Getting adequate calcium is key for people with arthritis and related conditions, who may be at higher risk of fracture due to their disease, age or medications that can cause bone loss. However, getting higher amounts of daily calcium may not offer more protection for bones than moderate amounts, according to a study published online in the BMJ.

“[People] don't need to have an intake higher than about 700 milligrams per day. There is no additional benefit in fracture risk prevention above this level,” says study co-author Karl Michaëlsson, MD, PhD, a professor in medical epidemiology at Uppsala University in Sweden.

Swedish researchers wanted to see if higher calcium intake offered more protection against the bone loss that occurs naturally with aging. For the study, they reviewed data from a large, longitudinal study of more than 61,000 Swedish women born between 1914 and 1948. Participants were asked, in the period between 1987 and 1990 and again in 1997, to fill out questionnaires about their diet, intake of calcium, intake of supplements and vitamins, menopausal status, height, weight, smoking status and physical activity habits. Between 2003 and 2009, the researchers prospectively gave a subgroup of 5,022 women bone scans and asked them to fill out another questionnaire about diet and lifestyle factors.

Results showed that during the course of 19 years, nearly 15,000 women (24 percent of the study group) experienced a first fracture, of which almost 4,000 (6 percent) were hip fractures. In the subgroup, more than 1,000 women (20 percent) were diagnosed with osteoporosis.

When researchers compared how much calcium the women got, they found that a woman’s fracture risk was lowest when she consumed about 700 mg of calcium a day; getting more didn’t decrease her risk of osteoporosis or fracture, although getting less did increase the risk. In fact, women who got the most  calcium had a slightly higher rate of hip fractures.

“The take-home message is that having a dietary intake of calcium in moderate amounts is enough to avoid fractures in this population, meaning that dietary calcium in adequate amounts – 700 to 800 mg – would be enough,” explains lead author Eva Warensjö, PhD, a researcher in the department of surgical sciences in the section of orthopaedics at Uppsala University. “We see that if you have a lower intake – less than 700 mg – then you are prone to fractures.”

U.S. experts say the study findings are in line with the recommendations in this country. Clifford J. Rosen, MD, is a senior scientist at the Maine Medical Center Research Institute in Scarborough, Maine, and a member of the U.S. committee that set new calcium-intake recommendations through the Institute of Medicine, or IOM, late last year. He says this study fits well with his group’s recommendations that most Americans, depending on their age, should be getting between 700 and 1,300 mg a day.

“Seven hundred is a threshold. What they are establishing is really a threshold. Anything below that will be associated with an increased risk of fracture but that doesn’t mean that’s the recommended allowance for most people,” Dr. Rosen explains.

Dr. Rosen says his committee discovered that the majority of Americans are getting between 750 and 900 mg through diet, so some people don’t need to take supplements. He recommends talking to your doctor or nutritionist to see if you’re getting enough.

Donald Miller, chair of the department of pharmacy practice at North Dakota State University in Fargo, agrees. “You don’t need to go crazy taking calcium supplements. Talk with your doctors and find out if you need to take a calcium supplement before going out on your own,” he says. “Americans love to take supplements and think, ‘Well, it can’t hurt.’”

But, actually, it could. Dr. Rosen says you don’t want to get too much calcium because there’s a risk of kidney stones and possible cardiovascular risk, which is still being studied. He says one exception is people taking corticosteroids, such as prednisone, because these drugs can cause higher fracture risk. “There is some evidence to suggest that calcium intake in that group should be above 1,000 mg,” Dr. Rosen says.

It’s also important for your bone health to keep track not just of your calcium intake, but also how much vitamin D you are getting because vitamin D helps absorb calcium, he adds. The IOM recommendations suggest people get between 600 and 800 international units of vitamin D daily. “If vitamin D is low then the calcium intake is critical because they feed off each other,” Dr. Rosen explains.

But Dr. Rosen says overall, he thinks the message about calcium and vitamin D is getting out and being heard. “Most people are now consuming more calcium and vitamin D and I think the bottom line message is if you have low calcium intake you are at increased risk of fracture but it is easy to fix, and if your vitamin D is low then more calcium is necessary,” he says.