Regional difference in sodium chloride content in home-made and store-bought preparations of miso paste

Miso, a fermentation product of salted soya beans and rice (or soya beans and barley), is one of the leading sources of sodium chloride intake for Japanese people. Sodium chloride contents in 973 home-made preparations collected from 39 Regions in 20 Prefectures in Japan showed wide variation from 9.1 to 18.2% on the Region average, while the levels in store-bought samples were rather low and constant at 10 to 12%. When classified by Regions or Prefectures, positive and significant correlations were observed between indices of sodium chloride intake via miso (i.e., sodium chloride in home-made miso, or frequency of miso soup intake) and death rate indices for cerebrovascular diseases.