DASH Diet, A Good Way to Help Manage High Blood Pressure
A new study confirms that people with high blood pressure can reduce their risk of heart disease by making simple changes in their diet. Our Healthwatch contributor Dr. Bernadine Healy tells us more.
Hypertension, or high blood pressure, affects nearly 50 Million Americans, putting them at high risk for heart disease. The January 4 issue of the New England Journal of Medicine compares the effectiveness of the so-called DASH Diet--Dietary Approaches to Stop Hypertension, and a reduced-salt diet, and both, in reducing high blood pressure.
Interview with Dr. Bernadine Healy
What is the DASH diet and how long has it been around?
It's a low-fat diet, rich in fruits and vegetables. It's a prudent, heart-healthy diet. And originally it didn't worry about sodium. It showed that just by putting someone on a heart-healthy diet, that reduced High Blood Pressure.
There was guidance issued in 1997 that also said that we should look at weight reduction, limited alcohol intake, regular physical activity, moderate salt intake, and potassium from bananas, as well as calcium from low-fat dairy foods.
What's new about this study?
All this study showed is that if you take these guidelines one step further, that is to go from moderate sodium intake to lower intake is even better. It's already been showed that the DASH diet is effective in lowing blood pressure, no matter whether you are hypertensive or not. The DASH diet reduces blood pressure no matter what. But we shouldn't just focus on salt to prevent high blood pressure.
How do we know how much salt we're getting?
If you just leave the salt shaker on the table and don't use it, you're probably fine. The diet doesn't get bland and unpalatable until you have to avoid processed foods.
Can I salt my food if I promise to eat my fruits and vegetables?
The general rule is to eat fruits and vegetables whatever you want. You don't have to buy low-sodium foods. But you take the saltshaker off the table. In other words, don't salt your celery or carrots. You'll have an 8-gram or 9 gram per day without using the salt shaker. Avoid pickles or French fries. But you don't get that on the DASH diet anyway. If you go on the DASH diet, you can eat almost anything.
How can I lower my salt intake if the foods I buy at the store have high salt content?
Avoid processed foods, and foods with visible salt, such as salty pretzels or potato chips. If you can avoid those foods, you'll be at an intermediate level of sodium intake, and that's okay. To go to a low sodium intake, that's pretty unpalatable. But what this study shows is that you don't have to do that, but still lower your blood pressure.
What are some other ways to bring down high blood pressure?
Let's focus on a holistic approach. Lifestyle changes like exercise and diet. But also stress reduction, know what your stress is, and it's different for different people. If you're always in a hurry r always late, get up 15 minutes earlier. Learn to say no. Don't curse every stoplight. Do some internal relaxation exercises such as meditation. There are other factors that affect blood pressure other than salt. Drugs, the mildest, a diuretic prescribed by your doctor.
There three approaches to manage and control high blood pressure:
Diet--DASH diet, rich in fruits and vegetables, low-fat dairy foods, moderate-to-low sodium intake, and increased potassium.
Lifestyle--weight reduction, moderate alcohol intake, regular physical activity, and stress reduction.
Medication--multiple step approach
What is a normal blood pressure?
We consider 120 over 80 as a normal blood pressure. 120 is the systolic, and 80 is diastolic. The higher number is the register of your heart contracting--when the heart squeezes the blood out. And the diastolic is the force of the heart as it relaxes--pulsation. Blood is pulsed through the body.
When you exercise your blood pressur may go up to 150. It's normal for your blood pressure to change under certain physiological conditions, like exercise. And there are different grades of high blood pressure mild (140/90), moderate (160/100), and severe (180/100).
Why is it bad to have high blood pressure?
Mild high blood pressure can sometimes be treated with lifestyle and diet changes alone. Sustained high blood pressure can cause stroke, heart failure, and kidney disease. And the higher the level, the greater your risk for those diseases. When your blood pressure exceeds the target of 120 / 80, you have to intervene.
Is this the final word on high blood pressure?
There's never a final word in medicine. We are always learning newer and better ways to treat. However, the link between a diet rich in vegetables, low in fat and high in calcium and potassium--those benefits are not going to change. The argument over salt will continue forever!
One of the biggest arguments among heart specialists has been the focus on salt. Different people react to salt differently. Some people are greatly affected, and some people even lower their blood pressure with salt! What this study shows is that if you can tolerate a really low-salt diet, it will help you. But can it be tolerated?
Isn't salt necessary?
Salt is essential. But it's a question of what level is enough. And that's where the arguments will continue among heart specialists. People do vary. Some are much more sensitive to salt than others. Use common sense. Don't overdo your salt.
Dash Diet
The "DASH" (Dietary Approach to Stopping Hypertension) diet is a diet that emphasizes fruits, vegetables and low-fat dairy products, and includes whole grains, poultry, fish and nuts. The DASH diet contains small amounts of red meat, sweets and sugared beverages, and decreased amounts of total and saturatd fat and cholesterol. This diet has been shown to effectively lower blood pressure in people with and without high blood pressure (hypertension), perhaps MORE effectively than reducing salt in one's diet!
The New Study
The new DASH-Sodium study differs from previous DASH-diet studies in that it controls sodium intake in the study diet. It's important to note that salt is an important part of a healthy diet. As Dr. David Kritchevsky, a nutrition scientist at the University of Pennsylvania, says, "the key to a good diet is common sense -- moderation, not martyrdom." The study was part of the DASH project, funded by the National Heart, Lung and Blood Institute.
The Good News
The DASH-Sodium Study is a head-to-head comparison of the achievable DASH diet, with the previously recommended low-sodium diet, which has proved so difficult for the public to follow. Now Americans have new hope that a few simple, common sense dietary changes can reduce their risks of heart attack.
The new DASH-Sodium study confirms that most of the blood pressure benefits of combining the DASH Diet with sodium reduction comes from the DASH Diet itself, not the amount of sodium in the diet. Not only is the DASH Diet a "realistic" diet, it is also appropriate for every American, with or without high blood pressure. Clearly, though, the group that benefits the most is the group that needs the most help -- those with high blood pressure.
Methodology
The study evaluated 412 volunteers, half of whom ate a typical US diet an half consumed the DASH diet. At the same time, volunteers consumed one of three different levels of salt. The patients stuck with each diet for 30 days, then switched to a diet with a different salt content.
Those who ate three grams of salt a day instead of the typical diet of nine grams a day lowered their systolic blood pressure (the higher number in a blood pressure reading) by nearly seven points if they were on a regular diet and by three points if they ate the DASH diet.
The Results
The diastolic pressure (the lower number) also declined -- by 3.5 points with the regular diet and 1.6 points on the low-fat diet. Consuming six grams of salt produced an intermediate benefit. A healthy diet and lower salt intake "both lower blood pressure substantially, with greater effects in combination than singly," Sacks and his colleague concluded.
Reducing blood pressure by three points may not seem like a lot, Dr. Philip Greenland of Northwestern University Medical School in Chicago said in an editorial in the <em>New England Journal of Medicine</em>. But the population-wide impact could be significant.
*** A decrease in two diastolic points cuts the risk of high blood pressure by 17 percent, the risk of heart disease by 6 percent and the chance of a stroke or angina by 15 percent. ***
Scarcity of Low-Salt Food
Researchers stressed that the health benefits of the diet would not be proven conclusively unless it was followed for a long period. Also, low-salt products are hard to find. "The attainment of a lower sodium level in the population as a whole presents challenges, since sodium is widely prevalent in the food supply" and most of the salt in the US diet comes from processed foods, the team noted. "Hence, efforts to reduce sodium intake must ultimately rely both on consumers' selection of low-sodium foods and, perhaps more important, on the increased availability of low-sodium products."
Other Good Advice
It's well known that dietary factors are associated with four of the 10 leading causes of death: Heart disease, stroke, some cancers and Type 2 diabetes. Yet, so many people disregard diet as a way of building good health. Here are some suggestions to maintain good health:
If you have a family history of heart disease or other diet-related disease, do all you can through diet to lower your risk. The following web sites offer helpful information and good advice:
American Dietetic Association: www.eatright.org
Mayo Clinic Health Oasis: www.mayohealth.org
National Institute of Nutrition: www.nin.ca
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