Salt, one of the most effective and most widely used of all food preservatives, has been such an important element of life that it is the subject of many stories, fables, folktales and fairy tales. Also symbolizing purity in religious rituals in many cultures, it is almost ironic that this once precious commodity has been linked to numerous health problems including stroke, heart disease and high blood pressure.
In the U.S, the Food and Drug Administration have just issued voluntary sodium reduction guidelines for food manufacturers, food service operations and restaurants, spanning nearly 150 food categories. The aim is to try and limit sodium consumption to 3 grams per day in the short term (two years) and 2.3 grams per day in the long term (ten years).
Sodium intake in the U.S. exceeds the recommendations of most experts by 50 percent, with the majority it coming from processed and prepared foods therefore making it difficult for people to identify and reduce salt in their diets. As there are persisting concerns that salt reduction is not as beneficial as many claim, BMC Public Health takes the opportunity to look back at some of its articles published on this topic.
A number of modelling studies have been published looking at the health gain and associated costs implications of dietary sodium reduction. One such study in BMC Public Health used a Markov macro-simulation model to estimate quality-adjusted life-years (QALYs) gained and net health system costs for four dietary sodium reduction interventions. The research found that the largest health gain resulted from a legal requirement to replace some of the sodium chloride in all processed foods with other salts, which subsequently led to a health gain of 294,000 QALYs over the lifetime of the cohort of 2.3 million people.
In Australia, average salt consumption is estimated to be between 7 and 12 grams per day, far exceeding the suggested dietary target of 4 grams per day in this country and current Australian salt reduction efforts are based upon reformulation of the food supply to contain less salt through a public private partnership with the food industry. An article published in the journal aimed to determine the effect of a multi-faceted community-based salt reduction intervention in this region on mean salt intake, as estimated from measures of 24-h urinary sodium excretion made before and after the intervention was implemented. The work’s findings suggest improvements in several important knowledge, attitudes and behavior parameters in relation to dietary salt following the intervention. Most prominent among these included a nearly 6 fold increase in the number of participants who reported use of spices during cooking (corresponding to one of the key messages of the intervention program) and a significant 15% increase in subjects who avoided eating out.
A cluster-randomized controlled trial also being carried out in Australia has set out to quantify the effects of advocacy delivered by a local non-government organization on the salt content of food products produced or marketed by companies. Results of the trial are expected to have important implications for the future of Australian efforts to reduce the large burden of disease caused by poor diet.
Despite the research linking high sodium consumption to poor health outcomes, the Salt Institute argues that salt reduction will lead to other health problems including iodine deficiency and insulin resistance. But should we be concerned?
With the re-emergence of iodine deficiency observed in the early 2000’s in Australia—attributable to low usage of iodized table salt and replacement of iodine-rich sanitizers in the dairy industry—salt-reduction and iodine deficiency elimination strategies should be implemented synergistically as explained in a BMC Public Health article examining the potential effects of salt-reduction strategies on sodium and iodine intakes.
The debate on the FDA’s long-awaited decision is raging but, as voluntary targets have been introduced in 33 countries around the world and a further nine countries have now mandated maximum sodium/salt limits for certain products, it looks like the evidence justifying this decision has prevailed.