The concept of salt sensitivity in man has a long and controversial story, but it is well accepted in rodents where the existence of a genetic component in the arterial pressure response to high salt was identified almost 40 years ago [1]. The most convincing demonstration of salt sensitivity in an animal species close to homo sapiens is that obtained by Denton et al. [2] in the mid-1990s. To date, this study constitutes the most accurate experimental analysis of the long-term relationship between salt intake and arterial pressure. The experiment started with a long 1-year control period during which the chimpanzees were observed at their natural low-sodium, high-potassium, fruit and vegetable diet. This control period was followed by a 20-month phase where increasing amounts of salt (up to 15 g) were gradually added to the natural diet. The animals were finally reverted to their habitual, low-salt diet. The study design fully ensured that one variable only (salt) was changed, with all other variables maintained accurately constant (potassium, calcium, social conditions). The effect of salt was large and consistent because the systolic pressure rise was of 26 mmHg at the top salt intake, and as much as 70% of the chimpanzees were 'salt-sensitive'. An experiment of such duration, completeness and elegance is unrealistic in man. If homo sapiens does not represent an exception regarding the salt-arterial pressure relationship, which seems untenable, salt sensitivity must also be pervasive in humans. However, the behavioural complexity of mankind is such that the issue of salt sensitivity is very difficult to study.
Salt sensitivity phenotype: a death bell toll or a quest for better ways of testing the risk associated with 'sodium genes'?
2003
Abstract
The concept of salt sensitivity in man has a long and controversial story, but it is well accepted in rodents where the existence of a genetic component in the arterial pressure response to high salt was identified almost 40 years ago [1]. The most convincing demonstration of salt sensitivity in an animal species close to homo sapiens is that obtained by Denton et al. [2] in the mid-1990s. To date, this study constitutes the most accurate experimental analysis of the long-term relationship between salt intake and arterial pressure. The experiment started with a long 1-year control period during which the chimpanzees were observed at their natural low-sodium, high-potassium, fruit and vegetable diet. This control period was followed by a 20-month phase where increasing amounts of salt (up to 15 g) were gradually added to the natural diet. The animals were finally reverted to their habitual, low-salt diet. The study design fully ensured that one variable only (salt) was changed, with all other variables maintained accurately constant (potassium, calcium, social conditions). The effect of salt was large and consistent because the systolic pressure rise was of 26 mmHg at the top salt intake, and as much as 70% of the chimpanzees were 'salt-sensitive'. An experiment of such duration, completeness and elegance is unrealistic in man. If homo sapiens does not represent an exception regarding the salt-arterial pressure relationship, which seems untenable, salt sensitivity must also be pervasive in humans. However, the behavioural complexity of mankind is such that the issue of salt sensitivity is very difficult to study.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
