Calcium is one of the most important, and most plentiful, minerals in the human body. In addition to maintaining strong bones and teeth, calcium is essential for myriad other functions. Sending and receiving signals from nerves, maintaining a normal heartbeat, contracting and relaxing muscles and releasing hormones are just a few of calcium's responsibilities. When you eat calcium-rich foods or take calcium supplements, the body absorbs the mineral in the small intestine and distributes it where the body needs it most, and a complex regulation system sustains the proper level of calcium for physiological performance.
Sources of Calcium
Though calcium is the body's most common mineral -- with 99 percent of total calcium contained in bones and teeth, and 1 percent in blood and surrounding tissues -- you must replenish the body's supply regularly through consuming calcium-rich foods or dietary supplements. Good sources of calcium include dairy products like milk, yogurt and cheese; green leafy vegetables such as broccoli, collard greens, kale, bok choy and turnip greens; and legumes, nuts or seeds like almonds, Brazil nuts, sesame seeds, sunflower seeds and beans. Dietary supplements can supply needed calcium for people who are on vegan or low-dairy diets. Consult your physician before beginning or changing any dietary regimen.
Calcium Absorption
Your body absorbs calcium in foods or supplements the same way. Calcium absorption takes place in your duodenum, or small intestine, when food is undergoing digestion. The presence of vitamin D in your digestive tract aids calcium absorption, so many supplements contain both calcium and vitamin D. Once absorbed, the mineral is distributed throughout the body, primarily to synthesize bone. Oxalic acid, found in some vegetables and legumes, and phytic acid in whole grains may inhibit optimal calcium absorption.
Regulating Absorption
Calcium's role in maintaining physiological function is so crucial, your system will take calcium away from bones to maintain proper blood calcium levels when daily intake is insufficient. In this scenario, parathyroid hormone stimulates the conversion of vitamin D to its active form, calcitriol. The combination of PTH and calcitriol stimulates both the release of calcium from your bones and your duodenum's ability to absorb calcium. But when calcium intake from food or supplements is sufficient, you stop secreting PTH. To prevent bone demineralization, the USDA recommends that healthy adults consume between 1,000 and 1,200 mg of calcium per day.
Benefits
Proper levels of calcium in your body maintain overall health and may prevent some diseases. Osteoporosis, the most common form of bone disease, occurs when you fail to form enough new bone and results in a loss of bone density and frequent fractures. Eating calcium-rich foods or taking supplements over time can help replace lost bone. Treatments for osteoporosis include increasing your daily intake of calcium to 1,200 mg and vitamin D up to 1,000 international units, and eating a diet high in calcium, vitamin D and protein to slow the loss of bone density.
Member Comments