Resolving the issues
The issues of greatest saliency are two: 1) achieving sustainable salt iodization globally (currently at 70%) and 2) resolving whether medical evidence supports any recommended intake level for dietary salt.
Sustainable salt iodization requires an active partnership between government food agencies and salt producers. Ideally, this partnership should be part of a broader multi-sectoral national coalition to create and sustain political support for an effective food regulatory program that ensures consistent adherence to quality standards in food production and credible ingredient labeling. In some instances, national governments, international development agencies like UNICEF and the World Health Organization, or special purpose iodine nutrition advocacy groups like ICCIDD and The Network, may need to provide transitory technical assistance to salt producers who do not know how to iodize salt.
Salt Intake Recommendation
Population dietary guidelines should be “evidence-based” recommendations that improve health. They should avoid areas where the science is unclear or where only a disease risk factor is affected; a demonstrable health benefit should be supported by quality science. We need to consult real evidence, not settle for consulting real experts. Data trumps opinion.
In the case of salt, we concur with the Cochrane Collaboration: there is insufficient evidence to recommend that the entire population modify its salt intake level. The few studies considering the health outcomes of diets reduced in dietary sodium (e.g. cardiovascular mortality, heart attack incidence, etc.) offers no support for the “sodium hypothesis” that people would live longer and healthier lives and experience fewer cardiovascular events. In fact, the literature suggests lowering salt intakes may create additional risks as an unintended consequence. This literature, however, is based solely on observational studies; we badly – and urgently – need a controlled trial of the question. The U.S. National Heart, Lung and Blood Institute has conducted the prototype study, the Trials of Hypertension Prevention, phase II, but measured the wrong variable – blood pressure rather than health outcomes. That study methodology is proven. A five-year trial would establish once and for all whether, if salt intakes be lowered, if there would be a health benefit achieved. We doubt it based on the evidence today, but, as a society, we should insist on better studies to make possible an “evidence-based” recommendation on dietary salt.
If a controlled trial were to conclude that reducing intake levels of dietary salt would confer a health benefit, we could then move forward to consider questions of how to avoid the unintended adverse health effects, how to modify humans’ hard-wired salt appetite, how to engineer healthy foods with lower salt content and how to modify diets so that the foods selected achieve the salt reduction goal. These are all serious and complicated issues, but dedication of resources to addressing them without first knowing that solving them would improve people’s health would be an enormous waste of resources.