Mary Bertino

Increasing dietary salt alters salt taste preference

In previous studies with humans, moderate reduction of dietary sodium decreased preference for salty foods. It had been hypothesized that this occurred via reducing taste stimulation with salty foods. Taste function after increasing dietary salt (NaCl), either with or without increasing salt taste stimulation, was examined in two experiments. In Experiment 1, one group of subjects was required to add crystalline salt to food daily for 4 weeks. A second group ingested salt tablets for the same period. A third group ingested a placebo. Whereas urinary sodium excretion increased in both groups ingesting supplemental salt, the concentration of salt in soup rated as tasting most pleasant increased only in the group adding salt to food. Rated intensity of salt did not change. In Experiment 2, salt supplementation was extended to 6 weeks and taste function was tested more extensively. At the end of the experiment, the concentration of salt in soup rated as tasting most pleasant increased in the group which added the crystalline salt to food. This group also added more salt to soup to taste than did the salt tablet group. The most pleasant concentration of KCl in soup was not significantly affected. Taken together these two experiments suggest that the preferred concentration of salt in soup can be increased after dietary salt supplementation and that increased salt taste stimulation is probably required for this to occur.

Modification of Salt Taste

Salt appetite and sodium intake in humans are controlled in part by taste. A distinction can be drawn between salt appetite that occurs when the organism is sodium deficient (in need) and when the organism has sufficient sodium stores (non-need) but continues to ingest salt. Although the latter case is most relevant to human sodium consumption, little is known about its physiologic, developmental, and experiential bases. Recent studies show that changes in dietary sodium consumption are followed by taste changes. Moderate decreases in dietary sodium of 2 months or more are followed by a decrease in the concentration of salt in food judged most pleasant.

Taste perception in three individuals on a low sodium diet.

There is little information on the effect of dietary sodium on taste responses to sodium in humans. Since individuals with hypertension are routinely suggested to maintain a low sodium diet, knowledge of effects of changes in dietary sodium on taste is important. Three subjects were placed on a low sodium diet for three and a half weeks. Detection thresholds for salt and sucrose solutions, and sensory and hedonic responses to salt in soup and sucrose in Kool-Aid were monitored before, during, and after placement on the diet. Detection thresholds for salt and sugar solutions, and intensity and pleasantness ratings of sweetened Kool-Aid were unaffected by dietary manipulation whereas intensity and pleasantness ratings of salt in soup were altered. While the subjects were on the low sodium diet, highly salted soup was judged to taste less intense and more pleasant compared with pre- and post-diet periods. These data parallel results obtained with sodium deficient rats.