Dash diet and salt reduction work together to reduce cardiovascular risk

Dash diet and salt reduction work together to reduce cardiovascular risk

A new analysis shows that combining a low sodium diet with lean eating habits reduces cardiovascular risk by over 14%, with the biggest victories for women and black adults with high blood pressure.

In a recently published article in theAmerican Journal of Prudemitive CardiologyIn the United States, researchers used data collected in the United States to examine how reducing sodium in the diet either in isolation or during the Dietary Approaches to Prevent Hypertension (DASH) diet affects the risk of atherosclerotic cardiovascular disease (ASCVD) over 10 years.

Their results suggest that adherence to Dash dietary patterns and sodium reduction independently reduce ASCVD risk, with the greatest benefits observed when the two interventions were combined.

background

Cardiovascular disease (CVD) remains the world's leading cause of mortality, but more than half of cases are associated with modifiable lifestyle factors such as physical activity and diet. In the United States, unhealthy dietary habits, particularly excessive sodium intake, which affect more than 90% of American adults, are essential to poor cardiovascular health.

The DASH diet, endorsed by national recommendations, promotes intake of low-fat dairy products, whole grains, vegetables and fruits and reduces consumption of added sugars, cholesterol and saturated fats. It has been associated with lower CVD incidence, reduced cardiac injury, and reduced risk of ASCVD.

While a previous study called Dash-Sodium showed that both the DASH diet and sodium reduction were effective in improving blood pressure, their effects on the long-term risk of ASCVD have not been analyzed.

About the study

In this study, researchers conducted a secondary analysis using data collected during the Dash Sodium Project to evaluate whether reducing sodium intake alone or alongside the DASH diet could reduce the risk of ASCVD over ten years.

The researchers hypothesized that decreasing sodium consumption alone would reduce the risk and that combining it with the DASH diet would have an additive effect.

The Dash Sodium Project was a randomized, multicenter feeding trial conducted at four U.S. clinical sites between 1997 and 1999. It included adults with elevated blood pressure who were at least 22 years old, while excluding those with insulin-dependent diabetes, heart disease, renal insufficiency, poorly controlled dyslipidemia, excessive alcohol intake, or those on prehypertensive medications. Participants were randomized to follow the DASH diet or an average American diet for 12 weeks. Each participant consumed three levels of sodium - high, which is 1.6 mg of sodium for each kilocalorie consumed (about 3,500 mg/day for a diet of 2,000 Kcal) (1.1 mg per kilocalorie, about 2,400 mg/day) or low (0.5 mg per kilocalorie, about 1,150 mg/day), i.e. a consumer (1.1 mg per kilocalorie). Each sodium level was consumed for approximately 30 days with washout periods in between.

The study provided all meals to ensure consistent nutrient intake. The highest sodium intake represented typical American consumption, while the medium level was guideline limits and the lowest level was below the recommended intake.

The primary outcome was the ten-year ASCVD risk score, calculated using the pooled cohort equation (PCE). Static risk factors such as age and smoking were measured at baseline, while dynamic variables such as blood pressure and cholesterol were measured after each feeding time.

Blood samples and blood pressure values ​​were collected using standardized methods. Data were analyzed using mixed effects models and taking repeated measures into account. Sensitivity analyzes addressed participants outside the valid range of the PCE by triggering or excluding them outside the range. Stratified analyzes assessed outcomes by age, sex, race, hypertension status, obesity, and smoking.

It is important to note that each sodium intervention period lasted only 30 days. While this allowed for controlled measurement of short-term changes in ASCVD risk scores, it does not provide evidence of the long-term effects of sustained dietary changes.

Results

Among the 390 participants, baseline characteristics were similar in the control and DASH diet groups. The DASH diet resulted in a greater reduction in estimated ASCVD risk over ten years compared to the control diet, with an absolute difference of −0.12% and a relative difference of −5.33%.

Sodium reduction further reduced ASCVD risk, with low sodium intake having greater risk reductions than medium or high sodium intake. The combined DASH diet and low sodium intake resulted in the greatest decrease in ASCVD risk with an absolute difference of −0.35% and a relative difference of −14.09% compared to the control diet, which was high in sodium.

A stratified analysis showed greater sodium reduction effects in women, black adults, and patients with stage 2 hypertension, while no significant differences were observed by age, obesity, or smoking status. Sensitivity analyzes supported these results.

The study also noted that race was dichotomized as black versus non-black, so effects among other minority groups could not be determined.

Conclusions

The DASH diet significantly reduced the estimated 10-year ASCVD risk compared to a typical American diet. Sodium reduction reduced risk, particularly when combined with the DASH diet, with greater benefits in women, black adults, and patients with stage 2 hypertension.

These results are consistent with previous findings supporting Dash and sodium reduction for cardiovascular health. However, no long-term randomized trials have confirmed the impact of Dash on actual CVD events, as most evidence is based on risk factor reduction and risk assessment rather than direct clinical outcomes. The optimal sodium intake level also remains debated.

Nevertheless, even moderate sodium reductions appeared to be beneficial and to increase public health efforts to reduce sodium intake. The authors note that the study's exclusion criteria (such as those with existing heart disease, diabetes, or those on antihypertensive medications) and the relatively short intervention times may limit the generalizability of the results. Future research should focus on long-term outcomes, include a broader range of participants, and further refine sodium intake guidelines.

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