The Pittsburgh Post Gazette reports on a study released on-line in The Clinical Journal of the American Society of Nephrology which indicates that physiology, not public policy, determines a human’s daily sodium intake. This research likely represents a important step forward in light of past and current efforts by government agencies and government funded organizations to set progressively restrictive guidelines for salt intake among U.S. citizens.
The study, Can Dietary Sodium Intake be Modified by Public Policy? (David A. McCarron, Joel C. Geerling, Alexandra G. Kazaks, Judith S. Stern), analyzed existing research to determine whether sodium or salt intake follows a pattern consistent with a range set by the brain to protect normal function of organs such the heart and kidney. The analysis is based upon 19,151 subjects studied in 62 previously published surveys and reflects the differing ‘food environments’ of 33 countries across the globe. The data reported documents that humans have a habitual sodium intake in the range of 2800 to 4600 mg/day with an average of 3600 mg/day. Currently, the U.S. consumes an average of about 3,500 mg/day.
The Dietary Guidelines Advisory Committee of the U.S. Health and Human Services and the U.S. Department of Agriculture considers 2,300 mg/day sodium to be a healthy maximum. However, that is almost 20% lower than the minimum intake observed in the 19,000-plus subjects reported in this first-time analysis. In spite of that reality, the Committee is in the midst of a review to determine whether that recommendation should be lowered even further. An Institute of Medicine Committee is also considering a strategy to reduce dietary sodium.
This study's lead author is David A. McCarron, MD, FACP. Dr. McCarron is the author of more than 250 scientific publications, over 500 scientific papers at research meetings and serves on the editorial boards of several professional journals. He has served as a consultant, investigator, media contact, or medical board member to many organizations (both public and private) over the past 25 years. Dr. McCarron believes that policy makers should thoughtfully consider this evidence that sodium intake is physiologically set and tightly regulated by networks in the human brain, thus making it unlikely that public policy can change it.
“If sodium intake is physiologically determined, then our national nutrition guidelines and policies must reflect that reality,” he stated. “It is unrealistic to attempt to regulate America’s sodium consumption through public policy when it appears that our bodies naturally dictate how much sodium we consume to maintain a physiologically set normal range. To do otherwise will expend valuable national and personal resources against unachievable goals.”
Joining in this study is
Joel C. Geerling, a neuroscientist and physician formerly of Washington University in St. Louis, and now at New York–Presbyterian Hospital/Columbia University Medical Center.
“Decades of neuroscience research have revealed highly sophisticated brain circuits which regulate sodium appetite by facilitating communications between the brain and multiple organs throughout the body,” Dr. Geerling said. “One purpose of these pathways is to ensure that the body is obtaining adequate sodium from the diet to fulfill physiologic needs.”
Dr. Judith Stern,
Distinguished Professor at UC Davis, and a recognized expert on nutrition and health matters, said lawmakers "need to work on setting priorities," and should be focusing on more immediate public health issues, such as childhood obesity.
- Amy Alkon:
What Don't They Want to Control?
