Diets high in sodium and low in potassium are known to raise blood pressure. Around 1.28 billion people worldwide have high blood pressure, and only 42% of those are diagnosed and treated. Hypertension, another word for high blood pressure, is a major cause of premature death globally.
In salt substitutes, a proportion of sodium chloride (NaCl) is replaced with potassium chloride (KCl).
Large study of salt substitutesâ€™ effect
Dr. Bruce Neal, executive director at The George Institute for Global Health Australia and professor of medicine at the University of New South Wales Sydney, was one of several researchers who conducted the Salt Substitute and Stroke Study. Commencing in 2014 and lasting five years with over 20,000 participants from 600 rural villages in China, the study is billed as one of the largest dietary interventions ever conducted. It found that switching out regular salt for a dietary salt substitute reduced the risk of stroke by 14%, risk of major cardiovascular events by 13%, and risk of death by 12%. Study participants experienced no harmful effects from injecting the salt substitute.
The researchers undertook a systemic review to show that itâ€™s not only the Chinese who have something to gain by switching to dietary salt substitutes.
â€œI think their goal was to show some consistency in their results across different populations and different areas,â€ said Dr. Jennifer Wong,a cardiologist and medical director of noninvasive cardiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, California.
Analysis of global data
Researchers scoured databases for studies that looked at salt substitutes. Ultimately, they included 21 studies in the meta-analysis.
â€œ. . . We basically just go through those papers in a really systematic, standardized way, extract the same information from every paper, and then put it together in . . .a narrative summary to figure out what it all actually means as a whole,â€ Dr. Neal told ishonest.
The 21 studies were carried out in Europe, the Western Pacific Region, the Americas, and South-East Asia. The duration of the intervention with a dietary salt substitute ranged from one and 60 months. The proportion of sodium chloride in the salt substitutes varied from 33% to 75%; the proportion of potassium chloride ranged from 25% to 65%.
Salt substitute and blood pressure
Blood pressure is measured in mm HG. It includes two numbers: systolic and diastolic. Systolic is the higher number that indicates the force at which the heart pumps blood around the body, and diastolic is the lower number that indicates the lower pressure in the arteries during the brief resting period between heartbeats.
In the systemic review, the researchersâ€™ analysis showed that dietary salt substitutes produced an overall reduction in systolic blood pressure of 4.61 mm HG. The overall reduction in diastolic blood pressure was 1.61 mm HG.
The analysis of the results from five of these trials showed that dietary salt substitutes lowered the risks of early death from any cause by 11%, from cardiovascular disease by 13%, and the risks of heart attack or stroke by 11%.
Factors like geography, age, sex, history of high blood pressure, weight, baseline blood pressure, and baseline levels of urinary sodium and potassium did not seem to impact the reductions in blood pressure.
The studies showed no evidence that higher dietary potassium from the salt substitutes caused any harm to participants.
Dr. Wong told MNT she appreciated hearing that because she worries about the effects of too much potassium on patients with kidney disease. â€œSo itâ€™s very reassuring to have a large trial that shows us that there can be no adverse effects, at least at this amount of potassium that they used in these trials,â€ she said.
Evidence of salt substitutesâ€™ benefits
Dr. Neal told MNT that cardiologists regularly tell patients to replace salt with dietary salt substitutes to lower their blood pressure. He added that the large Salt Substitute and Stroke Study is valuable because it showed that using salt substitutes delivers outcomes outside of a number on a blood pressure cuff.
â€œHaving the evidence that actually it doesnâ€™t just lower blood pressure, it also lowers strokes, heart attacks, and death in a really large scale trial, that changes public perception in a massive way,â€ Dr. Neal explained. â€œThere might have been a view among some people that this was sort of settled, but having that really big study is really important in terms of trying to get policymakers, salt manufacturers, and retailers to actually start recommending salt alternatives in a way that they currently donâ€™t.â€
Changing the worldâ€™s salt supply
Over the next decade, Dr. Neal plans to work on changing how the citizens of the world consume salt.
â€œThe worldâ€™s salt supply has been changed once already over the last few decades from regular salt to iodized salt to try and address thyroid disease problems on a global basis,â€ Dr. Neal told MNT. â€œSo what we would like to do now is work on changing the world salt supply from regular iodized salt to iodized potassium enriched salt.â€
The impact on health would be enormous, Dr. Neal believes. While undertaking the Salt Substitute and Stroke Study, the researchers calculated the impact of people in China switching to iodized potassium-enriched salt.
â€œWe found that if they did that, they would prevent a million strokes and heart attacks in China alone every year,â€ Dr. Neal said.
Making small changes in salt intake
A beautiful thing about it, Dr. Neal said, is that switching to dietary salt substitutes is a doable behavior modification. â€œTheyâ€™re low cost and easy for people to use,â€ he said. â€œYou donâ€™t have to make big changes to your lifestyle.â€
Roxana Ehsani, a registered dietitian, nutritionist, and national media spokesperson for the Academy of Nutrition and Dietetics, told MNT that the evidence is clear that individuals should try to limit their use of salt and switch to â€œsalt substitutions primarily.â€ She also suggests incorporating dried herbs and spices into cooking because they â€œadd flavor, antioxidants, but no sodium.â€
Taylor Wallace, president and CEO of Think Healthy Group, a food science, and nutrition consulting firm, said this systemic review adds to a body of research suggesting a need for reducing the amount of sodium in processed foods.
He recommends increasing potassium intake generally to balance the sodium in our diets. â€œPotassium is mainly derived from plant foods like fruits and vegetables,â€ he told MNT. â€œ. . .So make sure to indulge in your favorite fruits and veggies as well as reduce your sodium intake.â€