Calcium is the most prevalent mineral in the body, and it is essential for many important bodily functions including muscle action and blood vessel performance, heart rhythm, the secretion of hormones, and communication within the nervous system. Ninety-nine percent of the body’s calcium, however, is located in the bones and teeth, which provide a reservoir of calcium for the body. Because calcium helps the muscles, nerves, and brain to function, strengthens the bones, and reduces the risk of osteoporosis, everyone needs to consume calcium every day. The Recommended Dietary Allowances for calcium range from 1,000 mg to 1,300 mg for people over three years old, depending on age and sex. Daily calcium needs are highest (1,300 mg) for girls and boys from 9-18 years old because this is when their bones are developing. After age 50, women need to consume 1,200 mg of calcium each day to offset the bone loss that occurs after menopause. Both men and women who are over 70 need to take in 1,200 mg of calcium each day. Some studies suggest that on average people over 11 are only consuming about half the amount of calcium that they need.
Foods Rich in Calcium
The best sources of calcium for most Americans are milk, yogurt, and cheese. Eight ounces of plain yogurt and one cup of 2% milk provide 415 and 296 mg of calcium, respectively, which makes consuming three servings of dairy products each day an excellent way to meet your calcium needs. Calcium-fortified foods including fortified soy milk, orange juice, and tofu are also especially good sources of calcium for people who are lactose-intolerant or not fond of milk. Canned sardines and salmon eaten with the bones, calcium-fortified cereal, turnip greens, kale, Chinese cabbage, and broccoli are also good sources of this essential nutrient. Vitamin D plays an important role in helping the body absorb calcium. You can obtain vitamin D from fortified milk, salmon, liver, fish liver oil, egg yolks, and from spending at least 15 minutes outside in the sun without sunscreen each day.
The body very carefully regulates the amount of calcium in the blood, drawing on the calcium stored in the skeleton if necessary. When generally healthy people take in inadequate amounts of calcium, they usually do not experience any health consequences until later in life when their bones may be weakened and they may develop osteopenia and osteoporosis. Hypocalcemia may occur as the result of serious medical problems, including renal failure, or as a severe side effect of certain medications.
Excessive amounts of calcium in the blood are associated with renal insufficiency, kidney stones, and other health problems, but this is not generally caused by consuming too much calcium but by hyperparathyroidism. Recent studies have indicated that some older women who are taking calcium supplements and eating calcium-rich foods may be exceeding the Tolerable Upper Intake Levels. Most people will simply excrete excess calcium, but too much calcium can lead to constipation and may hinder the absorption of iron and zinc.