Reducing sodium intake by any amount can lower blood pressure over the long term – and may benefit everyone, including people with normal blood pressure, new research shows.
While the link between consuming less-salty foods and lower blood pressure is well established, researchers wanted to understand the exact nature of the link over a range of daily sodium amounts, not simply the results of eating a high-salt versus low-salt diet.
After analyzing 85 studies that followed participants for up to three years, they found any reduction in sodium decreases both systolic blood pressure (the top number in a reading) and diastolic pressure (the bottom number). This trend was seen across a spectrum of daily sodium levels, with no evidence there was a bottom threshold in benefit.
“We found this decrease in sodium was beneficial for people consuming very low sodium intakes, having normal blood pressure, and in the long term,” said Dr. Marco Vinceti, senior author of the analysis published Monday in the American Heart Association journal Circulation. Vinceti is professor of epidemiology and public health at the University of Modena and Reggio Emilia Medical School in Italy and an adjunct professor at Boston University School of Public Health.
Too much sodium in your system promotes water retention in the bloodstream. Over time, the extra volume of blood can stress and stiffen blood vessels, making the heart work harder to maintain blood flow. The whole process can lead to an increased risk of heart attack and stroke.
The ideal daily sodium limit to maintain healthy blood pressure, and thus lower the risk for cardiovascular diseases, has been debated for years. While people do need some sodium – less than 500 milligrams a day – to maintain the body’s functions, most Americans eat far too much of it.
The average person consumes about 3,400 mg of sodium per day, and most of it comes from packaged and prepared foods, according to federal dietary guidelines. Those guidelines recommend adults consume no more than 2,300 mg per day – that’s about 1 teaspoon of salt – to avoid hypertension and cardiovascular disease. The AHA, however, recommends most adults limit daily intake to 1,500 mg.