Dietary fiber, psyllium, attenuates salt-accelerated hypertension in stroke-prone spontaneously hypertensive rats

Although dietary fiber, psyllium seed husk (psyllium), is known to reduce blood glucose and lipid levels, the effect of psyllium on blood pressure elevation induced by salt ingestion has not been tested in human and rats. We observed the effect of psyllium on salt-accelerated hypertension in stroke-prone spontaneously hypertensive rats (SHRSP).

Forty male SHRSP (6 weeks of age) were divided into four groups: a plain laboratory diet (PL) group, groups receiving the PL diet substituted with 3% or 10% of psyllium, and a group fed the PL with 10% of cellulose. All those groups were given 0.5% salt water for drinking during the experiment. Urine and feces were collected during 24 hours with a metabolic cage on the 22nd and 29th days of experiment, and sodium and potassium were determined. On the 30th day of the experiment, five rats in each group were killed and heart weight was measured.

Salt-accelerated hypertension was significantly attenuated in the SHRSP fed with 3% and 10% psyllium diets compared to those fed the PL and 10% cellulose diets (15th, 22nd, 29th day; 10% psyllium versus PL or 10% cellulose, P < 0.05, 29th day; 3% psyllium versus PL or 10% cellulose, P < 0.05). Ventricular weight was decreased in rats fed 3% or 10% psyllium diets. The amount of sodium, the amount of sodium/the intake of sodium and the sodium/potassium ratio in the feces were significantly increased in the groups on 3% and 10% psyllium diets both on the 22nd and 29th days of experiment compared with those on PL and 10% cellulose diets.

The psyllium diet attenuated the salt-accelerated hypertension in SHRSP by a possible mechanism of increased fecal excretion of sodium absorbed into the psyllium.