High blood pressure, or hypertension, is a condition where the pressure of the blood flow against the walls of blood vessels is high enough to eventually lead to health problems. Interest in the use of calcium supplementation to reduce high blood pressure comes as the result of the recognition of calcium's role in the control of dilation and contraction of blood vessels
Hypertension
Hypertension is a problem that affects one in three Americans, many of whom do not know they have it, as hypertension has no symptoms in most cases. Hypertension is defined as a blood pressure reading consistently higher than 140/90. Uncontrolled high blood pressure can lead to stroke, blindness, heart disease and kidney disease.
Weak Evidence for Benefits
According to the Office of Dietary Supplements, clinical trials have shown a correlation between decreases in blood pressure and reduced risk of hypertension and increased calcium intake. A meta-analysis by H.O. Dickinson, et al., published in the "Cochrane Database of Systematic Reviews" in 2006, looked at the results of all the studies and found the results to be weak, at best, primarily due to poor study design and inconsistencies between studies.
DASH Diet and Low-Fat Dairy Products
The Dietary Approaches to Stop Hypertension, or DASH, study tested the effects of two alternatives to the typical American diet on blood pressure. One of the alternatives was high in fruits and vegetables, and the other added low-fat dairy products. The reduction in blood pressure was greater for the group that consumed low-fat dairy products. The ODS cautioned that this study did not look at the effects of calcium supplementation alone, but rather the addition of low-fat dairy products.
The DASH DIet
The DASH diet is higher in fruits, vegetables, whole grains, beans, poultry, fish, seeds and nuts than the typical American diet. It is lower in red meat, sugar, sugar-added foods, fats, and sodium than the typical diet. Additional information on the DASH diet can be found on the "Lowering Your Blood Pressure with DASH" page on the website of the National Heart Lung and Blood Institute, which is listed as a resource.
Other Ways to Treat Hypertension
There are several classes of drugs that are used to treat hypertension. Diuretics, such as hydrochlorothiazide, decrease the volume of the blood by increasing excretion of salt and water by the kidneys. Beta blockers, such as atenolol, reduce the strength of the heart's contractions. The newer calcium channel blockers, such as Norvasc, and the ACE inhibitors, such as lisinopril, act to dilate the arteries. The final class, angiotensin-receptor blockers such as candesartan, also act to dilate the arteries.
References
- Oregon State University, Linus Pauling Institute: Calcium
- MayoClinic.com: High Blood Pressure (Hypertension)
- MedlinePlus: Hypertension
- Office of Dietary Supplements: Dietary Supplement Fact Sheet: Calcium
- HealthCommunities.com: High Blood Pressure Medications
- "Cochrane Database of Systematic Reviews": Calcium Supplementation for the Management of Primary Hypertension in Adults; Dickenson et al.; 2006
