Heart Benefits of DASH Low-Sodium Diet 'Swift and Direct'

Megan Brooks

May 25, 2021

New data show for the first time that combining the DASH diet with sodium restriction decreases myocardial injury and cardiac strain, which are associated with subclinical cardiac damage and long-term cardiovascular risk.

"The benefits of healthy eating are swift and direct. High sodium is not just about taste, it causes heart strain," Stephen Juraschek, MD, PhD, from Beth Israel Deaconess Medical Center, Boston, told theheart.org | Medscape Cardiology.

"We should consciously follow a diet enriched with fruit and vegetables and low in sodium. Collectively, we should think about how foods are promoted in society and what is an acceptable amount of sodium for food supplies," said Juraschek.

The findings, from a secondary analysis of the Dietary Approaches to Stop Hypertension (DASH)-Sodium trial, are published in the June 1 issue of the Journal of the American College of Cardiology.

Renewed Focus on Diet

"These data should spur a renewed focus on the critical need for widespread adoption of the DASH-low sodium diet in the United States," write the co-authors of a linked editorial.

"The challenge remains moving the DASH-low sodium diet from the research world into the real world, where its significant health benefits can be fully realized," they add.

The researchers evaluated the impact of the DASH diet and sodium restriction, individually and combined, on biomarkers of cardiac injury (high-sensitivity cardiac troponin I [hs-cTnI]), cardiac strain (N-terminal B-type pro natriuretic peptide [NT-proBNP]), and inflammation (high-sensitivity C-reactive protein [hs-CRP]).

The DASH-Sodium trial was a controlled feeding study that enrolled 412 adults (mean age, 48 years; 56% women, 56% Black) with untreated systolic blood pressure between 120 and 159 mm Hg and diastolic blood pressure between 80 and 95 mm Hg. Mean baseline BP was 135/86 mm Hg.

Participants were randomly allocated to a typical American diet (control) or the heart-healthy DASH diet. Further, participants in both groups were assigned to each of three sodium intake levels: low (0.5 mg/kcal), medium (1.1 mg/kcal) or high (1.6 mg/kcal) for 30 days using a crossover design with wash-out periods in-between.

Compared with the control diet, the DASH diet reduced hs-cTnI by 18% and hs-CRP by 13% with no impact on NT-proBNP.

In contrast, lowering sodium from high to low levels reduced NT-proBNP independent of diet by 19%, but did not alter hs-cTnI and mildly increased hs-CRP (9%).

Combining the DASH diet with sodium reduction lowered hs-cTnI by 20% and NT-proBNP by 23%, with no significant change in hs-CRP, compared with the high-sodium-control diet.

"Together, these findings imply that 2 distinct dietary strategies might improve 2 key pathways of subclinical cardiac damage: injury and strain," Juraschek and colleagues write.

"These findings should strengthen public resolve for public policies that promote the DASH dietary pattern and lower sodium intake in the United States and globally," they conclude.

"We need to talk about DASH more. Most adults in the US have never heard of it," Juraschek told theheart.org | Medscape Cardiology.

"We need to promote nutrition literacy with regard to nutrition facts. Labeling is not very transparent and hard to understand. Many people don't know where salt is hiding in their diet," he added.

It will also be important to address disparities in access to healthy foods and food insecurity, Juraschek said.

"If we don't address food costs and access, disparities in healthy eating will persist. Greater equity is key. We should also be mindful about populations dependent on others for meal preparation (children in schools or older adults on meal plans). This might be regulated in ways that promote healthier eating population-wide, but for these patients, they may not have autonomy to choose what they eat," Juraschek said.

In their editorial, Neha J. Pagidipati, MD, and Laura P. Svetkey, MD, from Duke University School of Medicine and Duke Clinical Research Institute, Durham, North Carolina, say an important caveat is that the beneficial effects of diet and sodium restriction on cardiac injury and strain occurred in people without any clinical evidence of coronary artery disease or heart failure at baseline, "suggesting that this dietary combination can improve subclinical metrics of cardiac health."

"Further, the impact on these markers was seen within weeks, indicating a relatively rapid impact on cardiac damage," they add.

The measurement of cardiac biomarkers was supported by the National Institutes of Health (NIH)/National Heart, Lung, and Blood Institute (NHLBI). The original DASH trial was supported by the NHLBI, the Office of Research on Minority Health, and the National Center for Research Resources of the NIH. Juraschek and coauthors have disclosed no relevant conflicts of interest. Pagidipati has received research support to the institution from Amgen, AstraZeneca, Boehringer Ingelheim, Eli Lilly, Novartis, Novo Nordisk, Regeneron, Sanofi, and Verily Life Sciences; and has received consultation fees from Boehringer Ingelheim, Eli Lilly, AstraZeneca, and Novo Nordisk. Svetkey has no relevant disclosures.

J Am Coll Cardiol. 2021;77:2625-2634, 2635-2637. Abstract, Editorial


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