The salt-blood pressure hypothesis states that an excessive salt intake leads to an increase in blood pressure in genetically susceptible persons and, if high intake is maintained long term, ultimately leads to sustained hypertension. It is estimated that about 3.3 million South Africans (12.6% and 16.3% of adult men and women, respectively) are hypertensive. However, not all subjects within a particular population respond equally to exposure to high-salt diets. Methods to identify those who are 'salt sensitive' remain in the research domain; therefore a population approach to the restriction of dietary salt intake is warranted. The message to 'eat salt sparingly' will not interfere with the current nutritional and legal requirements regarding iodation of table salt. A salt intake as low as 5 g per day would provide an adequate amount of iodine, provided the salt is sufficiently iodated. Dietary factors other than sodium which have been shown to influence blood pressure include potassium, magnesium, calcium and alcohol. The 'Dietary Approaches to Stop Hypertension' (DASH) randomised controlled trial found that subjects fed a diet rich in fruit and vegetables for 8 weeks significantly reduced both systolic and diastolic blood pressure, compared with subjects on a typical American control diet. A 'combination' diet, rich in fruit, vegetables and low-fat dairy products, and with a reduced saturated and total fat intake, resulted in an even greater reduction in blood pressure. Translated into a practical diet, this information suggests a daily diet that includes large amounts of fruit and vegetables, a moderate intake of low-fat dairy products, lean meat and chicken, and a prudent alcohol intake. Salt should be used sparingly, if at all, at the table and in the preparation of meals, and the intake of processed foods high in salt should be limited. This would result in a reduction in intake from an average of around 9 g salt to about 6 g salt per day, which is the current USA recommendation. These blood pressure-related recommendations incorporate many of the various foodbased dietary guidelines, emphasising that the recommendations are congruent and mutually substantiative.
Charlton, K. E. & Jooste, P. L. 2001, 'East salt sparingly - sprinkle, don't shake!', South African Journal of Clinical Nutrition, vol. 14, no. 3, pp. S55-S64.