The INTERMAP study shows that fiber does have a favorable effect on blood pressure, even when potassium intake is taken into account.
Fibers have already accumulated many health successes. In particular, they are known to have an inverse association with the risk of cardiovascular disease, which, if not linked to a clear effect on blood lipids, could be due to effects on blood pressure. This is precisely what a British-American team wanted to verify using data from 2,195 Americans enrolled in the INTERMAP study (INTERnational study on Macro/micronutrients in blood Pressure).
Only a certain type of fiber
The results indicate that an increase of 6.8 g in total dietary fiber per 1000 kcal is associated with a reduction in systolic blood pressure (SBP) of 1.69 mmHg, attenuated to -1.01 mmHg after correction for potassium intake. The effect is attributed to insoluble fibre, of which an increase in intake of 4.6 g/1000 kcal is associated with a reduction in PSS of 1.81 mmHg. Soluble fiber has no association with blood pressure.
Foods Highest in Good Fiber
The main sources of total and insoluble fiber identified in this study are raw fruits, followed by whole grains and vegetables. Various factors are considered to help explain the effect of fibers on blood pressure: an effect on the release of nitric oxide, an improvement in endothelial function, cardiovascular risk factors and better sensitivity to insulin.
Aljuraiban GS: Total, insoluble and soluble dietary fiber intake in relation to blood pressure: the INTERMAP Study. British J Nut