A good diet and regular physical activity are effective strategies for lowering blood pressure.
Clinical trials have shown this to be true in people with hypertension (high blood pressure) who do not take hypotensive drugs, as well as in those who are treated with one or two drugs.
Yet among people with high blood pressure who do not respond to drug therapy, called resistant hypertension, studies examining the potential benefits of diet and exercise are almost nonexistent.
A randomized controlled trial at Duke University School of Medicine in Durham, North Carolina, found that the combination of diet, reduced sodium intake, and exercise resulted in significant blood pressure lowering effects in people with resistant hypertension.
What is resistant hypertension?
High blood pressure, which affects nearly one in four Canadians, is a leading preventable risk factor for heart disease, heart attack and stroke. Up to 30 percent of people with hypertension have resistant hypertension, defined as having blood pressure that stays above target despite taking three or more hypotensive drugs at optimal doses.
Over time, uncontrolled blood pressure is associated with a 50% higher risk of heart attack, stroke, and cardiovascular death than controlled blood pressure.
About the new research
The TRIUMPH study, published September 27 in the American Heart Association journal Circulation, was the first to test the effect of a complete lifestyle modification on resistant hypertension. (TRIUMPH stands for Treat Resistant Hypertension Using Lifestyle Modification to Promote Health.)
For the four-month trial, 140 participants with resistant hypertension received either intensive lifestyle intervention or standardized education and medical advice.
People in the lifestyle intervention group learned how to follow the DASH diet with calorie and sodium restriction. (DASH stands for Dietary Approaches to Stop Hypertension.) These participants also received feedback on their adherence to the diet in weekly 45-minute group sessions led by a dietitian and psychologist.
The lifestyle intervention also included 30 to 45 minutes of cycling and / or walking (and possibly jogging) three times a week under the supervision of an exercise physiologist.
Participants in the comparison group attended a one-hour educational session and received DASH diet materials. They were also given weight loss goals and exercise goals that they were expected to achieve on their own.
All of the participants adhered to their blood pressure medication regimens during the study.
After 16 weeks, both groups experienced a significant reduction in blood pressure, comparable to that seen with hypotensive drugs.
Participants in the Intensive Lifestyle Intervention group, however, achieved the greatest reduction in blood pressure. They also lost significantly more weight during the study period, 15 pounds compared to 8.5 for those in the comparison group.
Diet and exercise changes are often recommended before starting any blood pressure lowering medication. These new findings demonstrate that they are also an effective strategy when drugs alone are not enough to manage blood pressure.
What’s in the DASH diet?
The DASH diet, first proven to lower blood pressure in people with mild hypertension in 1997, focuses on fruits and vegetables, low-fat dairy products and beans, lentils, nuts and seeds. These foods provide lots of calcium, magnesium, and potassium, minerals that help regulate blood pressure.
The diet also emphasizes whole grains and limits red meat and sweets. It also limits foods high in saturated fat such as fatty meats, high fat dairy products, butter, and coconut oil. Sodium intake is limited to 1,500 to 2,300 milligrams per day. (One teaspoon of table salt contains 2300 milligrams of sodium.)
The DASH diet advises specific daily or weekly servings of food groups based on your calorie needs.
A 1,600 calorie DASH diet recommends, for example, eating three to four servings of vegetables, four servings of fruit, six servings of whole grains, two to three servings of low-fat dairy products, three to six servings of lean protein. and two servings of unsaturated oil per day. One serving of beans, lentils, nuts or seeds is recommended three times a week.
One serving equals half a cup of cooked vegetables or a cup of green salad, one medium-sized fruit or half a cup of fresh fruit, a slice of whole grain bread or half a cup of cooked cereal, one cup of milk or yogurt, an ounce of cooked fish or meat, a teaspoon of vegetable oil or two tablespoons of dressing and a third of a cup of nuts or half a cup of cooked beans or lentils.
Leslie Beck, a dietitian in private practice based in Toronto, is the Director of Food and Nutrition at Medcan. Follow her on Twitter @LeslieBeckRD
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