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acids, such as sulfuric acid generated from sulfur-containing amino acids commonly found in meats and other high protein foods. In the setting of an inadequate intake of bicarbonate precursors, buffers in the bone matrix neutralize the excess diet-derived acid, and in the process, bone becomes demineralized. Excess diet-derived acid titrates bone and leads to increased urinary calcium and reduced urinary citrate excretion. The resultant adverse clinical consequences are possibly increased bone demineralization and increased risk of calcium-containing kidney stones. In processed foods to which potassium has been added and in supplements, the conjugate anion is typically chloride, which does not act as a buffer. Because the demonstrated effects of potassium often depend on the accompanying anion and because it is difficult to separate the effects of potassium from the effects of its accompanying anion, this report primarily focuses on research pertaining to nonchloride forms of potassium—the forms found naturally in fruits, vegetables, and other potassium-rich foods.

On the basis of available data, an Adequate Intake (AI) for potassium is set at 4.7 g (120 mmol)/day for all adults. This level of dietary intake (i.e., from foods) should maintain lower blood pressure levels, reduce the adverse effects of sodium chloride intake on blood pressure, reduce the risk of recurrent kidney stones, and possibly decrease bone loss. Because of insufficient data from dose-response trials demonstrating these effects, an Estimated Average Requirement (EAR) could not be established, and thus a Recommended Dietary Allowance (RDA) could not be derived.

At present, dietary intake of potassium by all groups in the United States and Canada is considerably lower than the AI. In recent surveys, the median intake of potassium by adults in the United States was approximately 2.8 to 3.3 g (72 to 84 mmol)/day2 for men and 2.2 to 2.4 g (56 to 61 mmol)/day for women; in Canada, the median intakes ranged from 3.2 to 3.4 g (82 to 87 mmol)/day for men and 2.4 to 2.6 g (62 to 67 mmol)/day for women (Appendix Tables D-5 and F-3). Because African Americans have a relatively low intake of potassium and a high prevalence of elevated blood pressure and salt sensitivity, this subgroup of the population would especially benefit from an increased intake of potassium.

In the generally healthy population with normal kidney function, a potassium intake from foods above the AI poses no potential for

2  

To convert millimoles (mmol) of potassium to milligrams (mg) of potassium, multiply mmol by 39.1 (the molecular weight of potassium).

 



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