Are calcium supplements really necessary, and if so, are they necessary for all age groups? This is a debated issue at this point, and there are facts and studies that have results going both ways. The difficult part is deciphering which studies are accurate, which are applicable to specific groups of individuals, and which are simply ploys to make a profit. But no matter what the conclusions, all studies agree that calcium, in one form or another, is essential for forming and maintaining strong bones.
BONE BUILDING AND BONE LOSS
First of all, calcium is essential for the strengthening of teeth and bones, muscle and nerve function, and is also a necessary factor for blood clotting. Although most people are aware of this, calcium is severely deficient in most of our diets. As a result, we are experiencing an epidemic of osteoporosis in our society and high blood pressure, which causes kidney and heart damage and stroke. The human body is constantly building and destroying bone mass. As long as it is receiving sufficient calcium, exercise, and hormones, bone building stays ahead of bone loss; osteoporosis occurs in older people when bone loss outpaces their bone building. This was once considered to be an inevitable part of the aging process, but it is now recognized as the most common skeletal disease in the world, leading to debilitating injuries that can have serious complications and even result in death. Factors of this disease include genetics, ethnicity, family history, and body type. (http://www.ghc.org/nwhealth/julaug96/women.html)
CALCIUM NECESSARY FOR ALL AGES
An adequate calcium intake is essential for all ages. Young children need high doses because their entire skeleton is replaced over a two-year period. (http://www.tasdairy.com.au/healthandnutrition/calcium.html) Teenagers have rapid growth spurts during puberty, so their bones are still growing and becoming stronger. Also, we continue to lay down bone stores until we are in out mid to late twenties, so it's a big concern that kids who don't get enough calcium up through their early twenties have less bone stores stored. (http://www.ghc.org/nwhealth/julaug96/women.html) Adults over the age of 35 need to maintain their intake so that these stores of calcium in the bones aren't depleted. Therefore, no one is exempt .
SOURCES OF CALCIUM
The next problem concerns how we are to go about getting the calcium that we need- and this is where most of the conflict lies. The most common and trusted source of calcium is milk and other dairy products, which can be easily absorbed. However, this can become a problem for people who are lactose intolerant, allergic to milk, or disgusted by the taste of milk. In these cases, people drink calcium- fortified orange juice, increase their intake of calcium-rich foods, or begin to take calcium supplements. However, while foods have been fortified with calcium as a public health approach to increasing calcium, the use of calcium supplements is an individual and self-directed approach. Each individual must personally make the conscious effort to increase their calcium intake. For instance, most people are aware that there is a calcium deficiency problem, but many lack the interest or discipline to personally do anything about it. In addition to the previously stated reasons why some people don't rely on milk for calcium, there are also reasons why some people choose to rely on calcium supplements. A few of these include: concerns about the adequacy of calcium in their diets, misconceptions that calcium sources such as dairy foods will at the same time increase fat intake and cause weight gain, and desire to provide insurance against calcium deficiency. Hence, a number of critical questions have been raised, including whether or not the intake of supplements is necessary, and if so, is it sufficient? Concerns about these things and their safety resulted in new FDA regulations that state that labels for all dietary supplements of calcium must provide basic nutritional information. (http://wizard.oznet.ksu.edu/ext_F&N/_timely/CALCIUM.htm)
TYPES AND DOSES OF SUPPLEMENTS
There are over a dozen common calcium preparations and hundreds of different
formulations available. The most common is calcium carbonate; others include
tricalcium phosphate, dicalcium phosphate, bone meal, calcium citrate-malate,
oyster shell, calcium lactate, and calcium gluconate.
(http://wizard.oznet.ksu.edu/ext_F&N/_timely/CALCIUM.htm) But even once people choose a supplement, most are unaware of the correct dosage. Most physicians, including dietician Eileen Paul, recommend that children between the ages of 11 and 24 get between 1200 and 1500 mg a day. (http://www.ghc.org/nwhealth/julaug96/women.html)
CALCIUM IN TEENAGERS
Although calcium supplements are warranted for those who cannot meet their calcium needs from food, the picture is more complicated for teenagers, who in reality now get an average of 700 milligrams a day.
Some studies suggest that supplements simply don't build teens' bones as well as dietary calcium. For example, a study was done to test the effect of supplementation on girls from age 12-16 by giving some a placebo while the rest took daily 500- milligram calcium pills. The girls on supplements gained about 6% more bone mass than the others, and if sustained into adulthood, the gain might have cut their risk of osteoporosis in half. But soon after the girls stopped taking the pills, their bones lost extra mass. Therefore, teens that rely on supplements rather than food will have to be prepared to take them indefinitely. (http://www.phillynews.com/inquirer/97/Sep/08/health_and_science/CALC08.htm) And although Ca supplements can help meet the recommended daily requirement, family practice physician Fred Heidrich emphasizes the importance if nutrition instead, especially for teens. He believes that it's a mistake to start them that early in life believing that there's a pill for every problem or that good health is always linked to pills. (http://www.ghc.org/nwhealth/julaug96/women.html)
ABSORPTION OF CALCIUM
Just as important as type and dosage of calcium supplements is their solubility and absorption. For example, much of the calcium in supplements fails to be absorbed and passes out in the feces, and much of the rest that does get absorbed into the blood then travels to the kidneys where it is excreted in the urine. In fact, calcium carbonate was found to be insoluble in water. But it is attacked by acid, and the hope is that when it passes through the stomach, the gastric juice will convert it into soluble forms that can be absorbed. The level of calcium circulating in the blood is tightly controlled by the parathyroid hormone, calcitonin, and calciferol (Vitamin D). All together, they regulate how much is absorbed from food and how much spills over into the urine. (http://www.seattlejoe.com/~jkimball/BiologyPages/C/Calcium.html) According to one source, Vitamin D should be taken to enhance calcium absorption; calcium citrate is better absorbed and utilized than calcium carbonate, and the use of fluoride in a liquid formulation helps bind calcium to the bones. (http://www.realtime.net/anr/anrrda.html) Another source states that calcium carbonate provides basic calcium that has proven to be absorbed and incorporated into bone, and calcium citrate is easily absorbed as well. (http://cosmos.netgate.net/~pleiades/voices/health/15_3.html)
Many argue, however, that there is no real substantial basis for all of the hype about calcium supplements. One source claims that "The sale of over-the-counter calcium supplements has become a major growth industry. Most of this may represent money down the drain...There is little to indicate that these supplements halt, let alone reverse, osteoporosis." (http://www.seattlejoe.com/~jkimball/BiologyPages/C/Calcium.html) Another source warns against adverse effects of high intakes of calcium. They claim that it may interfere with the absorption of other nutrients such as iron, zinc, or other concurrently consumed medications. Chronic intakes of high doses may also lead to milk-alkali syndrome, hypervitaminosis D, iron deficiency anemia, and possible hypercalciuria leading to kidney stone formation. However, at the same time, restricting dietary calcium may increase urinary excretion of oxalate which in turn increases risk of kidney stones. (http://wizard.oznet.ksu.edu/ext_F&N/_timely/CALCIUM.htm)
CONCERNS ABOUT LEAD
Another concern about calcium supplements that has come to our attention is that they have been found to contain lead, which is toxic. The Natural Resources Defense Council has shown that the amount in some is enough to double what you'd normally get from other sources. Lead affects the developing nervous systems of young children and babies, and a fetus can get lead directly from its mother. It has effects at very low levels, so in essence, there is no safe level of exposure to lead. Consumer Reports recommends trying to get as much calcium as possible from foods you eat. Some manufacturers have already minimized how much lead they contain. To make sure that they do, Consumer Reports is urging the Food and Drug Administration to set a strict National limit. (http://www.wrgb.com/consumer/calcium.html)
There is always advice to be found and "new studies" that are being conducted to try to sell new products. These things try to convince people that they need to buy the latest pill, or booklet, or video to save them from the latest health risk. This is also true with some of the information on calcium supplements. But for the most part, the studies are done to inform people that there are good and bad points on both sides. Taking supplements isn't going to hurt you, but it's unclear exactly how much they help unless taken on a regular basis indefinitely. The important thing to realize is that there is a problem, and people are suffering from calcium deficiency. Everyone has to make their own individual decision about how they want to deal with this issue- ignoring it is only hurting yourself.
PREVENTION AND TREATMENT OF HEALTH PROBLEMS
Calcium is essential for the prevention and treatment of diseases such as osteoporosis, hypertension, and possibly colon cancer. Calcium supplements are useful when dietary intake is low, but many factors must first be considered. For instance, a consideration for calcium carbonate tablets is whether or not the tablet disintegrates and whether or not the presence of food in the stomach will hinder utilization. Based on present evidence, chelated calcium and refined calcium carbonate tablets may be safely and effectively used by most people at the recommended doses for the treatment and prevention of disease. (Whiting, 1997)
There is much evidence that connects the continual intake of calcium and Vitamin D to bone fragility, hypertension, colon cancer, and breast cancer. In susceptible individuals, long-term calcium restriction significantly promotes these health disorders. In addition, adequate calcium may protect against salt-sensitive and pregnancy-associated hypertension, while high intakes of both dietary calcium and Vitamin D are associated with reduced development of precancerous changes in colonic mucosa. (Barger-Lux, 1994)
One specific experiment was conducted to investigate whether high doses
of Ca, Vitamin D, and dairy products could protect against colon cancer:
0-6 months- 400 mg
6-12 months- 600 mg
1-10 years- 800-1200 mg
11-24 years- 1200-1500 mg
25-50 years (women)- 1000mg
postmenopausal- 1000- 1500 mg
adult men- 800 mg HYPERTENSION AND BLOOD PRESSURE
The effects of long-term high calcium diet and physical exercise and their combined effects on the development of hypertension were studied in spontaneously hypertensive rats with Wistar- Kyoto serving as normal controls.
"Hypertensive rats were made to exercise by running on a treadmill up to 900m/day. Calcium supplementation was instituted by increasing the calcium content of the chow from 1.1% to 2.5%. During the 23- week study, calcium supplementation attenuated the rise of blood pressure in both trained and non-trained hypertensive rats, whereas exercise training had no significant effect. (Sallinen, 1996) LEAD
It becomes increasingly evident in our calcium- deficient society that we are all at a huge risk for bone diseases, fractures, and even some cancers due to our lack of interest or incentive. Statistics show now more than ever that people are just not taking these facts seriously enough. It is becoming increasingly critical that we begin to look at what's happening and start doing something about it. If we can spend a little effort now to give our bodies the calcium they need, we will be saving ourselves from so much difficulty in the future.
Bostick RM. Potter JD. Sellers TA. McKenzie DR. Kushi LH. Folsom AR. American Journal of Epidemiology 137(12):1302-17, 1993 Jun 15. "Relation of calcium, Vitamin D, and dairy food intake to incidence of colon cancer among older women." Department of Family Practice and Community Health, Medical School, University of Minnesota, Minneapolis 55454.
Gallo, AM. Pediatric Nursing 22(5):369-74, 422, 1996 Sept-Oct. "Building strong bones in childhood and adolescence: reducing the risk of fractions in later life." Department of Maternal- Child Nursing, University of Illinois at Chicago, College of Nursing, USA.
Hatton, DC. Yue Q. McCarron DA. Seminars in Nephrology. 15(6): 593-602, 1995 Nov. "Mechanisms of calcium's effects on blood pressure." Division of Nephrology, Hypertension, and Clinical Pharmacology, Oregon Health Sciences University, Portland 97201, USA.
Kerstetter JE. Nutrition Reviews 53(11):328-32, 1995 Nov."Do dairy products improve bone density in adolescent girls?" School of Allied Health Professions, University of Connecticut, Storrs 06269-2101, USA.
Levenson DI. Bockman RS. Nutrition Reviews 52(7):221-32, 1994 Jul. "A review of calcium preparations." New York Hospital, Cornell University Medical Center, NY.
Saggese G. Igli Baroncelli G. Annali dell Instituto Superiore di Sanita. 31(4):461-79, 1995. "Nutritional aspects of calcium and Vitamin D from infancy to adolescence." Istituto di Clinica Pediatrica Universita degli Studi, Pisa, Italy.
Whiting SJ. Wood R. Kim K. Journal of the American Academy of Nurse Practitioners. 9(4):187-92, 1997 Apr. "Calcium supplements." University of Saskatchewan, Saskatoon, Canada.
Whiting SJ. Nutrition Reviews 52(3):95-7, 1994 Mar. "Safety of some calcium supplements questioned." University of Saskatchewan, Saskatoon, Canada.
Psychology DepartmentThe Health Psychology Home Page is produced and maintained by David Schlundt, PhD.
Vanderbilt Homepage | Introduction to Vanderbilt | Admissions | Colleges & Schools | Research Centers | News & Media Information | People at Vanderbilt | Libraries | Administrative Departments | Medical
|Return to the Health Psychology Home Page|
|Send E-mail comments or questions to Dr. Schlundt|