A global review by Santos JA et al in the Journal of Clinical Hypertension summarised and synthesised the evidence for changes in sodium levels in food products. The review included studies from 2013 to 2018 that were published in the Science of Salt Weekly newsletter, which are identified through a weekly MEDLINE search.
24 relevant studies were identified, including studies on packaged foods, restaurant foods, and meals in institutional settings, and 22 of these were in high income countries. Intervention types included voluntary reductions, labelling and institutional interventions.
For products matched at two time points, a decrease in sodium was observed in all studies of packaged food and in settings with no change in restaurant foods. For unmatched products, pooled analysis of change revealed a decrease overall and in five out of 10 packaged food categories.