DASH diet: Eating your way to healthier blood pressure
A low-sodium meal plan aligned with the Dietary Approaches to Stop Hypertension (DASH) diet principles—which include more grains and vegetables and cut back on sugar and sweetened foods—has remarkable blood pressure (BP)-lowering effects, reducing systolic (S)BP and diastolic (D)BP by up to 8.9 and 4.5 mm Hg, respectively, according to Ms Quek Wei Lin, a dietitian who spoke at the 13th Asian-Pacific Congress of Hypertension (APCH 2017) in Singapore.
Developed to prevent and control hypertension without any pharmacological intervention, the DASH diet promotes increased intake of fibre (31 g), calcium (>1,000 mg), potassium (>4,000 mg) and magnesium (>400 mg), as well as consumption of foods low in fat (30 percent of diet) and cholesterol (<150 mg).
Findings from an early trial showed that following the DASH diet for 8 weeks yielded significant reductions in SBP and DBP (5.5 and 3.0 mm Hg, respectively). Quek noted that such reductions were similar in magnitude to that observed in trials of drug monotherapy for mild hypertension. [J Am Diet Assoc 1999;99:8S35–39]
Further improvements in BP were noted when the diet was adopted in conjunction with limiting sodium intake to 50 mmol/day. Specifically, SBP dropped by 8.9 mm Hg and DBP, by 4.5 mm Hg. [J Am Diet Assoc 1999;99:8S94–104]
Actual intake vs DASH recommendations
The clear benefits of the diet aside, Quek pointed out that there is a lot of work that needs to be done in Singapore with respect to meeting the intake of different food groups as per the DASH diet principle, which is higher compared with the recommendations set forth by the Health Promotion Board (HPB).
For example, the DASH diet encourages consumption of four to five servings of fruits and juices daily (serving size: one medium fruit, one-fourth cup dried fruit or one-half cup fruit juice), whereas the HPB requires only two servings (serving size: one small fruit, one medium banana, 10 grapes, one-fourth cup dried fruit or one glass of juice). Meanwhile, the 2004 national survey reported that 71.4 percent were taking less than two servings of fruit.
Moreover, the salt intake locally is alarmingly high, reported at 8.3 g/day in the HPB’s 2010 salt study. This amount is almost 50 percent greater than the recommended daily intake level of 5 g by the HPB and 94 percent greater than the 3-g intake promoted in a low-sodium DASH diet.
There are ways to meet the consumption levels of nutrients recommended by the DASH diet, Quek said. One is to replace refined grains with whole grains and have vegetables served at every meal. Another is to eat a variety of fruits and vegetables, while limiting consumption of deep-fried food, coconut milk dishes, organ meat and seafood.
Also, given that dairy consumption is generally low in Asia, calcium intake may be increased by replacing snacks and desert with a serving of low-fat milk or yoghurt.
On the other hand, salt intake may be reduced by opting for fresh rather than processed foods, selecting food items that are cooked without sauces or gravies, replacing salt with spices or herbs, and reading food labels carefully, according to Quek.
Asian DASH diet
In a separate discussion, Ms Chow Pek Yee, principal dietitian at Khoo Teck Puat Hospital, highlighted the concept of a healthy plate, which emphasizes portions rather than serving size, in doing an Asian DASH diet.
The healthy plate provides a visual representation of the appropriate proportions of different food groups one should eat on a simple plate. In Singapore, the My Healthy Plate designed by HPB specifies filling half of the plate with fruits and vegetables, a quarter with whole grains, and the remaining quarter with meat and other products (eg, eggs, nuts and dairy products). [https://www.healthhub.sg/programmes/55/my-healthy-plate]
Chow explained that the consumption of whole grains—which contain fibre, vitamins, minerals and phytochemicals—is encouraged because it can cut the risk of developing heart disease and diabetes.
When it comes to fruit and vegetable intake, eating a rainbow of fruits and vegetables is ideal, while also taking into account how they are prepared. Avoid cooking vegetables until limp, watch the dressing when preparing salads, and use a blender to process the whole fruit or vegetable instead of a juicer that separates the fibre, Chow said.
The quarter of the plate allotted for meat and other foods can be filled with calcium-rich foods, lean meat, fish, poultry without skin and plant-based protein alternatives to increase intake of calcium and limit that of fat and cholesterol, she added.
Another way to cut back on fat is to use cooking spray instead of oil and employ cooking methods such as boiling, pressure cooking, grilling, poaching and steaming, among others.
Finally, it matters that a balance is struck between the energy put in and taken out. So in between eating meals, one must engage in at least 150 minutes of physical activity each week, as well as learn how to read and understand food labels in order to make healthier choices.