The advice on calcium used to be straightforward. Take a supplement, 1,000 to 1,200 milligrams a day, and you're done. Next question.
But it's not that simple anymore with the release of new studies and new federal health recommendations that bring calcium supplementation into question. So, what should we do? It depends on whom you ask.
Calcium has a big job.
It helps the brain send messages along nerves to every part of the body. It helps muscles contract and blood to circulate and release hormones and enzymes along the way. It keeps our joints healthy and helps keep blood pressure normal. And, it's the main mineral involved in the formation of bone, which is where the largest amounts of calcium are stored and drawn out as needed. Make too many withdrawals from the bone bank without making regular deposits, particularly as you age, and your bones may become weak and fracture or break more easily.
To prevent that, we've been told to get calcium every day along with vitamin D. The U.S. government recommends 1,000 to 1,200 milligrams of calcium a day for most healthy adults. That can be difficult to get from diet alone, unless you consume a lot of dairy, fish with bones and calcium-fortified foods.
Even then, it takes a concerted effort to get the recommended daily amount. People on weight-loss diets, strict vegetarians and vegans, the elderly and the chronically ill who may eat less because of health issues are among those who may fall short with diet alone.
That's partly why calcium supplements came into such widespread use. But recent research raises questions about the benefits of calcium from supplements and from the diet.
In 2012, the U.S. Preventive Services Task Force, a federally backed panel that advises doctors on matters of public health, issued a review of past research on calcium saying there's not enough conclusive evidence to recommend taking calcium or vitamin D supplements. And, in the case of certain postmenopausal women, the task force recommended against taking supplements because it didn't change an older woman's risk for fractures and slightly increased the risk of kidney stones.
Another study, released online in September by the British Medical Journal, said that in people over age 50, supplemental calcium may be deposited in the arteries, contributing to heart disease, or in the kidneys, causing kidney stones.
Other studies in the past two decades from Great Britain, Switzerland, New Zealand and the United States support those findings.
No one disputes the importance of calcium. But now, instead of telling everyone to take a calcium pill every day, many doctors are first asking patients how much calcium they get from food and then suggesting they make up the shortfall with a supplement.
"Yes, there is a large body of research out there and it can be confusing," said Dr. Andrea Singer, clinical director of the National Osteoporosis Foundation and a bone specialist at Medstar Georgetown University Hospital in Washington, D.C. "But the message should be, meet, do not exceed, the recommended daily amount of calcium. More is not better."
The National Osteoporosis Foundation recommends getting the U.S. RDA (Recommended Daily Allowance) of calcium and vitamin D from food sources. When that's not possible supplements are recommended.
The U.S. RDA for calcium for nearly all healthy adults ages 19 to 50 is 1,000 milligrams a day. After age 50, women are advised to get a little more, 1,200 milligrams a day.
BayCare Medical Group internal medicine specialist Dr. Laura Arline acknowledges the confusion over calcium but said it's still important to meet previously recommended amounts.
"It depends on which study you're looking at to know whether calcium is a good guy or a bad guy and how much to take," she said. "So I decide patient by patient because everyone has different needs."
Arline notes that patients who have osteoporosis, a history of falls or fractures, kidney failure or who are on chemotherapy or steroids may each need a different amount. Smoking and a high salt intake may also affect calcium absorption and affect your needs.
Some experts disagree with the U.S. RDA and say the World Health Organization's recommendation of 500 milligrams a day is sufficient for most adults. Harvard's Dr. Walter Willett, chairman of the Department of Nutrition, said in August's Harvard Women's Health Watch newsletter, that the U.S. RDA, established in 1997 and based on short-term studies, set the recommended daily dose too high and we could ". . . do just as well on half as much."
"We need further studies, and that will take years and many participants to get meaningful data," said Dr. Sahzene Yavuz, an endocrinologist and assistant professor of medicine at the University of Florida. She cites one study of older patients taking calcium supplements for two years who increased their bone density by about 1 percent and reduced their risk of fracture by 5 to 10 percent.
"Is that increase enough?" Yavuz asked. "It's not zero, it's just not as good as expected or what we thought it would be. But it was something."
Until more definitive research is available, she continues to suggest that most patients get 1,000 milligrams of calcium a day from dietary sources if possible, along with the RDA of 600 to 800 International Units of vitamin D a day.
Vitamin D is essential for calcium absorption. According to the National Institutes of Health, up to 30 minutes of sun exposure on the bare arms, face, legs or back at least twice a week should lead to adequate vitamin D production — providing it's not through glass, which blocks vitamin D-producing UVB rays.
Cod liver oil is loaded with vitamin D. But who's really going to swallow a tablespoon of that every day?
Many foods are fortified with vitamin D, including milk, margarine, breakfast cereals and some orange juice and yogurt. But if sunshine and food aren't good sources for you, vitamin D supplements may be recommended. Your doctor may want to check your vitamin D levels first with a blood test, then decide how much you should take. If deficient, you may temporarily need a higher dose.
If your doctor recommends a calcium supplement, it's important to divide the dose.
"Take no more than 500 to 600 milligrams at a time," Singer said. "And, if you take calcium carbonate, take it with food."
Singer adds that it's not necessary to divide the dose of vitamin D. You can take the full amount all at once.
If you still have questions, talk with your doctor or health care provider to decide what's best for you. And start tracking your calcium intake so you know where you stand.
Contact Irene Maher at [email protected]