Nutritional experts are right to advise caution when interpreting a potentially misleading review that investigates the relationship between vitamin D supplementation and bone health, writes Greg Weatherhead, NPD manager at BetterYou.
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.
So, 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 our bodies do not just require vitamin D for bone health, but a range of different nutrients which work in synergy with each other, 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.
Lastly 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.
BetterYou recommends and provides 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.
BetterYou is supporting Vitamin D Awareness Week (22-28 October 2018) to raise awareness and encourage people to test their levels and make sure they are supplementing appropriately.