About 75 million American adults – 1 out of every 3 – have high blood pressure, according to the Centers for Disease Control and Prevention. Another disturbing fact is that only about half, or 54 percent, have their condition under control (1).
High blood pressure, also called hypertension, is a dangerous condition. It increases your risk for a heart attack, a stroke, chronic heart failure and kidney disease, to name a few.
Many people are not aware of how much control you can actually have over your blood pressure. You can take steps to prevent or control high blood pressure and its complications.
One important step that most doctors recommend is to limit your salt intake. The Dietary Guidelines for Americans set the recommended sodium intake at 2,300 milligrams (mg) per day (2).
However, if you have hypertension or prehypertension, the guidelines recommend further limiting your daily sodium intake to just 1,500 mg (3).
How Salt Affects Your Blood Pressure
A heavy salt diet disrupts the natural sodium balance in the body. The kidneys have trouble keeping up with the excess sodium in the bloodstream.
As sodium accumulates, the body holds on to water to dilute the sodium. This in turn leads to an increase in both the amount of fluid surrounding cells and the volume of blood in the bloodstream.
An increase in blood volume means the heart has to work more, and there is more pressure on blood vessels. Gradually, this extra work and pressure constricts the blood vessels, leading to high blood pressure.
A high sodium level in the body also causes a reduction in the synthesis of nitric oxide, an arteriolar vasodilator. Less synthesis of nitric oxide means that blood flow experiences more resistance due to the constriction of blood vessels, also contributing to high blood pressure.
According to a study published in the Journal of Renal Nutrition in 2009, a decrease in dietary sodium leads to a small decrease (1.1 mm Hg) in median systolic but not diastolic blood pressure.
While the study concludes that sodium restriction in hypertensive patients reduces blood pressure, the long-term impact of reduced salt intake on blood pressure, mortality and morbidity needs to be further analyzed (4).
Another study published in 2013 in the BMJ found that a modest reduction in salt intake for four or more weeks causes a significant drop in blood pressure in both hypertensive and normotensive individuals, irrespective of gender and ethnic group (5).
A later 2014 study published in Electrolytes & Blood Pressure concludes that a reduction of dietary salt intake can decrease the number of deaths from hypertension, cardiovascular disease and strokes (6).
While a 2016 study by McMaster University researchers found that a low-salt diet may not be beneficial and may actually increase the risk of cardiovascular disease and death compared to average salt consumption, they noted that people with hypertension who have high salt consumption should reduce sodium in their diet (7).
Not just blood pressure, high salt intake can damage the heart, aorta and kidneys without increasing blood pressure. It is also bad for the bones.
Looking at the drawbacks of excess salt intake, it becomes important to limit salt intake in your diet. According to the Harvard School of Public Health, people over age 50, people who have high or slightly elevated blood pressure, people who have diabetes and African-Americans are at high risk of developing health problems related to salt consumption (8).