What is Calcium
Calcium, the most abundant mineral in the body, is found in some foods, added to others, available as a dietary supplement, and present in some medicines (such as antacids). Calcium is required for vascular contraction and vasodilation, muscle function, nerve transmission, intracellular signaling and hormonal secretion, though less than 1% of total body calcium is needed to support these critical metabolic functions . Serum calcium is very tightly regulated and does not fluctuate with changes in dietary intakes; the body uses bone tissue as a reservoir for, and source of calcium, to maintain constant concentrations of calcium in blood, muscle, and intercellular fluids.
The remaining 99% of the body’s calcium supply is stored in the bones and teeth where it supports their structure and function. Bone itself undergoes continuous remodeling, with constant resorption and deposition of calcium into new bone. The balance between bone resorption and deposition changes with age. Bone formation exceeds resorption in periods of growth in children and adolescents, whereas in early and middle adulthood both processes are relatively equal. In aging adults, particularly among postmenopausal women, bone breakdown exceeds formation, resulting in bone loss that increases the risk of osteoporosis over time.
Benefits of Calcium Supplement
Adequate calcium intake is essential for the maintenance of bone health during growing phases and the preservation of bone mineral density in elderly individuals. Therefore, calcium supplementation is generally recommended to individuals who might be at risk of inadequate dietary calcium intake or osteoporosis regardless of age in order to prevent the deterioration of bone strength. However, epidemiological studies have demonstrated that a significant proportion of people throughout the world fail to achieve the recommended daily calcium intake and calcium and vitamin D are administered to both the control and drug groups in a majority of randomized trials investigating osteoporosis drugs. In addition to its pivotal role in bone metabolism, the potential role of calcium in nonskeletal tissues has also been investigated, particularly in elderly people.
“Calcium supplementation can correct for negative calcium balance attributable to low calcium dietary intake and additional dermal losses from exercise.”
“Calcium supplement in the form of calcium lactate gluconate was adequately absorbed in elderly Chinese women with a calcium intake of less than 300 mg per day. It was effective in reducing bone loss at the hip, and there may be interaction effects with exercise in maintaining bone density.”
Exercise and Calcium Intake
The RDA for calcium in males and females, ages 11 – 24 years, is 1200 mg/day. For those 25 years and older, the RDA is 800 mg/day. Unfortunately many adults don’t meet these RDAs. Some foods rich in calcium are, cheese, milk, dark green vegetables, and legumes. It is very important for adolescents and young adults to have sufficient calcium intake because these are the years when bone density is maximized. Later in adulthood bone loss begins. This occurs sooner in women than in men. Starting at age 35 women begin to experience bone loss, which rapidly accelerates after menopause.
A well constructed training program is also important for healthy bone. Since bone responds to training loads (e.g., running, resistance training) by becoming stronger, a gradual build-up over time is preferable to a rapid increase in training volume. Too sudden a jump to heavy mileage is probably the most common error leading to stress fractures. Additionally, women who have lost too much weight via excessive training and have stopped having menstrual periods are at increased risk for stress fractures. Since estrogen protects against bone loss, the disturbance in normal hormonal status leads to accelerated bone loss and poor repair. For the same reason athletes with eating disorders are also at increased risk. The other concern related to bone, later in life, is osteoporosis. Additional factors which increase the chance of osteoporosis are, a sedentary lifestyle, smoking, heredity, and white or Asian race.
The effects of bone loading with adequate calcium intake are not fully identified and appear to vary during one’s lifespan. However, calcium is a major mineral that is vital to the bones, and is needed for the heart, muscles and nerves to function properly for the blood to clot. General recommendations for intake are as follows: 1,300 mg/day for girls 9 to 18 yr, 1,000 mg for women 19 to 50 yr., and for 1,200 for women over 50 yr (Gottlieb, B., 2002).
“Calcium absorption is best when a person consumes no more than 500 mg at one time. So a person who takes 1,000 mg/day of calcium from supplements, for example, should split the dose rather than take it all at once.”
The amount of calcium you need each day depends on your age. Average daily recommended amounts are listed below in milligrams (mg):
The downside of calcium supplements
“Although the issue remains controversial, an increasing amount of attention has been focused on the potentially harmful influence of excessive calcium supplementation on cardiovascular health.”
“A secondary analysis of a large study evaluating the effects of calcium on bone fractures and loss in New Zealand found that a calcium-supplemented group exhibited an increase in the number of cardiovascular events; however, these findings are contrary to those of previous observational studies.”
“Calcium supplements may cause gas, bloating, and constipation in some people. If any of these symptoms occur, try spreading out the calcium dose throughout the day, taking the supplement with meals, or changing the supplement brand or calcium form you take.”
“Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth’s crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate. Free calcium metal is too reactive to occur in nature. Calcium is produced in supernova nucleosynthesis.
Calcium is essential for living organisms, particularly in cell physiology where movement of the calcium ion into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bone, teeth and shells, calcium is the most abundant metal by mass in many animals.”