UVA Research: Recommended Salt Intake Differs for Each Person
University of Virginia researchers have found that - contrary to common advice - each person has a specific salt index and some people should actually consume more salt.
Experts usually recommend a low-salt diet to prevent blindness, kidney failure and strokes.
Researchers at the UVA School of Medicine have come up with a test that examines urine samples to identify the best salt intake for each person.
"We all have individualized bodies and we respond differently to foods and medication. So salt is no different than that. We each should find out where our salt index is and we should eat less than that number for a daily basis," said Robin Felder, professor of pathology at UVA.
The researchers hope to be able to offer this diagnostic test in doctor's offices within the next year.
University of Virginia Health Center MEDIA RELEASE
UVA Solving the Dietary Salt Question: Is a Low-Salt Diet Good for Everyone? New Diagnostic Test Can Identify Optimal Salt Intake for Each Person
CHARLOTTESVILLE, Va., April 30, 2013 – Researchers at the University of Virginia School of Medicine have cut through conflicting advice about salt consumption by demonstrating that each person has a "personal salt index," an upper limit on daily salt consumption for good health. In addition, they have developed a test to determine that level – and to identify people who should consume more salt.
How Much Salt? Numerous studies have demonstrated that high blood pressure can be reduced by a low salt diet. While nonprofit organizations such as the American Heart Association and the Institute of Medicine have a "one size fits all" recommendation on salt intake, the UVA research helps make clear that each individual is genetically programmed with a "personal salt index" and thus sodium chloride dietary guidelines should be personalized.
UVA's Robin Felder, PhD, the senior author on a paper on the topic published in the journal Clinica Chimica Acta, explained: "The blood pressure of about 25 percent of the population is sensitive to salt, increasing risk for strokes, heart attacks and kidney failure. An individual's response to salt cannot be measured in a doctor's office. Therefore, we developed a simple test to help the medical community determine an individual's ability to tolerate salt, which we are calling the 'personal salt index.'"
Felder added, "Lowering salt intake might not be good for everyone, since about 15 percent of individuals demonstrate an increase in blood pressure on a low-salt diet – just the opposite of what one would expect." There are other potentially harmful effects of low salt intake, leading to plaques and ultimately blockages in the arteries.
Conflicting Salt Recommendations People often face conflicting salt recommendations. The negative effects of salt appear at the highest and lowest levels of consumption. In other words, sodium chloride intakes that are above and below the range of 2.5–5.8 grams (1.0–2.3 grams of sodium) per day are associated with increased cardiovascular risk.
"If an individual consumes close to their daily personal salt index, they are likely to avoid salt-related illness," said Pedro A. Jose, MD, PhD, of the University of Maryland, a co-investigator in Felder's salt-related research program. "However, additional research will be needed to determine how close one has to adhere to a personal salt index in order to maintain the best state of wellness."
Felder's research was based on a study population tested previously at UVA by Cynthia Schoeffel, MD, and Robert M. Carey, MD, who evaluated how the kidney metabolizes salt and blood pressure in a population of 183 adult volunteers who agreed to follow a special diet of high salt for one week and very low salt for another week.
A Simple Salt Test Felder's laboratory developed the diagnostic test based on living kidney cells found in urine. These cells metabolize sodium similarly to how an individual metabolizes sodium, yet they can be isolated and tested in less than a day using methods developed in Felder's lab.
"Ultimately we could see an instrument in a doctor's office that would allow the doctor to generate a personal salt index during a routine exam and provide meaningful counseling on how to adopt a salt-healthy lifestyle," said John Gildea, PhD, the lead author on the study.
UVA's studies were funded by the National Institutes of Health's Heart, Lung, and Blood Institute.
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