Hypertension report stresses role of diet
potassium and fruit and veg intake, but they also stress caution
when it comes to supplements such as omega-3 and calcium, and
'unregulated' botanicals.
The United States' National High Blood Pressure Education Program (NHBPEP) has updated recommendations for preventing hypertension to include advice such as an adequate intake of potassium and a diet rich in fruit and vegetables.
New recommendations to lower blood pressure also advise a diet rich in low-fat dairy products, lowin saturated and total fat, and reinforcesearlier recommendations to limit consumption of sodium andalcohol, reduce excess body weight, and increase levels ofphysical activity.
Published in the 16 October issue of the Journal of theAmerican Medical Association, the report also cautionsthat some widely publicised approaches have less proven oruncertain efficacy.
Fish oil (omega-3 polyunsaturated fattyacids) and calcium supplements lower blood pressure onlyslightly in individuals with hypertension, according to the recommendations. They also advise that ability of herbal and botanical supplements to safely lowerblood pressure is unproven, and these 'unregulated products'can interact adversely with medications.
Developed by a panel of experts convened bythe NHBPEP Coordinating Committee, the advisory takes into account the latest scientific evidence and updates the firstrecommendations on preventing high blood pressure releasednearly a decade ago. Like the 1993 advisory, the newreport emphasises two overall strategies to keep bloodpressure from rising: a population-based strategy and anintensive strategy for high-risk individuals.
High bloodpressure (systolic blood pressure at or above 140 mmHg ordiastolic blood pressure at or above 90 mmHg) is associatedwith an increased risk of death and disability from heartdisease, stroke, congestive heart failure, and end-stagerenal disease.
"The United States has made substantial gains over the pastseveral decades in preventing high blood pressure and indetecting and controlling high blood pressure when it doesdevelop," said Dr Claude Lenfant, director of the NationalHeart, Lung, and Blood Institute (NHLBI), which coordinatesthe NHBPEP.
"However, Americans continue to be at high riskfor hypertension and related complications. These revisedrecommendations can help us do better."
Fifty million adults in the United States - including morethan one of every two adults over the age of 60 - havehigh blood pressure, according to the National Center forHealth Statistics. Furthermore, data from NHLBI's landmarkFramingham Heart Study suggest that middle-aged and elderlyindividuals face a 90 per cent risk of developinghypertension during their remaining years.
Framingham research has also shown that the risk ofcardiovascular disease associated with high blood pressureincreases gradually - even before hypertension occurs. Theapproximately 23 million adults in the US with high-normal blood pressure levels (systolic pressure of 130-139mmHg and/or a diastolic pressure of 85-89 mmHg) are 1.5 to2.5 times more likely to have a cardiovascular event or todie within 10 years, compared to those with optimal bloodpressure (systolic pressure of less than 120 mmHg anddiastolic pressure of less than 80 mmHg). Normal bloodpressure levels are 120-129 mmHg systolic and 80-84 mmHgdiastolic.
"Epidemiological data suggest that if we could lower theaverage systolic blood pressure among Americans by 5 mmHg,we'd see a 14 per cent drop in deaths from stroke, a 9per cent drop in heart disease deaths, and a 7 per cent dropin overall mortality," said Dr Paul Whelton, senior vicepresident for health sciences for Tulane University HealthSciences Center and co-chair of the NHBPEP working groupthat developed the latest recommendations.
"A reduction assmall as 2 mmHg in the average American's systolic bloodpressure could save more than 70,000 lives per year."
The report also cited research to show that increasing exercise can lower one's blood pressure and reduce the risk of a cardiovascular event.
The NHBPEP's new recommendations are based on results from the clinical trial known as Dietary Approaches to StopHypertension, or DASH, which has demonstrated the critical roleof nutrition in controlling blood pressure.
Furthermore, the NHBPEP urged foodmanufacturers to lower the amount of sodium in the foodsupply. It said that limiting daily dietary sodium intake to lessthan 2,400 mg of sodium (about 1 teaspoon of salt) per dayhelps lower or control blood pressure.
But although limitingthe amount of salt added during cooking and at the table isimportant, three quarters of the average individual's totalintake of salt and sodium comes from sodium added duringprocessing and manufacturing. The advisory suggested that manufacturers should offer lower salt products at equitable prices.
Other behavioural changes for people with blood pressureabove optimal levels include consuming more than 3,500 mgof dietary potassium per day - an approach especiallyimportant for individuals with high sodium intake - andlimiting alcohol consumption to no more than 1 ounce ofethanol (e.g. 24 oz beer, 10 oz wine, or 2 oz 100-proofwhiskey) per day in most men and to no more than 0.5 ounceper day in women.
The guidelines are targeted at the elderly andothers who are more likely to develop high blood pressure,such as those with high-normal blood pressure or a familyhistory of hypertension; those who are African American,overweight or obese, or inactive; and those who consumemore than the recommended amounts of dietary sodium oralcohol, or insufficient amounts of potassium.
The report advises, however, that efforts to prevent bloodpressure from rising in children are also important.
"Consumers need to be better informed about portion sizes,food content and labelling," added NHBPEP coordinator DrEdward Roccella. "Training programmes for health careproviders also need to focus more on nutrition and otherlifestyle issues related to blood pressure."
