How much does DASH actually lower blood pressure?

5.5 mmHg systolic and 3.0 diastolic against a typical American control diet in a trial where all food was provided, sodium was fixed and body weight was held constant. In the participants who had hypertension it was 11.4 and 5.5 mmHg. Combined with sodium reduction it reached 11.5 mmHg systolic in people with hypertension. Those are among the most reliable numbers on this site because the design removed almost everything else.

Does it prevent heart attacks and strokes?

Nobody knows, and this is the honest gap. A 2025 Cochrane review of the entire randomised literature found five trials and 1,397 participants, with follow-up no longer than 18 months, and where events were assessed there were none in either group. Long-running cohorts associate a high DASH score with 24 percent lower coronary heart disease and 18 percent lower stroke, but those are observational and a questionnaire score is not the diet that was fed.

Will I lose weight on it?

Not from the pattern itself. The trials that produced the blood pressure result held body weight constant on purpose, because that was the point. When a weight management programme was added on top in a free-living trial, blood pressure fell further and vascular measures improved more, so the weight loss was doing its own work rather than the diet producing it.

Is there anything in it that moves the wrong way?

HDL cholesterol fell 3.7 mg/dL against control at constant weight, most in the people who started highest, and the trial's own authors wrote that the possible opposing effect on coronary risk needed further study. It has not had much study since. There was also no significant triglyceride effect at constant weight.

Do I need to cut sodium as well?

They were tested separately and both worked. In the trial that crossed them, the diet lowered pressure at every sodium level and sodium reduction lowered pressure on both diets, with the largest effect from combining them. The two overlap rather than adding cleanly: the diet's own advantage was bigger at high sodium than at low, and in the 2025 diabetes feeding trial the authors reported that the sodium effect appeared stronger than the diet effect.

Whole-food12 human studies cited

DASH

Written by Aaron CuhaReviewed Sep 2026

Also called: Dietary Approaches to Stop Hypertension, DASH eating plan

The blood pressure effect is real, was measured with all food provided and body weight held constant, and is the cleanest result in this section. The outcome data is close to absent: a 2025 Cochrane review found five trials, no strokes and no heart attacks.

What it actually is

A pattern defined by food groups rather than by a macronutrient target: high in fruit, vegetables, low fat dairy, whole grains, nuts and legumes, reduced in saturated fat, total fat, cholesterol, red meat, sweets and sugar-sweetened drinks. It came out of a feeding trial rather than a book, and the design of that trial is the reason it is quoted with confidence. Participants were fed, sodium intake was fixed, and body weight was held constant, so the result is attributable to the composition of the food and to nothing else.

The mechanism its advocates propose

Not one lever but a combination, which its designers stated openly. Potassium, calcium, magnesium and fibre from fruit, vegetables and low fat dairy were each individually associated with lower blood pressure in earlier work, and the hypothesis was that assembling them into a whole pattern would produce a larger effect than any single nutrient supplement had. Reduced saturated fat and cholesterol were added to act on the lipid profile. Because it was built as a pattern, no trial has isolated which component carries the blood pressure effect, and the trial that removed the dairy and the fat reduction and kept only fruit and vegetables got about half the result.

What happened when calories were controlled

Strongest design available: controlled

Energy intake was matched between groups, so a difference in the result is attributable to the composition of the diet rather than to how much was eaten.

This is the rare pattern whose core evidence is controlled feeding. Food was provided, sodium was fixed, and body weight was deliberately held constant in the original trial and in every major follow-on, so the blood pressure and lipid results are not weight loss results. The size of the effect is 5.5 mmHg systolic against a typical American control diet, and 11.4 mmHg in the participants who had hypertension.

Appel 1997, 459 adults, three weeks on a run-in control diet then eight weeks randomised to that control, to a fruit and vegetable diet, or to the combination diet now called DASH. Sodium intake and body weight were maintained at constant levels. The combination diet lowered systolic pressure 5.5 mmHg and diastolic 3.0 mmHg more than control, p < 0.001 for each. The fruit and vegetable arm got 2.8 mmHg systolic (p < 0.001) and 1.1 mmHg diastolic (p = 0.07), so roughly half the effect came from fruit and vegetables alone.
The same trial split by baseline status, and this is the number that matters most. Among the 133 participants with hypertension the combination diet lowered pressure 11.4 and 5.5 mmHg more than control. Among the 326 without it, 3.5 and 2.1 mmHg. The pattern does more for people who need more.
Sacks 2001, the DASH-Sodium trial, 412 participants randomised to DASH or a control diet, each eating high, intermediate and low sodium for 30 days in random order. DASH at low sodium against control at high sodium produced a mean systolic pressure 7.1 mmHg lower in participants without hypertension and 11.5 mmHg lower in those with it. Sodium and diet stacked, and the diet's own advantage was larger at high sodium than at low, which means the two interventions partly overlap rather than adding cleanly.
Juraschek 2017 re-analysed DASH-Sodium by baseline pressure. Low sodium DASH against high sodium control produced systolic differences of 5.3, 7.5, 9.7 and 20.8 mmHg across baseline strata of under 130, 130 to 139, 140 to 149 and 150 mmHg or above. The sodium effect showed a significant trend across strata (p = 0.004) and the diet effect did not (p = 0.66). The 20.8 mmHg figure rests on the smallest stratum and the authors call for study above 160 mmHg, which nobody has done.
Obarzanek 2001 measured lipids in 436 of those participants while weight stayed constant. Against control, DASH lowered total cholesterol 13.7 mg/dL, LDL 10.7 mg/dL and HDL 3.7 mg/dL, all p < 0.0001, with no significant effect on triglycerides. The HDL fall is in the paper and is rarely repeated: the authors wrote that the possible opposing effect on coronary heart disease risk of HDL reduction needs further study. Men got a larger LDL reduction than women by 11.2 mg/dL (p < 0.02).
DASH4D, 2025, is the newest controlled feeding trial and it narrows the claim. 102 adults with type 2 diabetes and systolic pressure 120 to 159 mmHg, four five-week diet periods in crossover, all food provided, no outside food, weight held constant. A DASH-style diet modified for diabetes with lower sodium beat a typical US diet with higher sodium by 4.6 mmHg systolic (95% CI 7.2 to 2.0, p < 0.001) and 2.3 mmHg diastolic. Most of the reduction happened in the first three weeks, and the authors report that the sodium effect appeared stronger than the diet effect. 66 percent of participants were already on two or more antihypertensive drugs.

What happened when people just ate it

Free-living results are good and they are not the feeding trial results, and one trial in particular is worth knowing before adopting the pattern. PREMIER randomised 810 adults with above-optimal blood pressure to advice only, to an established behavioural programme covering weight loss, sodium reduction, physical activity and alcohol, or to that same programme plus DASH counselling. At six months the net systolic reduction was 3.7 mmHg for the established programme and 4.3 mmHg for established plus DASH. The difference between those two arms was 0.6 mmHg, p = 0.43. Adding DASH counselling on top of an already intensive lifestyle programme added essentially nothing to blood pressure, although the proportion still hypertensive was numerically lowest in the DASH arm at 12 percent against 17 and 26 percent, and that comparison against the established arm was also not significant at p = 0.12. ENCORE points the other way and tested a different question: 144 overweight or obese adults with high blood pressure, four months, free living. Clinic pressure fell 16.1 over 9.9 mmHg on DASH plus a weight management programme, 11.2 over 7.5 on DASH alone, and 3.4 over 3.8 on usual diet, p < 0.001. Pulse wave velocity, baroreflex sensitivity and left ventricular mass all improved more when weight loss was added. Azadbakht 2005 prescribed a calorie-reduced DASH diet to people with metabolic syndrome for six months and reported very large changes, including net reductions in systolic pressure of 11 mmHg and net weight losses reported as 15 to 16 kg against control. Weight losses of that size in a six-month free-living trial are far outside what other trials in this section produced, so the blood pressure and lipid results from it should be read as a package with an unusually large weight change rather than as a diet effect at constant weight.

Protein, and whether it confounds the result

DASH sets no protein target and none of its trials matched or reported protein between arms as an intervention variable. What the pattern does do is shift protein sources: low fat dairy, legumes, nuts, fish and poultry up, red and processed meat down. No DASH trial has measured lean mass, and the feeding trials were explicitly designed to keep body weight constant, so there is no body composition data here at all. Anyone combining this pattern with a weight loss drug or a resistance training programme gets no protein guidance from it and will have to add that separately.

The measured intakes behind the protein figures are on the protein page.

What reliably moves

Marker	Direction	From
Systolic blood pressure	Down, and this is the finding the pattern exists for	5.5 mmHg against a control diet at constant weight and fixed sodium, 11.4 mmHg in the participants who had hypertension. Combined with sodium reduction, 7.1 mmHg in people without hypertension and 11.5 mmHg in people with it. In adults with type 2 diabetes already on medication, 4.6 mmHg.
LDL cholesterol	Down	10.7 mg/dL against control with body weight held constant, p < 0.0001. Larger in men than women by 11.2 mg/dL.
HDL cholesterol	Down, and this is the finding advocates omit	3.7 mg/dL lower against control, p < 0.0001, and it fell most in the participants who started highest. The trial's own authors flagged it as a possible opposing effect on coronary risk that needed further study, and it has not had much.
Triglycerides	No significant effect	In the controlled feeding trial, with weight constant, there was no significant effect on triacylglycerol. Free-living trials that also produced weight loss report reductions, which is a different result from a different design.
Serum uric acid	Down	0.35 mg/dL against control (95% CI 0.65 to 0.05, p = 0.02) at constant weight, and 1.29 mg/dL in the eight participants whose baseline urate was 7 mg/dL or above. The same trial found that raising sodium intake lowered urate, which is the opposite of the direction most people assume.
High-sensitivity troponin I and C-reactive protein	Down	DASH against control lowered troponin I 18 percent and CRP 13 percent, with no change in NT-proBNP. Sodium reduction did the reverse: NT-proBNP down 19 percent, troponin unchanged, CRP mildly up 9 percent. Subclinical markers, not events.
Myocardial infarction, stroke, death	Unmeasured	A 2025 Cochrane review of the whole randomised literature found five trials and 1,397 participants. Where events were reported at all there were none in either arm, follow-up ran 16 weeks to 18 months, and every trial was primary prevention. This is the gap in the pattern.

Long term, and hard outcomes

The blood pressure evidence is strong and short, and the outcome evidence barely exists. A 2025 Cochrane review searched to May 2024 and found five randomised trials totalling 1,397 participants, intervention durations of 16 weeks to 12 months and follow-up of 16 weeks to 18 months. One trial of 144 people reported no myocardial infarctions and no strokes in either group over a year. Another reported no deaths in 90 people over six months. The comparison against minimal intervention produced a risk ratio for myocardial infarction of 2.99 with a confidence interval running from 0.12 to 73.04, which is a way of saying nothing was measured. No trial has assessed heart failure or revascularisation, none assessed secondary prevention, and the review's verdict is that the effect on major cardiovascular outcomes remains inconclusive due to a lack of robust long-term evidence, at low to very low certainty. The long-term signal is observational. Fung 2008 followed 88,517 female nurses for 24 years with diet assessed seven times, and found relative risks of coronary heart disease across quintiles of a DASH score of 1.0, 0.99, 0.86, 0.87 and 0.76 (95% CI 0.67 to 0.85, p < 0.001 for trend), with stroke at 0.82 across the same quintiles (p = 0.002 for trend). That is a cohort, people who score high on a DASH index differ from people who score low in many ways, and a diet score computed from a questionnaire is not the diet that was fed in the ward. Both halves belong in an honest account: the mechanism evidence is about as good as nutrition gets and the outcome evidence is not there yet.

Citations

Human1997
A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group.
New England Journal of Medicine
459 adults, eight weeks, food provided, sodium and body weight held constant. Combination diet lowered blood pressure 5.5 and 3.0 mmHg more than control (p < 0.001 each), 11.4 and 5.5 mmHg more in the 133 with hypertension, 3.5 and 2.1 mmHg in the 326 without. A fruit and vegetable arm without the dairy and fat changes got about half the effect.
Human2001
Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group.
New England Journal of Medicine
412 participants, three sodium levels for 30 days each within the assigned diet. DASH at low sodium against control at high sodium: systolic 7.1 mmHg lower without hypertension and 11.5 mmHg lower with it. The diet's advantage was larger at high sodium than at low.
Human2001
Effects on blood lipids of a blood pressure-lowering diet: the Dietary Approaches to Stop Hypertension (DASH) Trial.
American Journal of Clinical Nutrition
436 participants, weight stable. Against control: total cholesterol 13.7 mg/dL lower, LDL 10.7 lower, HDL 3.7 lower, all p < 0.0001, no significant triglyceride effect. The HDL reduction was largest in those with the highest baseline HDL and the authors flagged it as needing further study.
Human2017
Effects of Sodium Reduction and the DASH Diet in Relation to Baseline Blood Pressure.
Journal of the American College of Cardiology
Re-analysis of DASH-Sodium by baseline systolic pressure. Low sodium DASH against high sodium control gave differences of 5.3, 7.5, 9.7 and 20.8 mmHg across strata under 130 up to 150 or above. Sodium showed a significant trend across strata (p = 0.004), the diet did not (p = 0.66).
Human2021
Effects of Diet and Sodium Reduction on Cardiac Injury, Strain, and Inflammation: The DASH-Sodium Trial.
Journal of the American College of Cardiology
DASH against control lowered high-sensitivity troponin I 18 percent and CRP 13 percent but not NT-proBNP. Sodium reduction lowered NT-proBNP 19 percent independently of diet, left troponin unchanged and mildly raised CRP 9 percent. Subclinical biomarkers, not events.
Human2016
Effects of the Dietary Approaches to Stop Hypertension (DASH) Diet and Sodium Intake on Serum Uric Acid.
Arthritis and Rheumatology
103 adults, feeding trial, body weight constant. DASH lowered serum urate 0.35 mg/dL (95% CI 0.65 to 0.05, p = 0.02) and 1.29 mg/dL in the eight participants with baseline urate of 7 mg/dL or more. Higher sodium intake lowered urate, the opposite of the common assumption.
Human2025
Dietary Patterns, Sodium Reduction, and Blood Pressure in Type 2 Diabetes: The DASH4D Randomized Clinical Trial.
JAMA Internal Medicine
102 adults with type 2 diabetes, four five-week feeding periods in crossover, all food provided, weight constant. DASH4D with lower sodium beat a typical US diet with higher sodium by 4.6 mmHg systolic (p < 0.001) and 2.3 mmHg diastolic. Most of the effect landed in the first three weeks and the sodium effect appeared stronger than the diet effect.
Human2003
Effects of comprehensive lifestyle modification on blood pressure control: main results of the PREMIER clinical trial.
JAMA
810 adults, six months, free living. Net systolic reduction 3.7 mmHg for an established lifestyle programme and 4.3 mmHg for that programme plus DASH counselling. The difference between them was 0.6 mmHg, p = 0.43. Adding DASH on top of intensive lifestyle advice added essentially nothing to blood pressure.
Human2006
Effects of comprehensive lifestyle modification on diet, weight, physical fitness, and blood pressure control: 18-month results of a randomized trial.
Annals of Internal Medicine
The 18-month continuation of PREMIER. Cited here for the longer follow-up of the same randomised comparison; the six-month result above is the one with the head to head numbers.
Human2010
Effects of the DASH diet alone and in combination with exercise and weight loss on blood pressure and cardiovascular biomarkers in men and women with high blood pressure: the ENCORE study.
Archives of Internal Medicine
144 overweight or obese adults, four months, free living. Clinic blood pressure fell 16.1/9.9 mmHg on DASH plus weight management, 11.2/7.5 on DASH alone and 3.4/3.8 on usual diet, p < 0.001. Pulse wave velocity, baroreflex sensitivity and left ventricular mass improved more only when weight loss was added.
Human2005
Beneficial effects of a Dietary Approaches to Stop Hypertension eating plan on features of the metabolic syndrome.
Diabetes Care
116 adults with metabolic syndrome, six months, three prescribed diets. Net reductions against control on DASH of 11 mmHg systolic, 17 to 18 mg/dL triglycerides and 15 to 16 kg of weight. Weight losses that large in a six-month free-living trial are far outside the rest of this evidence base, so the other results travel with an unusually large weight change.
Human2008
Adherence to a DASH-style diet and risk of coronary heart disease and stroke in women.
Archives of Internal Medicine
88,517 female nurses, 24 years, diet assessed seven times. Coronary heart disease relative risks across DASH score quintiles 1.0, 0.99, 0.86, 0.87, 0.76 (95% CI 0.67 to 0.85, p < 0.001 for trend); stroke 0.82 at the top quintile (p = 0.002 for trend). Observational, and a questionnaire score is not the fed diet.
Review2025
Dietary Approaches to Stop Hypertension (DASH) for the primary and secondary prevention of cardiovascular diseases.
Cochrane Database of Systematic Reviews
Five randomised trials, 1,397 participants, follow-up 16 weeks to 18 months, all primary prevention. No myocardial infarctions and no strokes reported in either group where those outcomes were assessed. No data on heart failure or revascularisation. Certainty low to very low and the effect on major cardiovascular outcomes is inconclusive.

What people report

These are uncontrolled self-reports, not evidence. They are here because they tell you what to expect and what to watch for, which the trial literature does not. They cannot tell you whether anything works.

Blood pressure readings falling within the first two to three weeks, reported very commonly, and matching the feeding trial data closely enough that it is the one community claim the trials directly support.
No noticeable change at all, reported by people who were already eating close to the pattern. This is consistent with the trial design, where the comparator was a typical American diet and the gap being closed was large.
Disappointment at the absence of weight loss, which is exactly what the original trials predict, because they were built to prevent it.
Difficulty hitting the dairy servings, especially for people who are lactose intolerant or who avoid dairy for other reasons.
Hunger and food volume described as high rather than low, since the pattern adds food groups more than it removes them.
Cost and preparation time for the produce and dairy volume, the most common practical complaint.
Confusion about whether sodium reduction is part of it. In the original trial sodium was held constant and the diet still worked; in the follow-up trial the two were tested separately and both worked.

Sources: General hypertension and cardiology patient communities, dietitian write-ups, and the adherence data inside the trials, which is unusually strong because participants were fed. Uncontrolled self-report otherwise, useful for what to expect and for nothing else.

Who this is wrong for

Anyone with advanced chronic kidney disease or a tendency to hyperkalaemia, and anyone on a potassium-sparing diuretic, an ACE inhibitor or an angiotensin receptor blocker who is not having potassium monitored. The pattern is deliberately high in potassium, and the 2025 diabetes version was explicitly reformulated with lower potassium than the original for that population.
Anyone on antihypertensive medication who is not in contact with a prescriber. The effect is fast, most of it landing within three weeks in the feeding trials, and it stacks on top of drug treatment rather than replacing it.
Anyone who cannot or will not eat dairy and has no plan to replace calcium. Low fat dairy is a defining component, and the arm of the original trial that took fruit and vegetables without it got about half the blood pressure effect.
Anyone adopting it for weight loss. The feeding trials held body weight constant by design. The free-living trials that produced weight loss did so by adding a weight management programme, and that addition is what produced the extra blood pressure reduction in ENCORE.
Anyone who wants a triglyceride result. At constant weight there was no significant effect, and HDL fell by 3.7 mg/dL.
Anyone reading the blood pressure result as an outcome result. No trial of this pattern has recorded a heart attack, a stroke or a death in either arm.

Questions

How much does DASH actually lower blood pressure?: 5.5 mmHg systolic and 3.0 diastolic against a typical American control diet in a trial where all food was provided, sodium was fixed and body weight was held constant. In the participants who had hypertension it was 11.4 and 5.5 mmHg. Combined with sodium reduction it reached 11.5 mmHg systolic in people with hypertension. Those are among the most reliable numbers on this site because the design removed almost everything else.
Does it prevent heart attacks and strokes?: Nobody knows, and this is the honest gap. A 2025 Cochrane review of the entire randomised literature found five trials and 1,397 participants, with follow-up no longer than 18 months, and where events were assessed there were none in either group. Long-running cohorts associate a high DASH score with 24 percent lower coronary heart disease and 18 percent lower stroke, but those are observational and a questionnaire score is not the diet that was fed.
Will I lose weight on it?: Not from the pattern itself. The trials that produced the blood pressure result held body weight constant on purpose, because that was the point. When a weight management programme was added on top in a free-living trial, blood pressure fell further and vascular measures improved more, so the weight loss was doing its own work rather than the diet producing it.
Is there anything in it that moves the wrong way?: HDL cholesterol fell 3.7 mg/dL against control at constant weight, most in the people who started highest, and the trial's own authors wrote that the possible opposing effect on coronary risk needed further study. It has not had much study since. There was also no significant triglyceride effect at constant weight.
Do I need to cut sodium as well?: They were tested separately and both worked. In the trial that crossed them, the diet lowered pressure at every sodium level and sodium reduction lowered pressure on both diets, with the largest effect from combining them. The two overlap rather than adding cleanly: the diet's own advantage was bigger at high sodium than at low, and in the 2025 diabetes feeding trial the authors reported that the sodium effect appeared stronger than the diet effect.