In a study from the University of New South Wales and elsewhere, scientists found that dietary salt substitutes lower the risk of heart attack, stroke, and death from all causes and heart disease.
They suggest the beneficial effects of these substitutes are likely to apply to people all around the world.
Cardiovascular disease is the leading cause of death worldwide, and high blood pressure is a major risk for early death. A diet high in sodium and low in potassium is known to drive up blood pressure.
Blood pressure, which is measured in mmHg, is made up of two numbers: systolic—the higher number that indicates the force at which the heart pumps blood around the body; and diastolic—the lower number that indicates arterial pressure when the heart is filling with blood.
Salt substitutes, in which a proportion of sodium chloride (NaCl) is replaced with potassium chloride (KCl), are known to help lower blood pressure.
A previous study found that salt substitutes cut the risk of heart attacks, stroke, and early death, but it was unclear whether these benefits would apply to other parts of the world.
In the current study, the researchers reviewed findings from clinical trials to see the effects of a salt substitute on blood pressure, cardiovascular health, and early death.
They pooled the results of 21 relevant international clinical trials involving nearly 30,000 people, carried out in Europe, the Western Pacific Region, the Americas, and South-East Asia.
The study periods lasted from 1 month to 5 years. The proportion of sodium chloride in the salt substitutes varied from 33% to 75%; the proportion of potassium ranged from 25% to 65%.
The analysis showed that salt substitutes lowered blood pressure in all the participants.
The overall reduction in systolic blood pressure was 4.61 mm Hg and the overall reduction in diastolic blood pressure was 1.61 mmHg.
Reductions in blood pressure seemed to be consistent, irrespective of geography, age, sex, history of high blood pressure, weight (BMI), baseline blood pressure, and baseline levels of urinary sodium and potassium.
The team also found each 10% lower proportion of sodium chloride in the salt substitute was associated with a 1.53 mmHg greater fall in systolic blood pressure and a 0.95 mmHg greater fall in diastolic blood pressure.
There was no evidence that higher dietary potassium was associated with any health harm.
An analysis of the results of five of these trials involving more than 24,000 participants showed that 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%.
The researchers suggest that blood pressure lowering is the mechanism by which salt substitutes confer their heart protection.
The consistent blood pressure reductions make a strong case for the generalizability of the heart-protective effect.
If you care about heart health, please read studies about how drinking milk affects the risks of heart disease, and who has the lowest heart disease and stroke risks.
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The study was conducted by Xuejun Yin et al and published in the journal Heart.
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