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Lifestyle Modifications for Hypertension Management
Questions
1
What is the role of lifestyle modifications in the treatment of hypertension?
The 2017 American College of Cardiology/American Heart Association (ACC/AHA) Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults recommends lifestyle changes that can reduce systolic blood pressure (SBP) by approximately 4 to 11 mm Hg in patients with hypertension. These guidelines stress the importance of maintaining a healthy diet with limited sodium intake, routine exercise, weight management, tobacco cessation, and decreased alcohol consumption ( Tables 29.1 and 29.2 ). One of the original trials (published in 2002) that evaluated the efficacy of implementing all of these recommendations was the diet, exercise, and weight loss intervention trial (DEW-IT), which enrolled 44 adults who were overweight and had hypertension who were treated with a single blood pressure (BP) medication. DEW-IT consisted of a control group (no intervention) and a comprehensive intensive lifestyle program (Dietary Approaches to Stop Hypertension [DASH] diet and an exercise regimen that included 30 to 45 minutes of supervised moderate-intensity aerobic exercise 3 d/wk, and alcohol restriction). Five energy levels (1350, 1600, 2100, 2600, 3100 kcal/d) of the DASH diet were used, depending on the energy requirements of each participant. The DASH diet provided 18% kcal from protein, 55% kcal from carbohydrate, and 27% kcal from fat. After 9 weeks of intervention, the lifestyle group lost an average of 5.5 kg, whereas the control group had a mean weight loss of 0.6 kg. The mean change in 24-hour SBP and diastolic blood pressure (DBP) was −10.5/−5.9 mm Hg in the lifestyle group and −1.1/−0.6 mm Hg in the control group. BP reductions of this degree are similar to those accomplished with pharmacotherapy.
Table 29.1
Lifestyle Nonpharmacologic Interventions for Prevention and Treatment of Hypertension
Adapted from Whelton PK, Carey RM, Aronow WS, et al. ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. J Am Coll Cardiol. 2018;71:e127–248.
Table 29.2
Dietary Nonpharmacologic Interventions for Prevention and Treatment of Hypertension
Adapted from Whelton PK, Carey RM, Aronow WS, et al. ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. J Am Coll Cardiol. 2018;71:e127–248.
DASH , Dietary Approaches to Stop Hypertension.
2
How do you follow a low-sodium diet?
The United States Department of Agriculture (USDA) 2015–2020 Dietary Guidelines for Americans describe how Americans eat more sodium than recommended—an average of more than 3400 mg or 100 mEq of sodium daily! The USDA guidelines recommend limiting sodium intake to less than 2300 mg/d (roughly 1 teaspoon of salt) and patients with prehypertension or hypertension to reduce their sodium intake to 1500 mg/d. Reducing sodium intake can decrease BP by approximately 5/3 mm Hg (see Table 29.2 ). About 75% of dietary sodium comes from eating packaged and restaurant foods, whereas only a small portion (11%) comes from directly adding salt to food when cooking or eating. Foods such as bread, stock (broth) cubes, and breakfast cereals are often high in salt, which is often overlooked. Of note, current guidelines differ in the recommended amount of sodium intake for patients with heart failure. Observational studies uphold that sodium restriction improves heart failure outcomes, whereas other randomized controlled trials infer that dietary sodium restriction can cause hypovolemia and increased neurohormonal activation. Thus there remains controversy surrounding restricting dietary sodium content especially in regards to heart failure.
3
How do you calculate how much sodium is in foods or beverages?
There is a misconception that “salt” and “sodium” are synonymous terms. In reality, sodium (Na) is a mineral and a chemical element with the atomic number 11. Sodium also is a chemical element (other than chloride [Cl]) found in salt (sodium chloride [NaCl]). Foods and beverages may contain no salt (NaCl), but they still may be high in sodium because of the presence of naturally occurring sodium. Salt (NaCl) contains a 1:1 ratio of Na and Cl ions. The molar mass of Na is 22.99 g/mol and of Cl is 35.45 g/mol. One mole of NaCl equals 58.44 g NaCl. Therefore 100 g of NaCl contains 39.34 g Na and 60.66 g Cl, thus sodium (Na) is roughly 40% of the weight of salt, and chloride is the remaining 60%. Nutritionists often suggest diminishing salt intake, but it is sodium you will see listed on food labels ( Fig. 29.1 ). If you are cooking and want to figure out how much sodium you are adding, convert grams of salt to milligrams of sodium, then divide the amount of salt in grams by 2.5, and then finally multiply by 1000 to get milligrams. The amount of sodium in a serving of food is listed in milligrams (mg) and as a percent of the daily value on the nutrition label. The percent daily value (% daily value) for sodium gives a general idea of how much sodium a serving adds to your total daily diet. The percent daily value for sodium on the nutrition label shown here is baseline on a daily maximum value of 2300 mg.
4
How effective is the DASH diet?
The DASH diet is a widely used dietary intervention for hypertension. The DASH diet emphasizes fruits, vegetables, and low-fat dairy products with reduced intake in saturated fat and cholesterol. In terms of macronutrient composition, the nutrient goals of the DASH diet are as follows: total fat (27% of calories), saturated fat (6% of calories), protein (18% of calories), and carbohydrates (55% of calories). It includes a sodium goal of 2300 mg and potassium goal of 4700 mg. The original trial (Appel et al., NEJM, 1997) demonstrated the DASH diet reducing BP (reduced SBP by 11.4 mm Hg and DBP by 5.5 mm Hg) in subjects with known hypertension, but it also showed reductions in BP in subjects without hypertension (reduced SBP by 3.5 mm Hg and DBP by 2.1 mm Hg) compared to the control diet.
5
Is the DASH diet more effective with the addition of sodium restriction?
Because the DASH trial was conducted independent of testing the effect of sodium restriction, a subsequent multicenter, randomized trial was conducted to examine the combined effect of the DASH diet with sodium restriction on BP. The DASH diet showed to lower BP at high (3500 mg/d; typical of current US sodium consumption), intermediate (2400 mg/d; reflecting the upper limit of current US recommendations), and lower levels (1500 mg/d; reflecting potentially optimal sodium levels) of sodium intake, but the lowest SBP and DBP were seen in patients who were on the DASH diet with the lowest amount of sodium intake ( Tables 29.3 and 29.4 ). Thus the combined effects of low sodium intake (1500 mg/d) and DASH diet were greater than the effects of either intervention alone and they were substantial. In addition, in participants with hypertension, the effects were equal to or greater than those of single drug therapy. Although the DASH diet has been endorsed by the Joint National Committee, the American Diabetic Association, and the National Heart, Lung and Blood Institute Lifestyle Guidelines, the adherence to the DASH diet remains suboptimal across all races/ethnicities, education levels, and income levels across the United States.
Table 29.3
Effect of DASH Diet and Sodium Reduction on Blood Pressure
DASH , Dietary Approaches to Stop Hypertension; SBP , systolic blood pressure. Adapted from Sacks FM, Svetkey LP, Vollmer WM, et al. Effects on blood pressure of reduced dietary sodium and the dietary approaches to stop hypertension diet. N Engl J Med. 2001;344(1):3–10.
| DIET | SODIUM LEVELS RESTRICTION CHANGES a | SBP CHANGE (mm Hg) | SBP ABSOLUTE CHANGE (mm Hg) | |
|---|---|---|---|---|
| Control diet b | High to intermediate | −2 mm Hg | ∼133–131 mm Hg | |
| Control diet b | Intermediate to low | −5 mm Hg | ∼131–126 mm Hg | |
| DASH diet | High to intermediate | −1 mm Hg | ∼126–125 mm Hg | |
| DASH diet | Intermediate to low | −2 mm Hg | ∼125–123 mm Hg |
a High sodium level = 3500 mg; intermediate sodium level = 2400 mg; low sodium level = 1500 mg.
b Control diet: typical of what many people in the United States eat.
Table 29.4
Comparison of Control Diet against DASH Diet with Varying Sodium Levels
DASH , Dietary Approaches to Stop Hypertension; SBP , systolic blood pressure. Adapted from Sacks FM, Svetkey LP, Vollmer WM, et al. Effects on blood pressure of reduced dietary sodium and the dietary approaches to stop hypertension diet. N Engl J Med. 2001;344(1):3–10.
| SODIUM LEVELS a | DIET CHANGES b | SBP CHANGE (mm Hg) | SBP ABSOLUTE CHANGE (mm Hg) |
|---|---|---|---|
| High | Control to DASH diet | −6 mm Hg | ∼133–126 mm Hg |
| Intermediate | Control to DASH diet | −5 mm Hg | ∼131–125 mm Hg |
| Low | Control to DASH diet | −2 mm Hg | ∼126–123 mm Hg |
a High sodium level = 3500 mg; intermediate sodium level = 2400 mg; low sodium level = 1500 mg.
b Control diet: typical of what many people in the United States eat.
6
Can the DASH diet be used in patients with diminished kidney function to lower BP?
More than two thirds of US adults with chronic kidney disease (CKD) have uncontrolled hypertension. Lowering BP to recommended treatment targets slows down the progression of CKD, and the DASH diet may have an important role in BP control. In a pilot study, 11 participants with moderate CKD (epidermal growth factor receptor between 30 and 59 mL/min/1.73 m 2 ) were monitored after completing 1 week of reduced-sodium, run-in diet followed by a reduced-sodium DASH diet. The pilot date showed minimal acute metabolic abnormalities in adults with moderate CKD and a possible improvement in nocturnal BP. Overall, mean serum potassium was significantly higher after DASH diet week 1, but it was not significantly different from baseline after DASH diet week 2.
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