Warning: prepare for whiplash! We know that for the last 50 years you have heard a constant drum beat from public health officials, cardiologists, nutritionists and most other health professionals to lower your salt intake! It is hard to wrap your head around a different message, so please brace yourself.
In a the journal, JAMA Internal Medicine (online, October 28, 2013), an important article was published titled:
“The Institute of Medicine [IOM] Report Sodium Intake in Populations: Assessment of Evidence
Summary of Primary Findings and Implications for Clinicians”
What Did the Study Find?
People with diabetes, high blood pressure, kidney disease or cardiovascular disease may not achieve benefit and may actually experience harm at these reduced levels. There are no data showing that lowering sodium below 1,500 mg (a quarter teaspoon daily) is helpful. People with congestive heart failure may be harmed when sodium consumption drops below 2,300 mg daily.
Did the Experts Get Their Advice Exactly Wrong?
Yikes! It is precisely these high-risk patients who have been told for decades that they must lower their salt intake dramatically to be healthy. Now the IOM is saying that this advice to follow a low salt diet might have been wrong.
The Institute of Medicine represents the best and the brightest in American medicine. These experts are considered the final authority on most medical issues. Although they do suggest that a high-sodium diet is common in the U.S. and that we should try to moderate our salt intake, they also urge caution about the guidelines set by public health organizations to get sodium intake below 1500 mg daily.
Okay, that’s just the first article that challenges standard wisdom and policy. Here’s the knock-out punch. The November 2013 issue of The American Journal of Medicine has a review article titled: “Dietary Sodium Restriction: Take It with a Grain of Salt.”
Strap on your seatbelt. These experts have reviewed the research on sodium and they are far more outspoken than the Institute of Medicine. They contradict the American Heart Association’s goal to achieve “Ideal Cardiovascular Health” by lowering dietary sodium to 1500 mg per day. Here are some selected quotes:
Low Sodium Intake and Blood Pressure:
“Although there are reasonable data to support that sodium restriction lowers blood pressure, the effects may be transient and inconsistent, with some individuals even having paradoxical increases in blood pressure. The degree of blood pressure lowering on average might be clinically trivial, approximately 2 mm Hg in normotensive individuals and approximately 4 mm Hg in hypertensive individuals. Finally, sodium restriction also has the adverse effects of activating the renin-angiotensin-aldosterone system, increasing catecholamines, and adversely affecting insulin and lipids.”
What that means in plain English is that restricting sodium does not make a meaningful difference in blood pressure reduction and may lead to a stressful physiological reaction. Adrenaline (epinephrine) goes up along with insulin (not a good thing). Increases in lipid levels mean that your cholesterol levels could climb (also not a good thing).
But wait, it gets even more confusing. Here again are selected quotes from The American Journal of Medicine article about “Dietary Sodium Restriction: Take It with a Grain of Salt”:
Low Sodium Intake and Type 2 Diabetes:
These reviewers point out that people with type 2 diabetes who cut way back on salt may have a higher death rate from cardiovascular causes compared to diabetics who consume a normal level of salt. Even more heretical was their analysis of the data on heart failure:
Low Sodium Intake and Systolic Heart Failure:
“The low sodium diet caused increased mortality and heart failure hospitalizations versus normal sodium diet in patients with systolic heart failure. These results have been verified across multiple randomized, controlled trials in patients with systolic heart failure.”
Low Sodium Intake and Thyroid Function:
“A major source of dietary iodine is through salt. Therefore, a low sodium diet could lead to worsening of thyroid diseases.”
And for the grand finale, their summary:
There is no conclusive evidence that a low sodium diet reduces cardiovascular events in normotensive and pre-hypertensive or hypertensive individuals. On the contrary, there is sound evidence that a low sodium diet leads to a worse cardiovascular prognosis in patients with systolic congestive heart failure or type 2 diabetes mellitus. Worldwide sodium restriction, through its adverse effects on insulin resistance, may lead to an increase in the rates of type 2 diabetes mellitus…Advising low sodium diets seems misguided and potentially dangerous and illustrates the problem of guidelines based on flawed studies using surrogate measures.”
Wow and WOW! What are we to make of this turn around? For starters, your health professional has probably not read the IOM report or this article in The American Journal of Medicine. The CDC and the American Heart Association are still aiming for less than 1,500 mg of sodium a day. Here is what the premier public health organization (the Centers for Disease Control and Prevention” says on its website:
…”If you are in the following population groups, you should consume no more than 1,500 mg of sodium per day…
- You are 51 years of age or older
- You are African American
- You have high blood pressure
- You have diabetes
- You have chronic kidney disease
The 1,500 mg recommendation applies to about half of the U.S. population overall and the majority of adults. Nearly everyone benefits from reduced sodium consumption.”
How do you cope with these completely contradictory messages? We have to wonder whether our public health officials are even bothering to read the medical literature. What do you think? Please share your experience and your thoughts on this complicated and confusing issue below.