University of Bath

Mobilising vitamin D sequestered in adipose tissue in humans with exercise (VitaDEx)

Vitamin D can become ‘trapped’ in our adipose (fat) tissue and this study will examine whether exercise can help to release it.

Improving vitamin D status

Up to half of people in the UK have low levels of vitamin D in their blood. Finding ways to improve vitamin D status is a recognised health priority.

Vitamin D is lipophilic (fat-loving) and accumulates in our adipose tissue (fat stores) in large amounts. The entrapment of vitamin D in adipose (fat) tissue contributes to low levels of vitamin D in blood. A key challenge now and in the future, is to find ways to mobilise vitamin D from adipose tissue and help prevent vitamin D deficiency.

Our preliminary data indicates that physical activity is an effective way to mobilise vitamin D from adipose tissue; even without weight loss.

Project summary

In this project, we will use a 12-week randomised controlled trial (RCT) in men and women to examine the impact of exercise (versus control) on vitamin D status and metabolism. We will assess the impact of exercise on the various forms of vitamin D that are found in blood, and whether these changes lead to an improvement in the function of cells known to be affected by vitamin D status (a type of white blood cell called monocytes).

We will use stable isotopes (non-radioactive tracers) to examine how the turnover of vitamin D is affected by exercise. We will examine whether exercise improves the ability to mobilise vitamin D from adipose.

Funding

This project is funded by the Biotechnology and Biological Sciences Research Council (BBSRC).

Study design

The experimental work will start in January 2019 and should be completed by March 2021.

The study has two main parts.

Randomised controlled trial group

The main part of the study will be a 12-week RCT in overweight men and women (exercise versus control). We'll assign men and women to an exercise intervention or control group (a total of 50 participants, split 25:25).

Comparator group

To contextualise the effects of exercise and enable an assessment of the extent of ‘normalisation’ of adipose tissue mobilisation of 25OHD, we will also recruit an age-matched active lean group.

This group will be age-matched active lean men and women (a total of 20) and will not undertake any intervention.

Confounders

Variability in UV-induced vitamin D synthesis is a potential confounder. We will structure the experimental work to minimise the impact of UV exposure. Whilst recruitment will take place over most of the year, the experimental work will only be during the winter months (October to March) when there is little vitamin D synthesis.

Project team

University of Bath

University of Birmingham

University of Cambridge