Dietary fats and blood pressure.

The blood pressure lowering effect of elevating the dietary polyunsaturated/saturated (P/S) ratio has been assessed in a randomised, controlled trial in normotensive volunteers. Subjects were allocated either to a control group who ate a low P/S ratio diet throughout, or to one of two experimental groups who ate a high P/S ratio diet for one of two six week experimental periods. There were significant changes in estimated dietary P/S ratio and measured changes in plasma fatty acids and buccal mucosal cell phospholipids. Changes in blood pressure were not related to changes in P/S ratio. There were no changes in other factors which may have confounded the relationship between blood pressure and P/S ratio change. This study suggests that P/S ratio change, without changing other nutrients, does not affect blood pressure in normotensive subjects.