On average, study participants who used salt-substitutes for six months to two years had systolic blood pressure 4.9 mm Hg lower than those who used normal table salt, Chinese researchers found after reviewing five randomized controlled trials comparing the health effects of salt and salt substitutes on 1,974 participants.
Diastolic blood pressure also fell an average of 1.5 mm Hg in the groups that used the salt-substitute compared to the normal salt, according to the study.
Given the established connection between sodium intake and the development of hypertension which is linked to heart disease, these findings show “replacing normal salt with salt substitutes can be a relatively low-cost complement to clinical therapy for hypertension and a low-cost intervention at the community level to prevent hypertension,” the researchers conclude.
Impact of salt substitutes could hinge on culture
Prior to this meta-analysis, studies on the efficacy of salt-substitutes introduced in the 1980s to lower blood pressure were mixed, the researchers note. They hypothesized the inconsistent findings could be due in part to the diversity of the study participants and where the research was conducted.
They explain that in developing countries such as China, where four out of the five studies in their meta-analysis were conducted, people consume 75% or more of their sodium from salt added to home-cooking either during preparation or at the table. In more developed countries, however, most sodium comes from packaged foods and prepared meals at restaurants where consumers use less table salt and have less control over the sodium.
Based on their findings and this key cultural difference, the researchers predict “other low- and middle-income countries that are not advanced in the nutrition transition and in which the primary source of dietary salt is cooking may also benefit from salt substitutes.”
Conversely, this suggests that replacing regular salt with lower sodium salt-replacements for home use in developed countries likely will have less of an impact on overall sodium consumption and blood pressure than in countries where consumers manage most of their salt intake.
To test this hypothesis and further understand the potential impact of salt substitution, the researchers say “more studies in large diverse samples are needed to demonstrate their utility at the population level.”
They add: “Identifying culturally appropriate, economically sustainable interventions with long-term effectiveness is of utmost importance,” because blood pressure is the number one risk factor for the global burden of disease.