Vitamin D — AKA the Sunshine Vitamin
Vitamin D has received superstar status over the past year. And for good reason. Aside from its role in immune system function it contributes to mood, energy production, skin, bone health, and even sleep.
But what is the real deal when it comes to getting vitamin D naturally? Can we synthesise vitamin D when it is cloudy outside? Is sitting by a window inside enough? Read on as our nutritionist answers the most popular questions when it comes to vitamin D and the importance of light to our health and wellbeing.
How is vitamin D created
When our skin is exposed to sunlight, we synthesise vitamin D from cholesterol. To be exact, it is the ultraviolet B UVB energy that is responsible for this conversion. From there, vitamin D is carried to the liver and kidneys and transformed into active vitamin D and utilised in the body.
Remember when the sun is shining, not to miss the opportunity, to get outside and expose your skin to the sunlight to synthesise vitamin D.
Can we get vitamin D at any time of the day?
Midday is the best time to get sunlight, especially during the summer months. At noon, the sun is at its peak and this is when we get the strongest UVB rays. The stronger the UVB rays are at a time of day, the less time we need to spend in direct sunlight to get enough vitamin D.
How long do we need to spend outdoors?
According to the NHS there is no exact number of minutes, however most guidance suggests 15 minutes for a person with light skin is ample and this can go up to a few hours if you have darker skin.
People with darker skin typically have more melanin (a pigment in the skin) than those with lighter skin, which helps protect the skin against excess sunlight and damage. Therefore, those with darker skin will need significantly more time in the sun to reach their recommended daily intake.
Can we get vitamin D all year round?
In the UK, our sunlight doesn’t contain enough UVB rays between the months of October to March for our skin to be able to create enough vitamin D, which is why the NHS recommends that those living in the UK with little travel should consider a vitamin D supplement of 400iu/10mcg.
What about sun cream?
Sun cream may reduce the body’s ability to produce vitamin D as it protects our skin from UBV rays – we are not entirely sure how much. Most short-term studies show there is little difference to blood levels of vitamin D. It is best advised to wear a minimum of 15 SPF when sitting in the sun and the SPF factor should be more depending on how sensitive your skin is to sunlight.
What about sitting near a window?
Our bodies cannot synthesise vitamin D when sitting indoors by a sunny window. This is because ultraviolet B rays, the ones we need to produce vitamin D, are blocked by glass.
Why is natural light important?
The importance of natural light exposure goes beyond providing us with vitamin D.
Natural light prompts our circadian rhythm (our body clock) via light sensors within our eyes. Our eyes detect light and adjust our body clock so that the internal and external day are aligned.
With less natural light, particularly during the winter months, we can find our energy levels low or our sleep disrupted.
My top tip is to get natural light in your eyes in the morning to support that natural energy production or to give yourself a natural energy boost in the afternoon.