Registered Dietitian Nutritionist's Book Club Review: The Salt Fix

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Registered Dietitian Nutritionist's Book Club Review: The Salt Fix

09, May 2018 10:51 AM


In April, our Silicon Valley Dietetic Book Club reviewed, The Salt Fix: Why the Experts Got It All Wrong—and how Eating More Might Save Your Life by the Doctor of Pharmacy and Cardiovascular Research Scientist, James DiNicolantonio. His primary thesis: salt isn’t the dietary culprit that we have been led to believe, and the vast majority of Americans don’t need to restrict their sodium intake. Instead, this book suggests the real dietary villain is sugar. 

The author puts forward an evidence-based argument that consuming too little salt causes hunger and increases cravings for sugar. This can lead to weight gain which has negative secondary health consequences such as insulin resistance, type 2 diabetes increased blood pressure and heart rate. 

The book claims there is little evidence that a low-sodium diet will reduce blood pressure in the majority of people. “Evidence in the medical literature suggests that approximately 80 percent of people with normal blood pressure (less than 120/80 mmHg) are not sensitive to the blood-pressure-raising effects of salt at all. Among those with prehypertension, roughly 75 percent are not sensitive to salt. And even among those with full-blown hypertension, about 55 percent are totally immune to salt’s effects on blood pressure.” 

Dr. DiNicolantonio is not alone in questioning the Dietary Guidelines for American’s (DGA) sodium recommendations  of <2,300 milligrams of sodium per day. In fact, the Institute of Medicine (IOM) convened an expert panel on the topic in 2013, concluding that insufficient evidence exists to support the current DGA's recommendations for dietary sodium1.

Areas of Agreement

Additional factors are likely at play in the sodium-blood pressure relationship that were not recognized in the past. For example, potassium intake may lower blood pressure2,3,4, while high body mass index, low physical activity levels, sugar and alcohol intake and tobacco use are additional factors that may raise blood pressure. In fact, we agreed that the real problem may not be what people are eating in excess (e.g. sodium) but what is missing, specifically fruits, vegetables, dairy foods and physical activity. Further, we agree that if adding salt to vegetables increases vegetable consumption, then that is a good trade off.

Where We Differed

When a claim in a nutrition book sounds too good to be true, it usually isn’t. The book claims that by eating all the salt you desire you can:

  • “Improve everything, from your sleep, energy and mental fitness, fertility and sexual performance,”
  • “And stave off common chronic illnesses including heart disease.”

This article published in the Guardian takes it further and describes the recommendations in the book to be dangerous to public health. 

Bottom line

As health professionals it is important to acknowledge that politics can get in the way of effective decision-making. Well-meaning groups, individuals following agendas and old paradigms can influence committees to formulate policies that may or may not align with scientific facts. We must remain critical thinkers and review the science rather than accept recommendations blindly. 

Until the recommendations are more definitive, health professionals who work in clinical settings need to individualize, individualize, individualize. Acknowledge that the DGAs are a starting point for the public, and were never intended to be rigidly adopted by the individual. Ask about family history; assess body weight; examine other lifestyle factors; consider taste, culture, tradition, preferences … and then make recommendations that are feasible, realistic and appropriate for each individual client.

 

Maureen Bligh, MA, RDN
Director, Resource Development and Marketing

Kristal Shelden, MPH, RDN
Project Manager, Nutrition Sciences

 

Maureen and Kristal are registered dietitian nutritionists and members of the Academy of Nutrition and Dietetics.

 

References

1. Institute of Medicine. Sodium Intake in Populations: Assessment of Evidence. 2013. National Academies Press: Washington, DC, 2013.

2. O'Donnell M, Mente A, Rangarajan S et al. Urinary sodium and potassium excretion, mortality, and cardiovascular events. N Engl J Med 2014.

3. National High Blood Pressure Education Program Working Group. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 2004. 

4. Buendia et al. Longitudinal effects of dietary sodium and potassium on adolescent blood pressure. JAMA Ped 2015.
 




Tags: consensus science Dietary Guidelines for Americans Dietitians Book Review healthy eating patterns Kristal Shelden Maureen Bligh registered dietitian book club sodium

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