Table 1.

Summary of the main evidence reported by meta-analyses regarding the effect of salt restriction upon the main cardiovascular and renal outcomes.

Outcome	Evidence from Meta-Analyses
BP	Dose-response relationship between salt reduction and BP decrease (He 2013 [47], Taylor 2011 [48], Graudal 2020 [32], Aburto 2013 [49])
CV events	High sodium intake increased risk of: Stroke Stroke mortality Coronary heart disease (Strazzullo 2009 [40], Aburto 2013 [49], Jayedi 2019 [45]) 2 Low sodium intake: Decreased risk of all-cause mortality and CHD (Khan 2019 [50]) Increased risk of all-cause mortality and CVD incidence compared to the usual sodium intake (<2.7 g/day versus 2.7–7 g/day)—U-shaped curve (Graudal 2014 [42]) No strong effect on all-cause mortality and CVD morbidity (Taylor 2011 [48])
HF	Severe salt restriction: Increased all-cause mortality (Taylor 2011 [48]) Slightly improved clinical parameters in outpatient setting, but inconclusive results in hospitalized patients (Mahtani 2018 [51])
Lipids	Salt restriction: Increase in total cholesterol and triglycerides with severe salt restriction (Graudal 2020 [32]) No effect with long-term moderate salt restriction (He 2013 [47])
Kidney function	Salt reduction: Decrease in urinary albumin excretion, more so in CKD patients (d’Elia 2015 [31]) Decrease in proteinuria and albuminuria in early CKD, CKD stages 1–4 and diabetic kidney disease (McMahon 2021 [52], Garofalo 2018 [53], Chen 2022 [54])

BP = blood pressure, CV = cardiovascular, CHD = coronary heart disease, CKD = chronic kidney disease, CVD = cardiovascular disease, HF = heart failure.