But if you dig a little deeper, and if you put this study in context with other findings, you get a clearer picture.
First off, the actual methods of this study. 5292 people (aged 70+) were randomly divided into 4 groups: one got 800 IU of vitamin D3 per day. One got 1,000 MG of calcium (form is not listed), one group got both, and one group got placebos.
800 IU of vitamin D is 200 IU more than the current RDA. But it’s far below the level most Vitamin D experts consider to be necessary to see any actual benefits.
Even the lead author of the study, Dr Alison Avenell (who is also a researcher at the University of Aberdeen in England) admitted, “The dose of Vitamin D might not have been high enough.”
A full third of the participants died during the course of the study. (They were at least 70 years old at the beginning.) Plus, says Avenell in an email to Reuters Health, “People often stopped taking their tablets, so we might not have had enough people taking tablets to find effects.”
Still, when the results were “adjusted for compliance,” there was a slight reduction in mortality for those taking Vitamin D and a slight INCREASE in those taking calcium supplements alone. The authors are quick to point out that these findings are not statistically significant.
Both the authors and the media are also quick to forget findings such as a 2009 Meta-analysis of all then-current literature on Vitamin D. A meta-analysis combines data from multiple studies to analyze trends and overall results, sometimes for data that was collected but not necessarily the focus of the studies being analyzed.
This particular meta-analysis included 99,745 participants from 28 different studies. It found that those with the highest levels of vitamin D in their blood had a 48% reduction in cardiometabolic disorders. The authors state, “High levels of vitamin D among middle-age and elderly populations are associated with a substantial decrease in cardiovascular disease, type 2 diabetes and metabolic syndrome.”
So here are our takeaways from the current study in context with what is already known:
- 800 IU of Vitamin D per day is not enough to generate the benefits D is known for
- If taken with Calcium, you really need to add Vitamin K as well.