Data published in Bone Reports using radioisotope calcium-41 (41Ca) tracers indicated that there were no differences between fortified milk, yoghurt or tablets for boosting levels of calcium.
“The present study is the first to use the 41Ca-AMS [accelerator mass spectrometry] method in a dietary intervention study with dairy products and directly compares calcium and vitamin D intake from dairy foods vs. supplements on the same bone variables,” wrote researchers from the University of California, Davis, the USDA’s Agricultural Research Service, and Lawrence Livermore National Laboratory.
“The highly sensitive 41Ca-AMS technique represents an alternative method to other methods like bone turnover biomarkers that require large sample sizes and months of intervention to detect treatment differences. Both dairy products and calcium vitamin D supplements demonstrated comparable short term effect on calcium retention, but the dairy treatment provided a more nutrient dense diet for this group of postmenopausal women.”
Calcium and bone health
Boosting bone density in high-risk post-menopausal women by improved diet or supplements is one way to reduce the risk of osteoporosis. Recent data from the National Osteoporosis Foundation showed that approximately 9 million American adults currently have osteoporosis and another 48 million have low bone mass, placing them at increased risk. Women are four times more likely to develop osteoporosis than men.
An economic report from Frost & Sullivan and commissioned by the Council for Responsible Nutrition (CRN) recently found that supplements of calcium plus vitamin D for all US women with osteoporosis could provide healthcare cost savings of $1.08 billion per year.
While many studies have looked at calcium from dairy products, or calcium from supplements, or calcium plus vitamin supplements on bone health, very few have compared “equivalent calcium and vitamin D from dairy vs. supplements on the same bone outcomes”, explained the researchers.
They recruited 12 postmenopausal women to participate in their cross-over trial. The women were randomly assigned to consume four servings per day of milk or yogurt (1,300 mg calcium, 400 IU vitamin D3) or supplements (1,200 mg calcium carbonate/day and 400 IU vitamin D3) for six weeks. This was followed by a six week washout period before crossing over to the other interventions.
Results showed that the 41/40Ca ratio decreased significantly over time for both food and supplements and there were no statistically significant differences between the interventions.
While calcium levels were affected by the interventions, no changes to markers of bone formation were recorded by the researchers, which they postulated could be due to the relatively short (six weeks) intervention period.
“It is possible that the six week time frame of the present study was too brief to observe mineralization changes represented by bone formation markers such a bone alkaline phosphatase (BAP),” they wrote. “Likewise, no significant PTH change during either treatment is consistent with previous reports that calcium intake prevents increases in PTH over time. Calcium tablets have been shown to significantly decrease PTH after 6 months, but the six week treatment duration in the present study may have been insufficient to observe this suppressive effect.”
Source: Bone Reports
Volume 5, December 2016, Pages 117–123, doi: 10.1016/j.bonr.2016.05.001
“Is bone equally responsive to calcium and vitamin D intake from food vs. supplements? Use of 41calcium tracer kinetic model”
Authors: T.S. Rogers, et al.