Calcium is one of the most abundant minerals in the human body, accounting for between 2 to 3 pounds of total body mass. Adequate dietary sources of calcium are necessary throughout life for building and maintaining strong bones and teeth and regulating muscle growth. In conjunction with magnesium, calcium also plays a vital role in regulating electrical impulses in the central nervous system and activating hormones and enzymes required for digestion and metabolism. Calcium is also necessary for healthy blood pressure and blood clotting.
Inadequate intake of calcium can aggravate hypertension, and calcium supplements are known to lower blood pressure in some cases. There is also strong evidence that calcium plays a role in colon cancer, and those with low intake of calcium and vitamin D are more prone to this disease. Inadequate calcium levels can also result in tetany, a condition that commonly results in leg cramps and muscular spasms.
Inadequate intake of this mineral can also result in osteoporosis, a bone disorder caused by loss of calcium in the bones. Osteoporosis results in brittle, porous bones which can be easily fractured or broken. Contrary to popular belief, bones are very much alive, and are constantly losing and replacing calcium. Inadequate intake can result in a slow and dangerous loss of this mineral, leading to osteoporosis.
Half of America’s adults are not getting enough calcium according to a panel of experts assembled by the National Institutes Of Health (NIH). The federal committee estimates that calcium deficiencies, resulting in brittle bones and fractures, are costing the health care system $10 billion a year. The report said the recommended daily allowance for calcium was too low, leading to weakened bones for children, adults and, especially, elderly women. “Calcium is an essential nutrient for developing and maintaining strong bones,” the committee said. Without proper levels of calcium, children enter adulthood with a weakened skeleton, increasing their risk later for osteoporosis. Inadequate calcium intake in later years further aggravates the problem.
New studies show that recommended levels of calcium now carried on most food labels are far below what nature requires for strong bones. “Recent nutrition surveys have shown that the average diet of Americans has a calcium intake considerably below the recommended daily allowance.” according to Dr. John Bilezikian, professor of medicine at Columbia University and chairman of the committee.
The Dr. Bilezikian also emphasized the importance of getting the recommended levels of vitamin D, which is important for proper calcium absorption. Half of the recommended vitamin D dose of 400 international units (iu) are contained in two cups of milk, and the rest can be manufactured by the body with just a few minutes exposure to sunlight.
Calcium absorption takes place in the small intestines, and requires adequate amounts of vitamin D. The current Recommended Daily Allowance of calcium is 800 mg. for adults, 1,200 mg. for premenopausal women, and 1,500 mg for postmenopausal women unless taking estrogen. Those with kidney disorders should not take calcium supplements unless directed to do so by a health care professional.
Good dietary sources of calcium include all dairy foods, green leafy vegetables, and seafood . Absorption of dietary calcium can be drastically reduced by consuming large amounts of foods such as cocoa, spinach, kale, rhubarb, almonds, and whole wheat products which are high in oxalic acid, and are known to interfere with calcium absorption. Taking antibiotics such as tetracycline, or aluminum-containing antacids can also result in lower absorption of calcium. Alcohol, sugar, and coffee can also effect the body’s levels of this mineral.