We keep going on about the benefits of sunscreen and how it’s a must to wear it every day to protect our skin from the damage that UV rays cause, especially in the summer, when we get the most sunlight exposure.
But what about the side effects of sunscreen? Does sunscreen block vitamin D?
The vitamin that the skin synthesizes upon sun exposure and that’s vital for our skin and our wellbeing – is zinc oxide in sunscreens preventing it from reaching our system together with the UV rays?
Let’s dig deeper into this topic and find out.
What Is Vitamin D and Why Is It Important?
Vitamin D is both a nutrient we ingest through food and a hormone our body produces.
It’s been linked with the prevention of certain types of cancer. It can help control infections and reduce inflammation. It also helps our body absorb and retain calcium and phosphorus, which are both critical to the health of our bones.
But not many foods contain vitamin D, so the best way to get it is either through supplements, or natural sunlight exposure.
The way we get it naturally is when our skin comes in contact with the sun’s ultraviolet-B (UVB) rays. Chemical processes start happening in the skin and vitamin D is synthesized. Hence its nickname “the sunshine vitamin.”
That is the primary natural source of vitamin D in our body, but many people have insufficient levels, either because of the climate they live in, or from spending too much time inside.
Skin tone is also a factor. Darker phototypes have lower blood levels of vitamin D because the high level of melanin acts as a shade, limiting vitamin D production.
Image source: Freepik
So, Does Sunscreen Block Vitamin D Production?
In short, no.
It seems that 2023 has been a watershed year – the awareness about the importance of wearing SPF has never been this high. More and more people have been including sunscreen, especially facial sunblock, in their daily routine.
Which is a great thing!
But it’s also sparked debate from certain shady sources, who claim that, if you’re constantly blocking UV rays from penetrating the skin, you’re also blocking your body from synthesizing vitamin D.
But there’s no scientific evidence to prove that wearing sunscreen is harmful in any respect, including this.
So by all means, find your favorite sunscreen and slatter it up generously. As long as you eat a healthy, balanced diet, there’s nothing to worry about.
Does Zinc Oxide Block Vitamin D Production?
There’s no valid research that would back this.
Zinc Oxide is an ingredient that all mineral sunscreens contain. It physically sits on top of the skin to prevent UV rays from penetrating the skin – that’s why mineral sunscreens are referred to as physical.
Mineral sunscreens are generally safer since they don’t get absorbed into the skin, and they’re a good alternative to chemical sunscreen, especially for those with sensitive skin.
They provide protection when reapplied frequently enough, and just like with any other sunscreen, there’s no proven link between zinc oxide and vitamin D deficiency.
Does Sunscreen Use Lead to Vitamin D Deficiency?
Clinical studies have never found that everyday sunscreen use leads to vitamin D insufficiency.
Sunscreens are designed to filter out most of the sun’s UVB radiation, since it’s the major cause of skin damage such as sunburns or skin cancer. But UVB wavelengths also happen to be the exact wavelengths that trigger vitamin D production in our skin.
So theoretically, it might be logical to think that the result of regular sunscreen use would affect vitamin D levels.
But in reality, the prevailing studies show that people who used sunscreen on a daily basis maintained their normal vitamin D levels.
Several observational studies have shown that in real life settings, wearing sunscreen – any sunscreen, including those with zinc oxide – does not cause a vitamin D deficiency and should still be worn and reapplied every day.
One of the explanations for this is that no matter how high the SPF is or how often you reapply, some of the sun’s UV rays will still reach your skin. An SPF 15 sunscreen filters out 93% of UVB rays, SPF 30 filters out 97%, and SPF 50 keeps out 98%.
This means that 2 to 7% of solar UVB rays will still reach your skin, even with high-SPF sunscreens. And that’s if you use them consistently and reapply every two hours, as you should.
This means you can wear sunscreen daily and still get enough vitamin D to build strong bones and function properly. There is no valid evidence showing that wearing sunscreen causes vitamin D deficiency.
What Does Influence Our Vitamin D Levels
Your body creates vitamin D when sunlight hits the skin and triggers chemical processes within it.
We’ve now established that regular sunscreen use will not block vitamin D production or diminish its levels in your system. But what will? Here’s a list of the main factors:
The Climate You Live In
Basically, the further away from the Equator you live, the less vitamin D-producing UVB light will reach the earth during winter in your location.
Meaning that in many places during winter people might get little to no vitamin D. Short days and high-coverage clothing also limit UVB exposure.
Air Quality in Your Environment
The level of air pollution also impacts the extent of solar UVB rays that reach the earth’s surface.
As a result of reduced UVB passing, our skin is unable to convert these rays into vitamin D, which means that living in a polluted city can affect your vitamin D levels and cause a deficiency.
Your Skin Color
Melanin is the pigment that gives the skin color. Just like sunscreen, melanin can reduce the body’s ability to produce vitamin D from sun exposure by up to 99%.
This means that it takes a person with darker skin 3-6 times longer to get the same amount of vitamin D from sunlight as a person with lighter skin tone.
Since vitamin D is fat-soluble, people with higher amounts of body fat will ‘capture’ vitamin D in fat cells, leading to lower amounts circulating in the blood.
Because of this, people who are overweight will typically need higher amounts of vitamin D to maintain normal levels or to correct a deficiency.
What Are Normal Vitamin D Levels
Depending on all of these factors, different people will have different levels of vitamin D in their system.
According to the Skin Cancer Foundation, here’s what your vitamin D levels mean:
- Below 30: you have a vitamin D deficiency. Consult your GP about taking supplements.
- 30 to 50: you’re getting enough vitamin D for your bones and overall health.
- 50-125: you’re getting an adequate amount of vitamin D, but avoid increasing it.
- 125+: you’re getting too much vitamin D and this could cause side effects.
So Should You Keep Applying Your Sunscreen Regularly?
The answer is yes, absolutely. Because as we mentioned, according to real life studies, people who have used sunscreen consistently did not end up with lower vitamin D levels.
So don’t let the discussion about does sunscreen block vitamin D discourage you from applying SPF to protect your skin, especially in summer, when the risk of sunburns is highest.
Hopefully after reading this article you can relax, knowing that you can continue using your favorite sunscreen, and if you don’t have one yet, we have great recommendations for sunscreens for oily skin and for dry skin.
Find your match and enjoy the summer without worrying about sunburns or vitamin D deficiency!
Cover image source: Freepik