New data show for the first time that combining the DASH (Dietary Approaches to Stop Hypertension) diet with sodium restriction decreases myocardial injury and cardiac strain, which are associated with subclinical cardiac damage and long-term cardiovascular risk.
Dr. Stephen Juraschek
“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, said in an interview.
“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 Dr. Juraschek.
The findings, from a secondary analysis of the DASH-Sodium trial, were published 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,” wrote the coauthors 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 added.
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 of the prohormone brain 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 washout 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 two distinct dietary strategies might improve two key pathways of subclinical cardiac damage: injury and strain,” Dr. Juraschek and colleagues wrote.
“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 concluded.
“We need to talk about DASH more. Most adults in the U.S. have never heard of it,” Dr. Juraschek said in an interview.
“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, Dr. 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,” Dr. Juraschek said.
In their editorial, Neha J. Pagidipati, MD, and Laura P. Svetkey, MD, from Duke University and Duke Clinical Research Institute, Durham, N.C., said 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 added.
The measurement of cardiac biomarkers was supported by the National Institutes of Health/National Heart, Lung, and Blood Institute. The original DASH trial was supported by the NHLBI, the Office of Research on Minority Health, and the National Center for Research Resources. Dr. Juraschek and coauthors disclosed no relevant conflicts of interest. Dr. 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. Dr. Svetkey has no relevant disclosures.
A version of this article first appeared on Medscape.com.