Hypertension
Chronic high blood pressure, known as hypertension, is a serious medical condition that is estimated to affect 1 in 4 men and 1 in 5 women worldwide. Most people with hypertension have no symptoms at all. However, if left undetected for a long enough increased pressure in the blood vessels causes an increased friction known as sheer stress. Excessive sheer stress can lead to internal blood vessel wall damage and subsequent scaring. The scar tissue increases blood flow resistance and target organs such as the brain and kidneys can become damaged due to a reduced blood supply. Additionally, as blood pressure increases the heart must pump harder to compensate, adding further comorbidity risk. Comorbidities such as heart disease, kidney disease and strokes highlight the importance of hypertension prevention, detection and treatment.
Prevention
Hypertension is most commonly caused by the modern western diet, which characteristically combines high sodium and low potassium consumption. Excessive salt consumption increases the amount sodium in the bloodstream. Fluid is drawn to sodium which increases flow and subsequent sheer stress within the blood vessels.
The kidneys are responsible for regulating blood pressure. They do this by filtering the blood and removing excess fluid. This process relies on a balance between sodium and potassium to draw the fluid across a wall of cells from the bloodstream to be moved to the bladder and stored as urine. Lack of dietary potassium will compromise this process and in turn worsen hypertension.
Sodium in food is found in dietary salts. You’d think the best preventative measure would be to eliminate or reduce the amount of salt you add to your food both during cooking and at the table. However, in western countries the main source of salt intake comes from non-discretionary salt. This is the salt that is added to our foods during production. So, with that in mind, the best way to reduce your salt intake is to swap many processed food products for wholefoods. One great way to achieve this is to include more fruit and vegetables in your diet because these are also a great source of dietary potassium.
Detection
Blood pressure can be measured at your local general practitioner surgery. The doctor or nurse will look for a blood pressure measurement of when the heart beats (systolic) and when heart relaxes (diastolic). Both pressures are measured in millimetres of mercury (mmHg) and will be recorded together as systolic/diastolic mmHg.
Alternatively, you can measure your blood pressure easily at home using a digital sphygmomanometer. Both the following readings require that you seek further medical advice and make relative changes to your diet.
Stage 1 hypertension = pressure of 135/85 mmHg or higher.
Stage 2 hypertension = pressure of 150/95 mmHg or higher.
Treatment
The DASH (Dietary Approaches to Stop Hypertension) diet has been developed by the National Heart, Lung and Blood Institute (NHLBI), in coordination with several major stateside universities. The DASH diet has been shown to help lower blood pressure and reduce risk of heart disease, stroke and diabetes.
DASH Daily Nutrient Intake Targets
Fat = 27% of total energy intake
Saturated fat = 6% of total energy intake
Protein = 18% of total energy intake
Carbohydrate = 55% of total energy intake
Fibre ≥ 30 g
Sodium ≤ 1500 mg*
Potassium ≥ 4700 mg
Calcium ≥ 1250 mg
Magnesium ≥ 500 mg
*sodium intake of 2300 mg per day was also tested and found to be sufficient, but not as effective as 1500 mg, for lowering blood pressure.
Put Into Practice
Serving Suggestions
key: dots = where servings are found, colour = food type, numbers = number of portions
*Daily and Weekly DASH serving suggestion goals for a 2000-Calorie-a-Day Diet
Breakfast Muesli
250 mL of Skimmed Milk
60 g of Rolled Oats
30 g of Dried Apricots
30 g of Dried Raspberries
10 g of Flaked Almonds
Mix the dry ingredients in a bowl then pour in the milk.
Elevenses Snack Time
1 Medium Sized (roughly 175 g) Apple
Eat with skin left on.
Lunch Time Bagel and Yogurt Pot
1 Average Sized (roughly 75 g) Wholemeal Bagel
1 Small (roughly 80 g) Banana
1 Spread (roughly 20 g) of Low Salt Peanut Butter
Slice the bagel into 2 slices and toast. Spread one slice with the peanut butter. Slice the banana into discs and sandwich between both slices.
1 Cup (roughly 250 g) of Natural Greek Yogurt
½ a Cup (roughly 80 g) of Fresh Strawberries
1 Tbsp (roughly 20 g) of Honey
Half the strawberries and remove the stalks then place in a bowl. Top the strawberries with the yogurt then top the yogurt with the honey.
Dinner Time Fish Curry
1 Average Sized (roughly 120 g) Boneless & Skinless Cod Fillet
1 Cup (roughly 250 g) of Natural Greek Yogurt
80 g of Sweet Potato
80 g of Red Bell Pepper
55 g of Dried Brown Rice
½ (roughly 30 g) of a Small Onion
1 (roughly 20 g) Large Chilli Pepper
1 cup (roughly 20 g) of Baby Leaf Spinach
2 tsp (roughly 4 g) of Curry Powder
1 Tbsp of Olive Oil
Season to taste using 1 Wedge of Lime and Black Pepper
Heat the oil in a wide saucepan set over a medium heat. Add the onion and stir-fry for 5-6 minutes until softened.
Stir in the chilli, curry paste, red bell pepper and sweet potato, then add a cup full of water. Bring to the boil, reduce heat and simmer for 15 minutes.
Stir in the yogurt, add in the cod (cut into chunks) and simmer for a further 10 minutes.
Stir through the spinach and simmer for a final 2 minutes.
Serve the curry with the rice (cooked by adding to a pan with 140 mL of water, bringing to boil then reducing heat and simmered for 10 minutes) and the lime wedge alongside for seasoning.
Before Bed
1 Fish Oil Capsule, fortified with Vitamin D
Total Nutritional Breakdown
Fat ≈ 27% of total energy intake
Saturated fat ≈ 6% of total energy intake
Protein ≈ 18% of total energy intake
Carbohydrate ≈ 55% of total energy intake
Fibre > 30 g
Sodium < 1500 mg
Potassium > 4700 mg
Calcium > 1250 mg
Magnesium > 500 mg
Summary
With this example of a day on the DASH diet we have demonstrated how one can meet both the serving suggestion and nutrient intake targets. The key things to remember are:
Make whole grains your main source of energy because they are rich in fibre.
Eat plenty of fruits and vegetables because these are rich in potassium, magnesium, and fibre.
Moderate meat consumption or choose lean meats, as meat can be high in saturated fat, which raises bad cholesterol.
Include dairy because it is rich in calcium but moderate it's intake or choose low fat products because dairy can also be high in saturated fat.
Nuts, seeds and legumes are a good source of magnesium, protein, and fibre. However they are very high in calories, so should be eaten in moderation.
Choose monounsaturated fats for cooking because they are good for cholesterol but they are also high in calories so use in moderation.
Sweets and added sugars are a real treat! So, we should consume them that way.
Bibliography
National Heart, Lung and Blood Institute. (2019, September 19). Health Topics: Dash Eating Plan. Retrieved from NHLBI Web Site: https://www.nhlbi.nih.gov/health-topics/dash-eating-plan
Steinberg, D., Bennett, G., & Svetkey, L. (2017). The DASH Diet, 20 Years Later. The Journal of the American Medical Association, 317(15):1529-1530.
World Health Organization. (2019, September 13). Fact Sheet: Hypertension. Retrieved from World Health Organization International Web Site: https://www.who.int/news-room/fact-sheets/detail/hypertension
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