Recently, the National High Blood Pressure Education Program Coordinating Committee updated its 1993 recommendations for primary prevention of hypertension.1 Potassium supplementation and the DASH (Dietary Approaches to Stop Hypertension) diet are now recommended, in addition to the lifestyle changes outlined in the earlier report (weight loss, reduced intake of dietary sodium, moderation in alcohol(Drug information on alcohol) consumption, and increased physical activity) (Table 1). Complementary approaches with less proven efficacy, such as calcium, fish oil, and herbal supplementation, are also discussed in the guidelines.
Highlights of the recommendations follow.
A TARGETED APPROACH TO PREVENTION
The new guidelines target 2 groups: the general population-including children with higher than average blood pressure-and persons at high risk for hypertension.
General population. An estimated 43 million Americans over age 18 (24% of this population) meet the established diagnostic criteria for hypertension, and 23 million have high-normal blood pressure.2 Because high blood pressure is so prevalent among Americans, targeting the general public with prevention methods could decrease the incidence of hypertension by an estimated 17%.3 Population-based approaches include lowering the sodium and caloric content of foods andproviding convenient opportunities for exercise. However, the cultural and economic factors listed in Table 2 can hinder a widespread approach to prevention.
Children. Those with higher than average blood pressure are also included in the target group, because they are at risk for hypertension later in life. The lifestyle changes recommended for primary prevention of hypertension in adults, which are listed in Table 1, are also effective in children.4
Persons at risk. Focusing on groups at high risk provides an even greater opportunity to prevent hypertension. Factors that increase the risk of hypertension include:
High-normal blood pressure.
Family history of the disease.
African American ancestry.
Excess intake of dietary sodium.
Insufficient intake of potassium.
Excess consumption of alcohol.
Overweight or obesity.
Weight loss. Counseling that results in a modest reduction in body weight provides benefits both during and after the active therapy. In one study, persons who were assigned to weight-loss intervention reduced their body weight by 3.5 kg (7.7 lb); their systolic and diastolic blood pressures decreased by 5.8 and 3.2 mm Hg, respectively. The incidence of hypertension at 7-year follow-up was 18.9% in those who underwent weight-loss therapy and 40.5% in the control group.5
Dietary sodium reduction. In overweight persons, a 100 mmol/d increase in dietary sodium intake is associated with an increase in stroke (32%), stroke mortality (89%), coronary heart disease mortality (44%), cardiovascular heart disease mortality (61%), and mortality from all causes (39%).6 In 12 randomized controlled trials, normotensive persons who lowered their sodium intake by an average of 77 mmol/d reduced their systolic and diastolic blood pressures by 1.9 and 1.1 mm Hg, respectively.7
Increased physical activity. The quantity of exercise (the Surgeon General recommends 30 minutes a day most days of the week8) appears to be more important than its intensity.9 In 27 randomized controlled trials, normotensive persons who engaged in aerobic exercise were able to lower their systolic blood pressure an average of 4.04 mm Hg.9
Moderation in alcohol consumption. A reduction in self-reported consumption of alcohol by a median of 76% in 15 randomized controlled studies was associated with a decrease in systolic and diastolic blood pressures of 3.56 and 1.80 mm Hg, respectively.10 The relationship between reduced alcohol intake and lower blood pressure was dose-dependent.
Potassium supplementation. In 12 trials that included normotensive persons, potassium supplementation of 75 mmol/d reduced blood pressure by 1.8 mm Hg systolic and 1.0 mm Hg diastolic. The effects were greatest in those who had higher sodium intake.11
Modification of whole diets (DASH diet). The DASH diet emphasizes increased consumption of fruits, vegetables, and low-fat dairy products and reduced intake of saturated and total fat. Among normotensive persons who followed the DASH diet, systolic blood pressure decreased by 3.5 mm Hg.12
INTERVENTIONS WITH LESS PROVEN EFFICACY
Calcium supplementation. The reduction in blood pressure associated with calcium supplementation is modest and has been observed only in hypertensive persons.12 However, advise patients that adequate calcium intake (1000 to 1200 mg/d for adults) is important to overall health.
Fish oil supplementation. High doses (greater than 3 g/d) of a fish oil supplement may reduce the risk of coronary heart disease and stroke as well as provide a small reduction in blood pressure.13,14 The effect of fish oil is greatest in hypertensive patients.13 Adverse effects include eructation and a fishy taste.
Herbal and botanic dietary supplements. Although the use of herbal products has increased in recent years, few studies have shown that they are effective in preventing or treating hypertension or heart disease. The FDA does not regulate these products; thus, the amount of active ingredient can vary widely among different brands. Always ask patients whether they take herbal supplements, and keep in mind the possibility of herb-drug interactions.