A continuing survey by the U.S. Department of Agriculture shows that nearly 90 Percent of girls ages 12 to 19 aren’t getting enough calcium to promote good bone health. Bones need a lot of calcium to grow.

One reason girls might not be getting enough calcium is that they're drinking less milk, according to the California Advisory Board. Girls 12 to 19 in the United States drink twice as much soda as milk. A girl consumes an average of 650 cans of soda every year - 1.78 a day.

But girls aren’t the only ones missing calcium. About 78 percent of women are calcium deficient, the USDA report shows.

Insufficient calcium can be dangerous for females, because it puts them at risk for osteoporosis, a medical condition in which bones become more porous and brittle. Other factors that increase osteoporosis risk include smoking, lack of exercise and excessive alcohol consumption.

Fragile bones in a women can lead to hip fractures. Post menopausal Asian American Indian women at the highest risk for developing osteoporosis, followed by Hispanic, Caucasian and Black American women according to the National Osteoporosis Risk Assessment project, a study of 43,000 postmenopausal women.

A study funded by Smith-Kline Beecham - marker a Tums showed that older women might benefit from calcium supplements. The study, published earlier this year in the medical journal “Clinical Therapeutics, said that if hip fracture patents age 50 and older consumed about 1,200 milligrams of calcium supplements a day for 34 months, they might have avoided 134,764 hip fractures and related medical costs of $2.6 billion in 1995.

A Mayo Clinic four-year study of 177 women aged 61 to 77 with a history of osteoporosis showed that women who took 1,600 milligrams of calcium a day had slightly higher bone density - 1 percent more - than women who took the placebo. “The women who took the supplements also had a lower levels of chemical indicators for bone resporation in their blood,” a Mayo Clinic report stated. “Bone resporation is the opposite of bone formation and can lead to bone loss.”

Which Supplement?
A calcium-rich diet and regular weight-bearing exercise help build strong bones, according to the ADA. People also need vitamins D and K, which absorb calcium. So which calcium supplement is better, tablets or chew? From a taste standpoint, calcium chews Viactiv and CalBurst are less chalky and much easier on the palate then Tums tablets (which are also an antacid). CalBurst comes in chocolate and cherry flavors; Vicativ, in milk chocolate and mochaccino.

Each chew contains 500 milligrams of calcium and costs from 13 cents to 16 cents. One caveat: The chew tends to stick to the teeth.

Calcium supplements are available on a range of formulations.

Supplements are not made alike - so it’s important to read the label carefully, paying special attention to the serving size and the amount of calcium, according to a Mayo Clinic report. Some brands list the amount of calcium; others give only total weight of the supplement, Mayo Clinic suggests the following formulas:

Calcium carbonate: multiply by 0.4. Example: 500 milligrams of calcium carbonate multiplied by 0.4 equals 200 milligrams of calcium.
Calcium citrate: multiply by 0.21.
Calcium lactate: multiply by 0.13.
Calcium gluconate: Multiply by 0.09.

Take small doses, The Mayo Clinic report recommends. And take them with a meal. Drink water to minimize constipation. Don’t take more then the recommended amounts. Excessive calcium - double or triple the recommended dose - might increase the risk of kidney stones.

Calcium Requirements
How much does a body need?

The National Academy of Sciences in 1997 recommended the following “dietary reference intakes” for Calcium:

800 milligrams for girls and boys ages 4-8
1,300 milligrams for ages 9-18
1,000 milligrams for ages 19-50
1,200 milligrams for ages 50 and older

But the National Institute of Health Consensus Development Panel on Optimal Calcium Intake, aiming specifically at women recommends more for certain groups:

1,200-1,500 milligrams for women/girls ages 11-24
1,000 milligrams for women ages 25-49
1,200-1,500 milligrams for pregnant/nursing women ages 25-49
1,000 milligrams for women ages 50-64 on estrogen therapy
1,500 milligrams for women ages 50-64 not on estrogen therapy
1,000 milligrams for women ages 65 and older