A new study confirms the power of salt reduction in lowering blood pressure.
The Effect of Salt Reduction on Blood Pressure
A new study suggests that reducing daily salt intake can lower blood pressure as effectively as taking antihypertensive medications. The study showed that cutting just one teaspoon of salt from the daily diet can reduce blood pressure to the same extent as experienced after taking antihypertensive drugs.
The Effect of Salt Reduction on Cardiovascular Health
Many studies indicate that reducing salt in the diet can decrease high blood pressure. The new study demonstrated the extent of the impact that salt reduction can achieve, and these benefits apply even to individuals who are already taking medications for hypertension.
The Study and Results
The study involved 213 participants aged between 50 and 75 years. Unlike previous trials, this study included some individuals who were already taking antihypertensive medications. Participants were divided into four approximately equal groups: people with normal blood pressure who do not use medications, individuals with normal blood pressure thanks to medications, those using medications but with unstable blood pressure, and individuals with high blood pressure who do not take medications.
Each participant spent one week on a high-sodium diet followed by a week on a low-sodium diet. The high-sodium diet included the participants’ regular eating pattern plus an additional 2200 mg of sodium, while the low-sodium diet was designed by researchers to be uniform for all participants. At the end of the experiment, average blood pressure among all groups decreased while consuming the low-sodium diet, regardless of their baseline blood pressure readings or medication use.
Overall, Gupta’s team found that reducing blood pressure by cutting one teaspoon of daily salt for a week is equivalent to the drop that most people feel after starting antihypertensive medications. However, reducing the amount of salt consumed is not a substitute for prescribed medications, and you should consult your doctor before stopping or starting any medications.
The Mechanism of Hypertension Due to Salt
The effect of increased salt intake on high blood pressure remains somewhat unclear. The prevailing hypothesis is that when a person consumes a higher amount of sodium, it causes the body to retain more water. This, in turn, places greater hydrostatic pressure on the walls of blood vessels, leading to higher blood pressure.
However, scientists have not clearly established that this is the main mechanism behind salt’s ability to raise blood pressure. In fact, Gupta’s team plans to investigate another hypothesis. Although excess fluids may still play a role, Gupta says, “One of our study’s hypotheses is to determine whether sodium itself may have an inflammatory effect and trigger an immune response that actually leads to further stiffening of blood vessels.” He hopes to publish the results of that analysis in the near future.
The Importance of Salt and Recommendations for Reducing Intake
Humans certainly did not evolve to consume a high-sodium diet. Bruce Neal, an epidemiologist and researcher, and director of the George Institute for Global Health in Australia, who was not involved in the new research, says, “Our human ancestors probably consumed less than half a gram of sodium a day.” However, humans are programmed to crave salt because we need a certain amount of the mineral to survive.
Sodium
Essential for all types of bodily functions, including muscle contraction and relaxation, conducting nerve signals, and maintaining a healthy balance of internal body fluids. Liebman says, “It’s an extremely important electrolyte.” Too little salt can send your body into a state of relative sodium deficiency in the blood, a dangerous condition that can cause confusion, headaches, and in rare cases, seizures or coma. The importance of salt in the body explains why it tastes good to us – it was difficult for many of our distant ancestors to access, making its consumption something delightful. But just like hot peppers or strong cheese, a little goes a long way.
Currently, the average person in the United States consumes about 3,400 mg of sodium daily. Most of this amount – about 70 percent – comes from processed foods or restaurants, according to the American Heart Association. However, the Food and Drug Administration recommends consuming less than 2,300 mg daily. There are some exceptions to this rule; for instance, individuals with certain medical conditions like kidney failure may need to increase their sodium intake. Similarly, people recovering from severe dehydration or diarrhea may need to consume more salt for a few days. But generally, individuals following a typical Western diet should try to reduce their daily sodium intake.
How to Achieve Reduced Salt Consumption
We face a clear issue: how can you persuade people to consume less salt when it’s so prevalent in our diet? Neil has been working on answering this question for two decades. His research has repeatedly shown that simply telling people to consume less salt is not effective in the long term. Instead, encouraging them to use lower-salt alternatives works better. Neil says, “Cutting back is hard, switching is easy.”
Neil believes that switching regular salt for a blend made up of 75 percent sodium chloride and 25 percent potassium chloride – another type of salt – would be a simple and effective way to provide the minimum amount of sodium people need. These blends are already available in many health food stores, although they are currently more expensive compared to regular sodium chloride. The switch may be costly initially on both an individual and institutional level.
But Neil points out that we have widely changed our salt supply before. Iodized salt was introduced to grocery stores in the U.S. in 1924 in an attempt to reduce the incidence of goiter in children, which affected up to 70 percent of children in some regions of the country. These interventions were successful, and today only about 5 percent of Americans suffer from goiter.
Perhaps potassium-enriched salt will become a new source of low-sodium salt in the future. However, if you are trying to monitor your sodium intake, your best option is to cook meals at home and season them with a little salt – but not too much.
Copyright and permissions: Joanna Thompson is an insect enthusiast and was an intern at Scientific American. She is based in New York City. Follow Thompson on Twitter @jojofoshosho0
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