ISMNT NEWS: Disease Prevention by Exploring Molecular Mechanisms Linked to Nutrition

ISMNT News #19 is rewarding to see for anybody involved in disease prevention. We have been told that diets reduced in fat and rich in fruits and vegs should be favoured. However, definite scientific data were often missing. Over the last few years the situation has changed. For example, convincing data show that dietary habits influence the progression of hypertension. Please be aware that hypertension is very often associated with the risk of insulin resistance and hyperinsulinemia (NIDDM). For the U.S. we have to assume that approx 22-32% of adults are hypertensive (NHANES III)and control is achieved in only 14-25% so any news on blood pressure lowering interventions is good news.

Please note, this study is particularly important for affecting progression of hypertension, i.e. only patients were included with SBP<160 mm Hg (160/95 mm Hg was actually the 1990 objective for taking antihypertensive medication of the National High Blood Pressure Education Program).

The key reference is by:

Appel LJ, Moore TJ, Obarzanek E, Vollmer WM, Svetkey LP, Sacks FM, Bray GA, Vogt TM, Cutler JA, Windhauser MM, Lin PH, Karanja N A CLINICAL TRIAL OF THE EFFECTS OF DIETARY PATTERNS ON BLOOD PRESSURE. DASH COLLABORATIVE RESEARCH GROUP

Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD, USA

in

N Engl J Med 1997;336(16):1117-1124

BACKGROUND: It is known that obesity, sodium intake, and alcohol consumption factors influence blood pressure. In this clinical trial, Dietary Approaches to Stop Hypertension, we assessed the effects of dietary patterns on blood pressure.

METHODS: We enrolled 459 adults with systolic blood pressures of less than 160 mm Hg and diastolic blood pressures of 80 to 95 mm Hg. For three weeks, the subjects were fed a control diet that was low in fruits, vegetables, and dairy products, with a fat content typical of the average diet in the United States. They were then randomly assigned to receive for eight weeks the control diet, a diet rich in fruits and vegetables, or a "combination" diet rich in fruits, vegetables, and low-fat dairy products and with reduced saturated and total fat. Sodium intake and body weight were maintained at constant levels.

RESULTS: At base line, the mean (+/-SD) systolic and diastolic blood pressures were 131.3+/-10.8 mm Hg and 84.7+/-4.7 mm Hg, respectively. The combination diet reduced systolic and diastolic blood pressure by 5.5 and 3.0 mm Hg more, respectively, than the control diet (P<0.001 for each); the ruits-and-vegetables diet reduced systolic blood pressure by 2.8 mm Hg more (P<0.001) and diastolic blood pressure by 1.1 mm Hg more than the control diet (P=0.07).

Among the 133 subjects with hypertension (systolic pressure, > or =140 mm Hg; diastolic pressure, > or =90 mm Hg; or both), the combination diet reduced systolic and diastolic blood pressure by 11.4 and 5.5 mm Hg more, respectively, than the control diet (P<0.001 for each); among the 326 subjects without hypertension, the corresponding reductions were 3.5 mm Hg (P<0.001) and 2.1 mm Hg (P=0.003).

CONCLUSIONS: A diet rich in fruits, vegetables, and low-fat dairy foods and with reduced saturated and total fat can substantially lower blood pressure. This diet offers an additional nutritional approach to preventing and treating hypertension.