NEJM Study Shows Diet, Low Sodium Intake Lowers Blood Pressure 35975

NEJM Study Shows Diet, Low Sodium Intake Lowers BloodPressure
BOSTON--It's a fact--an overload of salt may be bad for you. The NewEngland Journal of Medicine (NEJM) (344 (1):3-10, 2001) published a studyJan. 4 stating the positive effects of reducing sodium uptake in conjunctionwith the Dietary Approaches to Stop Hypertension (DASH) diet. The DASH program,supported by the American Heart Association, is rich in vegetables, fruits,grains, low-fat and fat-free dairy products, fish, legumes, poultry and otherlean meats.
In the NEJM study, 412 participants--with and without hypertension--wererandomly assigned either a control diet mirroring the "typical,"high-fat American diet or the DASH diet. Within each diet, participants consumedfoods containing high (3,300 mg/d), intermediate (2,400 mg/d) and low levels(1,500 mg/day) of sodium for 30 consecutive days.
The researchers, led by Frank M. Sacks from the department of medicine atHarvard Medical School, noted that subjects with higher sodium levels at thestart of the study experienced greater reductions in blood pressure levels. Inthe control group, researchers reduced sodium intake from a high to intermediatelevel, thereby reducing systolic blood pressure by 2.1 mm Hg (millimeters ofmercury); in the DASH group, systolic blood pressure reduced by 1.3 mm Hg. Byreducing sodium from an intermediate to low level, there was an additionalreduction of 4.6 mm Hg in the control group and 1.7 mm Hg in the DASH group. TheNational Institutes of Health's (NIH) National Heart, Lung and Blood Institutesponsored the study and NIH noted that having blood pressure with even slightelevations above the recommended level of 120/80 mm Hg is unhealthy.
Compared to the control diet with a high sodium level, the DASH diet led to amean systolic blood pressure that was 7.1 mm Hg lower in participants withouthypertension and 11.5 mm Hg lower in participants with hypertension.
The researchers concluded that participants who reduced sodium to 1,500 mg perday (equivalent to 4 g or two-thirds of a teaspoon of table salt) and followedthe DASH diet experienced the best results for lowering blood pressure levels."Long-term health benefits will depend on the ability of people to makelong-lasting dietary changes and the increased availability of lower-sodiumfoods," noted the researchers.
In an editorial in the same issue of NEJM, Philip Greenland, M.D. fromNorthwestern University Medical School, wrote that the researchers "addresspreviously unanswered questions about the separate and interactive effects of areduction in dietary sodium and the DASH diet on blood pressure." Inaddition, this was the first trial where sodium intake levels were varied.
Greenland also wrote that the people most affected by consuming a DASH dietalong with reducing sodium intake included blacks, women, older people andpeople with hypertension. "The main message of this new trial, statedforcefully by the authors, is that the results appear to be applicable to mostpeople in the United States," Greenland said, adding that observationalstudies indicate that an overall dietary pattern--as opposed to a singlenutrient or food--is most effective in reducing the risk of chronic disease.
Media outlets widely reported the study results, while mainstream foodorganizations responded as well. The Grocery Manufacturers Association (GMA)noted that it "applauded" the study, adding that the key is"moderation, not martyrdom." The National Food Processors Association(NFPA), meanwhile, encouraged consumers to follow dietary guidance and uselabels wisely. "It is important to know that the amount of sodium in foodsis clearly labeled on food packaging," said Rhona Applebaum, executive vicepresident of scientific and regulatory affairs. "The wide variety of foodproducts on the market--coupled with the information contained on nutritionlabel--are critical components that enable consumers to choose food productsappropriate for their dietary needs."
For an abstract of the study, visit www.nejm.org.