Hypertension, or high blood pressure, is the leading cause of heart disease, affecting around one billion people worldwide. The importance of nutrition for the maintenance of healthy blood pressure is well known, and most people are aware that a reduction in dietary sodium intake is a good step towards lowered blood pressure. However, there is a growing body of evidence suggesting that an increased intake of certain other minerals and nutrients is also important.
A recent review of the roles of various minerals in the treatment of hypertension has revealed that a diet high in potassium may be able to significantly reduce blood pressure. Potassium is a mineral that is required by the body for the maintenance of normal kidney function and for muscle contraction. Observations of lower incidences of hypertension and heart disease among isolated populations and in vegetarians has led to speculation that this may be related to higher levels of potassium in these types of diets. On average, individuals living in isolated populations consume much less sodium and more potassium than individuals living in industrialized societies. This difference in diet is associated with a far lower incidence of hypertension, with only 1% of the population being affected, in comparison to nearly 1 in 3 people in industrialized societies.
Clinical trials have supported these findings, with four large meta-analyses showing an average lowering of systolic blood pressure by 2.4 - 11.2 mmHg and of diastolic blood pressure by 1.6-5.0 mmHg following potassium supplementation. Although these studies ranged in duration from 2 weeks to 8 weeks and the levels of potassium supplementation varied greatly, the results were consistently positive. In general, blood pressure was lowered by approximately 10% when total daily potassium intake (from diet and supplements combined) was increased to 1900-4700mg/day. Potassium’s role in reducing hypertension is likely related to its ability to induce vasodilation, or relaxation of the muscles in the walls of blood vessels.
The importance of potassium has been recognized by many health organizations with both the Institute of Medicine and the Canadian Hypertension Society recommending daily potassium intakes (from diet and supplementation combined) of at least 3.5-3.8g. In 2006 the American Heart Association issued guidelines suggesting a total daily intake of 4.7g/day. As such, it is important for individuals to be aware of the potassium content of their diet, and adjust their supplemental levels of potassium accordingly. For example, two slices of watermelon or two bananas each contain over 1000mg (1g) of potassium.
The potential blood pressure lowering effects of magnesium and calcium were also evaluated, but their role remains uncertain. Although there is some indication that diets containing 500-100 mg of magnesium and over 800 mg of calcium daily may be helpful in treating hypertension, the results of clinical trials and meta-analyses are inconsistent. These nutrients are involved in many pathways and processes linked to the circulatory system, and future studies could clarify their role in maintaining a healthy blood pressure.
Overall, potassium seems to be a key mineral in the battle against this very common and serious health condition. Its importance is reflected in the authors’ conclusion that "An increase in potassium with a decrease in sodium is probably the most important dietary choice (after weight loss) that should be implemented to reduce cardiovascular disease." This being said, individuals prone to hypertension should have their blood pressure checked regularly, even when following a proper regimen of diet and supplementation.
Houston, MC and Harper, KJ. Potassium, Magnesium, and Calcium: Their Role in Both the Cause and Treatment of Hypertension. The Journal of Clinical Hypertension. 2008. Volume 10, Supplement 2.
For more information see Ortho-Minerals , Magnesium + Potassium Aspartates and Ortho-Core
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