Nutritional experts are advising caution to be taken when interpreting a new review which investigates the relationship between vitamin D supplementation and bone health.
Authors of the review concluded that there is no evidence to justify taking vitamin D supplements for bone health, except for those at high risk of a few rare conditions.
The new meta-analysis led by professors at the University of Auckland, which concludes that vitamin D does not prevent fractures, falls or improve bone mineral density, has been criticised by experts in the field for its mix of studies in the review.
Limitations in the research
Professors and researchers worldwide have highlighted limitations in the study which include the fact that only four trials were undertaken in subjects with a deficiency in vitamin D.
It is believed that the broad range of studies confused the conclusions, with the review combining studies of high and low dose vitamin D, and those exploring vitamin D in people with adequate calcium intake as well as those without.
Greg Weatherhead, Nutritional Expert and NPD Manager at BetterYou, has provided some insight in to why the review requires further consideration.
“The recent meta-analysis assessing the randomised controlled trials (RCTs) conducted on vitamin D supplementation for bone health is a comprehensive review and the results have been interpreted as conclusive.
However, It is well established in the scientific and medical community that vitamin D is required for the proper formation and maintenance of healthy bone mineral density, with a lack of vitamin D leading to rickets in children and osteomalacia (bone softening) in adults.
These deficiencies are treated by supplementing vitamin D. Consequently, the utility of vitamin D for bone health is not in question."
Call for greater trial controls
"One of the main issues is adequately controlling the study. RCTs work well for approving pharmaceutical preparations where there is no risk of consuming the ingredient in day to day life.
However, for vitamins and minerals and especially for vitamin D, these are relatively ubiquitous in our day to day life and for vitamin D specifically, it can be obtained by simply being outside in the sun.
As such it becomes very difficult to have an adequately controlled placebo arm of the trial which risks negating any real benefits which may be obtained.
Secondly the majority of trials did not select participants based on their vitamin D levels, as such these participants may not even have required additional vitamin D in their diet to improve bone health.
We recommends a simple home test kit which lets people know their specific vitamin D requirements, if any and we would recommend that this is a strategy adopted by researchers for any future clinical trials, ensuring that the right people get the right levels of vitamin D."
Vitamin D and the bone health trifecta
"Lastly, our bodies do not just require vitamin D for bone health, but a range of different nutrients which work in synergy with each other’s, including vitamin K2, calcium and magnesium.
Therefore, it is not surprising that an isolated nutrient taken over short period of time (typically less than 3 months) does not have a marked impact on bone health.”
Watch the video below to find out more about how vitamin D and K2 work together for bone health.