Calcium Pills? They Can Help, Says Dr. Robert Heaney, but Bossy's Milk Is Better
updated 02/17/1986 AT 01:00 AM EST
•originally published 02/17/1986 AT 01:00 AM EST
Why is calcium important to health?
It is vital to the activity of every living cell—for gland secretion, the contraction of muscle cells and cell division. A constant level of calcium in the blood helps maintain communication between cells, particularly between nerve cells and between nerve and muscle cells. And in the form of calcium phosphate, it is the principal mineral component of our bones.
What happens if the constant level is not maintained?
If there is inadequate intake of calcium from the diet or its absorption happens to be blocked, the bones will be at risk. The human body will tear down bone in order to scavenge its calcium content. In extreme cases the body is capable of reducing bone right down to jelly.
Bone maintenance, then, is a major reason for the body's calcium needs?
Yes. Bone is continuously being remodeled in the body. The structure gets damaged from everyday use, and the damaged material has to be replaced. New bone is being laid down all the time.
What is the daily calcium requirement?
In 1984 the National Institutes of Health adopted the standard of 1,000 milligrams for middle-aged women who still have estrogen and 1,500 for post-menopausal women not on estrogen therapy. Children up to the age of' 12 need 800 milligrams and teens need 1,200. Men and younger women need 800, but men tend to achieve that level—because they generally are more active and drink more milk—while women fall far short of it.
How short is far short?
Two nationwide surveys in the '70s reported that the typical female over 12 is eating less than 600 milligrams of calcium a day. Even worse, one-fourth of white females in the U.S. consume less than 300 milligrams a day.
Do calcium needs change with age?
Yes, because calcium absorption efficiency declines with age. A woman reaches her peak bone mass at 35. When we did a study of 273 post-menopausal women, we found that half were not absorbing adequate amounts of calcium and were losing bone mass as a result.
Do bone structures differ markedly from person to person?
There are two main determinants of how much bone we have. First, an individual's genes are extremely important; some of us are small-boned, some large. Blacks tend to have heavier skeletons that resist being torn down for their calcium. Equally important is exercise—how hard we use the skeleton. Its mass will expand to meet the load placed on it. Even if you have been out of condition until age 45, you can start to train.
And if you don't?
You lose bone. All the calcium in the world can't prevent the bone loss that occurs because of inactivity, immobility, bed rest or anything that takes the load off our skeletons. You can say of bones, use them or lose them.
Does an unbalanced diet make the problem worse?
Yes. If you are on a very high protein diet, for example, you are going to lose calcium. Or a diet low in calcium obviously will fail to meet the body's needs. Put a tiger in a zoo on an all-red-meat diet with no bones and, within a few months, he'll break his leg just walking around. The tiger has torn down his own bone structure in order to get the calcium.
When should people begin to be concerned about their calcium intake?
At age 12, when there is a marked decrease in calcium consumption. Teenage girls cut down on food; they want to be slim. Surveys show their calcium intake has dropped 10 percent from the already inadequate level of the early '70s. I think we will reap a harvest of trouble in 40 years. Adolescent girls today are so low in calcium intake that they're a ticking time bomb.
Are other factors involved in osteoporosis besides calcium?
Osteoporosis is a catch-all term, a host of different conditions caused by different things: genetics, diet and lifestyle. Heavy smoking and alcohol intake can affect bone mass. But estrogen deficiency is the most important cause of bone loss after menopause. If we put every woman on estrogen for 30 years after menopause, we'd probably solve most of their osteoporosis problems. But estrogen therapy has risks, including cancer of the uterus and possibly the breast.
Would increased calcium intake benefit osteoporosis sufferers?
We do recommend exercise and a very high calcium intake, but most sufferers absorb calcium so poorly that we don't expect miracles. It's locking the barn door after the horse is gone. Once you have inactivity superimposed on osteoporosis, there isn't any way to reverse that with calcium alone.
Do calcium pills work if begun in time?
Don't say, "I have to take calcium pills to be healthy." You have to have a good diet to be healthy. Nutrients interact. An excess of one nutrient can create an imbalance of others. If you take a large quantity of calcium pills, you will interfere with zinc and iron absorption. Or calcium pills are wasted if you don't have enough phosphorous, because you can't put calcium in the bones except as calcium phosphate.
Should one avoid calcium pills then ?
When we get nutrients from food, we get them mixed with all the other elements, so it's easier to maintain nutrient balance. But if you can't get calcium from diet, then it may be better to get it from drugs than not at all.
How much calcium is too much?
It's highly relative. An elderly lady who doesn't eat much to begin with can develop some other kind of deficiency if she takes as little as 1,000 milligrams of calcium a day. A vigorous woman eating adequately is more likely to tolerate a calcium supplement. A small number of people who are hyperabsorbers of calcium should clearly not take supplements. That also applies to some persons with kidney stones, of which calcium is a component though not the cause of the disease.
What if you feel you need some "nutritional insurance" on calcium?
A single-nutrient supplement of calcium is less desirable than a one-a-day type of multiple nutritional supplement that contains minerals as well as vitamins. This tends to give you things in as good a balance as we know how in a pill. But remember, the garden and grocery store are still the right sources for all our nutrients.