Daily magnesium supplements can trigger small but significant decreases in blood pressure. This effect is greater in subjects with higher blood pressure. Supplementation with magnesium for 8 weeks significantly lowered blood pressure. Average blood pressure reductions were small, but noteworthy -- about 2.5 mm/Hg lower in the systolic (first number) reading, and 1.4 mm/Hg lower in the diastolic (second number) reading. Magnesium may help lower blood pressure through its ability to increase the diameter of blood vessels.
Hypertension August, 1998;32:260-265.
I wrote a journal article 13 years ago on the use of calcium to lower blood pressure (Calcium Supplementation in the Treatment of Hypertension. J Amer Osteo Assoc 85:104-107, 1985). It is quite clear that calcium and magnesium are both useful adjuncts in reducing blood pressure. However, the decrease is relatively small. Most of the benefit will be achieved with the use of the low grain diet. Again, the Heller book The Carbohydrate Addict Diet Lifespan Program is an excellent resource. The results are much better when one does not have the reward meal they suggest. It works to normalize high blood pressure in the majority of people who try this plan. Certainly not everyone willachieve this result but this wiil be achieved by probably somewhere between 70 and 80 percent. When I was studying physiology in college 25 years ago, I wondered why 95% of blood pressure was called "essential." This is a fancy term to state that science did not know what caused it. I did not understand the cause until about three years ago. Most doctors are still in the dark on this one.