"Lower Levels of Sodium Intake and Reduced Cardiovascular Risk"    
Circ  
http://circ.ahajournals.org/content/early/2014/01/10/CIRCULATIONAHA.113.006032.abstract 
"Conclusions—Results from the TOHP studies, which overcome the major methodological challenges of prior studies, are consistent with overall health benefits of reducing sodium intake to the 1500 to 2300 mg/day range in the majority of the population, in agreement with current dietary guidelines."