Published on January 25, 2018
As I read the headlines I wonder, is this true? Is vitamin D really not necessary for preventing fractures in community-dwelling adults? And by the way… what is a community-dwelling adult? Curious minds prevailed so I delved further and read the actual paper by Zhao, et al. that was online.
Only the abstract is available for free. (This is a common practice, it costs researchers $1000 – $5000 of their hard-earned grant money to have the full paper available ‘open source.’) As I read the abstract, with my 10 years of experience in vitamin D research, I thought… well, this sounds credible.
But, luckily I had access to the entire paper.
What is a “community dweller”?
For this paper, it refers to someone above 50 years old who lives on their own in the community, not in a nursing home or residential care facility.
Reading all the Research
I will caution you, if you do get your hands on this paper, it is quite technical. I will try and summarize as best I can. This is a meta-analysis which means that it does not present new data. It didn’t have a new group of people tested, instead, the researchers searched the internet for all papers that met certain criteria (in this case randomized controlled trials using vitamin D, calcium, or both to test reduction in fractures for older adults). There are thousands of papers, but using these criteria the researchers narrowed down the selection to 33 papers.
Of the 33, 24 had the participants take vitamin D or both vitamin D and calcium (9 studies used calcium supplements only). All the papers included were listed in a table, with a short summary of dosing, initial vitamin D level (if measured), and length of study (as well as a few other parameters).
Let’s start by throwing out all the bolus dosing
Why? Well, what would you say to a world-renown diet doctor who was going to make you fit and healthy by restricting your diet and increasing your exercise just one day a year? One day a quarter? Even one day a month? Would that work? No! And it is the same with vitamin D. Here is a longer explanation that includes research by Dr. Bruce Hollis.
There were 8 trials on the list that had bolus dosing, my favorite being the one that gave 500,000 IU once a year. Now we are down to 16 papers.
Throwing out the trials that are too short
Why do we have to throw out those that are too short? It takes about 2 months for vitamin D to make a change in your body, then it would have to be absorbed and affect the skeletal system. For the sake of this discussion let’s assume anything under a year is not long enough to show reliable results, that was another 4 studies on the list. Now we are down to 12 papers.
Throw out the trials with too little of a daily dose
One of the most important criteria for a trial to be reputable is for it to show a change in nutrient status. So, back to my diet analogy, what if you decided to up your vegetable intake (a great goal) by having one extra lettuce leaf a day? Would that have an impact on your health? I guess if you NEVER had any vegetables, for our analogy, this would be similar to a starting vitamin D level below 10 ng/ml, then it might have an effect. But for most people who are eating 1-2 servings of vegetables a day, similar to someone starting a vitamin D trial with 20ng/ml in their blood, it would have little effect.
I propose we throw out the studies with less than 1000 IU/day.
This got rid of all the calcium+vitamin D trials and 4 of the vitamin D alone trials.
It leaves us with one trial, BEST-D trial by Hin et al, 2017. The quick summary of this trial is that they gave 4000 IU/day, 2000 IU/day or placebo for one year to 305 white people, 65 years or older, in the UK. They found that 4000 IU/day was most effective in reaching optimal vitamin D levels (100-150 nmol/L) and that there were NO ADVERSE EFFECTS. In other words, it was safe. They had no conclusions on fracture rates and bone health because they thought their trial was too short for that analysis but instead wanted to use this data to have a multi-year study with older people using 4000 IU/day and testing for fracture rates.
Well, that puts a damper on the headlines.
The Devil is in the details
The moral of this story is that you can’t trust headlines. In effect, this study was not very conclusive at all. None of the papers were strong enough to make a conclusion either way.
Resources
Association Between Calcium or Vitamin D Supplementation and Fracture Incidence in Community-Dwelling Older Adults
Zhao et al.
JAMA
December 2017
Read Paper
Optimum Dose of Vitamin D for disease prevention in older people: BEST-D trial of vitamin D in primary care
H. Hin et al.
Osteoporosis International
March 2017
Read Paper
Press Release from JAMA
December 26, 2017
Read Press Release
What most people see in the news, due to JAMA’s press release, notice the similarities:
Vitamin D, calcium supplements may not lower fracture risk
Reuters
Lisa Rapaport
December 26, 2017
Read News Article
Calcium and vitamin D supplements may not protect against bone fractures
Washington Post (like this one)
Ariana Eunjung Cha
December 26, 2017
Read News Article
Vitamin D and Calcium Don’t Prevent Bone Fractures
The New York Times
Nicholas Bakalar
December 28, 2017
Read News Article
Two news story that got it right, thank you!
Experts rebuke report casting doubt on link to bone health
Omaha World-Herald
Rick Ruggles
December 28, 2017
Read News Article
Industry Criticizes New Study Challenging Benefits of Calcium and Vitamin D
WholeFoods Magazine
Staff
December 26, 2017
Read News Article
