Effect of dietary sodium restriction on overall nutrient intake

Sodium restriction, widely prescribed for hypertensive persons and recommended for the broader US population, may result in nutrient alterations that could either beneficially or detrimentally affect overall diet quality. Most dietary sodium comes from meats (including poultry and fish), grains, and diary products. These three groups also provide most dietary calcium, iron, magnesium, and vitamin B-6. Thus, reduced consumption of foods that are primary sodium sources could concurrently reduce the dietary content of these other nutrients below recommended daily intakes. This consequence of sodium restriction has not been specifically addressed in clinical trials. Although intake of most food groups was significantly reduced by a sodium-restricted diet in the Hypertension Prevention Trial, three other large clinical trials reported differing effects of sodium restriction on simultaneous energy and nutrient intakes. In the largest study of the effects of a sodium-restricted diet on intake of all major nutrients, sodium reduction was accompanied by lower energy intake and, concomitantly, lower intakes of total fat, saturated fat, protein, carbohydrate, and calcium. Present data are inadequate for determining the potential nutrient alterations of a broad prescription of sodium restriction. Difficulties in interpreting the available data result from the combination of sodium restriction with other interventions, intensive sodium reduction measures that do not reflect clinical implementation, poor compliance with sodium restriction, lack of analysis of changes in patterns of food intake, and interventions that are too short to reflect stable dietary patterns.