From the Journals
For Americans, less salt is still too much
Sodium content of packaged food is down since 2000, but most households still purchase above-optimal amounts of salt.
ANAHEIM, CALIF. – The low-sodium DASH diet lowered systolic BP a mean of 20.8 mm Hg among patients with a baseline systolic pressure of 150-159 mm Hg, and did so in just 4 weeks, according to a new analysis of the DASH-Sodium trial.
The original 2001 study found that combining low sodium and the DASH [Dietary Approaches to Stop Hypertension] diet lowered blood pressure more than either alone, but results were not broken out by hypertension severity (N Engl J Med. 2001 Jan 4;344[1]:3-10).
Dr. Stephen Juraschek
It found that there were “progressively greater reductions at higher levels of baseline systolic BP (SBP). Among participants with baseline SBP at or above 150 mm Hg, “mean SBP reduction was striking,” said Dr. Juraschek, of Harvard Medical School/Beth Israel Deaconess Medical Center, Boston.
The original trial randomized 208 subjects to the DASH diet and 204 to a control diet similar to what most Americans eat. While on their diets, the subjects cycled through three sodium levels for 4 weeks each: 1.5 g/d, 2.4 g/d, and 3.3 g/d. Although deemed high sodium in the study, 3.3 g/d is typical of the American diet.
The new study analyzed outcomes according to four baseline SBP categories: 120-129, 130-139, 140-149, and 150-159 mm Hg.
Among subjects on the control diet, reducing sodium from high to low intake reduced SBP 3.20, 8.56, 8.99, and 7.04 mm Hg across the four baseline SBP categories (P = .004). Among patients consuming high sodium, the DASH diet, compared with the control diet, reduced SBP 4.5, 4.3, 4.7, and 10.6 mm Hg, but the trend was not statistically significant.
The low-sodium DASH diet, versus the high-sodium control diet, reduced SBP 5.3, 7.5, 9.7, and 20.8 mm Hg in subjects with baseline SBP at or above 150 mmHg (P < .001).
“The DASH diet with low sodium, compared with the control diet with high sodium, lowered SBP by nearly 10 mm Hg among those with a baseline SBP of 140-149 mm Hg and [greater than] 20 mm Hg among those with a baseline systolic BP [at or above] 150 mm Hg. SBP levels between 140 and 159 mm Hg represent the majority of patients with hypertension. Thus, our findings suggest that most adults with uncontrolled BP can experience substantial reductions in SBP from dietary changes alone,” the investigator said.
“To place our results in context, compared to placebo, angiotensin-converting enzyme inhibitors reduce SBP by 12 mm Hg, beta-blockers reduce SBP by 13 mm Hg, and calcium-channel blockers reduce SBP by 16 mm Hg,” he said.
“For many patients, it’s hard to take that step to be on a chronic medication. A lot of them want to talk about diet, but” find it hard to believe that something as simple as changing what you eat could beat drugs. “It’s important for both patients and physicians to realize that if you take this seriously, you can have significant reductions in your blood pressure. We should take it seriously as the first step. That’s the key take away,” Dr. Juraschek said in an interview.
None of the participants were on blood pressure medications; 57% were women, and 57% were black. The mean age was 48 years, and mean baseline BP was 135/86 mm Hg. The DASH diet includes whole grains, poultry, fish, and nuts, with reductions in red meat, sweets, and sugary drinks.
The results were published, online simultaneously with Dr. Juraschek’s presentation (J Am Coll Cardiol. 2017 Nov 12;doi: 10.1016/j.jacc.2017.10.011).
The original study was funded by the National Institutes of Health. Dr. Juraschek had no relevant disclosures.