Effects of a sodium-potassium ion-exchanging seaweed preparation in mild hypertension

A nonpharmacological approach in the treatment of mild hypertension is often advocated. In an attempt to decrease sodium and increase potassium intake, sixty-two middle-aged patients with mild hypertension were given a potassium loaded ion-exchanging sodium-adsorbing potassium-releasing seaweed preparation (seaweed fiber, SF). The mean blood pressure (MBP), evaluated in a double-blind crossover manner with four weeks familiarization and wash-out periods, showed a significant decrease after four weeks on 12 and 24 g/day SF but not on 6 g/day or placebo treatment. Systolic blood pressure during submaximal exercise decreased on all three SF doses. The decrease in MBP appeared to be significantly higher in sodium-sensitive (11.2 mm Hg, P less than .001) than in sodium-insensitive (5.7 mm Hg, P less than .05) patients and was in salt-sensitive patients significantly correlated to the increase in plasma renin activity (PRA). The urinary sodium excretion decreased, the urinary potassium increased and the sodium/potassium urinary excretion ratio decreased, indicating that the decrease of MBP was dependent on the decreased intestinal absorption of sodium and increased absorption of potassium released from the seaweed preparation. A sodium-potassium ion-exchanging seaweed preparation is an effective means of decreasing sodium and increasing potassium intake, and may be used for antihypertensive treatment in mild hypertension.