Swapping table salt for salt substitutes may lower the risk of dying early

• A new study finds that consuming salt substitutes instead of table salt can reduce the risk of cardiovascular events and all-cause death.
• The salt substitute researchers tested also contained additional potassium, which may partially explain its health benefits.
• However, the study analyzes data from studies conducted largely in China, and its applicability to Western populations is not clear due to differences between the East and West in the way food is prepared and consumed.

Even though it is widely known that excessive sodium intake is associated with cardiovascular disease and mortality, many people continue to consume unhealthy amounts of salt — sodium chloride — in their foods. One strategy for continuing to satisfy one’s taste for salty foods while reducing health risks is the use of salt substitutes.

A new study from Bond University in Australia finds that the use of salt substitutes can result in a lower incidence of cardiovascular disease and a reduced risk of death from any cause for up to 10 years.

Salt substitutes are typically a mixture containing lower amounts of sodium and increased levels of potassium.

The study analyzes the results of 16 randomized controlled trials (RCTs). Of these, eight reported incidences of major cardiovascular events, and all-cause mortality for six months or greater. Seven of the eight RCTs were conducted in China and Taiwan. The remaining RCTs tracked hypertension, cause-specific mortality, and effective urinary excretion after six months.

The study is published in Annals of Internal Medicine.

While the study’s findings are likely applicable to people living in Asia, they may not be as relevant to Western populations.

The study’s first author, Hannah Greenwood, PhD, BPsychSc, research assistant at Bond University in Australia, pointed out the preponderance of data in the study came from Asian RTCs.

“While salt substitutes may still benefit Western populations, the currently available research evidence cannot confirm this because the data is not available. This is partially why the ‘certainty of evidence’ for our findings is graded as ‘low’ or ‘very low,’” she said.

Greenwood also noted that sodium consumption follows different patterns in the East and West.

“In the research populations,” she said, “salt consumption tends to be discretionary. That is, it is largely driven by salt added to food, which is only partially from added table salt, but also soy sauce and other condiments.”

Within the study population, food preparation more often occurs in the home, where adding sodium is a conscious choice.

“In Western populations, salt consumption is more driven by processed, packaged, and takeaway/restaurant food,” Greenwood said.

Jayne Morgan, MD, cardiologist and the Executive Director of Health and Community Education at the Piedmont Healthcare Corporation in Atlanta, GA, who was not involved in the study, noted the pervasiveness of sodium in the typical Western diet.

“Not only do many [Western] processed foods inherently contain salt, but often contain salt as a preservative as well as a flavor enhancer. This includes meats, etc., bought at supermarkets that are pre-seasoned,” Morgan said.

Snack foods also typically contain high amounts of sodium.

Still, Morgan felt the study is “definitely food for thought, as here in the U.S., we know that we are consuming too much sodium in our diets, but do not appear to be willing to give up the flavor. This, despite the hypertension, diabetes, obesity, and increased cardiovascular disease.”

The added potassium in the study population’s salt substitutes may also be a factor in the improved health outcomes observed.

“Potassium is essential for the balance of the electrical system of the heart, including heart muscle contraction and relaxation. It plays a role in the interplay of sodium and potassium in regulating blood pressure,” explained Morgan.

She also noted that one can ingest too much potassium, leading to hyperkalemiaTrusted Source, making a healthy balance between potassium and sodium a balancing act.

Senior investigator of the study, Loai Albarqouni, MD, PhD, MSc, assistant professor at Bond University in Australia, said it is hard to say how much extra potassium study participants received.

“This is difficult to quantify as our study did not examine whether it is the decreased sodium alone that is driving the effect, or whether the increased potassium has additional benefit,” he said.

“Another studyTrusted Source looking at both salt substitution and sodium restriction found reductions in cardiovascular risk for salt substitution but not salt restriction, pointing towards the benefit of increased potassium intake,” Greenwood added.

“In this area of China, people known to have lower potassium values, and so any increase might be beneficial but not push them into the range of hyperkalemia,” Morgan pointed out.

“So while our research doesn’t allow us to estimate the contribution of added potassium to the effect,” said Albarqouni, “we suspect that it plays a part.”

The RCTs investigated table salt substitutes instead of soy sauce substitutes that more commonly add salty flavorings in Asia.

Greenwood explained that this was because “there are currently no commercially available soy sauce products that have been similarly formulated to have reduced sodium and added potassium, although reduced sodium products already exist.”

She noted that many condiments, including soy sauce, used in Asia contain high levels of sodium, “so creation of and research into ‘salt substitute’ condiments may be worthwhile.”

As with any meta-study, there were variations between the RTCs included that limited the range of its findings.

Albarqouni mentioned “differences between our population of interest — Western, average cardiovascular risk — and the original research context, largely non-Western, higher than average cardiovascular risk, which affect generalizability of the results.”

“Other limitations include variations in methodological quality of the included studies and variation in how salt substitution was conducted between different studies,” he said.

“It’s important to remember that salt substitutes are not a holy grail to ending cardiovascular disease,” said Greenwood.

“There are many factors other than sodium intake that contribute to cardiovascular health, including smoking, diet, and exercise. There are also many other ways to reduce sodium intake, such as going for whole/unprocessed home-prepared food over processed or takeaway food. For someone looking for an easy way to reduce their sodium intake, without breaking the habit of adding salt to their food, using a salt substitute is a great option.”
— Hannah Greenwood