Calcium is the most abundant mineral in the human body. Average healthy males have about two and a half to three pounds of calcium while females have about two pounds. Approximately 99 percent of calcium is present in the bones and teeth, which leaves only about one percent in cells and body fluids. While the most important function of calcium involves the maintenance of skeletal health, the small percentage of calcium outside the bones is used to maintain a variety of vital body functions.
Vitamin D is known as the “sunshine” vitamin because it is formed in the body by the action of the sun’s ultraviolet rays on the skin. The fat-soluble vitamin is converted in the kidneys to the hormone calcitrol, which is actually the most active form of vitamin D. The effects of this hormone are targeted at the intestines and bones. Decreased vitamin D intake along with not enough sunlight exposure can cause a vitamin D deficiency. Other causes could be inadequate absorption and impaired conversion of vitamin D into its active form. When vitamin D deficiency occurs, bone mineralization is impaired which leads to bone loss. Rickets, osteomalacia, osteoporosis, crohn’s disease and cancer are associated with vitamin D deficiency.
Coronary artery calcified plaque has been linked to an increased risk of stroke and heart attack. For this reason, some women are concerned about taking calcium supplements to maintain bone strength. The purpose of a current study was to determine whether moderate doses of calcium and vitamin D3 increase deposits of calcium in the blood vessels of postmenopausal women. The randomized, placebo-controlled study included 754 women between the ages of 50 and 59 years.
Researchers used cardiac computed topography to measure calcium artery calcium(CAC) at the time of enrollment. The women were then randomized to receive either placebo or 1,000 milligrams of elemental calcium plus 400 IU daily for an average of seven years. The results revealed that CAC scores were similar in all of the women involved in the study even after years of supplementation with calcium and vitamin D3. These results suggest that postmenopausal women do not need to be concerned with increased calcium deposits in blood vessels due to moderate calcium supplementation.1
1 Manson JE, Allison MA, Carr JJ, et al. Calcium/vitamin D supplementation and coronary artery calcification in the Women’s Health Initiative. Menopause. Jun2010.