Yesterday, Reason 24/7 reported the new conclusion by the influential Institute of Medicine that a drastically low salt diet does not seem to improve health outcomes such as lower blood pressure and fewer deaths from heart disease. The recommendations from various medical groups, such as the American Heart Association, that Americans cut back their intake of salt rest on epidemiological findings that, by definition, ignore individual genetics and circumstances. In other words, we must all suffer bland food in order to make sure that the more sensitive among us are protected.
Good news—we who savor salt may no longer have to endure the scoldings (and regulations) of nutrition fundamentalists. Researches at the University of Virginia have developed a test that can identify the 25 percent of Americans who are salt sensitive. From the UVA press release:
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.
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 U.Va. research helps make clear that each individual is genetically programmed with a "personal salt index" and thus sodium chloride dietary guidelines should be personalized.
U.Va.'s Robin Felder, the senior author on a paper on the topic published recently 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.'"
He 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.
This particular test isolates kidney cells shed in a person's urine and analyzes them to see what effect salt consumption has. The researchers hope that their test will become a routine part of medical care in which salt sensitive folks are identified. This is what personalized medicine is about—not treating us with one-size-fits all treatments and recommendations.
For more background on the anti-salt crusade (NYC Mayor Bloomberg included), see my colleague Jacob Sullum's excellent reporting starting here.
Disclosure: I consume lots of salt daily and when it was checked last month my blood pressure was 115 over 70. That being said, if you have high blood pressure you really should get it treated.