FIGURE 5-1 Effect of potassium intake on frequency of salt sensitivity in nonhypertensive African-American men (solid bar) and white men (gray bar). No white men were tested with 4.7 g (120 mmol)/day of potassium. Throughout an initial 7-day period of salt loading in all study subjects, potassium intake as potassium bicarbonate was set at 1.2 g (30 mmol)/day, then increased to a total of either 2.7 or 4.7 g (70 or 120 mmol)/day for a subsequent 7-day period of salt loading. Reprinted with permission from Morris et al. (1999b). Copyright 1999 by W.B. Saunders Co.

sodium chloride per day, increasing dietary potassium as potassium bicarbonate to an intake of 6.6 g (170 mmol)/day abolished the salt sensitivity of all subjects (Schmidlin et al., 1999).

In aggregate, these trials document that supplemental potassium bicarbonate mitigates the pressor effect of dietary sodium chloride in a dose-dependent fashion. Furthermore, these trials highlight the potential benefit of increased potassium intake in African Americans, who have a higher prevalence of hypertension and of salt sensitivity and a lower intake of potassium than non-African Americans. Survey data from the Third National Health and Nutrition Examination Survey (NHANES III) in the United States (Appendix Tables D-6 and D-7) estimated that the median intake of potassium of non-Hispanic African-American men (aged 19 to 30 years) was 3.0 g (78 mmol)/day, while that for non-Hispanic white men (aged 19 to 30 years) was 3.4 g (87 mmol)/day, approximately 10 percent lower than their white counterparts. Similar differences