Author: Chelsea Amo-Tweneboah

Reviewer: Daniel Ambinder

Many factors within the realm of medicine have the potential to affect an individual’s blood pressure. Moreover, cardiac morbidity and mortality are heavily influenced by an individual’s intake of nutrients and quantity. Blood pressure has a positive association with higher sodium, alcohol, and protein and has an inverse relationship with potassium, calcium, and magnesium¹. 

The CARDIA-SSBP [Coronary Artery Risk Development in Young Adults], a cross-over trial, was presented at the American Heart Association in Philadelphia, Pennsylvania, published on November 11th, 2023, was an investigation to explore the impact of a high vs low sodium diet and its impact on blood pressure amongst middle-aged patients with varying degrees of hypertension and anti-hypertension medication use. The study led by Deepak K. Gupta, was an investigation was a randomized multicenter open-label trial.  Enrollment was 213 people with a demographic of individuals from the ages of 50-70 years with a median age of 61 years. The percentage of enrollees that were female was 65%. Notably, two-thirds of participants identified as Black⁴. Further analysis shows, 25% of individuals were normotensive, 31% had uncontrolled hypertension, and 25% had untreated hypertension³. For the initial baseline visit, patients maintained their usual diets and then completed either a high or low-sodium diet. The duration of follow-up was 21 days. Other significant statistics regarding individuals in the study were the percentage of those with hypertension being 48%, a median BMI of 31, the percentage with diabetes 21%, and a median systolic is 128 mm Hg. The sub-group analysis entailed no anti-HTN vs anti-HTN use, a baseline SBP £ 125 vs 125, and no Diabetes Mellitus vs Diabetes Mellitus. The primary endpoint for the study was a mean 24-hour ambulatory difference between high and low-sodium diets. At week 1 there was an 8 mm Hg mean difference between high and low sodium diets and by week two there was 7 mm Hg difference. Some adverse events noted in the study were headache, edema, and cramping. The ultimate result of the study showed a reduction of blood pressure from a high sodium to low-sodium diet was independent of hypertension status and antihypertensive use³.

The trial gives insight into ‘the power of salt’ and how modifications in sodium intake can significantly affect one’s blood pressure readings. However, the CARDIA-SSBP trial is not the first to show statistically significant results in the association between blood pressure and sodium intake. Its predecessor, the DASH Diet, Sodium Intake, and Blood Pressure Trial, was a multicenter trial randomized trial that assessed the different levels of sodium intake and two dietary patterns of individuals with optimal blood pressure or stage 1 hypertension⁵. The difference between the DASH trial and the CARDIA-SSBP trial was the DASH trial excluded individuals taking any form of antihypertensives¹. 

The question now lies in how this trial will impact our day-to-day approach to sodium consumption.  CARDIA-SSBP was able to show the impact of modifying salt for a week, but would participants have been adherent if it was over a longer period? In countries such as the United States, it is not difficult to go over the recommended intake of salt given the plethora of food options within supermarkets and in grocery stores. Moreover, many individuals tend to underestimate the amount of salt they consume, due to a lack of awareness of the true sodium content of their meals⁵. Although, the modification of sodium intake can produce comparable changes to blood pressure as anti-HTN, will patients be able to effectively adjust their sodium intake in the long term? According to Dr. Gupta, the lead trialist in this study, "We must simplify the process for participants and individuals to achieve success with their diets, whether it involves low sodium or other components."³.  Future studies may be warranted to assess for sustainability of a sodium modified diet. 

 

Dr. Chelsea Amo Tweneboah is a PGY1 resident at the Stony Brook University Hospital and served as a CardioNerds Conference Scholar for the American Heart Association 2023 Scientific Sessions.

References

1. Suter, Paolo M., Christophe Sierro, and Wilhelm Vetter. “Nutritional Factors in the Control of Blood Pressure and Hypertension.” Nutrition in Clinical Care 5, no. 1 (2002): 9–19. https://doi.org/10.1046/j.1523-5408.2002.00513.x.
2. American College of Cardiology. “Coronary Artery Risk Development in Young Adults–Salt Sensitivity of Blood Pressure.” Accessed November 12, 2023. https://www.acc.org/Latest-in-Cardiology/Clinical-Trials/2023/11/10/05/29/cardia-ssbp.
3. Gupta, Deepak K., Cora E. Lewis, Krista A. Varady, Yan Ru Su, Meena S. Madhur, Daniel T. Lackland, Jared P. Reis, Thomas J. Wang, Donald M. Lloyd-Jones, and Norrina B. Allen. “Effect of Dietary Sodium on Blood Pressure: A Crossover Trial.” JAMA, November 11, 2023. https://doi.org/10.1001/jama.2023.23651.
4. TCTMD.com. “Slash Dietary Sodium, Slash Blood Pressure: CARDIA-SSBP,” November 12, 2023. https://www.tctmd.com/news/slash-dietary-sodium-slash-blood-pressure-cardia-ssbp.
5. Svetkey, L. P., F. M. Sacks, E. Obarzanek, W. M. Vollmer, L. J. Appel, P. H. Lin, N. M. Karanja, et al. “The DASH Diet, Sodium Intake and Blood Pressure Trial (DASH-Sodium): Rationale and Design. DASH-Sodium Collaborative Research Group.” Journal of the American Dietetic Association 99, no. 8 Suppl (August 1999): S96-104. https://doi.org/10.1016/s0002-8223(99)00423-x.