What Is The DASH Diet?Editor's Choice
Main Category: Nutrition / Diet
Also Included In: Hypertension; Cardiovascular / Cardiology
Article Date: 11 Jan 2013 - 0:00 PST
What Is The DASH Diet?
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The DASH diet was promoted by the National Heart, Lung, and Blood Institute for patients with hypertension to control their blood pressure. U.S. News & World Report ranked the DASH diet as number 1 in January 2013.
DASH stands for Dietary Approaches to Stop Hypertension.
People on the DASH diet eat lots of fruits, vegetables, whole grain, low-fat dairy foods, as well as poultry, fish, meat, nuts and beans. The quantities of added fats, red meat, and sugar-laden drinks and foods are kept to a minimum.
The DASH diet focuses on portion size, consuming a wide variety of foods and obtaining proper amounts of nutrients.
The creators of the DASH diet say that not only is it designed to bring down high blood pressure, but is also a well-balanced approach to eating for people in general. The DASH diet encourages the dieter to consume less sodium (salt) and increase his/her intake of magnesium, calcium and potassium, in order to help lower blood pressure.
The USDA (US Department of Agriculture) recommends the DASH diet as "an ideal eating plan for all Americans". According to the Mayo Clinic, the DASH diet may also protect against stroke, heart disease, cancer, diabetes and osteoporosis.
A study by scientists at Duke University found that that African Americans are less likely to adopt the DASH diet than Caucasians.
The DASH diet - based on National Institutes of Health studiesResearchers from the NIH (National Institutes of Health) looked at three dietary plans and how effective they were. None of them were vegetarian diets, but the DASH plan added much more fruits and vegetables, as well as low fat or non-fat dairy, beans, nuts and other healthy foods.
The NIH says that the DASH plan includes much more than promoting good eating habits. Participants are offered suggestions on healthy alternatives to "junk food", and encourages dieters to stay away from processed foods.
The NIH even published a book, called "Your Guide to Lowering your Blood Pressure With DASH", which provides useful information on popular mainstream food items, as well as their healthy alternatives. The book also includes samples of meal plans and their nutritional values. At the end of the book, readers can see a list of resources and how to get hold of them.
How effective is the DASH diet?Patients with pre-hypertension who followed the DASH eating plan experienced an average drop of 6 mm Hg in systolic blood pressure and 3 mm Hg in diastolic blood pressure.
A study published in Circulation: Cardiovascular Quality and Outcomes found that the DASH diet reduces the 10-year risk of heart attack, especially among African-Americans.
These reductions in blood pressure occured without any changes in body weight. Daily calorie intake on the DASH dietary pattern ranges from 1,699 to 3,100.
Why was the DASH diet created?Hypertension has been a growing concern in the USA during the last fifty years. According to the NHLBI (National Heart, Lung and Blood Institute), high blood pressure is associated with a significantly greater risk of developing heart attack, heart failure, stroke and kidney disease. For patients aged from 40 to 70 years, for every rise of 20 mm Hg in systolic BP (SBP) or 10 mm Hg in diastolic BP (DBP), the risk of a cardiovascular disease doubles. US health authorities say that over half of all Americans with hypertension have poor blood pressure control.
As the incidence of hypertension in the USA grew, the NIH proposed funding to determine what impact dietary patterns might have on blood pressure. The NHLBI liaised closely with five well known medical research centers in different US cities to carry out the largest and most detailed study ever - it was called "The DASH study".
DASH was a randomized controlled trial, involving teams of nutritionists, nurses, doctors and research coordinators. Participants were recruited to take part in the following research centers - Brigham and Women's Hospital in Boston, Massachusetts, Kaiser Permanente Center for Health Research in Portland, Oregon, Johns Hopkins University in Baltimore, Maryland, Duke University Medical Center in Durham, North Carolina, and Pennington Biomedical Research Center in Baton Rouge, Louisiana.
Two DASH trials were carried out - their aim was to see what effects the dietary program could have on blood pressure. NIH described the trials as multi-center, randomized, outpatient feeding studies. The creators of the DASH diet said that it is based on foods that are conventionally consumed so that participants may follow it easily.
The first DASH study started in August 1993 and lasted until the end of July 1997. Preliminary results demonstrated that high consumption of certain minerals and fiber were linked to a drop in blood pressure. The nutritional focus of the DASH meal plans was based on part of this study.
The study compared two experimental diets with a "control diet":
- Fruits and vegetables diet - it was high in fruit and vegetables, but was otherwise similar to the typical American diet at the time, however, with fewer snacks and sweets. Magnesium and potassium levels were similar to the 75th percentile of US consumption. Fiber content was high.
- The DASH diet - high in fruits, vegetables, and low-fat dairy products. Overall fat and saturated fat levels were low, while fiber and protein levels were high. It was rich in potassium, magnesium, calcium, whole grains, poultry, fish, and nuts. Consumption of red meat, sweets and sweetened drinks were low.
- The control diet - this was similar to the typical American diet at the time, with low levels of fiber, potassium, magnesium and calcium, and high levels of fat and protein.
These two diets were compared to a third diet:
The researchers screened 8,813 people for the study, of whom 459 were eventually selected as participants. Participants consisted of healthy males and females aged (average) 46 years, with systolic blood pressure of less than 160 mm Hg and diastolic blood pressures within 80 to 95 mm Hg. As hypertension affects many minority groups disproportionately, the researchers aimed to make sure that they constituted two-thirds of the target sample (participant population). 49% of the participants were female.
The participants were randomly selected to follow one of the three diets mentioned above for a periods of 8 weeks. Their blood pressures were checked regularly throughout the study
The DASH study resultsThe DASH trial proved that eating patterns can affect blood pressure patients with moderate to severe hypertension. The minority-group participants on the DASH diet experienced particularly significant reductions in blood pressure, compared to those on the control diet.
Those in the fruit and vegetables group also experienced reductions in blood pressure, although these were modest in comparison to the results in the DASH group.
Even the participants on the DASH diet who started off without hypertension experienced reductions in their blood pressure. Blood pressure variations among this group on the other two diets were less noticeable.
The study showed that participants with hypertension on the DASH diet saw falls in blood pressure within two weeks of starting their diet.
Sodium levels in the DASH dietOne of the principal objectives of the DASH diet is to get participants to reduce their sodium intake. Sodium can raise blood pressure in sensitive people. Hence, there are two versions of the DASH diet:
- The Standard DASH diet - the dieter can consume up to 2,300 mg of sodium each day
- The Low Sodium DASH diet - the dieter can consume up to 1,500 mg of sodium each day
Studies have demonstrated that lower sodium consumption has an especially beneficial effect on blood pressure levels on people aged over 40 years, as well as African-Americans with hypertension.
What is included in the DASH diet?The DASH diet includes plenty of fruits, vegetables, low-fat dairy products, and whole grains, as well as some legumes, poultry and fish, plus small amounts of read meat, fats and sweets. It is low in saturated fat, total fat and cholesterol.
Below is what a typical 2,000 calorie-per-day DASH diet may consist of:
- 6 to 8 daily servings of grains - including pasta, rice, cereal and bread. One serving could be a slice of whole-wheat bread, ½ cup of cooked pasta, rice or cereal, or 1 oz of dry cereal.
- 4 to 5 servings of vegetables - these may include fiber- and vitamin-rich vegetables, including broccoli, sweet potatoes, greens, carrots or tomatoes. One serving could be ½ a cup of raw or cooked vegetables, or 1 cup of leafy green vegetables (raw).
- 4 to 5 servings of fruits - these are rich in fiber, magnesium, potassium, vitamins and other minerals. One serving may include ½ cup of fresh, canned or frozen fruit, or 1 medium fresh fruit.
- 2 to 3 servings of low-fat dairy - major sources of calcium, protein and vitamin D include cheese, yogurt and milk. For the DASH diet to work, these dairy products must be either low-fat or fat-free. One serving could include 1 cup of skim or 1% milk, 1.5 oz of cheese, or 1 cup of yogurt.
- Up to 6 servings of fish, poultry or lean meat - even though meats are rich in proteins, B vitamins, zinc and other nutrients, DASH dieters should keep these nutrients down and make sure the mainstay of their diet is high in fruit and vegetables. One serving may include 1 oz of poultry (cooked, skinless), lean meat or seafood, 1 egg, 1 oz of tuna (packed in water, no salt added).
- 4 to 5 servings of nuts, seeds and legumes - these are good sources of protein, potassium, magnesium, fiber, phytochemicals, and other essential nutrients. Examples include sunflower seeds, beans, peas, lentils, almonds, peanuts and pistachios.
- 2 to 3 servings of fats and oils - the human body needs fat to properly absorb essential vitamins as well as some other nutrients. For a healthy immune system, we have to consume adequate amounts of fats. One serving may include 1 teaspoon of margarine, 1 tablespoon of low-fat mayonnaise, or 2 tablespoons of light salad dressing.
- Up to 5 servings per week of sweets - being on a DASH diet does not mean giving up sweets altogether. Dieters need to keep their intake limited. One serving could include 1 cup of lemonade, ½ a cup of sorbet, 1 tablespoon of sugar, jam or jelly.
- Alcohol - DASH dieters should consume no more than two drinks for men and one drink for women per day.
Daily Nutritional Goals in the DASH diet (for a 2,000-Calorie Eating Plan)
|Total fat||27% of calories|
|Saturated fat||6% of calories|
|Protein||18% of calories|
|Carbohydrate||55% of calories|
* 1,500 mg of sodium in the low sodium DASH diet
The DASH diet was not designed as a weight loss regime. It was designed to reduce blood pressure.
DASH diet ranked Number 1U.S. News & World Report in January 2013 ranked the DASH diet as best overall diet. A panel of experts in diet, nutrition, obesity, heart disease, diabetes and food psychology reviewed 29 diets and ranked them according to safety, short-term and long-term weight loss, how easy they were to follow, nutritional completeness, diabetes prevention and management, and heart disease prevention.
The diets were ranked according to a star system, with five stars being the maximum score. Below are the diets which ranked best:
- DASH diet - 4.1 stars. Nutritionally complete, safe, can prevent and control diabetes, also promotes heart health.
- TLC diet - 4 stars. TLC stands for Therapeutic Lifestyle Changes. This diet was created by the National Institutes of Health to reduce levels of cholesterol. The panel said it is a healthy, well rounded diet. However, the dieter is left very much on his/her own.
- Mayo Clinic diet - 3.9 stars. Experts say it is safe and nutritious, and moderately effective for those aiming to lose weight.
- Mediterranean diet - 3.9 stars. The diet is rich in vegetables, fruits, olive oil, and other healthy nutrients. It was criticized for being too different to what Americans are used to and may consequently be hard to keep up.
- Weight Watchers - 3.9 stars. This diet was praised for the emotional support dieters receive, as well as being an easy one to stick to.
Written by Christian Nordqvist
Copyright: Medical News Today
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19 May. 2013. <http://www.medicalnewstoday.com/articles/254836.php>
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