With Calcium, More May Not Be Better
Getting enough for bone health is crucial, but too much doesn't help, researchers say
By Steven Reinberg
TUESDAY, May 24 (HealthDay News) -- Getting enough calcium for bone health is essential, but getting more than that doesn't appear to confer any additional benefit, Swedish researchers have found.
With age, bones start to lose calcium, their major building block. This puts older people, especially women, at risk for fractures and osteoporosis, a disease in which the bones become fragile and break easily.
To help prevent these devastating injuries, women with a low intake of calcium should increase their intake to avoid fractures caused by osteoporosis, "while women with a satisfactory intake should not," said lead researcher Eva Warensjo, a researcher in the department of surgical sciences section of orthopedics at Uppsala University.
"Dietary intake of less than 700 milligrams (mg) of calcium a day was associated with a higher risk of both fractures and osteoporosis, while higher intakes did not further reduce the risk in [a population-based] cohort of Swedish women," she added.
The researchers also found there was an increased risk of hip fracture at the highest intake level. "But, this result should be cautiously interpreted and needs to be investigated further," Warensjo said.
The report was published in the May 24 online edition of the BMJ.
For the study, Warensjo and colleagues collected data on 61,433 women born between 1914 and 1948 who took part in the Swedish Mammography Cohort study in 1987.
Women in the study responded to questions about their diet and use of calcium supplements and multivitamins. In addition, researchers used information they provided to adjust for weight, height, smoking, educational status and the use of estrogen-replacement therapy for menopause, among other factors.
During 19 years of follow-up, 24 percent of the women had a fracture for the first time. Of these, 6 percent were hip fractures, the researchers noted. In addition, an analysis of 5,022 women in a study subgroup found 20 percent had developed osteoporosis.
Warensjo's team found that women who consumed about 750 mg of calcium a day had the lowest risk of fracture. However, women who consumed more than 750 mg did not see their risk for fracture or osteoporosis decline further. On the contrary, they appeared have a higher risk of hip fracture, with a hazard ratio of 1.19, the researchers reported.
Hip fractures and other broken bones caused by osteoporosis result in higher health costs and widespread individual suffering, the authors noted.
The answer to the question of how much daily calcium is the right amount for people over 50 is still under debate globally, and recommendations vary from country to country. In the United States, for example, health agencies recommend 1,200 mg a day for women 50 and older, while U.K. scientists recommend 700 mg. The recommendation in Scandinavia is 800 mg and in Australia it's 1,300 mg, the researchers noted.
Another important caveat in interpreting the findings of the study is that this is an observational study and conclusions about cause-and-effect cannot be made, said Warensjo, who said that further research was needed.
Commenting on the study, Dr. Robert R. Recker, president of the National Osteoporosis Foundation, said the benefit of calcium levels off at some point and 1,000 to 1,200 mg a day is not too high because it takes into account daily variation in intake.
"This study does not shift that paradigm," Recker said. "I would not even consider changing my recommendation to patients based on this," he added.
Recker's approach is to ask patients about their diet and then he recommends calcium supplements if the patient is not getting enough calcium from diet alone. "I tell them between 1,000 and 1,200 mg per day is what's called for," he said.
Speaking of supplements, Recker noted that the body absorbs calcium only under certain conditions. Supplements, for example, need to be taken with food, he said.
More than 40 million people in the United States have or are at high risk for osteoporosis due to low bone mass, according to federal health agencies.
For more information on osteoporosis, visit the U.S. National Library of Medicine.SOURCES: Eva Warensjo, Ph.D., researcher, department of surgical sciences, section of orthopaedics, Uppsala University, Sweden; Robert R. Recker, M.D., president, National Osteoporosis Foundation; May 24, 2011, BMJ, online Related Articles
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