Short answer: Possibly, mainly through blood pressure, but the evidence is preliminary. DASH lowers blood pressure, and midlife hypertension is linked to dementia. One cohort linked higher DASH adherence to slower cognitive decline, and a small four-month trial found modest gains in some tests. No large trial has tested DASH on cognition. If your blood pressure is high, start here.

The DASH diet may help protect the brain, but the direct evidence is preliminary. Its strength is lowering blood pressure, which is one of the main risk factors for cognitive decline that you can change; only a few studies have looked at cognition itself.

DASH stands for Dietary Approaches to Stop Hypertension. The US National Heart, Lung, and Blood Institute developed it in the early 1990s. The original trial (Appel 1997) tested a diet rich in fruit, vegetables, whole grains and low-fat dairy, with less saturated fat and sodium. It lowered systolic blood pressure by an average of 5.5 mmHg in eight weeks. That is comparable to some blood pressure drugs.

What to eat on the DASH diet

Targets for a 2,000-calorie diet:

Food groupDASH target
Fruits4–5 servings per day
Vegetables4–5 servings per day
Whole grains6–8 servings per day
Low-fat dairy2–3 servings per day
Lean meats, poultry and fish6 or fewer servings per day
Nuts, seeds and legumes4–5 servings per week
Fats and oils2–3 servings per day, mostly unsaturated
Sweets and added sugars5 or fewer per week
Sodiumno more than 2,300 mg per day (1,500 mg in the stricter DASH-Sodium version)

The diet is high in potassium, calcium, magnesium and fiber, and low in sodium, saturated fat and added sugar.

Tips that make it work:

  • Potassium-rich foods: Bananas, oranges, cantaloupe, potatoes, spinach, tomatoes and legumes are the core of DASH’s blood pressure effect.
  • Sodium: Below 2,300 mg a day is a reasonable first target for most adults. People with hypertension or salt sensitivity may benefit from the 1,500 mg limit. Most sodium comes from processed food, restaurant meals, bread and deli meats, so cutting those does more than hiding the salt shaker.
  • Exercise: In the ENCORE trial below, DASH plus exercise and calorie restriction improved cognition more than DASH alone. Aim for at least 150 minutes a week of moderate aerobic activity.
  • A DASH-Mediterranean mix: Swap some low-fat dairy for extra-virgin olive oil, eat fatty fish twice a week or more, and add nuts daily. This keeps DASH’s blood pressure benefits and adds the Mediterranean diet’s broader profile.
  • Track your blood pressure: Home monitoring shows whether the diet is working. A steady 5–10 mmHg drop in systolic pressure, kept up over years, is linked to lower stroke risk and possibly lower dementia risk.

Who should check with a doctor first. People with chronic kidney disease should talk to their doctor, because the diet’s high potassium may be a problem when the kidneys don’t work well. So should people taking potassium-sparing diuretics, ACE inhibitors or angiotensin receptor blockers, because these drugs can raise blood potassium. If you already take blood pressure medication, DASH can add to its effect, but don’t change or stop your medication on your own.

Why blood pressure matters for the brain

The brain receives about 15 percent of the heart’s output and uses about 20 percent of the body’s oxygen. A dense network of small blood vessels delivers that oxygen and glucose. Long-term high blood pressure thickens and stiffens these vessels. Over time this leaves white matter lesions, small silent strokes and tiny bleeds. In a meta-analysis (Debette 2010), white matter lesions on MRI were linked to twice the risk of dementia and three times the risk of stroke.

Midlife blood pressure matters most.

  • Honolulu-Asia Aging Study (Launer 2000): 3,703 Japanese-American men had blood pressure measured in 1965–1971 and were checked for dementia in 1991. Among men never treated for hypertension, a midlife systolic pressure of 160 mmHg or higher was linked to about five times the odds of dementia, both Alzheimer’s and vascular. Blood pressure was not linked to dementia in men who had been treated.
  • Whitehall II (Abell 2018): In 8,639 British adults, a systolic pressure of 130 mmHg or higher at age 50 was linked to a 38 percent higher risk of later dementia. The same reading at 60 or 70 was not.

So vascular damage builds over decades, and much of it can’t be reversed once symptoms appear.

Alzheimer’s changes too. Rodrigue 2013 scanned the brains of 118 cognitively normal adults. People with both hypertension and the APOE ε4 gene variant had more amyloid in the brain than those with one or neither. In animal studies, chronic hypertension impairs the brain’s waste-clearing system.

Does lowering blood pressure protect cognition? The SPRINT MIND trial (Williamson 2019) assigned 9,361 adults with hypertension to intensive treatment (systolic target below 120 mmHg) or standard treatment (below 140 mmHg) with drugs. Intensive treatment did not clearly reduce probable dementia, the main cognitive outcome (hazard ratio 0.83, possibly because the trial stopped early). It did reduce mild cognitive impairment, a secondary outcome, by 19 percent. This supports the idea that lowering blood pressure can protect cognition, but whether lowering it with DASH does the same hasn’t been tested.

The Lancet Commission (Livingston 2020) estimated that eliminating midlife hypertension could prevent about 2 percent of dementia cases worldwide. Because dementia is so common, that is hundreds of thousands of cases.

What studies show about DASH and cognition

Rush Memory and Aging Project (Tangney 2014). This study followed 826 older adults in Chicago (average age about 81) for an average of 4.1 years. Higher adherence to both DASH and the Mediterranean diet was linked to slower cognitive decline. This is observational and can’t show cause.

The MIND diet study (Morris 2015). In the same research program, high DASH adherence was linked to a 39 percent lower risk of Alzheimer’s than low adherence. That was weaker than the 53–54 percent lower risk seen with high MIND and Mediterranean adherence. Moderate DASH adherence showed no clear link, while moderate MIND adherence did. These are observational results from one cohort.

ENCORE trial (Smith 2010). This is one of the few controlled trials. It assigned 124 sedentary, overweight adults with high blood pressure to DASH alone, DASH plus a weight-management program (aerobic exercise and calorie restriction), or their usual diet. After four months, the DASH-alone group did better than controls on psychomotor speed. The DASH-plus-weight-management group improved most, on psychomotor speed and on a combined measure of executive function, memory and learning. The gains seemed to come from better fitness and weight loss more than from the diet alone. With 124 people over four months, this is a proof of concept, not a definitive trial.

Review (van den Brink 2019). This review found that the Mediterranean, DASH and MIND diets were all linked to less cognitive decline and lower Alzheimer’s risk, with the strongest links for MIND. For DASH the evidence was thin: higher adherence was linked to better cognition in 1 cross-sectional study, 2 of 5 longitudinal studies, and 1 trial.

Magnesium. DASH is rich in magnesium from whole grains, nuts, legumes and leafy greens. In the Rotterdam Study of 9,569 adults (Kieboom 2017), both low and high blood magnesium levels were linked to about 30 percent higher dementia risk.

DASH vs Mediterranean vs MIND

All three emphasize fruit, vegetables, whole grains and lean protein, and limit processed food and saturated fat. The differences:

  • Fat: The Mediterranean diet is higher in fat (35–40 percent of calories), mainly from olive oil and nuts. DASH is lower (about 27 percent) and leans on low-fat dairy. The polyphenols in extra-virgin olive oil aren’t found in skim milk or canola oil.
  • Sodium: DASH centers on cutting sodium; the Mediterranean diet doesn’t target it but reaches comparable or better cardiovascular outcomes another way.
  • Dairy: DASH includes 2–3 daily servings of low-fat dairy. The Mediterranean diet uses yogurt and cheese sparingly, and MIND limits cheese to less than one serving a week. The effect of dairy on cognition is unclear.
  • Brain focus: Neither DASH nor Mediterranean was designed for the brain. The MIND diet was, built from the parts of both with the strongest links to brain health. If you follow MIND, you already follow a version of DASH.

For brain health, the evidence favors the Mediterranean and MIND diets over DASH alone. DASH’s clear advantage is lowering blood pressure. If your blood pressure is already well controlled, a Mediterranean or MIND pattern has more direct cognitive evidence.

Who benefits most

  • People with high or borderline blood pressure. DASH has consistent blood pressure effects across trials. Lowering systolic pressure by 5–10 mmHg over decades may reduce damage to the brain’s blood vessels.
  • Adults in their 40s and 50s. Because midlife hypertension is linked to later dementia, starting early has the most potential.
  • People with salt sensitivity. Their blood pressure rises more with sodium. This trait is more common in older adults, Black Americans and people with kidney disease, and they may gain the most from DASH’s sodium limits.

Frequently asked questions

Does the low-sodium part of DASH matter for the brain directly?

Mostly through blood pressure. High sodium raises blood pressure, which damages the brain’s blood vessels. There is limited, preliminary evidence that high sodium may also impair blood vessel function and reduce blood flow to the brain independently of blood pressure.

Is DASH as good as the Mediterranean diet for the brain?

Probably not, on current evidence. The Mediterranean diet has trial sub-studies on cognition from PREDIMED, while DASH has mostly observational data and one small trial. But if high blood pressure is your main risk, DASH targets it directly, and many people do well with a mix of both.

Sources

  • Appel, L. J., Moore, T. J., Obarzanek, E., Vollmer, W. M., Svetkey, L. P., Sacks, F. M., … & Karanja, N. (1997). A clinical trial of the effects of dietary patterns on blood pressure. New England Journal of Medicine, 336(16), 1117–1124. doi:10.1056/NEJM199704173361601

  • Tangney, C. C., Li, H., Wang, Y., Barnes, L., Schneider, J. A., Bennett, D. A., & Morris, M. C. (2014). Relation of DASH- and Mediterranean-like dietary patterns to cognitive decline in older persons. Neurology, 83(16), 1410–1416. doi:10.1212/WNL.0000000000000884

  • Morris, M. C., Tangney, C. C., Wang, Y., Sacks, F. M., Bennett, D. A., & Aggarwal, N. T. (2015). MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s & Dementia, 11(9), 1007–1014. doi:10.1016/j.jalz.2014.11.009

  • Smith, P. J., Blumenthal, J. A., Babyak, M. A., Craighead, L., Welsh-Bohmer, K. A., Browndyke, J. N., Strauman, T. A., & Sherwood, A. (2010). Effects of the Dietary Approaches to Stop Hypertension diet, exercise, and caloric restriction on neurocognition in overweight adults with high blood pressure. Hypertension, 55(6), 1331–1338. doi:10.1161/HYPERTENSIONAHA.109.146795

  • SPRINT MIND Investigators for the SPRINT Research Group; Williamson, J. D., Pajewski, N. M., Auchus, A. P., Bryan, R. N., Chelune, G., Cheung, A. K., … & Wright, C. B. (2019). Effect of intensive vs standard blood pressure control on probable dementia: a randomized clinical trial. JAMA, 321(6), 553–561. doi:10.1001/jama.2018.21442

  • Launer, L. J., Ross, G. W., Petrovitch, H., Masaki, K., Foley, D., White, L. R., & Havlik, R. J. (2000). Midlife blood pressure and dementia: the Honolulu-Asia Aging Study. Neurobiology of Aging, 21(1), 49–55. doi:10.1016/s0197-4580(00)00096-8

  • Abell, J. G., Kivimaki, M., Dugravot, A., Tabak, A. G., Fayosse, A., Shipley, M., Sabia, S., & Singh-Manoux, A. (2018). Association between systolic blood pressure and dementia in the Whitehall II cohort study: role of age, duration, and threshold used to define hypertension. European Heart Journal, 39(33), 3119–3125. doi:10.1093/eurheartj/ehy288

  • Debette, S., & Markus, H. S. (2010). The clinical importance of white matter hyperintensities on brain magnetic resonance imaging: systematic review and meta-analysis. BMJ, 341, c3666. doi:10.1136/bmj.c3666

  • Rodrigue, K. M., Rieck, J. R., Kennedy, K. M., Devous, M. D., Diaz-Arrastia, R., & Park, D. C. (2013). Risk factors for beta-amyloid deposition in healthy aging: vascular and genetic effects. JAMA Neurology, 70(5), 600–606. doi:10.1001/jamaneurol.2013.1342

  • Kieboom, B. C. T., Licher, S., Wolters, F. J., Ikram, M. K., Hoorn, E. J., Zietse, R., Stricker, B. H., & Ikram, M. A. (2017). Serum magnesium is associated with the risk of dementia. Neurology, 89(16), 1716–1722. doi:10.1212/WNL.0000000000004517

  • van den Brink, A. C., Brouwer-Brolsma, E. M., Berendsen, A. A. M., & van de Rest, O. (2019). The Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets are associated with less cognitive decline and a lower risk of Alzheimer’s disease — a review. Advances in Nutrition, 10(6), 1040–1065. doi:10.1093/advances/nmz054

  • Livingston, G., Huntley, J., Sommerlad, A., Ames, D., Ballard, C., Banerjee, S., … & Mukadam, N. (2020). Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet, 396(10248), 413–446. doi:10.1016/S0140-6736(20)30367-6