Sharing the Quick Truth
A study of more than 400 adults with prehypertension, or stage 1 high blood pressure, found that combining a low-salt diet with a heart-healthy DASH diet significantly lowers systolic blood pressure – the leading number on a blood pressure test – especially in people with higher baseline systolic readings.
Results of a pre -trial clinical trial of the combination diet, conducted by researchers at the Johns Hopkins University School of Medicine, PUBLISHED in the Nov. 12 issue of Journal of the American College of Cardiology.
“Our results add to the evidence that dietary interventions are as effective as – or more effective than – antihypertensive medications in those most at risk of high blood pressure, and should be a common option. to treat separately for such individuals, ”said Stephen Juraschek, MD, an adjunct professor at Johns Hopkins and a professor of medicine at Harvard Medical School.
The Dietary Approach to Stop Hypertension (DASH) diet, long promoted by the National Heart, Lung, and Blood Institute and the American Heart Association, is rich in fruits, vegetables and whole grains, along with low-fat or fat- free milk, fish, chicken, beans, seeds and nuts.
While both low-sodium and DASH diets have long been known to prevent or reduce high blood pressure, Juraschek said the new study is designed to examine the effects of combining the two diets. in adults with early or moderate forms of high blood pressure – considered the most risky for developing more severe forms of hypertension known to increase the likelihood of stroke, kidney disease, seizures of heart and heart failure.
For the study, investigators tested and followed 412 adults, including 234 women, aged 23 to 76 years and had a systolic blood pressure of 120-159 mm Hg and a diastolic blood pressure. between 80-95 mm Hg (i.e., prehypertension or stage 1 hypertension). Fifty-seven percent of the participants were African.
At the start of the study, participants were not on antihypertensive medication or insulin, had no prior or current diagnosis of heart disease, bladder insufficiency, poor cholesterol level control or diabetes.
The investigators placed all participants on a DASH diet or a control diet for 12 weeks. Dietary control is similar to a normal American diet based on the average macronutrient and micronutrient profile of the U.S. population.
All participants were also fed 50 (low), 100 (medium) or 150 (high) mmol / day sodium internally over a four -week period. Fifty mmol / day is equivalent to 1,150 mg of sodium. One teaspoon of salt is equivalent to 2,400 mg of sodium. A diet with 100 mmol / day of salt is equivalent to 2,300 mg of sodium – or about a teaspoon of salt. This is the highest level of sodium intake recommended by the U.S. Food and Drug Administration (FDA) and is believed to reduce the risk of heart disease and stroke.
At the time of the study, according to the National Health and Nutrition Examination Survey, Americans consumed nearly 150 mmol / day of sodium, which the FDA considers harmful and may increase a person’s risk for high blood pressure, heart disease and stroke
Participants were arranged into four groups according to their baseline systolic blood pressure: 120–129, 130–139, 140–149 and 150 or higher baseline systolic blood pressure.
After four weeks, the researchers found that the group with 150 or more standard systolic blood pressure on the DASH diet alone had an average 11 mm Hg reduction in systolic blood pressure compared with a 4 mm Hg reduction in those only on the DASH diet, but whose baseline systolic pressure was not less than 130.
When the researchers combined the DASH diet with the short -term diet and compared the blood pressures of participants with those with a high -sodium control diet, they found that the group had less than 130 systolic pressure. in baseline blood there is a 5 mm Hg decrease in systolic blood pressure; the group with 130–139 mm Hg baseline systolic blood pressure had a 7 mm Hg decrease; and the group with baseline systolic blood pressure between 140–149 had a 10 mm Hg decrease.
Most surprisingly, the researchers said, a participant with a baseline systolic blood pressure of 150 or more and consuming the low-sodium / DASH combination diet had an average reduction of 21 mm Hg in systolic pressure. in the blood versus high sodium control diet
“It’s amazing, it’s huge,” Juraschek says, because it suggests that those at the highest risk for severe hypertension can get the most benefit from the combination diet.
To put the potential impact of the findings in context, Juraschek said, the FDA requires any new antihypertensive agent to be submitted for approval to lower systolic blood pressure by 3-4 mm Hg. Most established drugs on the market, such as ACE inhibitors, beta-blockers, or calcium channel blockers, on average reduce systolic blood pressure by 10-15 mm Hg.
“What we observed from the combined dietary intervention was a reduction in systolic blood pressure as high, if not higher than, that achieved with the prescribed medications,” said the elderly study author. Lawrence Appel, MD, MPH, professor of medicine at Johns Hopkins University School of Medicine. “It’s an important message to patients that they can get a lot of mileage from following a healthy and low -sodium diet.”
The researchers cautioned that the study did not address the effects on people with a systolic blood pressure of 160 or more or on people with pre-existing heart disease or untreated diabetes. Further studies with larger sample sizes are needed to investigate the effect of a low-sodium / DASH diet in these populations.
A Johns Hopkins researcher who also participated in this study was Edgar Miller III, MD
This work was supported by the National Heart, Lung and Blood Institute under grant numbers U01-HL57173, U01HL57114, U01HL57190, U01-HL57139, K08 HL03857-01, U01-HL57156 and K23HL1 ;135271; General Program of the Clinical Research Center of the National Center for Research Resources under grant numbers M01-RR02635 and M01-RR00722; and the National Institute of Diabetes and Digestive and Kidney Disease under the number given T32DK007732-20.