Researchers from the University of Sheffield partnered with BetterYou, developers of the UK's first vitamin D oral spray, to carry out a clinical trial comparing the rate of change of vitamin D status in response to a vitamin D dose, in both capsule and oral spray methods of delivery.
Now published in the European Journal of Clinical Nutrition, the study concluded that the oral spray method of vitamin D was equally effective as taking a capsule and supported the same rate of improvement in vitamin D levels.
Dr. Bernard Corfe, senior lecturer in Molecular Gastroenterology at the University of Sheffield and principal investigator for the trial, said: "All participants achieved adequate levels of vitamin D after just 21 days of using an oral spray, with those individuals who were considered severely deficient at the beginning of the trial (with levels lower than 25(OH)D) experiencing the most effective uptake of the supplement."
A randomised, placebo-controlled, three-arm parallel design study was conducted in 75 healthy volunteers to compare the rate of change of vitamin D status in response to vitamin D3 (3000 IU/day) supplementation in capsule and sublingual spray preparations over a 6-week period between January and April 2017.
Blood 25(OH)D concentrations were measured after day 0, 3, 7, 14, 21 and 42 days of supplementation with 3000 IU per diem.
There was a significant elevation in blood concentrations of 25(OH)D in both of the treatment arms (capsule p = 0.003, spray p = 0.001) compared with the control.
The rate of change ranged from 0.69 to 3.93 (capsule) and 0.64 to 3.34 (spray) nmol/L day with average change in blood 25(OH)D levels of 2 nmol/l/day.
Rates followed a simple normal distribution in the study population (ks = 0.94 and 0.82 for capsule and spray, respectively).
A 2016 Scientific Advisory Committee on Nutrition report highlighted the need for all UK adults and children to take a vitamin D supplement throughout the winter months and the National Institute for Health Care Excellence extended this recommendation for children and young people to take a vitamin D supplement all year round.
"Vitamin D is essential to keep bones, teeth and muscles healthy, and is especially important for children's development," Dr. Corfe added.
"It's difficult for people to get enough vitamin D through their diet, and during the winter the sun isn't strong enough to help the body boost its levels.
"There is now more awareness of the need for people to supplement their vitamin D, but only around 40 percent of adults in the UK are considered to have sufficient levels. So this research is the opportunity to highlight the importance of this essential vitamin in supporting overall health, and in providing a valuable alternative source for those who may struggle to, or prefer not, to take tablets."
Of the participants that expressed a preference, 70 percent said they preferred taking vitamin D by an oral spray for ease of use and better taste.
Dr. Corfe added that often people don't want to take supplements in pill form for a number of reasons, including swallowing difficulties so this finding provides evidence that there is 'a real alternative' for those whose vitamin D levels are low.
Source: European Journal of Clinical Nutrition
Authors: Williams. C. E., et al.
"Rate of change of circulating 25-hydroxyvitamin D following sublingual and capsular vitamin D preparations"