Dietary prevention of stroke and its mechanisms in stroke-prone spontaneously hypertensive rats--preventive effect of dietary fibre and palmitoleic acid.

Previously it was reported that dietary protein, some amino acids and potassium are effective in preventing stroke in stroke-prone spontaneously hypertensive rats (SHRSP). The present study revealed that other dietary factors could also prevent cerebral lesions, and the mechanism of this effect was studied. In SHRSP given 1% NaCl in their drinking water, a diet containing 10% active fibre (powdered brown seaweed converted to K+ form) significantly lowered blood pressure (BP) and markedly reduced the incidence of stroke (0 versus 100% in controls on the 30th day of experiment). Since the faecal to urinary sodium (Na) excretion ratio was increased in this group and a similar increase in faecal Na content was noted in SHRSP given a diet containing 10% alginic acid, the inhibition of intestinal Na absorption by alginic acid in the seaweed fibre was considered to be a possible preventive mechanism. Among SHRSP given various fatty acids, a diet containing 1% palmitoleic acid (POA) significantly improved the survival rate, with concomitant reduction in the incidence of stroke in spite of their excess NaCl intake through 1% NaCl water for drinking. Since neither BP nor urinary Na excretion was changed by POA which had high affinity for the vascular wall, the preventive effect was ascribed to the possible direct metabolic improvement of vascular smooth muscle cells.