Interactions of the DASH Diet with the Renin-Angiotensin-Aldosterone System

From the kitchen to the medicine cabinet: Examples of food products and supplements used for therapeutic intent

"Food as medicine" has existed for centuries as the foundation of health for many cultures around the globe. It is a practice built on the knowledge that food and diet play important roles in disease prevention and management. Foods that claim to have therapeutic properties are often referred to as functional foods. These foods contain a number of nutritional and nonnutritional compounds that can interact with pharmacologically relevant receptors, either directly or indirectly via their metabolites, to regulate cellular biochemical processes. Although opinions are changing, the concept of food as a therapeutic intervention goes against conventional Western medicine. To provide guidance to clinicians interested in using these products, members of the Food as Medicine working group of the Nutrition Committee for the North American Society For Pediatric Gastroenterology, Hepatology & Nutrition (NASPGHAN), as part of a two-part review series, have created summaries of several frequently used nutritional products for therapeutic intent (i.e., fermented foods, fiber, and long-chain omega-3 fatty acids) that includes indications, doses, and caveats. Gaps in their use in pediatric patients are discussed. Evidence supporting their use for management of GI conditions, especially in the pediatric population, is provided when available.

Effect of the DASH diet on the sodium-chloride cotransporter and aquaporin-2 in urinary extracellular vesicles

The dietary approach to stop hypertension (DASH) diet combines the antihypertensive effect of a low sodium and high potassium diet. In particular, the potassium component of the diet acts as a switch in the distal convoluted tubule to reduce sodium reabsorption, similar to a diuretic but without the side effects. Previous trials to understand the mechanism of the DASH diet were based on animal models and did not characterize changes in human ion channel protein abundance. More recently, protein cargo of urinary extracellular vesicles (uEVs) has been shown to mirror tissue content and physiological changes within the kidney. We designed an inpatient open label nutritional study transitioning hypertensive volunteers from an American style diet to DASH diet to examine physiological changes in adults with stage 1 hypertension otherwise untreated (Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin PR, Miller ER 3rd, Simons-Morton DG, Karanja N, Lin PH; DASH-Sodium Collaborative Research Group. N Engl J Med 344: 3-10, 2001). Urine samples from this study were used for proteomic characterization of a large range of pure uEVs (small to large) to reveal kidney epithelium changes in response to the DASH diet. These samples were collected from nine volunteers at three time points, and mass spectrometry identified 1,800 proteins from all 27 samples. We demonstrated an increase in total SLC12A3 [sodium-chloride cotransporter (NCC)] abundance and a decrease in aquaporin-2 (AQP2) in uEVs with this mass spectrometry analysis, immunoblotting revealed a significant increase in the proportion of activated (phosphorylated) NCC to total NCC and a decrease in AQP2 from day 5 to day 11. This data demonstrates that the human kidney's response to nutritional interventions may be captured noninvasively by uEV protein abundance changes. Future studies need to confirm these findings in a larger cohort and focus on which factor drove the changes in NCC and AQP2, to which degree NCC and AQP2 contributed to the antihypertensive effect and address if some uEVs function also as a waste pathway for functionally inactive proteins rather than mirroring protein changes.NEW & NOTEWORTHY Numerous studies link DASH diet to lower blood pressure, but its mechanism is unclear. Urinary extracellular vesicles (uEVs) offer noninvasive insights, potentially replacing tissue sampling. Transitioning to DASH diet alters kidney transporters in our stage 1 hypertension cohort: AQP2 decreases, NCC increases in uEVs. This aligns with increased urine volume, reduced sodium reabsorption, and blood pressure decline. Our data highlight uEV protein changes as diet markers, suggesting some uEVs may function as waste pathways. We analyzed larger EVs alongside small EVs, and NCC in immunoblots across its molecular weight range.

Diet quality in relation to kidney function and its potential interaction with genetic risk of kidney disease among Dutch post-myocardial infarction patients

PURPOSE

We examined the relation between diet quality, its components and kidney function decline in post-myocardial infarction (MI) patients, and we explored differences by genetic risk of chronic kidney disease (CKD).

METHODS

We analysed 2169 patients from the Alpha Omega Cohort (aged 60-80 years, 81% male). Dietary intake was assessed at baseline (2002-2006) using a validated food-frequency questionnaire and diet quality was defined using the Dutch Healthy Diet Cardiovascular Disease (DHD-CVD) index. We calculated 40-months change in estimated glomerular filtration rate (eGFR, mL/min per 1.73m2). We constructed a weighted genetic risk score (GRS) for CKD using 88 single nucleotide polymorphisms previously linked to CKD. Betas with 95%-confidence intervals (CIs) were obtained using multivariable linear regression models for the association between DHD-CVD index and its components and eGFR change, by GRS.

RESULTS

The average DHD-CVD index was 79 (SD 15) points and annual eGFR decline was 1.71 (SD 3.86) mL/min per 1.73 m2. The DHD-CVD index was not associated with annual eGFR change (per 1-SD increment in adherence score: -0.09 [95% CI -0.26,0.08]). Results for adherence to guidelines for red meat showed less annual eGFR decline (per 1-SD: 0.21 [0.04,0.38]), whereas more annual eGFR decline was found for legumes and dairy (per 1-SD: -0.20legumes [-0.37,-0.04] and - 0.18dairy [-0.34,-0.01]). Generally similar results were obtained in strata of GRS.

CONCLUSION

The DHD-CVD index for overall adherence to Dutch dietary guidelines for CVD patients was not associated with kidney function decline after MI, irrespective of genetic CKD risk. The preferred dietary pattern for CKD prevention in CVD patients warrants further research.

Lifestyle Medicine as a Treatment for Resistant Hypertension

PURPOSE OF REVIEW

Approximately 10% of the adults with hypertension fail to achieve the recommended blood pressure treatment targets on 3 antihypertensive medications or require ≥ 4 medications to achieve goal. These patients with 'resistant hypertension' have an increased risk of target organ damage, adverse clinical events, and all-cause mortality. Although lifestyle modification is widely recommended as a first-line approach for the management of high blood pressure, the effects of lifestyle modifications in patients with resistant hypertension has not been widely studied. This review aims to provide an overview of the emerging evidence on the benefits of lifestyle modifications in patients with resistant hypertension, reviews potential mechanisms by which lifestyles may reduce blood pressure, and discusses the clinical implications of the recent findings in this field.

RECENT FINDINGS

Evidence from single-component randomized clinical trials demonstrated that aerobic exercise, weight loss and dietary modification can reduce clinic and ambulatory blood pressure in patients with resistant hypertension. Moreover, evidence from multi-component trials involving exercise and dietary modification and weight management can facilitate lifestyle change, reduce clinic and ambulatory blood pressure, and improve biomarkers of cardiovascular risk. This new evidence supports the efficacy of lifestyle modifications added to optimized medical therapy in reducing blood pressure and improving cardiovascular risk biomarkers in patients with resistant hypertension. These findings need to be confirmed in larger studies, and the persistence of benefit over extended follow-up needs further study.

Compliance with the DASH diet and risk of all-cause and cardiovascular mortality in patients with myocardial infarction

BACKGROUND & AIMS

The Dietary Approaches to Stop Hypertension (DASH) diet has been shown to effectively reduce blood pressure and body weight, but its effectiveness for reducing (cardiovascular) mortality rates has never been assessed in a clinical trial. Causal effects of dietary interventions are difficult to measure, due to practical limitations of randomized controlled diet trials. Target trial emulation can be used to improve causal inference in observational data. The aim of this study was to emulate a target trial assessing the relationship between compliance with the DASH diet and cardiovascular and all-cause mortality risk in patients with established CVD.

METHODS

Using data from the Alpha Omega Cohort, we emulated a DASH diet trial in patients with a history of myocardial infarction (MI). Inverse probability of treatment weighting (IPTW) was used to balance confounders over DASH-compliant and non-DASH-compliant participants. Hazard ratios (HRs) were estimated with IPT-weighted Cox models.

RESULTS

Of 4365 patients (79% male, median age 69 years, >80% treated with lipid- and blood pressure-lowering medication), 598 were classified as DASH-compliant (compliance score ≥5 out of 9). During a median follow-up of 12.4 years, 2035 deaths occurred of which 903 (44%) were of cardiovascular origin. DASH compliance was not associated with all-cause mortality (HR 0.92, 95%CI 0.0.80-1.06) and cardiovascular mortality (HR 0.90, 95%CI 0.72-1.11).

CONCLUSIONS

In an emulated target trial on the DASH diet in the Alpha Omega cohort no relation was found between DASH compliance and risk of all-cause and cardiovascular mortality in patients with a history of MI. The DASH diet's effects may have been modified in this population by concomitant use of blood pressure-lowering medications.

Serum Aldosterone and Urine Electrolytes Dynamics in Response to DASH Diet Intervention – an Inpatient Mechanistic Study

Background:

Methods:

Results:

Conclusion:

Blood pressure interactions with the DASH dietary pattern, sodium, and potassium: The International Study of Macro-/Micronutrients and Blood Pressure (INTERMAP)

BACKGROUND

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet enhances potassium intake and reduces sodium intake and blood pressure (BP), but the underlying metabolic pathways are unclear.

OBJECTIVES

Among free-living populations, we delineated metabolic signatures associated with the DASH diet adherence, 24-hour urinary sodium and potassium excretions, and the potential metabolic pathways involved.

METHODS

We used 24-hour urinary metabolic profiling by proton nuclear magnetic resonance spectroscopy to characterize the metabolic signatures associated with the DASH dietary pattern score (DASH score) and 24-hour excretion of sodium and potassium among participants in the United States (n = 2164) and United Kingdom (n = 496) enrolled in the International Study of Macro- and Micronutrients and Blood Pressure (INTERMAP). Multiple linear regression and cross-tabulation analyses were used to investigate the DASH-BP relation and its modulation by sodium and potassium. Potential pathways associated with DASH adherence, sodium and potassium excretion, and BP were identified using mediation analyses and metabolic reaction networks.

RESULTS

Adherence to the DASH diet was associated with urinary potassium excretion (correlation coefficient, r = 0.42; P < 0.0001). In multivariable regression analyses, a 5-point higher DASH score (range, 7 to 35) was associated with a lower systolic BP by 1.35 mmHg (95% CI, -1.95 to -0.80 mmHg; P = 1.2 × 10-5); control of the model for potassium but not sodium attenuated the DASH-BP relation. Two common metabolites (hippurate and citrate) mediated the potassium-BP and DASH-BP relationships, while 5 metabolites (succinate, alanine, S-methyl cysteine sulfoxide, 4-hydroxyhippurate, and phenylacetylglutamine) were found to be specific to the DASH-BP relation.

CONCLUSIONS

Greater adherence to the DASH diet is associated with lower BP and higher potassium intake across levels of sodium intake. The DASH diet recommends greater intake of fruits, vegetables, and other potassium-rich foods that may replace sodium-rich processed foods and thereby influence BP through overlapping metabolic pathways. Possible DASH-specific pathways are speculated but confirmation requires further study. INTERMAP is registered as NCT00005271 at www.clinicaltrials.gov.

Understanding resistant hypertension

ABSTRACT

Resistant hypertension affects about 17% of the US population. However, it is difficult to diagnose because of multiple factors that influence adequate treatment of BP, including patient lifestyle and comorbidities, improper therapeutic regimens, and secondary mechanisms. Possible causes of resistant hypertension include nonmodulator hypertension, which affects patients who have an inappropriate response to elevated sodium through the renin-angiotensin-aldosterone system. Early identification and frequent follow-up can help patients achieve BP goals more rapidly and may reduce morbidity and mortality associated with complications of hypertension, including cerebrovascular accident, cardiovascular disease, and kidney disease.

The Dietary Approaches to Stop Hypertension (DASH) Diet Pattern and Incident Heart Failure

BACKGROUND

The Dietary Approaches to Stop Hypertension (DASH) diet pattern has shown some promise for preventing heart failure (HF), but studies have been conflicting.

OBJECTIVE

To determine whether the DASH diet pattern was associated with incident HF in a large biracial and geographically diverse population.

METHODS AND RESULTS

Among participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort study of adults aged ≥45 years who were free of suspected HF at baseline in 2003-2007, the DASH diet score was derived from the baseline food frequency questionnaire. The main outcome was incident HF defined as the first adjudicated HF hospitalization or HF death through December 31, 2016. We estimated hazard ratios for the associations of DASH diet score quartiles with incident HF, and incident HF with reduced ejection fraction and HF with preserved ejection fraction using the Lunn-McNeil extension to the Cox model. We tested for several prespecified interactions, including with age. Compared with the lowest quartile, individuals in the second to fourth DASH diet score quartiles had a lower risk for incident HF after adjustment for sociodemographic and health characteristics: quartile 2 hazard ratio, 0.69 (95% confidence interval [CI], 0.56-0.85); quartile 3 hazard ratio, 0.71 (95% CI, 0.58-0.87); and quartile 4 hazard ratio, 0.73 (95% CI, 0.58-0.92). When stratifying results by age, quartiles 2-4 had a lower hazard for incident HF among those age <65 years, quartiles 3-4 had a lower hazard among those age 65-74, and the quartiles had similar hazard among those age ≥75 years (Pinteraction = .003). We did not find a difference in the association of DASH diet with incident HF with reduced ejection fraction vs HF with preserved ejection fraction (P = .11).

CONCLUSIONS

DASH diet adherence was inversely associated with incident HF, specifically among individuals <75 years old.

Associations of DASH Diet in Pregnancy With Blood Pressure Patterns, Placental Hemodynamics, and Gestational Hypertensive Disorders

Background The Dietary Approaches to Stop Hypertension (DASH) diet improves blood pressure in nonpregnant populations. We hypothesized that adherence to the DASH diet during pregnancy improves hemodynamic adaptations, leading to a lower risk of gestational hypertensive disorders. Methods and Results We examined whether the DASH diet score was associated with blood pressure, placental hemodynamics, and gestational hypertensive disorders in a population-based cohort study among 3414 Dutch women. We assessed DASH score using food-frequency questionnaires. We measured blood pressure in early-, mid-, and late pregnancy (medians, 95% range: 12.9 [9.8-17.9], 20.4 [16.6-23.2], 30.2 [28.6-32.6] weeks gestation, respectively), and placental hemodynamics in mid- and late pregnancy (medians, 95% range: 20.5 [18.7-23.1], 30.4 [28.5-32.8] weeks gestation, respectively). Information on gestational hypertensive disorders was obtained from medical records. Lower DASH score quartiles were associated with a higher mid pregnancy diastolic blood pressure, compared with the highest quartile (P<0.05). No associations were present for early- and late pregnancy diastolic blood pressure and systolic blood pressure throughout pregnancy. Compared with the highest DASH score quartile, the lower DASH score quartiles were associated with a higher mid- and late pregnancy umbilical artery pulsatility index (P≤0.05) but not with uterine artery resistance index. No associations with gestational hypertensive disorders were present. Conclusions A higher DASH diet score is associated with lower mid pregnancy diastolic blood pressure and mid- and late pregnancy fetoplacental vascular function but not with uteroplacental vascular function or gestational hypertensive disorders within a low-risk population. Further studies need to assess whether the effects of the DASH diet on gestational hemodynamic adaptations are more pronounced among higher-risk populations.

Dietary intervention for the management of hypertension in Asia

Hypertension is among the leading global risks for premature death. As the risks substantially increase along with the elevated blood pressure, a small reduction of blood pressure could have prevented numerous cardiovascular events in general population. Evidence has shown that dietary intervention is a cost-effective strategy that has been broadly advocated in the published guidelines. However, the implementation could be limited by different food cultures. This review details the mechanisms of each dietary intervention approach, evidence, and the implications in Asian populations, and the perspective of future research.

Lifestyle interventions for the prevention and treatment of hypertension

Hypertension affects approximately one third of the world's adult population and is a major cause of premature death despite considerable advances in pharmacological treatments. Growing evidence supports the use of lifestyle interventions for the prevention and adjuvant treatment of hypertension. In this Review, we provide a summary of the epidemiological research supporting the preventive and antihypertensive effects of major lifestyle interventions (regular physical exercise, body weight management and healthy dietary patterns), as well as other less traditional recommendations such as stress management and the promotion of adequate sleep patterns coupled with circadian entrainment. We also discuss the physiological mechanisms underlying the beneficial effects of these lifestyle interventions on hypertension, which include not only the prevention of traditional risk factors (such as obesity and insulin resistance) and improvements in vascular health through an improved redox and inflammatory status, but also reduced sympathetic overactivation and non-traditional mechanisms such as increased secretion of myokines.

Dietary Approaches to Stop Hypertension (DASH) Diet and Blood Pressure Reduction in Adults with and without Hypertension: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The Dietary Approaches to Stop Hypertension (DASH) diet is recognized as an effective dietary intervention to reduce blood pressure (BP). However, among randomized controlled trials (RCTs) investigating the DASH diet-mediated BP reduction, there are significant methodological and clinical differences. The purpose of this study was to comprehensively assess the DASH diet effect on BP in adults with and without hypertension, accounting for underlying methodological and clinical confounders. We systematically searched Medline and the Cochrane Collaboration Library databases and identified 30 RCTs (n = 5545 participants) that investigated the BP effects of the DASH diet compared with a control diet in hypertensive and nonhypertensive adults. Both random-effects and fixed-effect models were used to calculate the mean attained systolic BP (SBP) and diastolic BP (DBP) differences during follow-up. Subgroup and meta-regression analyses were also conducted. Compared with a control diet, the DASH diet reduced both SBP and DBP (difference in means: -3.2 mm Hg; 95% CI: -4.2, -2.3 mm Hg; P < 0.001, and -2.5 mm Hg; 95% CI: -3.5, -1.5 mm Hg; P < 0.001, respectively). Hypertension status did not modify the effect on BP reduction. The DASH diet compared with a control diet reduced SBP levels to a higher extent in trials with sodium intake >2400 mg/d than in trials with sodium intake ≤2400 mg/d, whereas both SBP and DBP were reduced more in trials with mean age <50 y than in trials of older participants. The quality of evidence was rated as moderate for both outcomes according to the Grading of Recommendations, Assessment, Development, and Evaluation approach. The adoption of the DASH diet was accompanied by significant BP reduction in adults with and without hypertension, although higher daily sodium intake and younger age enhanced the BP-lowering effect of the intervention. This meta-analysis was registered at www.crd.york.ac.uk/prospero as CRD42019128120.

Contemporary and Future Concepts on Hypertension in African Americans: COVID-19 and Beyond

Background

Cardiovascular disease related mortality is the leading cause of death in the United States, with hypertension being the most prevalent and potent risk factor. For decades hypertension has disproportionately affected African Americans, who also have a higher burden of associated comorbidities including diabetes and heart failure.

Methods

Current literature including guideline reports and newer studies on hypertension in African Americans in PubMed were reviewed. We also reviewed newer publications on the relationship between COVID-19 and cardiovascular disease.

Findings

While APOL1 has been theorized in the epidemiology of hypertension, the increased prevalence and associated risks are primarily due to environmental and lifestyle factors. These factors include poor diet, adverse lifestyle, and social determinants. Hypertension control can be achieved by lifestyle modifications such as low sodium diet, weight loss, and adequate physical activity. When lifestyle modifications alone do not adequately control hypertension, a common occurrence among African Americans who suffer with greater prevalence of resistant hypertension, pharmacological intervention is indicated. The efficacy of renal denervation, and the use of sodium-glucose cotransporter 2 and aminopeptidase A inhibitors, have been studied for treatment of resistant hypertension. Furthermore, the recent COVID-19 crisis has been particularly devastating among African Americans who demonstrate increased incidence and poorer health outcomes related to the disease.

Conclusion

The disparities in outcomes, which are largely attributable to a greater prevalence of comorbidities such as hypertension and obesity, in addition to adverse environmental and socioeconomic factors, highlight the necessity of specialized clinical approaches and programs for African Americans to address longstanding barriers to equitable care.