Calcium the most selling mineral supplement

In 2002, calcium was the number one selling mineral supplement in the US, totaling over $877 million in sales. While calcium is no doubt the most widely recognized nutritional mineral, it is also the most abundant mineral found in the human body.

At one point in time, every child has probably heard, “drink your milk if you want to grow up to be big and strong.” While children may find this repetitive statement annoying, it is completely true. Calcium is key to bone and teeth development and regulation. In fact, almost 99 percent of all calcium in stored in either the bones or the teeth.

Throughout our lifetime, our bones continue to remodel, constantly breaking down old bone cells, called resorption, replacing them with new cells, called bone formation. As we age however, the rate at which these two processes takes place, changes. For instance, as a child, our bones are continually forming, without much resorption or bone breakdown.

During our late teens to middle adulthood, these processes are about even. By the time we reach about 30 however, bone mass will have reached its peak. In older adults, most significantly postmenopausal women, the rate of resorption far exceeds the rate of new bone formation, greatly increasing the risk of developing porous, weakened bones, a condition known as osteoporosis.

Postmenopausal women with a family history of osteoporosis and who are also thin and inactive, as well, who drink excessively and smoke are at the greatest risk for weakened bones. Researchers contend that the greater your bone mass at age 30, the longer it will take for bone loss to occur with age, and as such, it is extremely important to maintain adequate calcium (and vitamin D) levels from early childhood on.

Osteoporosis has become a serious health risk, afflicting more than 10 million Americans according to statistics, 80 percent of those being women. Osteopenia precedes osteoporosis and is characterized by low bone mass. Another 34 million Americans suffer from this condition. Not only are these numbers alarming, but even more disconcerting is the fact that 1.5 million of these people also suffer from fractures to their hips, wrists, ribs, pelvis and other bones as a result of poor bone condition.

Many other factors contribute to both osteopenia and osteoporosis as well. Those who have a chronically low calcium intake will experience further bone resorption because their body must then use calcium stores to compensate and maintain normal body functions, including muscle and nerve function. Adequate vitamin D intake as well as the amount of calcium regularly excreted through such avenues as urine, also affects the risk of developing either of these conditions.

In 1993, the Food and Drug Administration, after recognizing the widespread and growing number of people at risk for degenerative bone conditions, allowed manufacturers to add health claims to their products containing calcium. Although osteoporosis affects people of all genders and races, women are at the highest risk, most likely due to their overall smaller stature (skeletons) and the bone loss normally associated with menopause. Weight bearing exercises, those that cause your muscles and bones to work against gravity while bearing your weight, have been shown to increase bone strength and the amount of bone tissue (bone density).

Women who regularly partake in this type of exercise, along with resistance exercises such as weight training to improve both muscle and bone strength, have a lower risk of developing osteoporosis.

Today, research suggests that not only is calcium essential for proper bone and teeth development, but it may also be the best kept secret for weight loss. Studies show that calcium, especially when derived form dairy products, could help regulate body fat. In particular, calcium obtained from low-fat dairy products is more effective in reducing body fat and body mass than supplemental calcium alone.¹

Calcium is also making headlines in the area of cancer research. Some studies currently suggest that increasing intakes of low-fat dairy sources along with supplemental calcium will lower the risk of developing colon cancer. A large heath survey conducted by the Nurses’ Heath Study indicates that those who take 700 to 800 mg of calcium per day have between a 40 and 50 percent lower risk of developing left-side colon cancer.²

On the contrary, studies also show that high calcium and dairy intake, 600mg to 2000 mg per day and 2.5 daily servings respectively, can actually increase the risk of prostate cancer.³ It is important to note however that these were merely observational studies and other studies have only noticed a nominal to non-existent relationship between calcium, dairy products and prostate cancer. Until further research is conducted therefore, health professionals recommend that men over the age of 19 consume only 1,000 to 1,200 mg of calcium per day, an amount below the tolerable limit of 2,500 mg per day.

Hypertension or high blood pressure is another hot issue among Americans today. Several studies suggest that vegetarians who eat a diet high in minerals, such as calcium, magnesium and potassium, and fiber as well as low in fatty foods, have lower blood pressure levels than those that don’t.⁴ DASH (Dietary Approaches to Stop Hypertension), a large study designed to investigate the effect of nutrients from food on blood pressure, looked at three types of diets using 450 participants. The diets included a “typical American” diet, one high in fruits and vegetables and the DASH diet, which is a combination of the fruit and vegetable diet along with low-fat dairy, thus calcium. After rigorous testing, it was found that the combination DASH diet was associated with the greatest decrease in hypertension. A revision of the DASH diet restricting sodium was later conducted. Interestingly, this trial showed that reduced sodium had no more effect on lowering blood pressure than the original DASH diet, leading researchers to believe that diets high in fruits, vegetables and calcium in the source of low-fat dairy products, is an effective preventative and treatment for high blood pressure.⁵

Excessive calcium intake was once thought to increase the incidence of kidney stones however, research to the contrary suggests that calcium may actually prevent this condition, characterized by crystallized calcium (along with other mineral) deposits in the urinary tract.⁶

As well, in cases of high cholesterol, calcium supplementation of 1,500 to 2,000 mg per day is reported to lower cholesterol levels. Incidences of stroke may also be reduced by long-term use of calcium in women according to some studies.

The highest sources of calcium are found in cheeses such as romano, parmesan, gruyere, mozzarella and feta. Black strap molasses and wheat-soy flour are also very calcium rich foods. Other sources include; dairy products including milk, butter, yogurt and ice cream, almonds, Brazil nuts, hazelnuts, cabbage, kelp, soybean flour, tahini, oysters, salmon, sardines and dark leafy greens such as bok choy, mustard, dandelion, collard, kale and Swiss chard. Many herbs also contain calcium including; savory, poppy seed, sage, ginseng, marjoram, oregano, parsley, dill weed, cinnamon, chervil, basil and fennel.

Calcium derived from some plant sources however, contains substances called phytates that may bind to calcium and prevent it from being efficiently absorbed. These substances only affect the available calcium in that particular food, and have no bearing on other foods consumed along with these vegetables. Fiber may also affect the amount of calcium absorption but unless low calcium levels are already present, eating these food sources (spinach, rhubarb, sweet potatoes, beans, seeds, nuts, grains and soybeans) should not have a significant effect on overall calcium intake.

Calcium supplements are available in several forms, each varying in absorption levels, calcium concentrations and cost. Calcium citrate is the most easily absorbed and digested form of calcium and is also most recommended for preventing osteoporosis. Calcium carbonate is less expensive than calcium citrate but is also less effective, It also requires more stomach acid to digest and absorb. Other forms include calcium lactate, calcium glucomate and calcium chloride, which are not recommended because it can irritate the stomach. Some supplements advertise calcium from oyster shells, bone meal and dolomite, however these may contain traces of lead, which is toxic.

The average recommended daily intake of calcium is 1,000 mg for those 19 to 50 years of age and 1,200 mg per day for those over 50. Research shows that the body can only absorb about 500 mg of calcium at any one time so supplements should be divided into separate doses and taken with 6 to 8 cups of water to avoid constipation.

Common side effects include stomach upset and constipation. Calcium overload (5,000 mg per day or more than 2,000 mg per day over an extended period of time) can result in nausea, vomiting, increased urination, kidney toxicity, irregular heartbeat and loss of appetite. These symptoms will subside however, when proper calcium levels are restored. There are several possible drug interactions with calcium including antibiotics, estrogens, diuretics, antacids, and corticosteroids used to treat osteoporosis, so if you are taking any medications it is always best to consult with a health professional prior to adding supplements or herbs of any kind.

References:

1. Heaney RP. “Calcium and weight: clinical studies”. J Am Coll Nutr, 2002;21:152S-155S.
2. Wu K, Willett WC, Fuchs CS, Colditz GA, Giovannucci EL, “Calcium intake and risk of colon cancer in women and men”. J Natl Cancer Inst, 2002;94:437-46.
3. Chan JM, Giovannucci E, Andersson SO, Yuen J, Adami HO, Wok A, “Dairy products, calcium, phosphorous, vitamin D, and risk of prostate cancer (Sweden).” Cancer Causes Control, 1998;9:559-566.
4. Beilin LJ, Armstrong BK, Margetts BM, Rouse IL, Vandongen R, “Vegetarian diet and blood pressure”, Nephron, 1987;47:37-41.
5. Vollmer W, Sacks FM, Ard J, et al “Effect of diet and sodium intake on blood pressure: subgroup analysis of the DASH-Sodium trial”, Ann Intern Med, 2001;135:1019-28.
6. Curhan G, Willett WC, Rimm E, Stampher MJ, “A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones”, N Engl J Med, 1993;328:833-8.