The DASH diet (which stands for Dietary Approaches to Stop Hypertension) is a diet that is low in sodium and emphasizes whole grains, fruits, legumes (beans), vegetables, and low-fat dairy products as the bulk of calories consumed. Some fish, poultry, and red meat are allowed. Sweets and fats are also allowed but only in small amounts.

Following the DASH diet typically results in 11/7 mm Hg (systolic/diastolic) drop in blood pressure, but when combined with a weight-loss program, those numbers are typically even better, with a 16/10 (systolic/diastolic) mm Hg reduction.¹

Why does it work?

Scientists have long wondered if there was something in vegetables that might account for the blood pressure lowering effects of the DASH diet. The DASH diet is naturally low in sodium and removing salt can certainly help reduce blood pressure, but so can eating foods high in potassium, calcium, and magnesium.²

Recently, scientists have turned their attention to nitrates and discovered that nitrates may be the main reason the DASH diet works. Nitrates have for a long time been erroneously associated with cancer. A poorly designed study that suggested nitrates were harmful was the root of this belief. The study was debunked rather quickly,³ but the public perception has lingered.

Nitrates can be converted in the body to nitrite, then into a molecule called nitric oxide; and it is nitric oxide that is the endogenous signaling molecule known to relax blood vessels (which can lead to a reduced blood pressure).

Typical intake of nitrate in the United States is around 10-100 milligrams a day, with 85 percent of that intake coming from vegetables.⁴ That intake is greatly increased to 1,222 milligrams when people participate in the DASH diet.⁵ Increasing dietary nitrates has been independently shown to reduce blood pressure.⁶ Nitrates are also thought to increase exercise performance⁷ and improve blood flow to the brain.⁸

While scientists are still trying to discover just how much of the DASH diet’s effects are due to nitrates, early studies have suggested that increasing nitric oxide concentration at the artery wall seems to be the key. The benefits of a high-vegetable diet for heart and overall health cannot be understated.

It may take a while to adapt to a lower salt, high-vegetable diet for your own life, but your health is worth it.

1. Blumenthal JA, Babyak MA, Hinderliter A, et al. 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. Arch Intern Med. 2010 Jan 25;170(2):126-35. PMID: 20101007.
2. Aaron KJ, Sanders PW. Role of dietary salt and potassium intake in cardiovascular health and disease: a review of the evidence. Mayo Clin Proc. 2013 Sep;88(9):987-95. PMID: 24001491.
3. van Loon AJ, Botterweck AA, Goldbohm RA, et al. Intake of nitrate and nitrite and the risk of gastric cancer: a prospective cohort study. Br J Cancer. 1998 Jul;78(1):129-35. PMID: 9662263.
4. Gangolli SD, van den Brandt PA, Feron VJ, Janzowsky C, et al. Nitrate, nitrite and N-nitroso compounds. Eur J Pharmacol. 1994 Nov 1;292(1):1-38. PMID: 7867685.
5. Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009 Jul;90(1):1-10. doi: 10.3945/ajcn.2008.27131. Epub 2009 May 13.PMID: 19439460.
6. Kapil V, Milsom AB, Okorie M, et al. Inorganic nitrate supplementation lowers blood pressure in humans: role for nitrite-derived NO. Hypertension. 2010 Aug;56(2):274-81. PMID: 20585108.
7. Lansley KE, Winyard PG, Bailey SJ, et al. Acute dietary nitrate supplementation improves cycling time trial performance. Med Sci Sports Exerc. 2011 Jun;43(6):1125-31. PMID: 21471821.
8. Presley TD, Morgan AR, Bechtold E, et al. Acute effect of a high nitrate diet on brain perfusion in older adults. Nitric Oxide. 2011 Jan 1;24(1):34-42. PMID: 20951824.