Vitamin D supplementation offers an easy and affordable method of increasing vitamin D levels. The most common form of supplement is a capsule. However, those with gastrointestinal issues often require alternative methods of maintaining healthy vitamin D levels, such as receiving safe sun exposure or using oral sprays.
Vitamin D given as an oral spray is primarily absorbed through the membranes in the oral cavity, allowing the vitamin D to bypass the gastrointestinal tract and go directly into the blood. Due to the potential therapeutic use of oral sprays in those with malabsorption issues, researchers assessed the efficacy of oral spray in comparison to capsules among 22 healthy adults.
Half of the adults were allocated to receive a daily oral spray containing 3000 IU of vitamin D3 for a total of four weeks; whereas the other half were allocated to receive three 1,000 IU vitamin D3 capsules daily for the same duration. Then, the researchers measured all participants’ vitamin D levels. All participants, then, went through a “washout period.” A washout period refers to a time allowed for all of the administered drug/supplement to be eliminated from the body. For vitamin D, this takes about 10 weeks.
Following the washout period, the participants completed a final four-week supplementation phase, using the opposite treatment. Therefore, those who were initially allocated capsules, received oral sprays and vice versa.
All participants were subject to both oral spray solutions and capsules for four weeks each per vitamin D supplementation method. Therefore, the researchers assessed the average increase of vitamin D status before and after treatment for each method of supplementation. Here is what they found:
- Two participants did not respond to oral spray and were considered outliers.
- At baseline, the average vitamin D status of those who received capsules was 24 ng/ml, which significantly increased after four weeks of treatment to a value of 36 ng/ml (p < 0.001).
- The average vitamin D levels of those who received oral spray significantly increased from the baseline value of 24 ng/ml to 34 ng/ml (p < 0.001).
- There was no significant difference between oral spray and capsule supplementation methods (p = 0.329).
The researchers concluded,
“Our findings demonstrate that oral spray vitamin D3 is just as effective as capsule supplementation at increasing total 25(OH)D concentrations in the healthy, adult population.”
The researchers call for future studies to assess the effectiveness of oral spray vitamin D supplementation against alternative methods among those with gastrointestinal malabsorption.
Tovey, A. & Cannell, JJ. Are oral sprays as effective as capsules? The Vitamin D Council Blog & Newsletter, 2016.
Todd, J. et al. Vitamin D3 supplementation in healthy adults: a comparison between capsule and oral spray solution as a method of delivery in a wintertime, randomised, open-label, cross-over study. British Journal of Nutrition, 2016.