DASH diet - healthy eating that helps lower blood pressure

What is the DASH diet?

The DASH diet, which stands for Dietary Approaches to Stop Hypertension, is a flexible eating plan that helps lower blood pressure (hypertension) and reduce your chances of heart disease.

Developed over 20 years ago with support from the National Heart, Lung, and Blood Institute (NHLBI), this diet involves no special foods or strict plan - instead, it puts emphasis on weekly nutritional goals, portion sizes, and eating a colourful variety of healthy foods including lots of vegetables and fruits.

Foods to include on the DASH diet and serving sizes based on a 2000 calories-per-day diet¹.

On the DASH diet, limiting your consumption of dietary salt, added sugars, and unhealthy fats while focussing on healthy foods rich in lean protein, fibre, and minerals can help protect your heart and control your blood pressure.

This diet isn't just for people with high blood pressure or conditions that increase their chances of heart problems - anyone can benefit. At the same time, you can tailor a DASH diet to suit your goals. For example, if you have high blood pressure - a reading of 135/85 or higher - and consume too much salt, the low-sodium DASH diet limits salt intake to no more than 1500mg a day, which is three-quarters of a teaspoon. This is slightly lower than the one teaspoon of recommended salt intake per day - and it results in a substantially bigger drop in blood pressure¹.

There's nothing unusual about this eating plan. It's based on established healthy eating knowledge and portion guidelines, and for this reason is similar to many other health-promoting diets, like the Mediterranean diet. However, it's emphasis on limiting salt has earnt it a place among the top heart healthy diets³.

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Low blood pressure

Low blood pressure (also called hypotension) is quite common and isn't usually a problem. However, it can cause symptoms in some people or some situations. Postural or orthostatic hypotension is low blood pressure on standing up from lying or sitting and is more common in teenagers and older people. edit

by Dr Rachel Hudson, MRCGP

Benefits of the DASH diet

Lowers blood pressure

Your blood pressure is the force at which your blood travels around the body through your blood vessels. Having high blood pressure means that this force is placing a dangerous amount of strain on your heart to push out the blood - causing damage to your blood vessels, heart muscle, and other organs and increasing your chances of life-threatening heart problems.

By following the DASH diet, you can significantly lower your blood pressure within weeks - whether it's already dangerously high or at healthier levels⁴. Here's why:

• Limits salt intake - salt pulls water into your bloodstream, increasing the force placed on blood vessel walls, raising blood pressure.

• Limits added sugars - these can block the production of nitric oxide (NO) in blood vessels, a chemical that allows blood vessels to expand and reduce pressure.

• Focusses on fruits and vegetables - which contain potassium, which relieves tension in blood vessels and helps your body flush out more salt through your pee.

Lowers bad cholesterol

High levels of unhealthy cholesterol - known to scientists as low-density lipoprotein (LDL) cholesterol - also increases your chances of heart problems, like heart disease and stroke. This is because LDL cholesterol, a fatty substance, can build up on your blood vessel walls, slow down blood flow, and prevent oxygen from reaching essential organs.

The DASH diet can significantly reduce the build-up of LDL cholesterol, and if fighting high cholesterol levels is your aim, adopting a higher-good fat, lower-carb version of the eating plan can be even more effective⁵. Here's why:

• Limits saturated and trans fats - foods containing these types of fats raise LDL cholesterol in the blood.

• Increases fibre - which slows digestion, keeping blood sugars from spiking, and prevents fats from being absorbed in the bloodstream.

• Limits added sugars - which lowers high-density lipoprotein (HDL) cholesterol, the good cholesterol that helps flush other cholesterol out of the body.

• A higher-fat DASH diet - as well as lowering LDL cholesterol, this modification of DASH also reduces triglycerides, fats that combined with high LDL cholesterol to increase your chances of heart problems.

Other potential benefits

The DASH diet can benefit anyone, whether healthy or in poor heart health. But it may also help people with particular health conditions or goals. For example:

• Diabetes management - lowering blood pressure is an important goal for people with diabetes. What's more, it could also improve insulin resistance, cholesterol, and weight management - all of which help to either manage or reverse diabetes¹.

• Healthy weight loss - given that the DASH diet cuts down on high-fat and sugary foods, some people can reach a healthy weight on the DASH diet, so long as they’re creating calorie deficit.

• Lowering the risk of cancer - following this diet may lower the risk of some cancers, including colorectal cancer⁶ and breast cancer⁷.

• Lowering the risk of metabolic syndrome risk - the DASH diet may reduce your chances of developing metabolic syndrome by up to 81%⁸.

Further reading

1. Campbell: DASH eating plan: an eating pattern for diabetes management.

2. Jurascheck et al: DASH diet combined with low sodium intake leads to greater BP-lowering in patients with higher baseline level.

3. National Heart, Lung and Blood Institute: NIH-supported DASH diet tops rankings for heart-healthy and healthy eating.

4. Filippou et al: Dietary approaches to stop hypertension (DASH) diet and blood pressure reduction in adults with and without hypertension.

5. Children's Hospital & Research Center Oakland: Higher fat variation of DASH diet lowers blood pressure, triglycerides, study shows.

6. Mohseni et al: The association of dietary approaches to stop hypertension (DASH) diet with the risk of colorectal cancer: a meta-analysis of observational studies.

7. Shu et al: Adherence to the dietary approaches to stop hypertension diet reduces the risk of breast cancer: a systematic review and meta-analysis.

8. Saneei et al: Adherence to the DASH diet and prevalence of the metabolic syndrome among Iranian women.