Flawed methodology
Flawed research undermines dietary salt guidelines that protect cardiovascular health
International researchers call for action
The scientific journal, Current Nutrition Reports, published an article in 2021 in which experts condemn the flawed North American-based claim that reducing salt intake causes harm. Twenty-five authors from 8 nations, of whom 14 are international cardiovascular experts, denounce the incorrect claim that helps the food, beverage and pharmaceutical industries to preserve and to market unhealthy products. These experts call on stakeholders to act.
Old myths and a controversy based on denial
The scientific journal, Current Nutrition Reports, published an article in 2022 in which a long list of experts from multiple countries (UK, Canada, USA, Costa Rica, New Zealand, Lithuania, Italy and Australia) describe a case study taken from eight articles published in a reputable journal in 2020 and 2021 showing how some researchers have propagated the myth that reducing sodium intake does not reduce CVD but rather increases it. The article summarizes the misleading claims, their objections, and it offers possible reasons for such claims. It finally identifies the steps needed to restore the credibility of science in this field since the public interest in the prevention and treatment of disease requires no less.
Prospective Urban and Rural Epidemiological (PURE) study
The PURE study was established to investigate the effects of urbanization on cardiovascular disease (CVD) through its influence on primordial risk factors (including physical activity and dietary patterns), primary risk factors (including obesity, hypertension, dysglycemia, dyslipidemia, and smoking), and downstream cardiovascular outcomes using a prospective design.
The PURE-Salt sub-study claimed to evaluate the association between dietary salt (sodium) intake, blood pressure (BP), and CVD outcomes. However, its central exposure assessment relied on spot urine samples to estimate sodium excretion as a proxy for usual salt intake, a methodological choice that is widely recognized as inappropriate for this purpose. This approach introduces substantial, systematic measurement error and bias, rendering individual-level sodium estimates unreliable and distorting observed associations with both BP and CVD events.
In this section, we present compelling experimental evidence and authoritative methodological critiques demonstrating that:
the principal findings of the PURE-Salt sub-study are methodologically invalid, fundamental flaws have been persistently ignored or dismissed, and the continued publication of studies using those methods represents a systemic failure of methodological rigour and editorial oversight, with significant implications for scientific integrity and public health policy, confusing both clinicians and policymakers.