in the SHRs. Intake of less-sodium soy sauce containing GABA might help to reduce overall cardiovascular risk.

Vegetarian diets and blood pressure among white subjects: results from the Adventist Health Study-2 (AHS-2)

OBJECTIVE

Previous work studying vegetarians has often found that they have lower blood pressure (BP). Reasons may include their lower BMI and higher intake levels of fruit and vegetables. Here we seek to extend this evidence in a geographically diverse population containing vegans, lacto-ovo vegetarians and omnivores.

DESIGN

Data are analysed from a calibration sub-study of the Adventist Health Study-2 (AHS-2) cohort who attended clinics and provided validated FFQ. Criteria were established for vegan, lacto-ovo vegetarian, partial vegetarian and omnivorous dietary patterns.

SETTING

Clinics were conducted at churches across the USA and Canada. Dietary data were gathered by mailed questionnaire.

SUBJECTS

Five hundred white subjects representing the AHS-2 cohort.

RESULTS

Covariate-adjusted regression analyses demonstrated that the vegan vegetarians had lower systolic and diastolic BP (mmHg) than omnivorous Adventists (β = -6.8, P < 0.05 and β = -6.9, P < 0.001). Findings for lacto-ovo vegetarians (β = -9.1, P < 0.001 and β = -5.8, P < 0.001) were similar. The vegetarians (mainly the vegans) were also less likely to be using antihypertensive medications. Defining hypertension as systolic BP > 139 mmHg or diastolic BP > 89 mmHg or use of antihypertensive medications, the odds ratio of hypertension compared with omnivores was 0.37 (95 % CI 0.19, 0.74), 0.57 (95 % CI 0.36, 0.92) and 0.92 (95 % CI 0.50, 1.70), respectively, for vegans, lacto-ovo vegetarians and partial vegetarians. Effects were reduced after adjustment for BMI.

CONCLUSIONS

We conclude from this relatively large study that vegetarians, especially vegans, with otherwise diverse characteristics but stable diets, do have lower systolic and diastolic BP and less hypertension than omnivores. This is only partly due to their lower body mass.

The central mechanism underlying hypertension: a review of the roles of sodium ions, epithelial sodium channels, the renin-angiotensin-aldosterone system, oxidative stress and endogenous digitalis in the brain

The central nervous system has a key role in regulating the circulatory system by modulating the sympathetic and parasympathetic nervous systems, pituitary hormone release, and the baroreceptor reflex. Digoxin- and ouabain-like immunoreactive materials were found >20 years ago in the hypothalamic nuclei. These factors appeared to localize to the paraventricular and supraoptic nuclei and the nerve fibers at the circumventricular organs and supposed to affect electrolyte balance and blood pressure. The turnover rate of these materials increases with increasing sodium intake. As intracerebroventricular injection of ouabain increases blood pressure via sympathetic activation, an endogenous digitalis-like factor (EDLF) was thought to regulate cardiovascular system-related functions in the brain, particularly after sodium loading. Experiments conducted mainly in rats revealed that the mechanism of action of ouabain in the brain involves sodium ions, epithelial sodium channels (ENaCs) and the renin-angiotensin-aldosterone system (RAAS), all of which are affected by sodium loading. Rats fed a high-sodium diet develop elevated sodium levels in their cerebrospinal fluid, which activates ENaCs. Activated ENaCs and/or increased intracellular sodium in neurons activate the RAAS; this releases EDLF in the brain, activating the sympathetic nervous system. The RAAS promotes oxidative stress in the brain, further activating the RAAS and augmenting sympathetic outflow. Angiotensin II and aldosterone of peripheral origin act in the brain to activate this cascade, increasing sympathetic outflow and leading to hypertension. Thus, the brain Na(+)-ENaC-RAAS-EDLF axis activates sympathetic outflow and has a crucial role in essential and secondary hypertension. This report provides an overview of the central mechanism underlying hypertension and discusses the use of antihypertensive agents.

Serum calcium levels and hypertension among U.S. adults

Serum calcium levels have been shown to be associated with cardiovascular disease (CVD); however, it is not clear whether serum calcium levels are related to hypertension, a risk factor for CVD. The authors examined the association between serum calcium and hypertension in a representative sample of US adults. A cross-sectional study of 12,405 third National Health and Nutrition Examination Survey participants 20 years and older was conducted. Serum total and ionized calcium levels were analyzed as quartiles. The main outcome of interest was hypertension (n=3437), defined as self-reported use of antihypertensive medication and/or systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg. Elevated serum total calcium levels were positively associated with hypertension, independent of potential confounders including C-reactive protein, estimated glomerular filtration rate, serum albumin, 25(OH)D, and phosphorous. Compared with the lowest quartile of serum total calcium (referent category), the multivariable odds ratio (95% confidence interval) of hypertension was 1.49 (1.15-1.93) for the highest quartile (P=.005). This association persisted in subgroup analyses stratified by sex, age, and race-ethnicity. In contrast, serum ionized calcium levels were not associated with hypertension. Higher serum total calcium levels are positively associated with hypertension in a representative sample of U.S. adults.

Does stress induce salt intake?

Psychological stress is a common feature of modern day societies, and contributes to the global burden of disease. It was proposed by Henry over 20 years ago that the salt intake of a society reflects the level of stress, and that stress, through its effect on increasing salt intake, is an important factor in the development of hypertension. This review evaluates the evidence from animal and human studies to determine if stress does induce a salt appetite and increase salt consumption in human subjects. Findings from animal studies suggest that stress may drive salt intake, with evidence for a potential mechanism via the sympatho-adrenal medullary system and/or the hypothalamo-pituitary-adrenal axis. In contrast, in the few laboratory studies conducted in human subjects, none has found that acute stress affects salt intake. However, one study demonstrated that life stress (chronic stress) was associated with increased consumption of snack foods, which included, but not specifically, highly salty snacks. Studies investigating the influence of chronic stress on eating behaviours are required, including consumption of salty foods. From the available evidence, we can conclude that in free-living, Na-replete individuals, consuming Na in excess of physiological requirements, stress is unlikely to be a major contributor to salt intake.

Left ventricular geometry in children and adolescents with primary hypertension

BACKGROUND

Children with hypertension (HTN) are at increased risk for left ventricular hypertrophy (LVH). Increased left ventricular (LV) mass (LVM) by the process of remodeling in response to volume or pressure loading may be eccentric (increased LV diameter) or concentric (increased wall thickness). Our objective was to classify LV geometry among children with primary HTN and examine differences in ambulatory blood pressure (ABP).

METHODS

Subjects aged 7-18 years with suspected HTN were enrolled in this cross-sectional study. ABP and LVM index (LVMI) were measured within the same 24-h period. LV geometry was classified as normal, concentric remodeling, concentric LVH, or eccentric LVH.

RESULTS

Children with LVH had significantly higher ambulatory systolic BP (SBP) and diastolic blood pressure (BP) (DBP) levels and body mass index (BMI) Z-score. Sixty-eight children had HTN based upon ABP monitoring (ABPM). Thirty-eight percent of the hypertensive subjects had LVH, with equal distribution in the concentric and eccentric groups. There were significant differences in the 24-h DBP parameters when the eccentric LVH group was compared to the normal geometry and concentric LVH groups. Relative wall thickness (RWT) was inversely associated with night time DBP parameters. These relationships persisted after controlling for BMI Z-score.

CONCLUSIONS

Although the risk for LVH is associated with increased SBP and BMI Z-score, those with eccentric LVH had significantly higher DBP.

Dietary intake, blood pressure and osteoporosis

Both hypertension and osteoporosis have common underlying nutritional aetiology, with regards to dietary cations intake. We tested the hypothesis that sodium intake reflected in urinary Na/Cr and blood pressure would be negatively associated with bone mineral density (BMD), whereas other cations may have opposite associations. Subjects were part of a study of bone health in 4000 men and women aged 65 years and over. A total of 1098 subjects who were not on antihypertensive drugs or calcium supplements and who provided urine samples were available for analysis. Logistic regression was used to examine associations between total hip and lumbar spine BMD, age, gender, body mass index (BMI), urinary Na/Cr, K/Cr, calcium and magnesium intake, systolic blood pressure and diastolic blood pressure. Total hip BMD was inversely associated with age, being female and urinary Na/Cr, and positively associated with BMI, urine K/Cr and dietary calcium intake. Lumbar spine BMD was inversely associated with being female and urinary Na/Cr, and positively associated with BMI, dietary calcium intake and SBP. We conclude that sodium intake, reflected by urinary Na/Cr, is the major factor linking blood pressure and osteoporosis as shown by the inverse relationship with BMD. The findings lend further emphasis to the health benefits of salt reduction in our population both in terms of hypertension and osteoporosis.

Effect of calcium and vitamin D supplementation on blood pressure: the Women's Health Initiative Randomized Trial

Experimental and epidemiological studies suggest that calcium and vitamin D supplements may lower blood pressure. We examined the effect of calcium plus vitamin D supplementation on blood pressure and the incidence of hypertension in postmenopausal women. The Women's Health Initiative Calcium/Vitamin D Trial randomly assigned 36 282 postmenopausal women to receive 1000 mg of elemental calcium plus 400 IU of vitamin D3 daily or placebo in a double-blind fashion. Change in blood pressure and the incidence of hypertension were ascertained. Over a median follow-up time of 7 years, there was no significant difference in the mean change over time in systolic blood pressure (0.22 mm Hg; 95% CI: -0.05 to 0.49 mm Hg) and diastolic blood pressure (0.11 mm Hg; 95% CI: -0.04 to 0.27 mm Hg) between the active and placebo treatment groups. This null result was robust in analyses accounting for nonadherence to study pills and in baseline subgroups of interest, including black subjects and women with hypertension or high levels of blood pressure, with low intakes of calcium and vitamin D or low serum levels of vitamin D. In 17 122 nonhypertensive participants at baseline, the hazard ratio for incident hypertension associated with calcium/vitamin D treatment was 1.01 (95% CI: 0.96 to 1.06.) In postmenopausal women, calcium plus vitamin D3 supplementation did not reduce either blood pressure or the risk of developing hypertension over 7 years of follow-up.

Potassium, magnesium, and calcium: their role in both the cause and treatment of hypertension

Despite advances in the prevention and treatment of hypertension over the past decade, hypertension remains an important public health challenge. Recent efforts to reduce the prevalence of hypertension have focused on nonpharmacologic means, specifically diet. An increased intake of minerals such as potassium, magnesium, and calcium by dietary means has been shown in some but not all studies to reduce blood pressure in patients with hypertension. This review will discuss the roles of potassium, magnesium, and calcium in the prevention and treatment of essential hypertension with specific emphasis on clinical trial evidence, mechanism of action, and recommendations for dietary intake of these minerals. A high intake of these minerals through increased consumption of fruits and vegetables may improve blood pressure levels and reduce coronary heart disease and stroke.

Supplementation of conventional therapy with the novel grain Salba (Salvia hispanica L.) improves major and emerging cardiovascular risk factors in type 2 diabetes: results of a randomized controlled trial

OBJECTIVE

To determine whether addition of Salba (Salvia hispanica L.), a novel whole grain that is rich in fiber, alpha-linolenic acid (ALA), and minerals to conventional treatment is associated with improvement in major and emerging cardiovascular risk factors in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Using a single-blind cross-over design, subjects were randomly assigned to receive either 37 +/- 4 g/day of Salba or wheat bran for 12 weeks while maintaining their conventional diabetes therapies. Twenty well-controlled subjects with type 2 diabetes (11 men and 9 women, aged 64 +/- 8 years, BMI 28 +/- 4 kg/m2, and A1C 6.8 +/- 0.9%) completed the study. This study was set in the outpatient clinic of the Risk Factor Modification Center, St. Michael's Hospital, Toronto, Canada.

RESULTS

Compared with the control treatment, Salba reduced systolic blood pressure (SBP) by 6.3 +/- 4 mmHg (P < 0.001), high-sensitivity C-reactive protein (hs-CRP) (mg/l) by 40 +/- 1.6% (P = 0.04), and vonWillebrand factor (vWF) by 21 +/- 0.3% (P = 0.03), with significant decreases in A1C and fibrinogen in relation to the Salba baseline but not with the control treatment. There were no changes in safety parameters including liver, kidney and hemostatic function, or body weight. Both plasma ALA and eicosapentaenoic polyunsaturated fatty acid levels were increased twofold (P < 0.05) while consuming Salba.

CONCLUSIONS

Long-term supplementation with Salba attenuated a major cardiovascular risk factor (SBP) and emerging factors (hs-CRP and vWF) safely beyond conventional therapy, while maintaining good glycemic and lipid control in people with well-controlled type 2 diabetes.

Effects of a short-term intervention with a paleolithic diet in healthy volunteers

OBJECTIVES

Prevention of cardiovascular diseases by paleolithic or hunter-gatherer diets has been discussed during recent years.

METHODS

Our aim was to assess the effect of a paleolithic diet in a pilot study on healthy volunteers during 3 weeks. The intention was to include 20 subjects, of whom 14 fulfilled the study. Complete dietary assessment was available for six subjects.

RESULTS

Mean weight decreased by 2.3 kg (P<0.001), body mass index by 0.8 (P<0.001), waist circumference by 0.5 cm (P=0.001), systolic blood pressure by 3 mm Hg (P=0.03) and plasminogen activator inhibitor-1 by 72% (P=0.020). Regarding nutrient intake, intake of energy decreased by 36%, and other effects were also observed, both favourable (fat composition, antioxidants, potassium-sodium rate) and unfavourable (calcium).

CONCLUSION

This short-term intervention showed some favourable effects by the diet, but further studies, including control group, are needed.

Effect of a γ-aminobutyric acid-enriched dairy product on the blood pressure of spontaneously hypertensive and normotensive Wistar–Kyoto rats

We investigated the blood-pressure-lowering effects of γ-aminobutyric acid (GABA) and a GABA-enriched fermented milk product (FMG) by low-dose oral administration to spontaneously hypertensive (SHR/Izm) and normotensive Wistar–Kyoto (WKY/Izm) rats. FMG was a non-fat fermented milk product produced by lactic acid bacteria, and the GABA contained in FMG was made from the protein of the milk during fermentation. A single oral dose of GABA or FMG (5 ml/kg; 0·5 mg GABA/kg) significantly (P>0·05) decreased the blood pressure of SHR/Izm from 4 to 8 h after administration, but did not increase that of WKY/Izm rats. The hypotensive activity of GABA was dose-dependent from 0·05 to 5·00 mg/kg in SHR/Izm. During the chronic administration of experimental diets to SHR/Izm, a significantly slower increase in blood pressure with respect to the control group was observed at 1 or 2 weeks after the start of feeding with the GABA or FMG diet respectively (P>0·05) and this difference was maintained throughout the period of feeding. The time profile of blood-pressure change due to administration of FMG was similar to that of GABA. FMG did not inhibit angiotensin 1-converting enzyme. Furthermore, an FMG peptide-containing fraction from reverse-phase chromatography lacked a hypotensive effect in SHR/Izm rats. The present results suggest that low-dose oral GABA has a hypotensive effect in SHR/Izm and that the hypotensive effect of FMG is due to GABA.

Chronic stress influences ambulatory blood pressure in adolescents

BACKGROUND

High ambulatory blood pressure (ABP) predicts cardiovascular events, even after controlling for clinic BP and other established risk factors.

PURPOSE

This study examined whether chronic or discrete stress in the past year was associated with greater ABP in adolescents.

METHOD

Participants were 217 male and female Black and White adolescents who wore ABP monitors on 2 consecutive school days and completed a survey of life events.

RESULTS

Report of discrete, negative events was not associated with ABP. Adolescents experiencing greater numbers of chronic, negative life events exhibited greater systolic blood pressure (SBP), independent of ethnicity; sex; body mass index; and location, position, physical activity, and consumption of food/caffeine/nicotine at time of measurement. Greater numbers of chronic, negative events were associated with greater diastolic blood pressure (DBP) among boys. When resting clinic BP was introduced into the model, the main effect of chronic, negative life events on ambulatory SBP became nonsignificant, whereas the effect of chronic, negative life events on male adolescents' DBP persisted.

CONCLUSIONS

Chronic stress is associated with greater ambulatory SBP among male and female adolescents and with greater ambulatory DBP among male adolescents. The latter association persisted after controlling for clinic BP, suggesting that males may be more vulnerable to chronic stress as a determinant of BP regulation than females early in life.

Clustering of metabolic abnormalities in adolescents with the hypertriglyceridemic waist phenotype

BACKGROUND

It remains unknown whether the hypertriglyceridemic waist (HW) phenotype, an appropriate screening tool in adults, can also be used to screen for metabolic abnormalities in adolescents.

OBJECTIVE

We aimed to evaluate metabolic risk factors identified by the HW phenotype in adolescents.

DESIGN

Anthropometric and biochemical measurements were assessed in a population-based cross-sectional study of 1413 male and 1623 female Iranian adolescents aged 10-19 y. The HW phenotype was defined as serum triacylglycerol concentrations > or = 110 mg/dL and concurrent waist circumference > or = 90th percentile for age and sex. Elevated fasting glucose (> or = 110 mg/dL), high LDL (> or = 130 mg/dL) and low HDL (< or = 40 mg/dL) cholesterol, hypercholesterolemia (total cholesterol > or = 200 mg/dL), and hypertension (systolic or diastolic blood pressure > or = 95th percentile for age, sex, and height) were considered as risk factors.

RESULTS

Adolescents with the HW phenotype had significantly higher prevalences of all metabolic risk factors except elevated fasting glucose than did those without the HW phenotype. After control for potential confounding variables, adolescents with the HW phenotype were significantly more likely to have high LDL cholesterol (odds ratio: 1.8; 95% CI: 1.3, 2.7), low HDL cholesterol (1.6; 1.3, 2.0), hypercholesterolemia (2.9; 2.0, 4.2), and > or = 1 (1.4; 1.1, 1.7) and > or = 2 (2.2; 1.6, 3.0) risk factors than were those without the HW phenotype. The HW phenotype had a significantly higher percentage of correct prediction of metabolic abnormalities than did overweight, elevated triacylglycerol concentration, or enlarged waist circumference.

CONCLUSION

This study shows a clustering of metabolic abnormalities in adolescents with the HW phenotype and suggests this phenotype as a simple marker for identifying adolescents at risk of metabolic syndrome and other metabolic abnormalities.

Hypertensive patients from two rural Chinese counties respond differently to benazepril: the Anhui Hypertension Health Care Study

PURPOSE

Essential hypertension, as a complex disorder with unknown etiology cause, is a major public health problem worldwide. Patients need constant drug therapy to maintain their blood pressure in a normal range. However, the current facts suggest that the treatment is not optimized in a large number of patients, and as a result they are at risk for compliance resulting in uncontrolled blood pressure. Genetic and environmental factors associated with individual variation in response to anti-hypertensive drug remain largely unknown.

METHODS

In order to illustrate the existence and to attempt to identify the factors modifying drug effect, we conducted a large-scale follow-up study in two Chinese rural counties differing in both genetic background and residential environment. Hypertensive patients were treated with benazepril, a commonly used angiotensin converting enzyme inhibitor, for 15 days, and the end-point effect was evaluated.

RESULTS

We found that there were large and significant differences in drug response between subjects from two counties, even after adjustment for known factors. The responses to benazepril, measured in diastolic blood pressure drop, in male patients from Yuexi was twice as effective as their counterparts from Huoqiu.

CONCLUSIONS

These results suggest that adjustment of treatment regimen is necessary to improve efficacy, and it could be done at the population level to make it more feasible and affordable.

Independent and opposite associations of waist and hip circumferences with diabetes, hypertension and dyslipidemia: the AusDiab Study

OBJECTIVE

Fat distribution as measured by waist-to-hip ratio has been shown to be an important independent predictor of glucose intolerance. Few studies, however, have considered the contributions of the waist and hip circumferences independently. The aim of this study was to investigate the independent associations of waist and hip circumference with diabetes in a large population-based study, and to investigate whether they also apply to other major components of the metabolic syndrome (hypertension and dyslipidemia). In addition, as previous studies were performed in older persons, we investigated whether these associations were present across adult age groups.

METHODS

Weight, height, waist and hip circumferences were measured in 11 247 participants of the nationally representative Australian Diabetes, Obesity and Lifestyle (AusDiab) Study. HDL-cholesterol, triglycerides, fasting and 2-h postload glucose were determined, and diastolic and systolic blood pressure was measured. After exclusion of persons already known to have diabetes, hypertension or dyslipidemia, logistic and linear regression were used to study cross-sectional associations of anthropometric variables with newly diagnosed diabetes, hypertension and dyslipidemia, and with continuous metabolic measures, all separately for men (n=3818) and women (n=4582). Analyses were repeated in the same population stratified for age.

RESULTS

After adjustment for age, body mass index and waist, a larger hip circumference was associated with a lower prevalence of undiagnosed diabetes (odds ratio (OR) per one s.d. increase in hip circumference 0.55 (95% CI 0.41-0.73) in men and 0.42 (0.27-0.65) in women) and undiagnosed dyslipidemia (OR 0.58 (0.50-0.67) in men and 0.37 (0.30-0.45) in women). Associations with undiagnosed hypertension were weaker (OR 0.80 (0.69-0.93) in men and 0.88 (0.70-1.11) in women). As expected, larger waist circumference was associated with higher prevalence of these conditions. Similar associations were found using continuous metabolic variables as outcomes in linear regression analyses. Height partly explained the negative associations with hip circumference. When these analyses were performed stratified for age, associations became weaker or disappeared in the oldest age groups (age > or =75 y in particular), except for HDL-cholesterol.

CONCLUSION

We found independent and opposite associations of waist and hip circumference with diabetes, dyslipidemia and less strongly with hypertension in a large population-based survey. These results emphasize that waist and hip circumference are important predictors for the metabolic syndrome and should both be considered in epidemiological studies. The associations were consistent in all age groups, except in age > or =75 y. Further research should be aimed at verifying hypotheses explaining the 'protective' effect of larger hips.

Nutrition therapy for hypertension

A contemporary approach to hypertension and prevention are covered in this article. It contains important information for clinicians, such as hypertension management, metabolic syndrome issues, lifestyle behavioral management, nutrient issues, weight loss treatments (ie, medications and surgical procedures), the role of physical activity, and pharmacologic treatment. The Dietary Approaches to Stop Hypertension (DASH) trial eating plan is discussed at length, as well as information from recent trials on hypertension, prevention, and treatment.