When East Coast residents turned to Google for dieting advice amid the pandemic, the letters DASH often appeared.
That's short for Dietary Approaches to Stop Hypertension. Officially branded an "eating plan", it was developed by researchers at the National Heart, Lung, and Blood Institute south of the border over 20 years ago.
Claiming to lower blood pressure, improve cholesterol and reduce the risk of heart disease, the diet has the stamp of approval from several health-related organizations in both Canada and the United States, including the Heart and Stroke Foundation.
DASH has a strong emphasis on vegetables, fruits, and whole grains and includes fat-free or low-fat dairy products, fish, poultry, beans, nuts, and vegetable oils. According to the Heart and Stroke Foundation Canada website, participants are urged to limit foods high in saturated fat and exercise will power when it comes to desserts and beverages.
Amanda Rodgerson is a registered dietitian and board member with the PEI Heart and Stroke Foundation. She notes, "If a patient has high blood pressure and are able to put in place the DASH recommendations, then it certainly is an eating plan that I would suggest. Also as a board member with the Heart and Stroke Foundation, I do support the DASH diet as this is an evidence-based recommendation."
High blood pressure causes the heart to work harder to pump nutrient- and oxygen-rich blood to the body. The arteries that deliver the blood become scarred and less elastic, causing the heart to work harder and leading to an increased risk of a heart attack or stroke.
Sticking with the eating plan also includes a commitment to maintaining a healthy lifestyle, including exercise and no smoking. The diet is similar to the recommendations of Canadas Food Guide, with its focus on vegetables, fruit, whole grains, and protein choices such as nuts, seeds, beans, lean meats, poultry, fish, and low-fat dairy foods. It also encourages less consumption of saturated fat, sugar, and salt.
"Eating a healthy balanced diet is one of the most important things we can do to protect our health," Rodgerson said, noting that 80 per cent of heart disease and strokes can be prevented with a healthy lifestyle.
"This diet has also shown to lower total cholesterol and low-density lipoprotein (LDL/ bad cholesterol) as well," she said.
"However, the greatest reminder is to take steps to improve eating and lifestyle habits and follow recommendations that are based on science."
The DASH plan offers recommendations for the number and size of servings for the various food groups. By contrast, Canadas Food Guide now focuses on what is called a "plate method" that
recommends every meal feature half vegetables and fruit with whole-grain and protein foods each making up a quarter of the meal.
Research conducted by the National Heart, Lung, and Blood Institute as the DASH plan was being developed divided participants into three groups, each with a specific diet. One group received a diet similar in nutrients to what most North Americans eat. The second group received essentially the same food, with extra fruit and vegetables, while the third group followed the DASH plan.
While the diet higher in vegetables and fruit and the DASH diet both reduced blood pressure, the Heart and Stroke website notes the DASH plan "had the greatest effect on blood pressure, lowering levels within two weeks of starting the plan. Not only was blood pressure reduced, but total cholesterol and low-density lipoprotein (LDL) or "bad cholesterol" were lower, too."
A follow-up study saw participants follow the eating plan, but with the salt intake varied from 3,300 milligrams (the average intake of North Americans) down to 1,500 milligrams or approximately two-thirds of a teaspoon. That research showed the less salt people consume, the greater the decrease in blood pressure, with the largest decrease in people who already had high blood pressure.
"We do know that the majority of Canadians consume too much sodium. It is recommended that we have no more than 2,300 mg of sodium each day (which visually is approximately one teaspoon)," Rodgerson said.
"A diet high in sodium can lead to high blood pressure which is a major risk factor for stroke, heart disease, and kidney disease. Too much sodium has also been linked to an increased risk of osteoporosis and stomach cancer."
Sodium occurs naturally in some foods and is also added during manufacturing, Rodgerson said. Many people also add it during cooking and at the table.
"Overall, more than 70 per cent of the sodium we eat comes from packaged and prepared foods (canned soups, lunch meats, and packaged items such as frozen dinners). These items, although "fast" and "convenient," can cause you to quickly exceed sodium recommendations," she said.
The plan recommends four to five servings of both vegetables and fruit daily, seven to eight servings of grains, two to three servings of low fat or no-fat dairy foods, two servings or less of lean meat, poultry, or fish, and two or three servings of fats and oils like margarine, low-fat mayonnaise or light salad dressing.
It also recommends between four and five servings a week of nuts, seeds, and dry beans.
The Heart and Stroke Foundation also recommends 30 to 60 minutes of physical activity most days of the week and limiting alcohol intake for women to no more than two drinks a day, to a weekly maximum of 10, and for men, no more than three drinks a day to a weekly maximum of 15.
"The DASH diet is recommended for anyone with high blood pressure. Studies have shown that anyone who follows the diet will have a positive effect on their blood pressure," Rodgerson noted. "The less salt people consumed, the greater decrease in blood pressure values. People who already had high blood pressure saw the largest decrease in the numbers."
The Heart and Stroke Foundation recommends moving to a DASH lifestyle gradually, perhaps by adding another serving of vegetables at lunch or dinner and adding more fruit to meals or replacing juice with a fruit serving.
"People who make small changes in their diet over a longer period of time, rather than a dramatic change all at once, are more likely to stay committed to a healthier diet," the organization's website notes.
Rodgerson agrees, saying over the past several years, "I've noticed overall that people are becoming more interested in their health and therefore taking the necessary steps to make healthier lifestyle choices."
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