Sir, Prof James Heffron (November 24th) is correct in his statement that the salt concentration of sea water is 2.8g per 100g. This corresponds to a sodium concentration of 1.1g per 100g, identical to the sodium concentration of Rice Krispies, 1.1g per 100g. Thus, I was correct in my original assertion that the salt content of this breakfast cereal is equivalent to that of sea water.
I am pleased to note that David Mackay on behalf of Kellogg's (November 25th) accepts the need to reduce the sodium content of some of their breakfast cereals. - Yours, etc., Prof Ivan J. Perry,
Department of Epidemiology and Public Health, University College, Cork.