Salt Intake and CVD: The Ongoing Debate
Posted:
2018-08-21
A Canadian and European Government- and NGO-funded study investigating the associations between community-level mean sodium and potassium intake, cardiovascular disease and mortality was recently published in The Lancet (1). The study reports on clinical outcomes based on an analysis of 94,378 participants from 18 countries. Participants were aged 35 to 70 years and did not have cardiovascular disease at baseline. As a surrogate for sodium intake, morning fasting urine was used to estimate 24-hour sodium and potassium excretion. The authors’ main interpretation was that sodium intake was associated with cardiovascular disease and stroke but only in communities where estimated mean sodium intake was greater than 5 g/day.
The validity of the results has been questioned by others (2,3) for two main reasons. First, this is an observational study based on community averages and not on individual data (ecologic study design). Second, 24-hour sodium excretion was estimated from urine collected after overnight fasting, which is not a reliable measurement of daily salt intake as is a repeated 24-hour urine sample. For more on the salt and hypertension debate, see Salt and Heart Disease: A Second Round of "Bad Science" and Expert Reaction to Study Looking at Salt Consumption and Health Risks.
See Additional PEN content: Does diet have a role in preventing hypertension?
References
- Mente A, O'Donnell M, Rangarajan S, Yeates K, Teo K, Yusuf S, et al. Urinary sodium excretion, blood pressure, cardiovascular disease, and mortality: a community-level prospective epidemiological cohort study. The Lancet. 2018 Aug;392(10146):496-506. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31376-X/fulltext
- Messerli FH, Hofstetter L, Bangalore S. Salt and heart disease: a second round of “bad science”? The Lancet. 2018 Aug;392:10146:456-8. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31724-0/fulltext?rss=yes
- Science Media Centre. Expert reaction to study looking at salt consumption and health risks. 2018 August 9. Available from: http://www.sciencemediacentre.org/expert-reaction-to-study-looking-at-salt-consumption-and-health-risks/