By Chantel Lott

MISSISSIPPI STATE -- Selecting more dairy products from the menu may be the best way to increase calcium in the body and protect bones from the weakening and crippling effects of osteoporosis.

"Calcium consumption and absorption are crucial in combating osteoporosis. Otherwise the body compensates by robbing Peter to pay Paul," said Melissa Mixon, a human nutrition specialist with Mississippi State University's Extension Service.

Calcium is a vital element in the bloodstream, but when people do not consume enough calcium in their diets, the body will rob internal sources of calcium such as the bones. Over time, the exploitation of bone's calcium may lead to serious bone problems like osteoporosis.

"Ninety-nine percent of calcium in the body is found in the bones. The other 1 percent is in the blood and cells. The blood and cells require calcium for regulatory functions, such as contraction and relaxation of muscles and transmission of nerve impulses," Mixon said. "The amount necessary is small, but it is always maintained."

Bones are always in a state of change called remodeling. Remodeling breaks down existing bone and deposits new bone in its place. At any time, 10 to 15 percent of bones in the body may be under reconstruction.

Milk and milk products are the best sources of calcium. In the 1990s, 73 percent of the calcium for the American public was found in the milk group milk, yogurt, cottage cheese, cheese, frozen yogurt and ice cream. Few other foods provide such a concentrated source of calcium that is as readily available for absorption as do milk and milk products. Milk's calcium absorption is about 30 percent.

Some foods reduce calcium absorption and actually increase the loss of calcium in the urine. The lower absorption of calcium from foods is usually linked to the presence of fiber, phytate or oxalate. Spinach, rhubarb, beet greens and red beans all contain oxalates, which are a salt of a crystalline organic acid also used as a bleach or rust remover. In spinach, only 5 percent of the calcium is absorbed because oxalate is present.

Other factors in calcium absorption are estrogen levels, pregnancy or lactation, caffeine consumption, smoking, alcohol intake, some diseases and some medications.

"Dietary supplements are becoming more widely available to consumers; however, questions about their effectiveness are being raised. Supplements may provide calcium, but they generally lack other vital nutrients," Mixon said.

Supplements should be supervised by a health professional and are recommended only for those individuals who for whatever reason are unable to eat foods rich in calcium.

Side effects to supplements are constipation, intestinal bloating, excess gas and reduced bioavailability of nutrients such as iron and zinc. Calcium carbonate present in some antacids that may be taken for additional calcium can inhibit the absorption of iron, according to the National Institute of Health. The NIH expert panel suggested taking such supplements only if necessary and then only in-between meals.

The National Academy of Sciences set recommendations for daily calcium intake in 1989, but these recommendations have been updated. Today they parallel the recommendations put forth by the National Institutes of Health Expert Panel in 1994 and are endorsed by the American Medical Association.

The current daily calcium recommendation is 800 milligrams for ages 4 to 8, 1,300 milligrams for ages 9 to18, 1,000 milligrams for ages 19 to 50, and 1,200 milligrams for ages 51 and older.

Additional information about dairy nutrition can be found at http://www.nationaldairycouncil.org/.