Tags: absorbable mineral, bone remodeling, Calcium Mineral, calcium-fortified, Daily Value, elemental calcium, Good food sources, human papillornavirus, human skeleton, Institute of Medicine, kidney stones, Mineral Description, neurotransmitters, osteoporosis, parathyroid hormone, phosphorus, stomach acid
Daily Value: 1,000 milligrams
Good Food Sources: Skim milk, nonfat yogurt, cheeses, collard greens, mustard greens, kale, broccoli, canned salmon with bones, sardines with bones, corn tortillas processed with lime, calcium-fortified orange juice
By now, just about everyone knows that getting enough calcium helps prevent diseases such as osteoporosis. Less well known is just how calcium goes about doing this.
When you eat cheese or drink milk, the calcium in these foods is absorbed through your small intestine and into your blood. The amount of calcium in your blood is regulated by a substance called parathyroid hormone. When calcium intake is low, parathyroid hormone signals for bone to be broken down, releasing calcium into the bloodstream. “Diets with adequate calcium intake produce less parathyroid hormone, so that we conserve more calcium and more bone,” says professor of nutrition.
Calcium then combines with phosphorus to help form hard, crystal-like substances that create the latticework that undergirds strong bones and teeth. In fact, 99 percent of the calcium in your body is stored in your skeleton. Researchers call this ongoing process of removing old bone and forming new bone remodeling.
You also need a stable level of blood calcium for a normal heartbeat, nerve and muscle function, and blood clotting. Living cells require calcium to act as a messenger and to help respond to hormones and neurotransmitters.
Even though calcium is vital for bone growth and maintenance in everyone, experts don’t advise a one-size-fits-all intake. Here are the Adequate Intakes (A Ts) of calcium as set by the Institute of Medicine.
A) Infants, birth through age 6 months: 210 milligrams
B) Infants, ages 7 to 12 months: 270 milligrams
C) Children, ages 1 to 3 years: 500 milligrams
D) Children, ages 4 to 8 years: 800 milligrams
E) Children, adolescents, and young adults, ages 9 to 18: 1,300 milligrams
F) Pregnant and nursing women, ages 14 to 18: 1,300 milligrams
G) Pregnant and nursing women, ages 19 to 50: 1,000 milligrams
H) Adults, ages 19 to 50: 1,000 milligrams
I) Adults, ages 51 and older: 1,200 milligrams
Consume It In Right Way :
Not all calcium supplements are created equal. The actual amount of calcium contained in a supplement, called elemental calcium, varies from one form of calcium to the next. Calcium citrate, which contains about 21 percent of elemental calcium, is the most easily absorbed and digested by the body. Calcium carbonate has a higher concentration of elemental calcium (40 percent), but it’s slightly more difficult to absorb, especially for people with decreased stomach acid, so it should always be taken with food.
A newer form of calcium called calcium formate has more absorbable calcium than calcium citrate, but it’s not widely available. There are several other forms of calcium to consider, but most of them have lower concentrations of elemental calcium or they aren’t nearly as digestible as calcium citrate. Calcium lactate and calcium gluconate contain only 13 percent and 9 percent elemental calcium, respectively. Calcium phosphate has a much higher percentage of calcium, but it’s difficult to absorb.
Another consideration when choosing a supplement is how the calcium was obtained. Supplements that are products of oyster shells, dolomite, and bone meal may contain traces of lead, mercury, or arsenic. Many manufacturers have taken steps to reduce these traces, and some labels indicate that the supplements are “lead-free.”
Calcium is best absorbed when it’s taken with food and at a dose not exceeding 500 milligrams. This means that if you’re taking supplements exceeding that amount, you should take them in divided doses throughout the day.
High calcium intake (more than 2,000 milligrams a day) may cause constipation and kidney stones and inhibit the absorption of minerals, like zinc and iron.