A reduction or elimination of discretionary salt use (i.e., salt added during food preparation and at the table) is frequently prescribed for hypertensive patients and has been recommended for the general U.S. population. Due, in part, to the decreased palatabiity of foods on reduced Na+ diets, however, adherence to this type of regimen is often inadequate. As a result, little health benefit is realized. Studies undertaken to ascertain how the palatability of foods could be maintained with less total salt revealed the sensory appeal of a wide array of foods remained at an acceptable level when surface salt (analagous to table salt) was eliminated. This source of Na+ is estimated to contribute 15-20% of the total Na+ in the average American diet and both epidemiologic and clinical studies indicate that, on a population basis, a reduction of this magnitude could result in significant declines in hypertension related morbitity and mortality. The reduction in Na+ intake and subsequent blood pressure response would, of course, be less than that expected from the elimination of all discretionary salt use, but the anticipated improved compliance with the no table salt dietary regimen could offset this theoretical advantage and result in a longer term health benefit. The purpose of this proposed investigation is to ascertain both the contribution of selected sources of Na in the diet and the acceptability of and compliance with a diet reduced in Na+ by elimination only of table salt. During two baseline assessments, the blood pressure, dietary intake (determined by 7-day diet records, urinary electrolyte excretion values, drinking water collections and questionnaires), height, weight, salt use (assessed by questionnaire and the use of pre-weighed salt shakers provided to subjects with instructions for their use (e.g., only for table or cooking salt use)), and taste preferences (evaluated by questionnaire and ratings for salted food samples) of 75 healthy adults will be measured. Subjects will then be randomly assigned to one of three groups. The first will be allowed to continue their customary dietary practices and will serve as controls for time and repeated testsing effects. Group 2 will be asked to eliminate table salt use and group 3 will be instructed to refrain from all discretionary salting. The same parameters evaluated during the baseline period will then be re-assessed at stipulated time periods during and 6 months following the eight week dietary manipulation period. Contributions of the different sources of sodium will be assessed and changes in Na+ intake and ratings for the acceptability of the diets will be compared between groups to ascertain the efficacy of the compromised dietary prescription. Findings from this proposed investigation should facilitate the development of improved dietary guidelines for individuals who elect, or are advised, to reduce their Na+ intake.
| Mattes, R D; Donnelly, D (1991) Relative contributions of dietary sodium sources. J Am Coll Nutr 10:383-93 |
