Study under review: Effect of High-Dose Vitamin D Supplementation on Volumetric Bone Density and Bone Strength: A Randomized Clinical Trial
Vitamin D has been a major focus in the context of musculoskeletal conditions, especially osteoporosis and bone fractures, due to its role in bone formation. Vitamin D is required for the optimal formation of bone tissue and functions largely because it modulates key bone cells called osteoblasts and osteoclasts. Vitamin D also works indirectly to improve bone mineral density (BMD) by increasing intestinal calcium absorption, and other ways laid out in Figure 1. As such, supplementing with vitamin D, specifically D3, the most biologically active form, has been investigated as an intervention to improve BMD.
Previous trials have yielded disparate results, and a recent meta-analysis suggested that vitamin D supplementation does not have any meaningful effect on bone mineral density or the risk of fractures among adults. One of the major shortcomings of earlier trials and those included in the abovementioned meta-analysis is their reliance on dual x-ray absorptiometry (DXA) scans to measure BMD, which does not address all the important components of bone strength: bone mass, morphology, and architecture. Recently, more sensitive measurements have been developed that can provide a more accurate representation of bone strength: peripheral quantitative computed tomography (HR-pQCT). This method can measure aspects of bone structure related to bone strength beyond density. Also, measurements derived from this method have been found to predict fracture risk independent of BMD.
The study under review explored the dose-response effects of vitamin D supplementation among healthy community-dwelling adults over 36 months using HR-pQCT to assess BMD and bone strength. This study used relatively high doses at 4000 and 10000 IU per day.
Vitamin D plays a key role in bone formation and bone strength. Previous studies have found that vitamin D supplementation does not improve bone strength among otherwise healthy adults. However, more sensitive and accurate measures have been developed that may provide a more accurate view on exactly how vitamin D supplementation might affect bones in otherwise healthy adults.
Other Articles in Issue #59 (September 2019)
Losing weight is more important than reducing saturated fat intake for improving atherogenic lipids
Cutting saturated fat or replacing it with polyunsaturated fat is one way to improve blood lipids. However, lipids in people with higher BMI don't budge as much compared to those with lower BMI.
NERD Mini: The best diets to control blood lipids in people with diabetes
Improving blood lipid profile is especially important for people with diabetes, who are already at a higher risk for cardiovascular problems. Are some diets better than others at achieving this goal?
Does essential amino acid supplementation cause insulin resistance?
Aging brings with it a loss in muscle mass, which can negatively impact insulin sensitivity. Amino acid supplementation can help maintain muscle mass, but some evidence also suggests it may promote insulin resistance. Are older adults stuck between a rock and a hard place?
Does the feeding window matter for muscle mass?
Time-restricted feeding (TRF) may have a negative impact on muscle mass, at least in theory. This study put the question to the test by examining both TRF’s and HMB supplementation’s effects in resistance-training women.
NERD Mini: The latest evidence on the nutritional interventions’ effects on cardiovascular health
How good is the evidence concerning different nutritional interventions' impact on cardiovascular endpoints? A recent umbrella review explored the issue.
Beyond brawn: can protein supplementation fuel aerobic improvement?
It's well known that protein supplementation pairs well with resistance training, but can casein outperform carbs when paired with cardio?
Omega-3s for peripheral artery disease
Recent evidence suggests that high-dose pharmaceutical grade omega-3s can impact cardiovascular disease. How well does it work for PAD, though?