Antacids With Calcium Are Fine, to a Point
As a point of reference, antacid tablets can contain anywhere from 200 to 800 milligrams of calcium, depending upon whether they are regular or extra strength. All the manufacturers do list daily limits on the packaging.
The NIH notes that its guidelines are based on calcium from the diet plus any calcium taken in supplemental form, so it's important that the consumer know how much calcium is in each supplement and pay heed to suggested limits.
Of course, there are other considerations, too. Adequate amounts of vitamin D are essential for optimal calcium absorption. Daily food intake, hormones, drugs, age, and genetic factors also influence the amount of calcium required for optimal skeletal health.
The National Academy of Sciences (NAS) and the National Osteoporosis Foundation say that a healthy way to increase the amount of calcium in your diet is to eat calcium-rich foods such as low-fat milk, yogurt, and cheese. Most people who consume four cups of milk a day will receive an adequate amount of calcium, plus the proper amount of vitamin D needed to absorb it. Also, many foods such as orange juice, cereals, and breakfast bars are fortified with calcium.
Other good dietary sources of calcium include fish, primarily those where you can eat the bones, too, such as sardines, salmon, and smelt. Also on the high-calcium list: collard greens, spinach, broccoli, tahini, tofu (if calcium is added to the liquid), oats and oatmeal, seaweed, and dandelion leaves.
Nutritionists agree the preferred source of calcium is through calcium-rich foods such as dairy products. Calcium-fortified foods and calcium supplements are other means by which optimal calcium intake can be reached in those who cannot meet this need by eating conventional foods. But this is where the problems can occur. While it takes a great deal of calcium to cause hypercalcemia -- between four and 60 grams per day -- eating enough calcium and additional supplementation can easily push an adult over the recommended amount. Also, sometimes prescription medicines contain calcium. Adding antacids on top of all that can easily push someone beyond their needs.
Jan Stein Carter, MS, an assistant professor of biology at the University of Cincinnati's Clermont College, mentions the advertising of over-the-counter antacids as a source of dietary calcium. "This raises a number of important questions to consider," says Carter. "Is an antacid really the best way to get calcium? Overconsumption of calcium-alkali antacids can lead to hypercalcemia, which can adversely affect a number of organ systems, including the kidneys, bones, muscles, and pancreas."
Still, "patients with life-threatening hypercalcemia are rare," Vanpee writes. The key is to flush the system of the excess calcium. "Patients with this syndrome need at least six liters of fluid per day."