Effects of a high salt intake and potassium supplementation on QT interval dispersion in normotensive healthy subjects

Sodium Toxicity in the Nutritional Epidemiology and Nutritional Immunology of COVID-19

Dietary factors in the etiology of COVID-19 are understudied. High dietary sodium intake leading to sodium toxicity is associated with comorbid conditions of COVID-19 such as hypertension, kidney disease, stroke, pneumonia, obesity, diabetes, hepatic disease, cardiac arrhythmias, thrombosis, migraine, tinnitus, Bell's palsy, multiple sclerosis, systemic sclerosis, and polycystic ovary syndrome. This article synthesizes evidence from epidemiology, pathophysiology, immunology, and virology literature linking sodium toxicological mechanisms to COVID-19 and SARS-CoV-2 infection. Sodium toxicity is a modifiable disease determinant that impairs the mucociliary clearance of virion aggregates in nasal sinuses of the mucosal immune system, which may lead to SARS-CoV-2 infection and viral sepsis. In addition, sodium toxicity causes pulmonary edema associated with severe acute respiratory syndrome, as well as inflammatory immune responses and other symptoms of COVID-19 such as fever and nasal sinus congestion. Consequently, sodium toxicity potentially mediates the association of COVID-19 pathophysiology with SARS-CoV-2 infection. Sodium dietary intake also increases in the winter, when sodium losses through sweating are reduced, correlating with influenza-like illness outbreaks. Increased SARS-CoV-2 infections in lower socioeconomic classes and among people in government institutions are linked to the consumption of foods highly processed with sodium. Interventions to reduce COVID-19 morbidity and mortality through reduced-sodium diets should be explored further.

Estimated salt intake and risk of atrial fibrillation in a prospective community-based cohort

INTRODUCTION

Hypertension predisposes to atrial fibrillation (AF) - a major risk factor for ischaemic stroke. Since a high dietary salt consumption is associated with hypertension, we investigated the association between urinary sodium excretion as a marker for dietary sodium intake and risk of new-onset AF in community-dwelling adults.

METHOD

The UK Biobank includes 40- to 69-year-old British residents recruited 2006-2010. Participants were divided into sex-specific quintiles according to 24-hour sodium excretion estimated based on spot samples with the Kawasaki equation. We excluded participants with AF at baseline. Cox regression adjusted for cardiovascular risk factors was used to assess associations with risk of AF, using the third quintile as reference.

RESULTS

A total of 257 545 women and 215 535 men were included. During up to 10 years' follow-up, 2221 women and 3751 men were diagnosed with AF. There was a tendency for an increased risk of AF in the lowest and highest quintiles of estimated daily salt intake in both women and men. In the fully adjusted model, significant associations were seen amongst men in the lowest and highest quintiles of sodium excretion (hazard ratio, HR_Qv1 , 1.20; 95% CI, 1.08-1.32, P < 0.001, and HR_Qv5 1.15, 95% CI, 1.03-1.27, P = 0.011).

CONCLUSION

We found evidence for a U-shaped association between estimated daily salt intake and AF risk amongst men. A suggestive J-shaped association in women was not statistically confirmed, but analyses were likely underpowered. Our results suggest that above a certain physiological minimum level progressively higher salt intake is associated with increasing risk of AF.

Dietary Sodium Intake and Health Indicators: A Systematic Review of Published Literature between January 2015 and December 2019

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.

Effect of Dietary Factors on Cardiac Rhythm

The interaction between arrhythmias and certain lifestyle factors such as obesity and alcohol consumption is well-established. There is significant public and professional interest in the role of various diets, vitamins, and minerals in cardiovascular health. However, many widely held beliefs are not supported by the literature. There is limited evidence for routine magnesium and omega-3 poly-unsaturated fatty acids supplementation, while coffee, tea, nuts, antioxidant vitamins, and even chocolate may have some antiarrhythmic properties. Saturated fat, added salt, and excessive energy drink consumption appear to be harmful for patients with rhythm disorders. However most recommendations are based on observation studies, and this remains a fertile area for further research.

Sodium and Its Role in Cardiovascular Disease - The Debate Continues

Guidelines have recommended significant reductions in dietary sodium intake to improve cardiovascular health. However, these dietary sodium intake recommendations have been questioned as emerging evidence has shown that there is a higher risk of cardiovascular disease with a low sodium diet, including in individuals with type 2 diabetes. This may be related to the other pleotropic effects of dietary sodium intake. Therefore, despite recent review of dietary sodium intake guidelines by multiple organizations, including the dietary guidelines for Americans, American Diabetes Association, and American Heart Association, concerns about the impact of the degree of sodium restriction on cardiovascular health continue to be raised. This literature review examines the effects of dietary sodium intake on factors contributing to cardiovascular health, including left ventricular hypertrophy, heart rate, albuminuria, rennin-angiotensin-aldosterone system activation, serum lipids, insulin sensitivity, sympathetic nervous system activation, endothelial function, and immune function. In the last part of this review, the association between dietary sodium intake and cardiovascular outcomes, especially in individuals with diabetes, is explored. Given the increased risk of cardiovascular disease in individuals with diabetes and the increasing incidence of diabetes worldwide, this review is important in summarizing the recent evidence regarding the effects of dietary sodium intake on cardiovascular health, especially in this population.