Boosting calcium no help: study
AUCKLAND UNIVERSITY-LED studies have cast doubt on the value to older people of boosting calcium intake through food or supplements.
The two studies were published in the British Medical Journal. which also carried an editorial calling for the reconsideration of recommended calcium levels for older people.
A daily intake of 1000-1200 milligrams had long been recommended for older people for bone health and prevention of fractures, the studies said. In comparison, the average dietary intake for older people in Western countries was 700-900mg/day.
In some western countries 30-50 per cent of older women were taking calcium supplements but studies had found minor adverse effects, such as constipation, and a small risk of severe side effects such as cardiovascular events, kidney stones, and acute gastrointestinal symptoms.
As a result, older people had been encouraged to improve bone health by increasing calcium intake through food.
Ministry of Health guidelines show the main sources of dietary calcium are milk, bread, cheese, vegetables and dairy products.
The studies analysed randomised controlled trials and observational studies of extra dietary or supplemental calcium in women and men aged over 50.
‘‘In the first study, we found that increasing calcium intake from dietary sources or by taking supplements produces small (1 to 2 per cent) increases in bone mineral density, which are unlikely to lead to a clinically meaningful reduction in risk of fracture,’’ Auckland University Associate Professor of Medicine Dr Mark Bolland said.
‘‘The second study found that dietary calcium intake is not associated with risk of fracture, and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures.’’
Bolland, who led the team of researchers involved in the studies, said the results suggested clinicians, advocacy organisations and health policymakers should not recommend increasing calcium intake for fracture prevention, either by use of calcium supplements or dietary sources.
‘‘For most patients who are concerned about their bone health, they do not need to worry about their calcium intake,’’ Bolland said.
The researchers looking for fracture outcomes could find only two randomised controlled trials involving dietary sources of calcium – one looking at milk powder and the other a preparation of hydroxyapatite, which is a major component or normal bones and teeth.
They also found 50 publications from 44 cohort studies reporting relations between fracture outcomes and dietary calcium, milk, dairy intake, or supplements.
In the BMJ editorial, Uppsala University Department of Surgical Sciences professor Karl Michaelsson said 700-800mg/day of dietary calcium for adults seemed to be enough, while noting the amount needed had been debated for decades.