Your body produces vitamin D when your skin is reached by the sun’s UVB rays. At the same time, we apply sunscreen to protect ourselves from these very rays. But does using sunscreen mean that you get lower vitamin D levels?
Sunscreen and vitamin D production
Sunscreen has actually been shown to be able to reduce the body’s production of vitamin D, especially when it is used regularly and correctly. Despite this, no major reduction in vitamin D production associated with sunscreen use has been observed at the group level. This may have two possible explanations.
- It may be because sunscreens are simply not used correctly. (This may involve the wrong type, amount, SPF, or simply not applying it correctly.)
- It may also be that sunscreens do not manage to block all UVB rays, even though they protect against a large proportion of them. Since it does not take very much UVB radiation to initiate the production of vitamin D in the skin, the small amount that gets through the sunscreen may be enough.
How much sun do I need?
Now you may be wondering how much sun you need for your body to produce enough vitamin D. Generally speaking, exposing yourself to 5–30 minutes of unprotected sunlight on your hands, arms and face three times a week between 11 a.m. and 3 p.m. is enough to avoid vitamin D deficiency. If you want to assess your specific needs, you can use the following:
- The UV index for your area (measures how strong the harmful part of the sun’s UV radiation is when it is at its strongest).
- Your skin type on the Fitzpatrick scale (a measure that estimates how different skin types react to UV light).
When the UV index in your area exceeds 3, people with
- skin type 1 or 2 should spend no more than 10 minutes in unprotected sunlight.
- skin type 3 or 4 should spend no more than 15 minutes in unprotected sunlight.
- skin type 5 or 6 should spend no more than 30 minutes in unprotected sunlight.
During the summer in Sweden, the UV index usually varies between 4 and 8 from north to south. The UV index is highest in July in southern Sweden.
It may be good to keep in mind that spending longer periods in the sun does not necessarily mean higher vitamin D levels, as UVB rays will eventually cause an inactivation of the vitamin D in your skin. This is one of the body’s built-in safety mechanisms designed to protect you from vitamin D toxicity.
Sunscreen – yes or no?
You do not need to stop using sunscreen to increase your body’s vitamin D levels. Instead, continue to expose your skin to an appropriate amount of sunlight under safe conditions and make sure to supplement your body’s own vitamin D production by frequently eating foods that are rich in vitamin D (e.g. fatty fish) or taking a good vitamin D supplement. A supplement is usually a common recommendation for those of us in Sweden, as we live so far north that the sun’s rays do not reach us in the same way as they do in other parts of the world.
