08 Jan Salt Intake Reduced By Warnings on Salt Containers
Medical Research: What is the background for this study? What are the main findings?
Dr. Rumboldt: Arterial hypertension is the major common denominator of a number of cardiovascular diseases and untoward outcomes including stroke, myocardial infarction, terminal renal insufficiency, heart failure and death. Excessive salt intake is the leading causative factor of blood pressure elevation across the world. It has been shown beyond any reasonable doubt that reduction in salt consumption decreases the prevalence of arterial hypertension and eases its management. Therefore many endeavors and campaigns aimed at moderation in salt ingestion have been launched with fair but less than expected results. The main source of ingested salt in developed countries is processed food, while in transitional and developing countries it is addition during food preparation (cooking), serving and salting at the table.
This study, executed in Mostar, Bosnia and Herzegovina, and Split, Croatia, was designed to evaluate the effects of emphasized warning, consisting in self-adhesive stickers with clear, short message, put on household salt containers. Analyzed were 150 treated hypertensives, randomized in two groups, both receiving oral information and written leaflet concerning salt-hypertension relationship; the intervention group received in addition warning labels to be put on salt containers. In both groups measured were 24-hour urinary sodium excretion (natriuria), blood pressure, and several other parameters at inception of the trial, and one and two months later. In the intervention group observed was a marked decrease in sodium excretion (e.g. from 211 mmol/l at the beginning to 176 mmol/l at two months), much less (from some 207 to 200 mmol/l) in the control group. At the same time, the mean blood pressure (already fairly well controlled) was reduced by additional 4 mm Hg in the intervention group (from 104 to 100 mm Hg), which was not the case in the control group (from 104 to 103 mm Hg).
Medical Research: What should clinicians and patients take away from your report?
Dr. Rumboldt: The take away message would be that reduction in salt intake, from the current 10-13 g/day to the desired 5 g/day is an arduous, hardly achievable mission. One of the additional measures, similar to the anti-smoking campaign is to put warning on salt containers. Such strategy may increase the awareness of the hazards and encourage less consumption. Indeed, in this very trial we have shown that emphasized warning may reduce daily salt intake by over 35 mmol (i.e. more than 16%), at least during the first two months.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Rumboldt: These data are encouraging but may not be extrapolated beyond two months of the actual study duration. Such patients should be followed up (the results after 12 moths will be published soon) and encouraged in the same direction. As we have shown with smoking cessation (Croat Med J 2003;44:219-44) initial optimistic results otherwise fade off. Only concerted efforts may achieve satisfactory results in this demanding field.