The link between calcium and blood pressure was noticed years ago when researchers realized that people drinking hard water had less high blood pressure than those drinking soft water.
Hard water contains more minerals, including calcium.
In fact, a secret weapon against high blood pressure may be calcium-rich foods.
Some experts contend that high blood pressure is more likely due to a calcium deficiency than a surplus of sodium and that adequate calcium intake can cancel the blood-pressure-raising effects of sodium in some people.
According to Dr. David A. McCarron of Oregon Health Sciences University, some people simply need more calcium than others to keep blood pressure normal, and quite often those are people who are "salt sensitive", that is, whose blood pressure rises from eating too much sodium.
One theory is that such individuals retain water when they eat to much sodium, increasing the blood volume, hence raising blood pressure.
Calcium seems to act like a natural diuretic, helping the kidneys release sodium and water, thus reducing blood pressure.
Another more complex explanation is that when calcium levels in the blood drop, parathyroid hormone (PTH) is released, which, in turn, causes calcium to be released from the bones to increase calcium blood levels and PTH can raise blood pressure.
Whatever the reason, in some people calcium does reduce blood pressure.
Research into the relationship between calcium and blood pressure at the University of Texas Health Science Center showed that 800 mg of calcium a day reduced mild to high blood pressure in 20% of subjects by a dramatic 20 to 30 points.
Most, however, had small drops and, oddly, blood pressure went up in about 20%.
Another study found that people under age 40 may cut their chances of developing high blood pressure by eating enough calcium.
In fact, the chances of high blood pressure went down an average 20% for each 1,000 mg. of calcium consumed per day in moderate drinkers (not more than one drink a day) who were not overweight.
In people who drank less alcohol, the risk plunged by 40 %. Apparently, alcohol tends to counteract calcium's powers to lower blood pressure, said study author James H. Dwyer of the University of Southern California School of Medicine in Los Angeles.
As mentioned earlier, some people respond better to supplemental calcium than others. Apart from people who are salt sensitive and individuals with a high sodium intake, others include African-Americans, elderly, pregnant women, menopausal women, and those with Type II diabetes.
Milk and dairy foods, of course, are rich in calcium and the American Heart Association has reported that women who consume more low-fat or fat free milk products, and/or had diets high in calcium, are far less likely to suffer from high blood pressure than women with lower calcium levels in their diets.
But milk and dairy products can cause digestive problems and allergies in many people and, of course, the full-fat varieties are, well ... full of fat (especially saturated fat), so widen your horizons and consider the other sources of calcium and try to include them in your diet as much as you can.
The ability of the body to use calcium depends not only on its intake but also on its absorption. The amount absorbed depends on the food, but is normally around 20-30%.
For better results you need to supplement calcium along with vitamin D.
Vitamin D aids the absorption of calcium from the small intestine and it controls the deposition of calcium in bones.
One study supplemented women 1200 mg of calcium for blood pressure.
When they added 800 IU of vitamin D, systolic blood pressure decreased an average of 9.3%.
Many studies show that appropriate levels of vitamin D are required for the metabolism and absorption of calcium.
Thus, while studies indicate that higher amounts of calcium and dairy products result in lower blood pressure, they also caution that sufficient vitamin D must be a part of the diet as well.
So people may be eating enough calcium-rich foods and still suffer with high blood pressure because their intake of vitamin D is not adequate.
Very few foods are naturally rich in vitamin D. Milk is most often fortified with 125 IU of vitamin D per glass. There is also some vitamin D in eggs, organ meats, and fish such as salmon, sardines, and herring.
Vitamin D is also manufactured in the skin right after direct exposure to sunlight. Sunlight exposure to the hands, face and arms for as little as 10-30 minutes, 2-3 times per week is helpful to produce vitamin D during the summer months.
Magnesium works along with calcium not only for maintaining bone density but also for the good functioning of blood vessels.
The average diet is relatively high in calcium but deficient in magnesium, because milk, a major source of calcium, is not a very good source of magnesium.
There's no point in increasing calcium intake if magnesium status is poor. Without magnesium, calcium absorption will also be poor.
Both minerals are present in green leafy vegetables, nuts and seeds. And if you supplement with calcium, you need to supplement with magnesium as well.
This article is the last in the series of healing foods for high blood pressure. Go back at the beginning by clicking on Causes of High Blood Pressure or choose one article from the list below.