Peru salt substitute study illustrates NHLBI’s commitment to global health research
January/February 2025 | Volume 24 Number 1
Photo courtesy of Jaime MirandaDr. Jaime Miranda lectures at a Global Alliance for Chronic Diseases event
Eating too much salt increases blood pressure. If blood pressure becomes too high, it affects the body’s arteries, forcing the heart to work harder pumping blood. Hypertension (another word for high blood pressure) is a common condition worldwide, one that contributes to heart disease and stroke.
Too often, low- and middle-income countries (LMICs) like Peru have poor rates of controlling hypertension and lack strategies for maintaining normal pressure. “Peru is a context where we have many limitations on the supply side of the health system—we have very few doctors, very few medicines, very few trained people. So adding more things at the health system level would have very limited advantage,” said Jaime Miranda, MD, PhD, founding director of CRONICAS Center of Excellence at Cayetano Heredia Peruvian University in Lima.
To address hypertension in Peru, Miranda decided that a population-level solution was needed. He and his colleagues, including Robert Gilman, MD, Johns Hopkins Bloomberg School of Public Health, conducted a
community-wide study in which a salt substitute replaced conventional table salt with the aim of lowering blood pressure in the general population. Their findings could be applicable in low-resource settings across the globe.
Miranda and Gilman, both long-standing Fogarty grantees, found support for their project from the
National Heart, Lung, and Blood Institute (NHLBI) as part of its commitment to the
Global Alliance for Chronic Diseases (GACD).
Birth of an international alliance
In 2007, an
article published in Nature identified the chronic, non-communicable diseases that caused the greatest share of disability and accounted for about 60% of all deaths worldwide: cardiovascular diseases, type 2 diabetes, chronic respiratory diseases, and certain cancers. To stem this rising tide of chronic illness, the article’s authors established research priorities and argued for increased international funding. Spurred by this publication, NHLBI and other global funders helped found GACD in 2009 to bring together international research funders to address chronic diseases in LMICs as well as in underserved populations in high income countries.
Since then, NHLBI’s influence on GACD has remained strong. In 2011, NHLBI’s Deputy Director Dr. Susan Shurin was elected chair of GACD. Shurin attracted interest and support across the National Institutes of Health. Also during her term, GACD established working groups within specific disease areas and launched its first round of funding focused on hypertension.
Three years later, NHLBI answered a GACD research call and backed Miranda’s salt substitution project.
Photo courtesy of Robert GilmanDr. Robert Gilman views Puerto Ocopa, PeruA matter of taste
Miranda, who is now director of the public health school at University of Sydney, began his project with an “attack” on the salt supply of six participating villages in the Tumbes region of Peru, where hypertension levels are high. “We went through the villages, to the shops, street vendors, community kitchens, households, and every single potential storage point of regular salt, and we replaced it with the salt substitute,” he explained. “This meant more than 2,000 people—every single individual, every single adult in the community—were part of the study, whether they had high blood pressure or not.”
Importantly, their salt substitute contained 75% sodium chloride and 25% potassium chloride. Gilman said the idea for this formulation came from a study in China that used a mix of 62% sodium, 13% flavoring, and 25% potassium chloride which relaxes artery walls and lowers blood pressure. This formula, though, didn’t fit Peru.
“Food is important in Peru, it's our flagship as a country,” said Miranda. “So we did some ‘triangle tests,’ experiments where, in a way, we trick people so that we can understand the exact level of additives where they start saying ‘this tastes different.’”
The study ran from 2014 to 2017. At its end, participants with hypertension showed a decrease in systolic pressure—the top number in a blood pressure reading—of 1.92 millimeters of mercury (mm Hg). (Generally, hypertension is 130/80 mm Hg or higher.) Participants over age 60 with hypertension saw a 2.17 mm Hg drop, while average declines in systolic pressure was 1.18 mm Hg for participants without hypertension. Though these changes seem slight, observational studies suggest that a reduction of even 2 mm Hg could lead to approximately 10% lower risk of death from stroke and roughly 7% lower risk of death from heart disease.
Importantly, new cases of hypertension fell by half among those using the salt substitute. “We showed prevention—that was the major finding of this study,” said Gilman.
The horizon
Use of salt substitutes to lower hypertension is gaining traction globally, and recently the World Health Organization issued guidance on its use, said Miranda. “Most of the time a traditional clinical cardiology solution for high blood pressure is what receives funding, so we're grateful to NHLBI for this opportunity to show another way of doing things that can achieve the same goals.”
Though committed to GACD, NHLBI maintains its own Global Health Research Program, providing research training and career development, mentoring, and capacity-strengthening and infrastructure expansion in LMICs. Still the collaboration is fruitful; Miranda’s and Gilman’s GACD project in Peru, funded by NHLBI, has potential implications in both developing and developed nations alike, wherever communities might benefit from cost-effective interventions for chronic conditions.
Meanwhile, Gilman is looking at the big picture and taking aim against siloed thinking. “We need to join infectious disease with chronic disease.” He explained, “What happens in diabetes, a chronic illness, is people become neuropathic and lose feeling in their feet, then they get an ulcer or infection in their feet, which, if it goes untreated, can lead to amputation.” Another example of the connection between infectious and non-communicable diseases is Chagas disease, which spreads through contact with the feces of parasite-carrying bugs. Almost a third of infected people develop chronic heart issues, some dying of heart failure. “This is why an infectious disease guy like me got involved in chronic disease.”
More information
Updated February 12, 2025
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