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Researchers look for the best way to help shake too much sodium

Multiple times each day, about a third of blacks hold onto sodium – and higher blood pressure – for at least an hour after the stress that raised their pressure has passed, scientists say.

Now they want to know how chronic mental stress, obesity, and inflammation conspire to produce this unhealthy response so they can determine the best ways to treat it.

“We know that holding onto sodium is bad for you – these patients have increased damage to their hearts, their kidneys, and their vasculature – so how do we optimally treat them?” said Dr. Gregory Harshfield, Director of the Georgia Prevention Institute at the Medical College of Georgia at Georgia Regents University and Dorothy A. Hahn, MD Chair in Pediatrics.

Nearly a third of American adults – about 67 million people – are hypertensive and 35.8 million have uncontrolled hypertension, including 16 million individuals who are taking one or more medications, according to the Centers for Disease Control and Prevention.

Harshfield is Principal Investigator on a $10.6 million Program Project grant re-renewal from the National Heart, Lung and Blood Institute that’s enrolling 1,200 people in six different studies at MCG designed to parse the unfortunate synergy and test therapeutic strategies they hope will significantly reduce the uncontrolled number.

To better discern how all the multiple factors interact, parallel animal studies are being conducted by Drs. David and Jennifer Pollock, Director and Co-Director, respectively, of the Section of Translational Cardio-Renal Research at the University of Alabama at Birmingham School of Medicine.

Sodium retention, which is regulated by the kidneys, is a natural way the body responds to stress. It’s part of the fight-or-flight survival mechanism that gets the heart pounding and the body moving quickly when needed, Harshfield said.

But he has shown that about 30 percent of blacks – and about 15 percent of whites – hold onto an additional 250 milligrams of salt – about what’s found in a medium order of fast-food fries – each time they are stressed.

Now he and a team of researchers that also includes Dr. Ryan A. Harris, clinical exercise physiologist, and Dr. Yanbin Dong, geneticist and cardiologist, want to know exactly how that occurs. They suspect that it can vary with the individual. “We are trying to tease out the mechanism underlying sodium retention,” Harshfield said.