Hypertension is a leading risk factor for cardiovascular disease. The main dietary focus in the past has centred on the role played by sodium in blood pressure regulation, but research attempting to link high sodium diets to hypertension has been contradictory. While reduced sodium diets do lower blood pressure in some individuals, it appears that in many cases dietary restriction has no effect. There are many confounding variables and the link between sodium and hypertension is complex. Recent evidence suggests that potassium, magnesium, calcium and sodium levels in the diet are all involved in the maintenance of proper blood pressure and an imbalance in these macrominerals can lead to the development of hypertension. A negative association between potassium and blood pressure has been identified and several short term studies have found a blood pressure reducing effect of potassium.
For example, research published in the American Journal of Clinical Nutrition1 investigated the effect of on blood pressure of 1981 veterans in a retirement home (mean age: 74.8 years). The subjects were assigned to receive food prepared with potassium rich salt or regular sodium rich salt. The researchers then monitored the deaths in each group for the next 31 months. In the control group, the number of cardiovascular related deaths was 20.5 per 1000 subjects, but in the treatment group the number of cardiovascular deaths was 13.1 per 1000. This difference represented a significant difference in cardiovascular related deaths in the treatment group. This translated to the subjects in the treatment group living for a mean 0.3 to 0.9 month longer than subjects in the control group. The treatment group also has a significant reduction in the number of hospitalisations for cardiovascular related complaints.
These results support previous findings that show a link between macromineral intakes and cardiovascular disease. Generally, Western diets are higher in sodium and calcium but lower in magnesium and potassium. This creates mineral imbalances in the body which can cause physiological changes to the nervous and cardiovascular systems. Animal studies have shown that potassium and magnesium deficiencies can cause changes in neuromuscular function that can lead to spasms, convulsions, tremors, cramps and tetany, and that individuals dying of sudden cardiac death have lower levels of potassium and magnesium (here). Fruits and vegetables are rich in potassium and a diet rich in plant material is a good way to increase potassium intakes. Potassium rich salt is also commercially available and this can be substituted for regular table salt as was done in this research.
RdB
