Salt consumption is regulated by the body
Many people are trying to reduce their salt consumption in an effort to reduce elevated blood pressure, or because they think that too much salt consumption is bad in some way for them. A new study shows that the body is pretty good at regulating its salt intake, and efforts to reduce the level of salt in foods (think restaurant foods which often are heavily salted) will not work since the body will seek extra salt elsewhere.
The study documents in humans what neuroscientists have reported for some time: animals' sodium (salt) intake is controlled by networks in the brain and not by the salt in one’s food. The findings have important implications for future U.S. nutrition policy directed at sodium intake.
Findings from the new study, entitled "Normal Range of Human Dietary Sodium Intake: A Perspective Based on 24-hour Urinary Sodium Excretion Worldwide," is published online in advance of the print edition of the American Journal of Hypertension.For decades, U.S. health policies have emphasized the importance of limiting salt consumption in order to lower the risks of cardiovascular disease related to high blood pressure. This new scientific review, however, found that people have a very predictable and narrow range of daily sodium intake (approximately 2,600 mg to 4,800 mg per day) that has remained quite constant during more than 50 years and across at least 45 countries.
"Our data clearly demonstrate that humans' sodium (salt) intake is regulated within a relatively narrow 'normal' range that is defined by the body's physiology and biological need rather than by the food supply," said the study’s lead author David McCarron, a physician and adjunct professor in the UC Davis Department of Nutrition. "The nation’s future health policies and guidelines should be developed based on that biologically determined range."
He noted that these findings were recently presented to an Institute of Medicine committee, which prepared the report "Sodium Intake in Populations — Assessment of Evidence."
"In releasing that report, the Institute of Medicine acknowledged for administrative reasons that it remained silent on what constituted the 'normal range' of sodium intake for humans and specifically what defined 'excessive' intake," McCarron said. He noted that the institute's report was explicit in stating that the current U.S. sodium guidelines for healthy individuals (no more than 2,300 mg per day) and for those at risk of heart disease (no more than 1,500 mg per day) were unsupported by data in the medical literature.
"However, our research team's new study, combined with our 2009 publication, now defines what for humans is the normal range of sodium or salt intake and suggests what would constitute both an excessive and deficient sodium intake in terms of promoting optimal health," McCarron said. "Our data demonstrate that past U.S. guidelines for sodium (salt) intake are well below human needs."
Salt on wooden spoon image via Shutterstock.
Read more at University of California.