If we needed a trial to show that relying on your diet is a poor strategy to try and fulfill the IOM’s vitamin D intake requirements, that trial just recently came out in the journal BMC Pediatrics. This new study, which took place in Italy, was in the form of a randomized controlled trial and sought to find out if good dietary counseling was good enough for vitamin D, or whether children needed to actually supplement.
Researchers, led by Professor Linda Cosenza of the University of Naples “Federico II”, enrolled 24 children aged 3-17 and their families. The children were randomized into either a group whose families received nutrition counseling and vitamin D and calcium supplements (for daily intake of 400 IU/day and 400 mg/day, respectively) or nutrition counseling alone. The dietitians who gave counseling were unaware of the study aims, but were instructed, among many things, to focus on teaching families how to get the right amount of vitamin D and calcium from their diet.
The researchers recorded estimated vitamin D and calcium intake and measured vitamin D blood levels at baseline and after 4 months (the length of the trial) in the children. Here is what they found:
- At baseline, vitamin D and calcium intake was low for all children. The researchers estimated that calcium intake was a mean 507-588 mg/day, while vitamin D was 62-79 IU/day.
- After the trial, calcium intake significantly improved in both groups, increasing to 907-925 mg/day.
- After the trial, vitamin D intake only significantly increased in the group that received supplements, despite both groups getting counseling. The counseling only group intake remained low, while the supplement group intake jumped up to 484 IU/day.
- All children in the supplement group had vitamin D levels over 30 ng/ml after the end of the trial, while only one child in the counseling only group achieved this threshold.
The researchers concluded,
“According to our findings, a dietary counseling alone is unable to obtain an adequate vitamin D intake that is necessary for body health and to reach optimal 25(OH)D serum levels.”
This study is good proof that seeking vitamin D from your diet is poor strategy. Furthermore, this study also shows that traditional techniques to encourage good nutrient intake is inadequate for the nutrient vitamin D. While calcium intake improved in both groups of children after nutrition counseling, whether or not they received calcium supplements, the same could not be said for vitamin D.
If there was ever a study that answered the question, “Why are you so focused on vitamin D?” in a nutritional context, this might be it. This is a good-quality study that highlights the dire need to approach vitamin D education much differently than other nutrients. This is why the Vitamin D Council has always worked hard to clearly communicate the need for sun exposure and supplements and keep the focus off diet.