Published in the October 16 issue of The Journal of the American Medical Association, the report also cautions that some widely publicized approaches have less proven or uncertain efficacy. Fish oil (omega-3 polyunsaturated fatty acids) and calcium supplements lower blood pressure only slightly in individuals with hypertension. In addition, the ability of herbal and botanical supplements to safely lower blood pressure is unproven, and these unregulated products can interact adversely with medications.
Developed by a distinguished panel of experts convened by the NHBPEP Coordinating Committee, the advisory reflects the latest scientific evidence and updates the first recommendations on preventing high blood pressure released nearly a decade ago. Like the 1993 advisory, the new report emphasizes two overall strategies to keep blood pressure from rising: a population-based strategy and an intensive strategy for high-risk individuals. High blood pressure (systolic blood pressure at or above 140 mmHg or diastolic blood pressure at or above 90 mmHg) is associated with an increased risk of death and disability from heart disease, stroke, congestive heart failure, and end-stage renal disease.
"The United States has made substantial gains over the past several decades in preventing high blood pressure and in detecting and controlling high blood pressure when it does develop," said Dr. Claude Lenfant, director of the National Heart, Lung, and Blood Institute (NHLBI), which coordinates the NHBPEP. "However, Americans continue to be at high risk for hypertension and related complications. These revised recommendations can help us do better."
Fifty million adults in the United States -- including more than one of every two adults over the age of 60 -- have high blood pressure, according to the National Center for Health Statistics. Furthermore, data from NHLBI's landmark Framingham Heart Study suggest that middle-aged and elderly individuals face a 90 percent risk of developing hypertension during their remaining years.
Framingham research has also shown that the risk of cardiovascular disease associated with high blood pressure increases gradually - even before hypertension occurs. The approximately 23 million adults in the U.S. with high-normal blood pressure levels (systolic pressure of 130-139 mmHg and/or a diastolic pressure of 85-89 mmHg) are 1.5 to 2.5 times more likely to have a cardiovascular event or to die within 10 years, compared to those with optimal blood pressure (systolic pressure of less than 120 mmHg and diastolic pressure of less than 80 mmHg). Normal blood pressure levels are 120-129 mmHg systolic and 80-84 mmHg diastolic.
"Epidemiological data suggest that if we could lower the average systolic blood pressure among Americans by 5 mmHg, we'd see a 14 percent drop in deaths from stroke, a 9 percent drop in heart disease deaths, and a 7 percent drop in overall mortality," said Dr. Paul Whelton, senior vice president for health sciences for Tulane University Health Sciences Center and co-chair of the NHBPEP working group that developed the latest recommendations. "A reduction as small as 2 mmHg in the average American's systolic blood pressure could save more than 70,000 lives per year."
Proven behavioral changes can lower one's blood pressure and reduce the risk of a cardiovascular event. The report cites one study, for example, that found that people with normal blood pressure levels who increased the amount of regular physical activity lowered their systolic blood pressure by more than 4 mmHg. In another study, overweight participants with normal blood pressure levels significantly lowered their systolic blood pressure by losing weight (fewer than 8 lbs); in addition, the percentage of participants in this group who had high blood pressure seven years later was less than half of the percentage of the control group which remained overweight.
The clinical trial known as Dietary Approaches to Stop Hypertension, or DASH, has demonstrated the critical role of nutrition in controlling blood pressure. Based on the results of DASH, the NHBPEP now recommends an eating plan that is rich in fruits, vegetables, and low-fat dairy products and that has limited saturated and total fat.
Furthermore, limiting daily dietary sodium intake to less than 2,400 mg of sodium (about 1 teaspoon of salt) per day helps lower or control blood pressure. In one study, older patients with hypertension significantly lowered their systolic blood pressure and decreased their need for medications by moderately reducing how much sodium they consumed. The advisory highlights that although limiting the amount of salt added during cooking and at the table is important, three-fourths of the average individual's total intake of salt and sodium comes from sodium added during processing and manufacturing. Therefore, NHBPEP urges food manufacturers to lower the amount of sodium in the food supply - and to offer these products at equitable prices.
Other behavioral changes for people with blood pressure above optimal levels include consuming more than 3,500 mg of dietary potassium per day - an approach especially important for individuals with high sodium intake - and limiting alcohol consumption to no more than 1 ounce of ethanol (e.g., 24 oz beer, 10 oz wine, or 2 oz 100-proof whiskey) per day in most men and to no more than 0.5 ounce per day in women.
These lifestyle factors are essential for seniors and others who are more likely to develop high blood pressure, such as those with high-normal blood pressure or a family history of hypertension; those who are African American, overweight or obese, or inactive; and those who consume more than the recommended amounts of dietary sodium or alcohol, or insufficient amounts of potassium.
The report advises, however, that efforts to prevent blood pressure from rising in children are also important. School administrators can help by offering heart healthy foods in their cafeterias and health education programs in their classrooms.
"Our society needs to better support individuals who are trying to make healthy lifestyle changes," said Dr. Jiang He, who co-chaired the NHBPEP working group with his Tulane colleague. For instance, reimbursement of counseling services for hypertension prevention could help consumers adopt healthy behaviors.
"Consumers need to be better informed about portion sizes, food content and labeling," added NHBPEP Coordinator Dr. Edward Roccella. "Training programs for health care providers also need to focus more on nutrition and other lifestyle issues related to blood pressure."
Established in 1972, the NHBPEP strives to reduce death and disability related to high blood pressure through programs of professional, patient, and public education. NHBPEP is a cooperative effort among professional and voluntary health agencies, state health departments, and community groups.
To learn more, visit the NHLBI Web site at www.nhlbi.nih.gov. Click on Special Web Pages and Interactive Applications, then High Blood Pressure for interactive quizzes and tools, such as a body mass index calculator; tips, recipes and real-life examples to help control blood pressure; and other educational materials for consumers and clinicians.
NHLBI is part of the National Institutes of Health (NIH) in Bethesda, Maryland. NIH is an agency of the U.S. Department of Health and Human Services.