New insights into the effects on blood pressure of diets low in salt and high in fruits and vegetables and low-fat dairy products

High Salt Upregulates Ca2+-Sensing Receptor Expression and Ca2+-Induced Relaxation of Contracted Mesenteric Arteries from Dahl Salt-Sensitive Rats

High Ca2+ lowers blood pressure in hypertension, but the mechanism is not clear. The missing link may be the perivascular sensory nerve Ca2+-sensing receptor (CaSR) that mediates a vasodilator system after activation by interstitial Ca2+ Our results show that high salt increased CaSR expression in mesenteric arteries as well as Ca2+ relaxation of contracted mesenteric arteries from salt-sensitive (SS) rats. The CaSR was expressed as a doublet (≈120-150 kDa) in arteries from animals fed a high-salt diet for 1-4 weeks. The higher molecular weight glycosylated protein increased in arteries from SS animals; however, expression of the low molecular mass high-mannose protein decreased over 4 weeks of feeding the diet. In tissues from salt-resistant (SR) rats, the diet decreased CaSR expression after 4 weeks. Ca2+ relaxation of mesenteric arteries under phenylephrine tone increased in SS rats but decreased in arteries from SR rats fed the high-salt diet. Ca2+-activated K+ channels have a larger role in Ca2+ relaxation of arteries in SR than SS rats. The data suggest that high salt epigenetically regulates the receptor at the translational level in vivo and that the in vitro effect of Ca2+ is on receptor trafficking and signaling. In conclusion, upregulated expression of the CaSR in salt sensitivity increased receptor-mediated vascular relaxation. These findings show that CaSR signaling may compensate for changes in the vasculature in salt-sensitive hypertension. SIGNIFICANCE STATEMENT: The perivascular sensory nerve Ca2+-sensing receptor (CaSR) mediates Ca2+ relaxation of isolated mesenteric arteries under tension. This receptor may therefore play a significant role in relaxation of resistance arteries in vivo, thus explaining the blood pressure-lowering effect of dietary Ca2+. The present studies describe the effect of high salt-induced upregulation of the CaSR in salt-sensitive rats and the roles played by Ca2+-activated K+ channels and nitric oxide in Ca2+ responses.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Accordance to the Dietary Approaches to Stop Hypertension diet pattern and cardiovascular disease in a British, population-based cohort

The dietary approaches to stop hypertension (DASH) diet could be an important population-level strategy to reduce cardiovascular disease (CVD) in the UK, but there is little UK-based evidence on this diet pattern in relation to CVD risk. We tested whether dietary accordance with DASH was associated with risk of CVD in a population-based sample of 23,655 UK adults. This prospective analysis of the EPIC-Norfolk cohort study analysed dietary intake (assessed using a validated food frequency questionnaire) to measure accordance with DASH, based on intakes of eight food groups and nutrients, ranking the sample into quintiles. Cox proportional hazards regression models tested for association between DASH accordance and incident stroke, ischemic heart disease (IHD) and total incident CVD (stroke and IHD only), as well as CVD mortality, non-CVD mortality and total mortality. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated adjusting for age, sex, behavioral and clinical risk factors and socioeconomic status. Over an average of 12.4 years follow-up, we ascertained 4129 incident CVD events, of which stroke accounted for 1011. Compared to participants with the least DASH-accordant diets, those with the most DASH-accordant diets had 20% lower risk of incident stroke (HR, 95% CI 0.80, 0.65-0.99) and 13% lower risk of total incident CVD (0.88, 0.79-0.99) but no lower risk of CHD (0.90, 0.79-1.02). CVD-related mortality also showed strong inverse associations with DASH accordance (0.72, 0.60-0.85). This study provides evidence for the cardioprotective effects of DASH diet in a UK context.

A blend of sesame oil and rice bran oil lowers blood pressure and improves the lipid profile in mild-to-moderate hypertensive patients

BACKGROUND

Sesame oil and rice bran oil are known for their unsaturated fatty acids and antioxidants contents and have been reported to reduce the cardiovascular risk.

OBJECTIVE

To determine the effect of a blend of 20% unrefined cold-pressed lignans-rich sesame oil and 80% physically refined γ-oryzanol-rich rice bran oil (Vivo) as cooking oil in mild-to-moderate hypertensive patients.

METHODS

In this prospective, open-label dietary approach, 300 hypertensive patients and 100 normotensives were divided into groups as: (1) normotensives treated with sesame oil blend, (2) hypertensives treated with sesame oil blend, (3) hypertensives treated with nifedipine, a calcium channel blocker (20 mg/d), and (4) hypertensives receiving the combination of sesame oil blend and nifedipine (20 mg/d). Sesame oil blend was supplied to respective groups, and they were instructed to use it as the only cooking oil for 60 days. Resting blood pressure was measured at days 0, 15, 30, 45, and 60, whereas the fasting lipid profile was measured at days 0 and 60.

RESULTS

Significant reduction in blood pressure (systolic, diastolic, and mean arterial) from days 0 to 15, 30, 45, and 60 were observed in hypertensives treated with sesame oil blend alone (P < .001), nifedipine alone (P < .001), and combination of sesame oil blend and nifedipine (P < .001). Sesame oil blend with nifedipine-treated group showed greatest reduction in blood pressure. Total cholesterol, low-density lipoprotein cholesterol, triglycerides, and non-high-density lipoprotein cholesterol levels reduced, whereas high-density lipoprotein cholesterol levels increased significantly only in hypertensives treated with sesame oil blend alone and the combination of sesame oil blend and nifedipine (P < .001).

CONCLUSION

We demonstrate for the first time that using a blend of sesame oil and rice bran oil as cooking oil showed a significant antihypertensive and lipid-lowering action and had noteworthy additive effect with antihypertensive medication.

Evaluation of salt content in school meals

OBJECTIVE: High blood pressure is a major rick factor for cardiovascular disease, and it is closely associated with salt intake. Schools are considered ideal environments to promote health and proper eating habits. Therefore the objective of this study was to evaluate the amount of salt in meals served in school canteens and consumers' perceptions about salt. METHODS: Meals, including all the components (bread, soup, and main dish) were retrieved from school canteens. Salt was quantified by a portable salt meter. For food perception we constructed a questionnaire that was administered to high school students. RESULTS: A total of 798 food samples were analysed. Bread had the highest salt content with a mean of 1.35 g/100 g (SD=0.12). Salt in soups ranged from 0.72 g/100 g to 0.80 g/100 g (p=0.05) and, in main courses, from 0.71 g/100 to 0.97 g/100g (p=0.05). The salt content of school meals is high with a mean value of 2.83 to 3.82 g of salt per meal. Moreover, a high percentage of students consider meals neither salty nor bland, which shows they are used to the intensity/amount of salt consumed. CONCLUSION: The salt content of school meals is high, ranging from 2 to 5 times more than the Recommended Dietary Allowances for children, clearly exceeding the needs for this population, which may pose a health risk. Healthy choices are only possible in environments where such choices are possible. Therefore, salt reduction strategies aimed at the food industry and catering services should be implemented, with children and young people targeted as a major priority.

Salt intake in children 10-12 years old and its modification by active working practices in a school garden

OBJECTIVE

The aim of the study was to evaluate the 24-h urinary sodium excretion in children of 10-12 years at a school in the north of Portugal and to examine the influence on salt intake and blood pressure of three different educational interventions for 6 months.

METHODS

Blood pressure (BP) and sodium excretion in 24-h urinary samples (UNa) validated with urinary creatinine were measured in 155 children 10-12 years old belonging to nine classes at baseline and after 6 months of three educational interventions in students from three classes each after parents consent was obtained. Interventions consisted in no additional action [control (CTR)], weekly lessons about the dangers of high salt intake [Theoretical (THEOR)] and both lessons and working practices in the school garden of planting, collection of herbs for salt substitution at home [practical (PRACT)].

RESULTS

At baseline 139 students (76 girls and 63 boys) were eligible showing average 24-h UNa of 132±43 mmol/24 h (mean salt intake of 7.8±2.5 g per day) and BP of 118/62 (13/9) mmHg that did not correlate to each other. At the end of the study, versus baseline, BP decreased by 8.2/6.5 mmHg in CTR (n=31), by 3.8/0.6 mmHg in THEOR (n=43) and by 3.5/0.7 mmHg in PRACT (n=53) and salt intake was reduced by 0.4±2.4 g per day in CTR, by 0.6±3.2 g per day in THEOR and by 1.1±2.5 g per day in PRACT. It was observed that salt intake variation was not independent of the group (CRT, THEOR and PRACT) (χ, 9.982, P=0.041). Salt intake was significantly reduced only in the PRACT group (1.1 g per day) and in the PRACT group the percentage of children who reduced salt intake by at least 1g per day from baseline to the end of the study was significantly higher (50.9%) than that of the other groups, THEOR, 48.8% and CTR, 32.2%.

CONCLUSION

Our data indicates that children 10-12 years old have a high salt intake that is well above the proposed recommendations and that a strategy based on theoretical and practical education may achieve in some children an important reduction in daily salt intake which, if maintained over time, may assume important public health implications. These results suggest that in those children a more complete theoretical and practical intervention is more productive and efficient towards reduction of salt intake than single theoretical or no intervention.

How dietary patterns could have a role in prevention, progression, or management of diabetes mellitus? Review on the current evidence

OBJECTIVE

To investigate the role of dietary patterns in prevention and management of type 2 diabetes mellitus.

MATERIALS AND METHODS

A systematic review of databases which were published in ISI, Cochrane Central Register of Controlled Trials databases, PubMed, Iran Medex, and MagIran was performed. "Diabetes" and "dietary pattern" were used as the keywords.

RESULTS

A total of 58 studies which aimed to focus on diabetes mellitus, insulin resistance, metabolic syndrome, dietary pattern, and other related key words were reviewed. More than 47,447 articles were found and 46,709 entries of the extracted studies were excluded on the basis of the title and abstracts. The major dietary patterns were: "Healthy", "Western", "Traditional", "Prudent", "Unhealthy", "Mediterranean", "Modern", and "Dietary Approach to Stop Hypertension" (DASH) diets. Comparison of the effects of different diets revealed that dietary patterns containing fiber-rich foods have a protective role in managing diabetes mellitus. "Healthy", "Mediterranean", "Prudent", and "DASH" dietary patterns were associated with lower risk of hyperglycemia.

CONCLUSIONS

The adherence to the Mediterranean, Prudent, or DASH diets could control hyperglycemia. The higher intake of vegetables, fruits, nuts, whole grains, and lower intake of red meat could reduce the risk of type 2 diabetes mellitus.

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.

The Rapid Shifts in Stages of the Nutrition Transition: The Global Obesity Epidemic

This chapter examines the types of shifts in food availability, dietary intake patterns, and obesity that have taken place in developing countries during a period of rapid globalization and urbanization. The effects of globalization and urbanization on dietary and activity patterns and nutritional status in developing countries are complex. These forces are associated with potentially beneficial dietary shifts, such as increases in energy sufficiency and reduced micronutrient deficiency, but also appear to promote potentially obesogenic shifts, such as increased intakes of edible oils, animal foods, and caloric sweeteners. While there have been substantial reductions in undernutrition in this period of rapid development and social change, being overweight has become an increasing problem.

Beneficial effects of a Dietary Approaches to Stop Hypertension eating plan on features of the metabolic syndrome

OBJECTIVE

To determine the effects of a Dietary Approaches to Stop Hypertension (DASH) eating plan on metabolic risks in patients with the metabolic syndrome.

RESEARCH DESIGN AND METHODS

This was a randomized controlled outpatient trial conducted on 116 patients with the metabolic syndrome. Three diets were prescribed for 6 months: a control diet, a weight-reducing diet emphasizing healthy food choices, and the DASH diet with reduced calories and increased consumption of fruit, vegetables, low-fat dairy, and whole grains and lower in saturated fat, total fat, and cholesterol and restricted to 2,400 mg Na. The main outcome measures were the components of the metabolic syndrome.

RESULTS

Relative to the control diet, the DASH diet resulted in higher HDL cholesterol (7 and 10 mg/dl), lower triglycerides (-18 and -14 mg/dl), systolic blood pressure (SBP) (-12 and -11 mmHg), diastolic blood pressure (-6 and -7 mmHg), weight (-16 and -14 kg), fasting blood glucose (FBG) (-15 and -8 mg/dl), and weight (-16 and -15 kg), among men and women, respectively (all P < 0.001). The net reduction in triglycerides (-17 and -18 mg/dl), SBP (-11 and -11 mmHg), diastolic blood pressure (-5 and -6 mmHg), and FBG (-4 and -6 mg/dl), weight (-16 and -15 kg), and increase in HDL (5 and 10 mg/dl) among men and women, respectively, was higher in the DASH group (all P < 0.05). The weight-reducing diet resulted in significant change in triglycerides (-13 and -10 mg/dl), SBP (-6 and -6 mmHg), and weight (-13 and -12 kg) among men and women, respectively (all P < 0.05).

CONCLUSIONS

The DASH diet can likely reduce most of the metabolic risks in both men and women; the related mechanisms need further study.

Increasing fruit and vegetable intake in homebound elders: the Seattle Senior Farmers' Market Nutrition Pilot Program

INTRODUCTION

Diets that are high in fruits and vegetables lower an individual's risk of chronic disease and contribute to healthy aging. Homebound seniors often have low intake of fruits and vegetables and limited access to fruits and vegetables with the most protective nutrients and phytochemicals. From June through October 2001, the Seattle Senior Farmers' Market Nutrition Pilot Program delivered bi-weekly market baskets that included a variety of fresh, locally grown produce to 480 low-income Meals on Wheels participants. The purpose of this study was to determine if the program increased fruit and vegetable intake in individuals who received the baskets.

METHODS

One hundred basket recipients were recruited to complete a telephone survey before and at the end of the farmers' market basket season. Fifty-two low-income homebound seniors who lived outside the project service area were recruited to serve as control respondents. Fruit and vegetable intake was determined with modified versions of the 6 fruits and vegetables questions in the Behavior Risk Factor Surveillance System.

RESULTS

Seniors who received the baskets reported consuming an increase of 1.04 servings of fruits and vegetables. The difference between the mean servings in the seniors who received the baskets compared to the controls was 1.31 (95% CI, 0.68-1.95, P < .001). At baseline, 22% of the basket recipients were consuming 5 or more servings of fruits and vegetables per day, but by the end of the season, 39% reported consuming 5 or more per day.

CONCLUSION

Home delivery of fruits and vegetables is an effective way to increase fruit and vegetable intake in homebound seniors.

The DASH diet and blood pressure

High blood pressure (also called hypertension) is one of the most important and common risk factors for atherosclerotic cardiovascular disease (CVD) and other chronic diseases. National guidelines recommend that all individuals with blood pressure readings of 120/80 mm Hg or higher adopt healthy lifestyle habits, including the Dietary Approaches to Stop Hypertension (DASH) diet, to manage their blood pressure. The DASH diet, which is high in fruits, vegetables, and low-fat dairy products and reduced in fat, has been shown in large, randomized, controlled trials to reduce blood pressure significantly. The DASH diet also has been shown to reduce blood cholesterol and homocysteine levels and to enhance the benefits of antihypertensive drug therapy. The DASH diet should be promoted, along with maintaining healthy weight, reducing sodium intake, increasing regular physical activity, and limiting alcohol intake, for lowering blood pressure and reducing the risk of CVD.

Soy milk lowers blood pressure in men and women with mild to moderate essential hypertension

Soy-based diets reduce blood pressure in spontaneously hypertensive rats, but apparently not in hypertensive humans. In the present study, the antihypertensive potential of soy milk (500 mL twice daily) compared with cow's milk was investigated in a 3-mo double-blind randomized study of 40 men and women with mild-to-moderate hypertension. Before initiation of the study, urinary isoflavonoids (measured by HPLC) were undetectable in most cases (for genistein, they were always <100 micromol/L). After 3 mo of soy milk consumption, systolic blood pressure decreased by 18.4 +/- 10.7 mmHg compared with 1.4 +/- 7.2 mmHg in the cow's milk group (P < 0.0001), diastolic blood pressure decreased by 15.9 +/- 9.8 mmHg vs. 3.7 +/- 5.0 mmHg in the cow's milk group (P < 0.0001) and mean blood pressure decreased by 16.7 +/- 9.0 mmHg compared with 3.0 +/- 4.6 mmHg in the cow's milk group (P < 0.0001). Urinary genistein was strongly (r = -0.588) and significantly (P = 0.002) correlated with the decrease in blood pressure, particularly for diastolic values. In conclusion, chronic soy milk consumption had modest, but significant hypotensive action in essential hypertensive subjects. This hypotensive action was correlated with the urinary excretion of the isoflavonoid genistein.