If you suffer from ulcers, gastroesophageal reflux disease (GERD), or chronic “dyspepsia,” you’re probably taking a medication to reduce stomach acid secretion. Anti-ulcer drugs are divided into two main classes — H2-blockers and proton pump inhibitors (PPIs) — and representatives of both classes are available in prescription and over-the-counter formulations.
Recently, scientists have linked the chronic use of proton pump inhibitors to an increased risk of osteoporotic fractures, raising concerns that long-term suppression of stomach acid interferes with calcium absorption. Decreased calcium absorption, in turn, increases your risk for developing osteoporosis.
Maintaining Calcium Levels at the Expense of Bone Density
The proper function of your heart, muscles, and nerves depends on serum calcium concentrations that fall within a fairly narrow range. Therefore, your body works very hard to maintain a serum calcium level that’s not too high or too low.
Elevated serum calcium levels prompt a variety of physiologic responses that decrease intestinal calcium absorption and increase the excretion of calcium through your kidneys, thus reducing your serum calcium concentration. In contrast, falling calcium levels trigger the release of parathyroid hormone (PTH) from your parathyroid glands and the production of vitamin D in your kidneys. Under normal circumstances, PTH and vitamin D enhance absorption of calcium via your intestine and kidneys, thereby increasing your serum calcium level. However, if there isn’t enough calcium in your diet or if the calcium in your intestine is not readily absorbed — a situation that might arise from reduced stomach acid secretion — vitamin D and PTH work together to remove calcium from your bones.
Osteoporosis Is the Principal Cause of Fractures in Elderly People
Throughout your life, your skeleton is constantly remodeled to keep it healthy. New bone is deposited by cells called osteoblasts while old bone is removed by another group of cells called osteoclasts. As you age, osteoblast activity tends to decline; eventually, bone removal outstrips bone deposition. If your bones are not robust during early life, you can develop a condition called osteoporosis (“porous bones”) in your later years.
Osteoporosis affects 2 percent of men and 10 percent of women over the age of 50 in the United States, and it is responsible for most of the bone fractures occurring in elderly men and women. Calcium deficiency — usually the result of chronically low calcium intake or poor absorption — contributes to osteoporosis by forcing your body to turn to bone stores to maintain your serum calcium level.
Ulcer Medications Set the Stage for Poor Calcium Absorption
Anti-ulcer medications exert their effects by interfering with stomach acid production, but the mechanism of acid suppression is not the same for all of these drugs. Proton pump inhibitors, such as Prilosec, Nexium, or Protonix, are far more effective at suppressing stomach acid secretion than H2-blockers, such as Zantac or Tagamet.
When acid production is effectively eliminated, as it is when you take a PPI, calcium absorption typically decreases. Whether this contributes to osteoporosis and fracture risk is controversial. A review published in the May 2010 issue of Archives of Internal Medicine showed that PPIs have a marginal effect on bone density after several years of use, and — while they are associated with an increased risk of spine, forearm, wrist, and total fractures — they do not appear to increase your risk for hip fractures, which are the most devastating of osteoporotic injuries.
Ranitidine and other H2-blockers do not suppress acid production as effectively as proton pump inhibitors, so their effects on calcium absorption are less pronounced. Several studies show that chronic use of H2-blockers has no significant effect on bone density, but a 2010 trial conducted by the Kaiser Permanente Division of Research in Oakland, California, revealed that H2-blockers and PPIs both increase the occurrence of hip fractures in patients who already have other risk factors for these injuries (alcohol abuse, arthritis, diabetes, kidney disease, or use of corticosteroid medications).
Separate Anti-Ulcer Drugs from Calcium
Calcium absorption is improved in the presence of stomach acid. Medications that interfere with acid production — H2-blockers and proton pump inhibitors — tend to reduce calcium absorption, thereby triggering processes in your body that contribute to bone reabsorption and osteoporosis. However, the association between anti-ulcer medications and osteoporotic fractures is still unclear, and there is not yet a concerted effort to reduce the use of PPIs or H2-blockers. To be on the safe side, take your calcium and anti-ulcer medication several hours apart to maximize calcium absorption, and ask your doctor if your calcium needs are being met.