Download Lifestyle Modification as a Means to Prevent and Treat High Blood

J Am Soc Nephrol 14: S99–S102, 2003
Lifestyle Modification as a Means to Prevent and Treat High
Blood Pressure
LAWRENCE J. APPEL
Professor of Medicine, Epidemiology, and International Health (Human Nutrition), Welch Center for
Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland.
Abstract. High BP is one of the most important and common
risk factors for atherosclerotic cardiovascular disease and renal
disease. The contemporary approach to the epidemic of elevated BP and its complications involves pharmacologic treatment of hypertensive individuals and “lifestyle modification,”
which is beneficial for both nonhypertensive and hypertensive
persons. A substantial body of evidence strongly supports the
concept that lifestyle modification can have powerful effects
on BP. Increased physical activity, a reduced salt intake,
weight loss, moderation of alcohol intake, increased potassium
intake, and an overall healthy dietary pattern, termed the Di-
etary Approaches to Stop Hypertension (DASH) diet, effectively lower BP. The DASH diet emphasizes fruits, vegetables,
and low-fat dairy products and is reduced in fat and cholesterol. Other dietary factors, such as a greater intake of protein
or monounsaturated fatty acids, may also reduce BP but available evidence is inconsistent. The current challenge to health
care providers, researchers, government officials, and the general public is developing and implementing effective clinical
and public health strategies that lead to sustained lifestyle
modification.
Efforts to control the epidemic of high BP and its cardiovascular and renal complications have traditionally focused on
pharmacologic treatment of persons with established hypertension. Such efforts reflect an impressive body of evidence that
has documented the beneficial effects of antihypertensive drug
therapy in preventing BP-related clinical complications. Still,
reliance on drug therapy alone is an incomplete solution to the
epidemic of high BP and its complications. First, it is well
recognized that the risk of BP-related cardiovascular and renal
disease increases progressively throughout the range of BP,
including ranges of BP previously considered normal. Furthermore, a large fraction of adults have a BP that is above optimal
and yet is below the traditional threshold for drug treatment.
Such BP levels nonetheless place individuals at increased risk
of BP-related complications, yet they are not candidates for
drug therapy. In view of these considerations, national and
international policy-making bodies recommend lifestyle modification as a means to prevent and treat hypertension and
thereby prevent cardiovascular and renal disease in the whole
population.
individuals, lifestyle modifications can serve as initial treatment before the start of drug therapy and as an adjunct to
medication in persons already on drug therapy. In hypertensive
individuals with medication-controlled BP, these therapies can
facilitate drug step-down and drug withdrawal in highly motivated individuals who achieve and sustain lifestyle changes. In
nonhypertensives, lifestyle modifications have the potential to
prevent hypertension, and more broadly to reduce BP and
thereby lower the risk of BP-related clinical complications in
whole populations. Indeed, even an apparently small reduction
in BP, if applied to an entire population, could have an enormous beneficial effect on cardiovascular events. For instance,
a 3-mmHg reduction in systolic BP should lead to an 8%
reduction in stroke mortality and a 5% reduction in mortality
from coronary heart disease (1).
The following sections highlight the effects of specific lifestyle therapies that reduce BP.
Increasing Physical Activity. An increased level of physical activity can lower BP, independent of concomitant
changes in weight. A recent meta-analysis of 27 randomized
trials documented a 4 mmHg net reduction in systolic BP
among individuals assigned to an aerobic exercise intervention
(2). Interestingly, the magnitude of BP change appeared to be
independent of the exercise intensity. In addition to a direct
beneficial effect on BP, increased physical activity should also
lower BP by facilitating initial weight loss and by promoting
maintenance of weight loss, once achieved. In aggregate, these
findings support the recommendation of the US Surgeon General that persons exercise 30 min or more most, if not all, days
of the week.
Reducing Salt (Sodium Chloride) Intake. A high intake
of salt (sodium chloride) adversely affects BP. Evidence includes results from animal studies, epidemiologic studies, and
Role of Lifestyle Modification
Lifestyle modification, previously termed nonpharmacologic therapy, has important roles in hypertensive as well as
nonhypertensive individuals (see Table 1). In hypertensive
Correspondence to Dr. Lawrence J. Appel, Johns Hopkins Medical Institutions, 2024 East Monument Street, Suite 2-645, Baltimore, MD 21205-2223.
Phone: 410-955-4156; Fax: 410-955-0476; E-mail: [email protected]
1046-6673/1407-0099
Journal of the American Society of Nephrology
Copyright © 2003 by the American Society of Nephrology
DOI: 10.1097/01.ASN.0000070141.69483.5A
S100
Journal of the American Society of Nephrology
J Am Soc Nephrol 14: S99–S102, 2003
Table 1. Role of lifestyle modification therapies in
hypertensive and nonhypertensive individuals
●Hypertensive individuals
-initial therapy
-adjunct to drug therapy
-facilitate drug step-down or withdrawal
●Nonhypertensive individuals
-reduce blood pressure
-prevent hypertension
clinical trials. Recent studies have documented that a reduced
sodium intake can prevent hypertension (TOHP2, phase 2 of
the Trials of Hypertension Prevention) (3), can facilitate hypertension control in older-aged persons on medication
(TONE, Trials of Non-Pharmacologic Interventions in the Elderly) (4), and can potentially prevent cardiovascular events in
overweight individuals (5,6). TOPH2 documented that sodium
reduction, alone or combined with weight loss, can reduce the
incidence of hypertension by approximately 20%. In the
TONE, a reduced salt intake with or without weight loss
effectively reduced BP and the need for antihypertensive medication in older persons. In both trials, the dietary interventions
reduced total sodium intake to approximately 100 mmol/d.
Such data reinforce current guidelines to limit salt intake to 6
g/d, the equivalent of 100 mmol of sodium (2400 mg) per day.
Results from the recently completed the Dietary Approaches
to Stop Hypertension (DASH)-Sodium feeding study have
documented that an even lower intake of sodium, approximately 60 mmol/d, further reduces BP in a broad population of
nonhypertensive and hypertensive individuals (7). The DASHSodium trial tested the effects on BP of three levels of sodium
reduction in two distinct diets. The three sodium levels were
“higher” (target of approximately 143 mmol/d, reflecting typical US consumption), “intermediate” (target of 106 mmol/d,
reflecting the upper limit of current US recommendations), and
“lower” (target of 65 mmol/d, reflecting a level that could
produce additional lowering of BP). Main results are displayed
in Figure 1. In a typical American (control) diet, reducing
sodium intake from the higher to the intermediate level significantly reduced systolic BP by 2.1 mmHg; reducing sodium
intake from the intermediate to the lower level further reduced
systolic BP by 4.6 mmHg. In the DASH diet, corresponding
changes in systolic BP were ⫺1.3 and ⫺1.7 mmHg, respectively. The effects of sodium reduction tended to be greater in
blacks than whites. Compared with the control diet with higher
sodium, the DASH diet with lower sodium reduced systolic BP
by 7.1 mmHg in nonhypertensive persons, and 11.5 mmHg in
hypertensives. The pattern of results was similar for diastolic
BP.
Results from the DASH-Sodium trial support current, population-wide recommendations to lower salt intake. These data
also document the benefit of consuming the DASH diet (discussed below) and reducing salt intake. To reduce salt intake,
consumers should choose foods low in salt and limit the
amount of salt added to food. However, even motivated indi-
Figure 1. Effects of reduced sodium intake in a typical American
(control) diet and the Dietary Approaches to Stop Hypertension
(DASH) diet: Main results from the DASH-sodium trial, adapted with
permission from reference 7.
viduals find it difficult to reduce salt intake because of the huge
amount of salt added by food manufacturers during food processing. Hence, any meaningful strategy to reduce salt intake
must involve the efforts of food manufacturers who should
reduce the amount of salt added during preparation.
Maintaining a Healthy Body Weight. A consistent body
of evidence from observational studies and clinical trials indicates that weight is positively associated with BP and hypertension. The importance of this relationship is reinforced by the
high and increasing prevalence of overweight and obesity
throughout the world. Virtually every clinical trial that has
examined the influence of weight loss on BP has documented
that weight reduction lowers BP (8). Interestingly, reductions
in BP occur before (and without) attainment of desirable body
weight. In one study that aggregated results across 11 weight
loss trials, average systolic and diastolic BP reductions were
1.6/1.1 mmHg per kilogram of weight loss (9). Lifestyle intervention trials have uniformly achieved short-term weight loss.
In several instances, substantial weight loss has also been
sustained over 3 yr or more.
Moderating Alcohol Intake (among Those Who Drink).
The relationship between high alcohol intake (typically three or
more drinks per day) and elevated BP has been documented in
many epidemiologic studies. Trials have also reported that
reductions in alcohol intake can lower BP in normotensive and
hypertensive men who are heavy drinkers. In the Prevention
and Treatment of Hypertension Study, which studied moderate-to-heavy drinkers, a reduction in alcohol intake lowered BP
to a small, nonsignificant extent (10). In aggregate, available
evidence supports a recommendation to limit alcohol intake to
no more than two drinks per day (men) and one drink per day
(women) among those who drink.
Increasing Potassium Intake. In contrast to the direct
relationship of salt intake with BP, high levels of potassium are
associated with low BP. Although observational data have
been reasonably consistent, data from individual clinical trials
have been less consistent and persuasive. However, a metaanalysis of these trials documented that supplementation of diet
J Am Soc Nephrol 14: S99–S102, 2003
with potassium lowered BP (11). On average, a typical dose of
60 to 120 mmol/d of supplemental potassium reduced systolic
and diastolic BP by 4.4 and 2.5 mmHg in hypertensives and by
1.8 and 1.0 mmHg in normotensives. This study also documented greater BP reductions from potassium in blacks compared with whites and greater BP reduction from potassium at
higher levels of salt intake. Because a high dietary intake of
potassium can be achieved through diet rather than pills and
because potassium derived from foods also comes with a
variety of other nutrients, the preferred strategy to increase
potassium intake is to consume foods rich in potassium rather
than supplements.
Consuming a Diet That Emphasizes Fruits, Vegetables,
and Low-Fat Dairy Products, and That Is Reduced in Fat
and Cholesterol. Certain dietary patterns have been associated with low BP. For instance, in observational studies and
two clinical trials, vegetarian diets have been associated with
lower BP. The nutrients responsible for the BP-lowering effects of these diets have remained uncertain. Attention has
focused on macronutrients (particularly the type and amount of
fat), micronutrients (potassium, magnesium, and calcium) and
fiber. However, data from observational studies and small scale
trials have been extremely inconsistent. Phase 1 of TOPH
tested the individual effects of these micronutrients and lifestyle factors on BP (12). In this large scale trial that enrolled
over 2000 persons with high normal diastolic BP (80 to 89
mmHg), calcium and magnesium had no significant effect on
BP, whereas weight loss and sodium reduction each lowered
BP (Figure 2).
In view of these perplexing and inconsistent data, the DASH
trial was a controlled feeding study designed to test the effects
of modifying whole diets on BP (13). Main results are displayed in Figure 3. The most effective diet, now termed the
DASH diet, emphasizes fruits, vegetables, and low-fat dairy
products; includes whole grains, poultry, fish, and nuts; and is
reduced in fat, red meat, sweets, and sugar-containing beverages. The diet is rich in potassium, magnesium, and calcium.
Among nonhypertensive individuals, this diet reduced systolic
and diastolic BP by 3.5 and 2.1 mmHg, respectively. In hypertensives, corresponding BP reductions were striking, i.e.,
Figure 2. Effects on BP at 6 mo from weight loss (Wt), sodium
reduction (Na), and stress management (SM) interventions, and pill
supplementation with calcium (Ca), magnesium (Mg), potassium (K),
and fish oil (FO): Main results from phase 1 of the trials of hypertension prevention (TOHP1), adapted with permission from reference
12.
Lifestyle Modification and Blood Pressure
S101
Figure 3. Mean blood pressure by week of feeding in a typical
American diet (control diet), a diet rich in fruits and vegetables, and
the DASH diet (rich in fruits, vegetables, and low-fat dairy products
and reduced in saturated fat, total fat, and cholesterol): Main results of
the DASH trial, adapted with permission from reference 13.
11.4 and 5.5 mmHg. Similar to the meta-analysis of potassium,
the DASH diet reduced BP to a greater extent in African
Americans than non-African Americans.
Other Factors That Might Influence BP. Evidence from
observational epidemiologic studies and several small trials
suggest that supplementation of diet with omega-3 polyunsaturated fatty acids (omega-3 PUFA, commonly termed “fish
oil”) can reduce BP. In two meta-analyses, high doses of
omega-3 PUFA, typically 3 g or more of fish oil per day,
reduced BP (14). Significant BP reductions were evident in
hypertensive individuals but not in nonhypertensive persons.
However, the high dose of omega-3 PUFA with its attendant
side effects precludes recommendations for its routine use as a
means to lower BP.
The effects of monounsaturated fatty acids on BP have
received scant attention. In one recent trial, a diet rich in
monunsaturated fatty acids lowered systolic and diastolic BP
by 8 and 6 mmHg, respectively (15). In view of these results,
as well as the enormous interest in “Mediterranean” style diets
that are associated with reduced risk of cardiovascular disease,
additional research on the BP effects of monounsaturated fatty
acids is warranted.
Epidemiological studies strongly support the hypothesis that
increased protein intake can lower BP (16). This inverse relationship has been documented in several populations, including
Japanese rural farmers, Japanese-American men in Hawaii,
American men in two cohort studies, British men and women,
Chinese men and women, and American children. The source
of protein, animal versus nonanimal, may also have a differential effect on BP. To date, only small, underpowered trials
have tested the effect of protein, amount or type, on BP.
S102
Journal of the American Society of Nephrology
J Am Soc Nephrol 14: S99–S102, 2003
Discussion
Multiple dietary factors influence BP. The effects of each
factor are typically modest, particularly in normotensives, yet
the combined effects can be substantial. Hence, public health
and clinical recommendations should remain multifaceted. A
related theme is that it is exceedingly unlikely that a “magic
nutrient” will be found. Even the impressive reductions reported in the DASH study are best interpreted as a combined
effect from multiple dietary factors rather than the effects of a
single factor.
Hypertensive individuals, older-aged persons, and blacks are
groups that are especially sensitive to the effects of diet on BP.
The greater efficacy of lifestyle modification in hypertensives
compared with nonhypertensives is a ubiquitous finding. In the
DASH-Sodium feeding study, persons ⬎45 yr achieved significantly greater BP reductions from the DASH diet with
reduced salt intake than younger individuals (17). The TONE
trial, which enrolled individuals 60 to 80 yr of age with
medication-treated high BP, documented that older-aged persons can achieve and sustain reductions in sodium and weight
and that these lifestyle changes lower BP and the need for
antihypertensive medication (4). Likewise, evidence from clinical trials has documented that a reduced salt intake, increased
potassium intake, and the DASH diet are particularly effective
in blacks (7,11,13). Given the substantial burden of vascular
disease in hypertensives, older-aged persons, and blacks, targeted public health efforts that promote lifestyle modifications
in these populations are warranted and, if adequately implemented, should be especially effective.
Summary
Multiple dietary factors influence BP. Although each factor
typically has a modest effect, the combined effects can be
substantial. From a public health perspective, even a small
reduction in BP should have a tremendous, beneficial effect on
the occurrence of hypertension and its complications. In view
of the current epidemic of BP-related diseases and the proven
effects of lifestyle modifications on BP, the current challenge
to health care providers, researchers, and public officials is to
develop and implement effective clinical and public health
strategies that achieve and maintain healthy lifestyle
modification.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
References
1. Stamler J, Rose G, Stamler R, Elliott P, Dyer A, Marmot Michael: INTERSALT study findings: Public health and medical
care implications. Hypertension 14: 570 –577, 1989
2. Whelton SP, Chin A, Xin X, He J: Effect of aerobic exercise on
blood pressure: A meta-analysis of randomized, controlled trials.
Ann Int Med 136: 493–503, 2002
3. The Trials of Hypertension Prevention Collaborative Research
Group. Effects of weight loss and sodium reduction intervention
on blood pressure and hypertension incidence in overweight
people with high-normal blood pressure. The Trials of Hyper-
15.
16.
17.
tension Prevention, Phase II. Arch Intern Med 157: 657– 667,
1997
Whelton PK, Appel LJ, Espeland MA, Applegate W, Ettinger W,
Kostis JB, Kumanyika S, Lacy CR, Johnson K, Folmar S, Culter
J for the TONE Collaborative Research Group: Efficacy of
sodium reduction and weight loss in the treatment of hypertension in older persons: Main results of the randomized, controlled
trial of nonpharmacologic interventions in the elderly (TONE).
JAMA 279: 839 – 846, 1998
He J, Ogden LG, Vupputuri S, Bazzano LA, Loria C, Whelton
PK: Dietary sodium intake and subsequent risk of cardiovascular
disease in overweight adults. JAMA 282: 2027–2034, 1999
Tuomilehto J, Jousilahti P, Rastenyte D: Urinary sodium excretion and cardiovascular mortality in Finland: A prospective
study. Lancet 357: 848 – 851, 2001
Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA,
Harsha D, Obarzanek E, Conlin PR, Miller ER, Simons-Morton
DG, Karanja N, Lin PH, for the DASH-Sodium collaborative
research group: A clinical trial of the effects on blood pressure of
reduced dietary sodium and the DASH dietary pattern (the
DASH-sodium trial). N Engl J Med 344: 3–10, 2001
NHLBI: Clinical guidelines on the identification, evaluation, and
treatment of overweight and obesity in adults: The evidence
report. J Obesity Res 6: 51S–209S, 1998
Staessen J, Fagard R, Lijnen P, Amery A: Body weight, sodium
intake, and blood pressure. J Hypertens 7: S19 –S23, 1989
Cushman WC, Cutler JA, Hanna E, Bingham SF, Follmann D,
Harford T, Dubbert P, Allender PS, Dufour M, Collins JF, Walsh
SM, Kirk GF, Burg M, Felicetta JV, Hamilton BP, Katz LA,
Perry HM Jr, Willenbring ML, Lakshman R, Hamburger RJ:
Prevention and Treatment of Hypertension Study (PATHS): Effects of an alcohol treatment program on blood pressure. Arch Int
Med 158: 1197–1207, 1998
Whelton PK, He J, Cutler JA, Brancati FL, Appel LJ, Follmann
D, Klag MJ: Effects of oral potassium on blood pressure. Metaanalysis of randomized controlled clinical trials. JAMA 277:
1624 –1632, 1997
The Trials of Hypertension Prevention Collaborative Research
Group. The effects of nonpharmacologic interventions on blood
pressure of persons with high normal levels. JAMA 267: 1213–
1220, 1992
Appel LJ, Moore TJ, Obarzanek E, Vollmer WM, Svetkey LP,
Sacks FM, Bray GA, Vogt TM, Windhauser MM, Pao-Hwa L,
Karanja N for the DASH Collaborative Research Group: A
clinical trial of the effects of dietary patterns on blood pressure.
N Engl J Med 336: 1117–1124, 1997
Appel LJ, Miller ER, Seidler AJ, Whelton PK: Does supplementation of diet with “fish oil” reduce blood pressure? A metaanalysis of controlled clinical trials. Arch Intern Med 153: 1429 –
1438, 1993
Ferrara LA, Raimondi S, d’Episcopa L, Guida L, Russo AD,
Marotta T: Olive oil and reduced need for anti-hypertensive
medications. Arch Intern Med 160: 837– 842, 2000
He J, Whelton PK: Effect of dietary fiber and protein intake on
blood pressure: A review of Epidemiologic evidence. Clin Exper
Hypertension 21: 785–796, 1999
Vollmer WM, Sacks FM, Ard J, Appel LJ, Bray GA, SimonsMorton DG: Effects of dietary patterns and sodium intake on
blood pressure: subgroup analysis of the DASH-sodium trial.
Ann Int Med 135: 1019 –1028, 2001