Protective effects of high dietary potassium: nutritional and metabolic aspects

Potassium (K+) requirements have been largely overlooked because severe deficiencies are uncommon due to the ubiquity of this element in foods. However, a transition toward modern ("Westernized") diets has led to a substantial decline of K+ intake compared with traditional food habits, and a large fraction of the population might now have suboptimal K+ intake. A high K+ intake was demonstrated to have protective effects against several pathologic states affecting the cardiovascular system, kidneys, and bones. Additionally, fruits and vegetables contain K/organic anion salts (malate, citrate), which exert alkalinizing effects, through KHCO(3)(-) generation, which serves to neutralize fixed acidity in urine. Low-grade metabolic acidosis, when not properly controlled, may exacerbate various catabolic processes (bone Ca++ mobilization, proteolysis), especially in the elderly. Fruits and vegetables are therefore receiving great attention in a strategy to increase the nutritional value of meals while reducing energy density and intake. The need to ensure a 2.5- to 3.5-g daily K+ supply from fruits and vegetables represents a strong rationale for the "5-10 servings per day" recommendations.