A study conducted at the Cleveland Clinic Bone Clinic has determined when it is best to take your Vitamin D. Many patients who take Vitamin D fail to achieve adequate levels despite taking high doses of Vitamin D. This study explored a group of patients who had failed to reach adequate levels of Vitamin D despite taking doses ranging from 1000-50000IU.

 

The study included patients taking a large range of doses and dosage forms of Vitamin D. Some were taking D2, while others were taking D3. Some were taking an oil preparation and others a solid preparation. But all were having difficulty achieving optimal levels.

* One group was taking approximately 1,400 IUs of Vitamin D3 (either oil or solid capsule) a day, with a baseline 25OHD averaging 28.9ngms/ml
* One group was taking 50,000 IUs of Vitamin D2 (oil preparation) per week with a baseline 25OHD averaging 31.3ngs/ml
* One small group of 3 was taking >50,000 (average dose of 183,333 IUs a week) IUs of Vitamin D2 (oil preparation) per week with a baseline 25OHD averaging 32.4mg/ml.

 

All the participants were told to keep taking their usual Vitamin D supplement, but to take it with their largest meal of the day, usually dinner. After two to three months the participants had their Vitamin D levels measured, and everyone ended up with an average increase of around 50% over baseline in their Vitamin D levels.

* patients taking 1,400 IUs of D3 went from 28.9 before to 45.4 ng/mL
* patients taking 50,000 IUs of D2 went from 31.3 before to 48.3 ng/mL
* patients taking >50,000 IUs of D2 went from 32.4 to 48.7 ng/mL

 

 So by the end of the study period, Vitamin D levels had risen to an average of 47.2 ng/ml (118 nmol/l) -an average increase in vitamin D levels of about 57%.

This study is not totally ideal in that it lacked a control group - a group of individuals who continued to take their Vitamin D as usual and not with the biggest meal of the day. However the study does show us that even patients who have difficulty rasing their Vitamin D levels can do so by taking their supplement with food. It also demonstrated that the formulation of Vitamin D, either oil-based or a solid tablet formulation, did not make a difference as some have suspected.

 

Ref: J Bone Miner Res. 2010 Apr;25(4):928-30.
Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D. Mulligan GB, Licata A.
Department of Endocrinology, Diabetes, and Metabolism, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.