What is the role of dietary sodium and potassium in hypertension and target organ injury?

There is substantial evidence from both observational epidemiology studies and randomized controlled trials that dietary intake of sodium and potassium is important in the etiology of hypertension. However, the direct evidence for a direct link between dietary sodium and potassium and risk of cardiovascular and renovascular events is limited. Epidemiological studies should be designed to examine the relationship between dietary intake of sodium and potassium and risk of stroke, coronary heart disease, left ventricular hypertrophy, and renal disease in a prospective manner. In these studies, dietary intake of sodium and potassium should be estimated using multiple 24-hour urine collections. These studies should be focused on African Americans because they are at a disproportionately high risk of developing hypertension and blood pressure-related vascular disease. Moreover, this group has been underrepresented in most previous epidemiological studies.     

Dietary Fiber Intake and Cardiometabolic Risks among US Adults,NHANES 1999-2010

Background

Dietary fiber may decrease the risk of cardiovascular disease and associated risk factors. We examined trends in dietary fiber intake among diverse US adults between 1999 and 2010, and investigated associations between dietary fiber intake and cardiometabolic risks including metabolic syndrome, cardiovascular inflammation, and obesity.

Methods

Our cross-sectional analysis included 23,168 men and nonpregnant women aged 20+ years from the 1999-2010 National Health and Nutrition Examination Survey. We used weighted multivariable logistic regression models to estimate predicted marginal risk ratios and 95% confidence intervals for the risks of having the metabolic syndrome, inflammation, and obesity associated with quintiles of dietary fiber intake.

Results

Consistently, dietary fiber intake remained below recommended adequate intake levels for total fiber defined by the Institute of Medicine. Mean dietary fiber intake averaged 15.7-17.0 g. Mexican Americans (18.8 g) consumed more fiber than non-Hispanic whites (16.3 g) and non-Hispanic blacks (13.1 g). Comparing the highest with the lowest quintiles of dietary fiber intake, adjusted predicted marginal risk ratios (95% confidence interval) for the metabolic syndrome, inflammation, and obesity were 0.78 (0.69-0.88), 0.66 (0.61-0.72), and 0.77 (0.71-0.84), respectively. Dietary fiber was associated with lower levels of inflammation within each racial and ethnic group, although statistically significant associations between dietary fiber and either obesity or metabolic syndrome were seen only among whites.

Conclusions

Low dietary fiber intake from 1999-2010 in the US, and associations between higher dietary fiber and a lower prevalence of cardiometabolic risks suggest the need to develop new strategies and policies to increase dietary fiber intake.     

Dietary Sodium Restriction: Take It with a Grain of Salt

The American Heart Association recently strongly recommended a dietary sodium intake of <1500 mg/d for all Americans to achieve “Ideal Cardiovascular Health” by 2020. However, low sodium diets have not been shown to reduce cardiovascular events in normotensive individuals or in individuals with pre-hypertension or hypertension. Moreover, there is evidence that a low sodium diet may lead to a worse cardiovascular prognosis in patients with cardiometabolic risk and established cardiovascular disease. Low sodium diets may adversely affect insulin resistance, serum lipids, and neurohormonal pathways, leading to increases in the incidence of new cardiometabolic disease, the severity of existing cardiometabolic disease, and greater cardiovascular and all-cause mortality. Although a high sodium intake also may be deleterious, there is good reason to believe that sodium intake is regulated within such a tight physiologic range that there is little risk to leaving sodium intake to inherent biology as opposed to likely futile attempts at conscious control.     

Dietary intake and the prevalence of gallbladder disease in Mexican Americans

Mexican Americans have a high prevalence of gallbladder disease. We examined the contribution of ethnic preferences in food intake to the risk of gallbladder disease in Mexican Americans and non-Hispanic whites. Participants in a population-based health survey were questioned about any history of gallbladder disease, and were interviewed to determine their dietary intake. After adjusting for age, body mass index, and ethnic group, we found that women with the highest intake of total fat and linoleic acid had reduced risks of gallbladder disease, although an opposite trend was observed in men. High levels of sucrose intake and low levels of cholesterol intake were associated with an increased risk for both sexes, but the odds ratios were not statistically significant. Although Mexican Americans and non-Hispanics differed in their intake of several nutrients, the elevated risk of gallbladder disease in Mexican American women was unchanged after ethnic differences in food intake were taken into account. Although the dietary preferences of Mexican Americans as reflected in 24-h diet recall interviews do not appear to explain their high prevalence of gallbladder disease, this finding should be interpreted with caution because of methodologic limitations in measuring habitual food intake.     

Dietary magnesium intake and the future risk of coronary heart disease (the Honolulu Heart Program)

Magnesium (Mg) deficiency is believed to have adverse cardiovascular consequences that are broad and complex, although an association between dietary Mg intake and the risk of coronary heart disease (CHD) has not been clearly identified. The purpose of this study is to examine the relation between dietary Mg intake and future risk of CHD. Reported findings are based on dietary Mg intake in 7,172 men in the Honolulu Heart Program. Intake of Mg was recorded at baseline examinations that took place from 1965 to 1968 when the men were aged 45 to 68 years. In 30 years of follow-up, 1,431 incident cases of CHD were identified. Within 15 years after dietary assessment, the age-adjusted incidence decreased significantly from 7.3 to 4.0 per 1,000 person-years in the lowest (50.3 to 186 mg/day) versus highest (340 to 1,183 mg/day) quintiles of Mg intake (p <0.001). When adjustments were made for age and other nutrients (singly or combined), there was a 1.7- to 2.1-fold excess in the risk of CHD in the lowest versus highest quintiles (p <0.001). The excess risk ranged from 1.5- to 1.8-fold after further adjustment for other cardiovascular risk factors (p <0.05). Associations between dietary Mg and coronary events occurring after 15 years of follow-up were modest. We conclude that the intake of dietary Mg is associated with a reduced risk of CHD. Whether increases in dietary Mg intake can alter the future risk of disease warrants further study.     

Dietary salt intake and cerebrovascular damage

AIM: Diet is a major contributor to variation in the occurrence of hypertension and cardiovascular disease, including stroke, worldwide. Dietary salt intake plays a critical role in blood pressure regulation. However the question of whether high dietary salt intake increases risk of stroke, either indirectly via effects on blood pressure or directly via alternative mechanisms has received limited attention. DATA SYNTHESIS: Narrative review of evidence linking dietary salt intake with left ventricular hypertrophy and cardiovascular disease end-points. CONCLUSIONS: There is accumulating evidence that high salt intake predicts left ventricular hypertrophy, independent of other variables including body mass index and blood pressure. Data are now available from nine different studies worldwide consistent with a significant independent effect of salt intake on left ventricular hypertrophy. There is also evidence from animal experiments and ecological studies of an independent association between salt intake and risk of stroke. However, data from prospective observational studies on the relation between sodium intake and cardiovascular endpoints (including stroke) are sparse and inconsistent. Data from Alderman et al suggesting that there may be a significant inverse association between urinary sodium excretion and risk of cardiovascular disease has attracted controversy. In a number of prospective studies no association between salt intake and cardiovascular disease end-points (including stroke) has been observed. In a recent analysis from the US NHANES follow-up study, there was evidence that high salt intake is strongly and significantly associated with risk of stroke, other cardiovascular disease and all cause mortality in overweight persons, but not in those of normal weight. These findings need to be replicated. However, current data on the association between salt intake, blood pressure and left ventricular hypertrophy support public policy recommendations on the need for a moderate reduction in dietary salt intake at the population level.     

Dietary haem iron and coronary heart disease in women.

AIMS: A role for iron in the risk of ischaemic heart disease has been supported by in vitro and in vivo studies. We investigated whether dietary haem iron intake is associated with coronary heart disease (CHD) risk in a large population-based cohort of middle-aged women. METHODS AND RESULTS: We used data of 16 136 women aged 49-70 years at recruitment between 1993 and 1997. Follow-up was complete until 1 January 2000 and 252 newly diagnosed CHD cases were documented. Cox proportional hazards analysis was used to estimate hazard ratios of CHD for quartiles of haem iron intake, adjusted for cardiovascular and nutritional risk factors. We stratified by the presence of additional cardiovascular risk factors, menstrual periods, and antioxidant intake to investigate the possibility of effect modification. High dietary haem iron intake was associated with a 65% increase in CHD risk [hazard ratio (HR)=1.65; 95% confidence interval (CI): 1.07-2.53], after adjustment for cardiovascular and nutritional risk factors. This risk was not modified by additional risk factors, menstruation, or antioxidant intake. CONCLUSION: The results indicate that middle-aged women with a relatively high haem iron intake have an increased risk of CHD.     

Effect of race and genetics on vitamin D metabolism, bone and vascular health

The pathophysiology of chronic kidney disease-mineral and bone disorder accounts for an inverse relationship between bone mineralization and vascular calcification in progressive nephropathy. Inverse associations between bone mineral density (BMD) and calcified atherosclerotic plaque are also observed in individuals of European and African ancestry without nephropathy, suggesting a mechanistic link between these processes that is independent of kidney disease. Despite lower dietary calcium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, African Americans have higher BMD and develop osteoporosis less frequently than do European Americans. Moreover, despite having more risk factors for cardiovascular disease, African Americans have a lower incidence and severity of calcified atherosclerotic plaque formation than do European Americans. Strikingly, evidence is now revealing that serum 25(OH)D and/or 1,25 dihydroxyvitamin D levels associate positively with atherosclerosis but negatively with BMD in African Americans; by contrast, vitamin D levels associate negatively with atherosclerosis and positively with BMD in individuals of European ancestry. Biologic phenomena, therefore, seem to contribute to population-specific differences in vitamin D metabolism, bone and vascular health. Genetic and mechanistic approaches used to explore these differences should further our understanding of bone-blood vessel relationships and explain how African ancestry protects from osteoporosis and calcified atherosclerotic plaque, provided that access of African Americans to health care is equivalent to individuals of European ethnic origin. Ultimately, in our opinion, a new mechanistic understanding of the relationships between bone mineralization and vascular calcification will produce novel approaches for disease prevention in aging populations.     

Oxidants, antioxidants, and the degenerative diseases of aging.

Metabolism, like other aspects of life, involves tradeoffs. Oxidant by-products of normal metabolism cause extensive damage to DNA, protein, and lipid. We argue that this damage (the same as that produced by radiation) is a major contributor to aging and to degenerative diseases of aging such as cancer, cardiovascular disease, immune-system decline, brain dysfunction, and cataracts. Antioxidant defenses against this damage include ascorbate, tocopherol, and carotenoids. Dietary fruits and vegetables are the principal source of ascorbate and carotenoids and are one source of tocopherol. Low dietary intake of fruits and vegetables doubles the risk of most types of cancer as compared to high intake and also markedly increases the risk of heart disease and cataracts. Since only 9% of Americans eat the recommended five servings of fruits and vegetables per day, the opportunity for improving health by improving diet is great.     

Sodium and blood pressure 2003

PURPOSE OF REVIEW: In view of the ongoing controversy about the importance of dietary sodium intake in blood pressure control, consideration of the most recent findings in this area is useful. RECENT FINDINGS: New observations regarding the relation between salt intake and its reduction on blood pressure have emerged. Evidence regarding physiologic factors associated with the increased sensitivity of blood pressure to salt and the relation of this increased sensitivity to other cardiovascular disease risk factors and disorders of end-organ function have been reported. Several meta-analyses and assessments of the impact of interventions on the global risk of cardiovascular disease have also been presented. SUMMARY: Compelling evidence of the role of salt intake on blood pressure and on other risk factors for cardiovascular disease, as well as new information regarding the feasibility of reducing salt intake, call for renewed efforts in this area as a major influence in reducing cardiovascular morbidity and mortality.     

Phylloquinone intake and risk of cardiovascular diseases in men

Background and aimsDietary patterns high in fruits and vegetables have been associated with lower risk of cardiovascular diseases. It is difficult to assess whether individuals are following a dietary pattern recommended for cardiovascular disease prevention in large population based studies. Therefore, the association between phylloquinone (vitamin K₁) intake, derived mainly from green vegetables, and risk of cardiovascular diseases [total and fatal coronary heart disease (CHD), non-fatal myocardial infarction, total and ischemic stroke] was prospectively assessed.Methods and resultsThe study was conducted in 40,087 men who participated in the Health Professionals' Follow-up Study during 1986–2000. There were 1857 CHD events and 617 strokes. After adjustment for lifestyle factors, the relative risks of total CHD events in increasing quintile categories of phylloquinone intake were 1 (reference), 0.84, 0.87, 0.82 and 0.84, respectively (P for trend 0.05). However, the risk of CHD events and strokes did not remain significantly associated with phylloquinone intake after adjustment for lifestyle and other dietary factors.ConclusionThese results suggest that although not an independent risk factor, high phylloquinone intake may be a marker of dietary patterns associated with lower CHD risk and useful when used within that context.     

Salt and Hypertension: Is Salt Dietary Reduction Worth the Effort?

In numerous epidemiologic, clinical, and experimental studies, dietary sodium intake has been linked to blood pressure, and a reduction in dietary salt intake has been documented to lower blood pressure. In young subjects, salt intake has a programming effect in that blood pressure remains elevated even after a high salt intake has been reduced. Elderly subjects, African Americans, and obese patients are more sensitive to the blood pressure-lowering effects of a decreased salt intake. Depending on the baseline blood pressure and degree of salt intake reduction, systolic blood pressure can be lowered by 4 to 8 mm Hg. A greater decrease in blood pressure is achieved when a reduced salt intake is combined with other lifestyle interventions, such as adherence to Dietary Approaches to Stop Hypertension. A high salt intake has been shown to increase not only blood pressure but also the risk of stroke, left ventricular hypertrophy, and proteinuria. Adverse effects associated with salt intake reduction, unless excessive, seem to be minimal. However, data linking a decreased salt intake to a decrease in morbidity and mortality in hypertensive patients are not unanimous. Dietary salt intake reduction can delay or prevent the incidence of antihypertensive therapy, can facilitate blood pressure reduction in hypertensive patients receiving medical therapy, and may represent a simple cost-saving mediator to reduce cardiovascular morbidity and mortality.     

Dietary Salt, Blood Pressure, and Microalbuminuria

The relationship between dietary salt, blood pressure, and risk for cardiovascular disease has been debated for decades. Microalbuminuria is a biomarker for both cardiovascular and kidney disease. The presence of microalbuminuria correlates directly with the risk for myocardial infarction and stroke and indicates individuals at risk for the development of progressive kidney disease. Since patients with the metabolic syndrome, diabetes, or chronic kidney disease often are blood pressure salt sensitive, and it is well known that increasing dietary salt may offset both the antihypertensive and antiproteinuric effects of renin-angiotensin system blocking drugs, physicians must consider increased salt intake as a potential modifiable risk factor for progression of chronic kidney disease and possibly even cardiovascular disease.     

Seaweed Intake and Risk of Cardiovascular Disease: The Circulatory Risk in Communities Study (CIRCS)

Aim: Seaweed contains soluble dietary fibers, potassium, and flavonoids and was recently reported to be inversely associated with the risk of coronary heart disease and mortality from stroke. However, epidemiological evidence on this issue has remained scarce. Methods: At the baseline survey of four Japanese communities between 1984 and 2000, we enrolled 6,169 men and women aged 40–79 years who had no history of cardiovascular disease. We assessed their seaweed intake using the data from a 24 h dietary recall survey and categorized the intake into four groups (0, 1–5.5, 5.5–15, and ≥ 15 g/day). We used sex-specific Cox proportional hazards models to examine the association between seaweed intake and risk of cardiovascular disease (stroke, stroke subtypes, and coronary heart disease). Results: During the 130,248 person-year follow-up, 523 cases of cardiovascular disease occurred: 369 cases of stroke and 154 cases of coronary heart disease. Seaweed intake levels were inversely associated with the risk of total stroke and cerebral infarction among men but not among women. Adjustment for cardiovascular risk factors did not change the associations: the hazard ratios (95% confidence intervals; P for trend) for the highest versus lowest categories of seaweed intake were 0.63 (0.42–0.94; 0.01) for total stroke and 0.59 (0.36–0.97; 0.03) for cerebral infarction. No associations were observed between seaweed intake and risks of intraparenchymal hemorrhage, subarachnoid hemorrhage, or coronary heart disease among men or women. Conclusions: We found an inverse association between seaweed intake and risk of total stroke, especially that from cerebral infarction, among Japanese men.     

Associations of dietary magnesium intake with mortality from cardiovascular disease: the JACC study

The authors sought to investigate the relationship between dietary magnesium intake and mortality from cardiovascular disease in a population-based sample of Asian adults. Reported findings are based on dietary magnesium intake in 58,615 healthy Japanese aged 40-79 years, in the Japan Collaborative Cohort (JACC) Study. Dietary magnesium intake was assessed by a validated food frequency questionnaire administered between 1988 and 1990. During the median 14.7-year follow-up, we documented 2690 deaths from cardiovascular disease, comprising 1227 deaths from strokes and 557 deaths from coronary heart disease. Dietary magnesium intake was inversely associated with mortality from hemorrhagic stroke in men and with mortality from total and ischemic strokes, coronary heart disease, heart failure and total cardiovascular disease in women. The multivariable hazard ratio (95% CI) for the highest vs. the lowest quintiles of magnesium intake after adjustment for cardiovascular risk factor and sodium intake was 0.49 (0.26-0.95), P for trend = 0.074 for hemorrhagic stroke in men, 0.68 (0.48-0.96), P for trend = 0.010 for total stroke, 0.47 (0.29-0.77), P for trend < 0.001 for ischemic stroke, 0.50 (0.30-0.84), P for trend = 0.005 for coronary heart disease, 0.50 (0.28-0.87), P for trend = 0.002 for heart failure and 0.64 (0.51-0.80), P for trend < 0.001 for total cardiovascular disease in women. The adjustment for calcium and potassium intakes attenuated these associations. In conclusion, dietary magnesium intake was associated with reduced mortality from cardiovascular disease in Japanese, especially for women.     

Effect of heterozygosity for the methionine synthase 2756 A-->G mutation on the risk for recurrent cardiovascular events

Increased dietary intake of folate has been shown to significantly reduce the risk for fatal myocardial infarction, possibly by lowering homocysteine levels. We therefore investigated the association between recurrent cardiovascular events and a mutation in methionine synthase (2756 A-->G)--an enzyme directly involved in folate and homocysteine metabolism. This mutation significantly reduced the risk for recurrent cardiovascular events and elevated red blood cell folate levels.     

Fish, n-3 fatty acids, and cardiovascular diseases in women of reproductive age: a prospective study in a large national cohort

Previous studies have indicated a protective effect of long-chain n-3 polyunsaturated fatty acids (LCn3FAs) against cardiovascular disease; however, women are underrepresented in cardiovascular research. The aim of this study was to explore the association between intake of LCn3FAs and the risk of cardiovascular disease in a large prospective cohort of young women (mean age at baseline: 29.9 years [range: 15.7-46.9]). Exposure information on 48 627 women from the Danish National Birth Cohort was linked to the Danish National Patients Registry for information on events of hypertensive, cerebrovascular, and ischemic heart disease used to define a combined measure of cardiovascular diseases. Intake of fish and LCn3FAs was assessed by a food-frequency questionnaire and telephone interviews. During follow-up (1996-2008; median: 8 years), 577 events of cardiovascular disease were identified. Low LCn3FA intake was associated with an increased risk of cardiovascular disease (adjusted hazard ratio for women in lowest versus highest LCn3FA intake group: 1.91 [95% CI: 1.26-2.90]). Restricting the sample to women who had consistently reported similar frequencies of fish intake across 3 different dietary assessment occasions tended to strengthen the relationship (hazard ratio for lowest versus highest intake: 2.91 [95% CI: 1.45-5.85]). Furthermore, the observed associations were consistent in supplementary analyses where LCn3FA intake was averaged across the 3 dietary assessment occasions, and the associations were persistent for all 3 of the individual outcomes. Our findings based on a large prospective cohort of relatively young and initially healthy women indicated that little or no intake of fish and LCn3FAs was associated with an increased risk of cardiovascular disease.     

Dietary Total Isoflavone Intake Is Associated With Lower Systolic Blood Pressure: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

The effect of dietary isoflavone intake on systolic blood pressure (SBP) has not been studied in a large community‐based cohort inclusive of African Americans. The authors analyzed data from the year 20 examination of the Coronary Artery Risk Development in Young Adults (CARDIA) study, including medical history, physical examination, and dietary intake surveys for 3142 participants. Multivariable linear regression models controlled for age, sex, body mass index, smoking, physical activity, and intakes of alcohol and total energy. Effect modification by race was tested. Overall, patients with hypertension had a lower daily intake of total dietary isoflavones (2.2±5.2 mg/d vs 4.1±11.7 mg/d; P<.001). In fully adjusted models, the highest quartile of dietary isoflavone intake was associated with a 4.4 mm Hg lower SBP on average compared with SBP for the lowest quartile. The relationship between dietary isoflavone intake and SBP was more pronounced among African Americans compared with Caucasians (P for interaction <.001). Greater dietary intake of isoflavones was independently associated with a lower SBP.     

Dietary Saturated,Monounsaturated, or Polyunsaturated Fatty Acids and Estimated 10-Year Risk of a First Hard Cardiovascular Event

BackgroundThe effects of dietary saturated, monounsaturated, or polyunsaturated fatty acids on the risk of cardiovascular events remain controversial.MethodsThis cross-sectional study was performed in 4211 patients, aged 40 to 79 years, from the National Health and Nutrition Examination Survey between 1999 and 2018. The independent variables were saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The dependent variable was the 10-year risk of a first hard atherosclerotic cardiovascular event. The other variables were considered as the potential confounding factors. Multivariate linear regression models and smooth curve fittings were used to evaluate the association between saturated fatty acids, polyunsaturated fatty acids, or monounsaturated fatty acids and the 10-year risk.ResultsThere was no association between dietary saturated fatty acids and 10-year risk after adjusting for all the potential confounding factors; 10-year risk decreased by 0.022% each 1-g increase in monounsaturated fatty acids intake from 0 to 153.772 g, and 0.025% each 1-g increase in polyunsaturated fatty acids intake from 0 to 98.323 g, respectively. Moreover, subgroup analysis showed that monounsaturated fatty acids and polyunsaturated fatty acids were both negatively correlated to 10-year risk in nondiabetes and non-high–low-density lipoprotein patients; monounsaturated fatty acids were also negatively associated with 10-year risk in hypertensive patients.ConclusionsThere was no association between dietary saturated fatty acids and 10-year risk. Increased dietary intake of monounsaturated fatty acids or polyunsaturated fatty acids decreased 10-year risk, particularly in nondiabetes, non-high-low density lipoprotein patients.     

Relations between dairy food intake and arterial stiffness: pulse wave velocity and pulse pressure

Modifiable risk factors, such as diet, are becomingly increasingly important in the management of cardiovascular disease, one of the greatest major causes of death and disease burden. Few studies have examined the role of diet as a possible means of reducing arterial stiffness, as measured by pulse wave velocity, an independent predictor of cardiovascular events and all-cause mortality. The aim of this study was to investigate whether dairy food intake is associated with measures of arterial stiffness, including carotid-femoral pulse wave velocity and pulse pressure. A cross-sectional analysis of a subset of the Maine-Syracuse Longitudinal Study sample was performed. A linear decrease in pulse wave velocity was observed across increasing intakes of dairy food consumption (ranging from never/rarely to daily dairy food intake). The negative linear relationship between pulse wave velocity and intake of dairy food was independent of demographic variables, other cardiovascular disease risk factors, and nutrition variables. The pattern of results was very similar for pulse pressure, whereas no association between dairy food intake and lipid levels was found. Further intervention studies are needed to ascertain whether dairy food intake may be an appropriate dietary intervention for the attenuation of age-related arterial stiffening and reduction of cardiovascular disease risk.