[Definition of "salt sensitivity"]

To examine how the term "salt sensitivity" has heretofore been defined, two medical data bases, DIMDI and MEDLINE were searched. 32 clinical studies, published between 1978-1992 and using the terms salt-, sodium- or sodium chloride-sensitive or sensitivity were found and analysed. Salt sensitivity was experimentally determined and applied in quite varied ways to normotensive and hypertensive persons. There were three types of studies: in type 1 (n = 15), a phase of low sodium intake was followed by one with a high intake; in type 2 (n = 8), a phase of high or "normal" sodium intake was followed by a low intake one; in type 3 (n = 9), there was a randomized sequence of differing sodium intake phases, in some cases with cross-over. It is concluded from these studies that there is insufficient evidence to distinguish between salt sensitive and salt insensitive subjects. Consequently scientific discussion of this question should not lead to hypertensives being discouraged from reducing their salt intake.