Could light play a role in supporting vitamin D production?

A bright room. A sunny window. A day spent indoors.

We might feel surrounded by light. But for vitamin D production, brightness is not the whole story. Our bodies need a specific invisible part of sunlight, ultraviolet B radiation, or UVB, to initiate vitamin D production in the skin. And UVB does not pass through glass.
 

Did you know the global population spends more than 90% of their time indoors? Insufficient sunlight exposure has become a global concern as vitamin D is important for supporting the health of our bones, teeth, muscles, immune system, and many more processes in the body. Research involving 7.9 million participants from 81 countries found that 77% of participants had insufficient vitamin D levels.

These findings invite a compelling opportunity, 

How to supplement artificial UVB?
 

Finding the right balance between too little and too much UVB is essential. Signify scientist Remy Broersma combined solar modelling and real-world research to find the sweet spot. Research participants wore patches that measured ultraviolet exposure during walks throughout the year. 
 

“Over a period of 2 years I have been walking outside collecting actual UVB exposure data, wearing multiple sensors on my face and arms. By now, I am known as the guy covered with sensors.” says Remy.
 

The research identified an ultra-low daily dose designed to support vitamin D production while remaining within safety limits. This dose was tested in a winter study, where office workers using UVB-enhanced lighting saw an improvement in their vitamin D levels compared with those using standard lighting. The findings point to an intriguing possibility, that indoor lighting could play a role in complementing natural sunlight when access to it is limited.

How is this being explored?
 

At AZ Groeninge hospital in Belgium, this idea is being explored in an intensive care room without natural daylight. The hospital is testing a lighting environment that combines simulated daylight and a view of the sky with controlled UVB*. Over the coming months, feedback will help the team understand how this approach may support well-being in a setting where patients and staff have limited access to daylight.