It is hard to find a more controversial (and more important!) health topic than the recommended level of salt in the diet.
Sodium is the chemical substance that is necessary for the hydration and normal functioning of our bodies. In the scientific literature, salt intake is considered equivalent to sodium intake, since sodium is the component of salt that triggers our kidneys to regulate the amount of water in the body. There is, however, also a direct relationship between total sodium intake and increased blood pressure.
Because of this relationship between sodium intake and elevated blood pressure, several organizations make recommendations about the maximum “safe” sodium intake. Most notably, the United States Department of Agriculture (USDA) and the Centers for Disease Control and Prevention (CDC) recommend that the general population consume fewer than 2,300 milligrams (mg) of sodium per day. Additionally, the American Heart Association (AHA) makes further recommendations for people who are at increased risk of high blood pressure—the AHA recommends that they limit their sodium intake to fewer than 1,500 mg per day.
Almost certainly it is not. Why do I say this? Because population-based surveys suggest that almost nobody meets these strict dietary limitations for sodium intake. In fact, the average sodium intake for Americans has ranged between 3,000 and 4,000 mg per day for the last 50 years.
In a recent research investigation called the PURE Sodium study, 100,000 people across 10 countries documented their average daily sodium intake. Sodium intake ranged from 4,200 to 4,800 mg/day in North America, South America, and Europe, and it increased to more than 5,500 mg/day in China.
Using urine measures of sodium excretion, the researchers were able to determine that just 3.1 percent of people have sodium intakes of less than 2,300 mg/day, and that less than one percent had intakes below 1,500 mg/day.
When the investigators included other dietary information to calculate “usual intake” of sodium, they found that essentially nobody—zero percent of people—meets the above guidelines!
So don’t feel too bad if your sodium intake comes in a bit high compared with the recommendations of the experts.
Dr. Salim Yusuf, one of the preeminent epidemiologists in the world, commented that “we are making recommendations that most people, 99 percent of the world, cannot follow. From a practical point of view it makes no sense.”
Why do we have guidelines that nobody can follow? Is there a simpler message?
Recently, the influential Institute of Medicine (IOM) issued a report about sodium intake that reignited a firestorm of controversy. In summary, this report stated that there is insufficient data to continue recommending a reduction in sodium intake from average levels to less than 2,300 mg/day. In addition, the IOM report also concluded that it may be harmful to reduce sodium intake to less than 1,500 mg/day. This was a sharp break from prior summaries of the data.
The main issue is this: Does everybody need to slash their sodium intake, or do strict sodium restrictions apply only to susceptible individuals whose blood pressure is elevated?
While this controversy over the recommended sodium intake for the average person rages on, certain things are universally agreed upon:
Most of my patients tell me that they “don’t add salt to their food.” Unfortunately, added salt is just a fraction of the sodium that all of us are really consuming.
Excessive sodium presents itself in snacks like:
The first thing to do is to limit the pre-prepared foods you eat, to make sure that you are not in the group that ingests very high levels of sodium (greater than 5,000 mg/day). Second, please increase your fresh fruits and vegetables! Third, be prudent—but not excessive—in limiting salt in other parts of your diet.
If you are older (for example, greater than age 60) or have hypertension, reducing your salt intake may benefit your health. While everyone should watch the amount of salt they consume, the message to reduce salt intake is most appropriately directed at you!
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