Controlling blood pressure with the DASH diet

The most compelling evidence in support of diet as a means of controlling blood pressure comes from two trials sponsored by the National Institutes of Health. Together the studies are known as the DASH diet. Here's what you need to know about the DASH diet before deciding if it's right for you.

The first study, carried out in 1997, was called "DASH," for Dietary Approaches to Stop Hypertension.

• It found that blood pressure levels could fall significantly with an eating plan low in total fat, saturated fat and cholesterol, and rich in fruits, vegetables and low-fat dairy products.
• The diet was shown to prevent hypertension and in some cases reduce blood pressure as much as an antihypertensive drug.
• Results were seen within two weeks, and benefits remained eight weeks later regardless of a person's gender, ethnicity or starting blood pressure.

The DASH diet provides foods that are high in fibre, calcium, magnesium and potassium, all of which have been associated with lower blood pressure. It is also low in saturated fat. The diet calls for eating eight to 10 servings of fruits and vegetables and 250 to 500 grams (two to three cups) of low-fat dairy foods daily. Here are the broad DASH guidelines you can follow in menu planning:

• Grains and grain products: seven to eight servings daily
• Fruits and vegetables: four to five servings of each daily
• Low-fat or nonfat dairy foods: two to three servings daily
• Meats, poultry, and fish: two or fewer 85 gram (three ounce) servings daily
• Nuts, seeds or legumes: four to five servings per week
• Fats: two to three servings daily; avoid saturated fat
• Sweets: five per week

A follow-up trial, held in 2000, examined whether reducing salt could enhance results even more.

• Sodium in table salt and in other foods can raise blood pressure by causing the body to retain water thereby increasing blood volume and thus blood pressure. Sodium also causes small blood vessels to constrict.
• This study showed that the DASH diet combined with salt reduction was superior to either strategy alone. All the participants benefited from limiting their salt intake.

The DASH diet might be the right option for you. Keep this guide in mind and talk to your doctor before making any dietary changes.