A novel technique for assessing the sources of dietary sodium.

Li can be used to track Na during the cooking and eating process as it is handled by the body in a manner similar to Na. A new approach to study the sources of salt using Li is described. When this technique was applied in an epidemiological context using 12 consecutive 24-hour urine collections, we found that at least 83% of the salt ingested by a population in Cambridgeshire, England, was derived from processed food. Only a small amount of the total salt intake came from cooking or from using salt on the table. The total amount of salt eaten was not as high as was previously estimated indirectly. There was a clear sex difference in salt intake which in part related simply to the finding that salt intake correlates with body weight of an individual. This study implies that those who wish to advocate a reduction in salt intake in order to prevent hypertension must reconsider their approach. Any health education programme that is geared simply to reduce discretionary salt use in the home, will have little impact on the total amount of NaCl ingested by the population.