Monica addresses a listener's concern about sunscreen inhibiting vitamin D production. While sunscreen can reduce the skin's ability to produce vitamin D, it is essential for protecting against UV-related skin damage. She explores how to balance safe sun exposure and adequate vitamin D intake, emphasizing that we can get vitamin D through various sources, such as food, supplements, and responsible sun exposure. Ultimately, finding a middle ground ensures both skin protection and sufficient vitamin D levels for overall health.
How do we balance the need to protect our skin from UV rays with our body’s need for vitamin D?
Mentioned in this episode:
DMinder (iOS/Android) - http://dminder.ontometrics.com/
Vitamin D and UV Tracker (Android) - https://play.google.com/store/apps/details?id=com.uv.vitamindtracker
SunDay Vitamin D and UV Tracker (iOS) - https://apps.apple.com/us/app/sunday-vitamin-d-uv-tracker/id1133953409
Hello and welcome to the Nutrition Diva podcast, a show where I help you make sense of the latest nutrition news, headlines, and trends and answer your questions about nutrition.
Today’s listener question is about vitamin D and sunscreen, "My mother refuses to wear sunscreen because she says they are all toxic and prevent us from getting vitamin D. What is your stance on this?"
Given all the purported benefits of vitamin D, you might have also wondered how to balance your dermatologists’ advice to wear sunscreen at all times with news reports about widespread vitamin D deficiency. Let’s talk about how to thread that needle.
It's true that sunscreen does inhibit the skin's ability to convert UV rays into vitamin D. However, it also blocks those same UV rays from damaging the collagen in our skin (which leads to wrinkles) and from harming our DNA (which increases the risk of skin cancer).
So, how do we strike a balance? Well, it doesn't have to be an either-or situation. We can be judicious about both our sun exposure and our sunscreen use to maximize vitamin D production while still protecting our skin.
But before we get into the specifics of how to do that, let's take a step back and look at what vitamin D is and why it's so important.
Vitamin D is unique in a couple of ways. First, it actually functions more like a hormone than a nutrient, regulating the secretion of other hormones such as parathyroid hormone (which controls calcium levels in the blood). In fact, vitamin D is ultimately converted by the kidneys into a steroid hormone!
Vitamin D is found naturally in a few foods, including cod liver oil, oily, fish, liver, and egg yolks, and mushrooms. Mushrooms are the only plant-based foods that naturally contain vitamin D and it’s because mushrooms produce vitamin D when exposed to sunlight, similar to the way human skin does.
In fact, here’s a cool tip: You can increase the amount of vitamin D in your mushrooms by placing them in direct sunlight briefly–15 to 30 minutes will do. (It won’t work through a window.) And you can maximize the vitamin D production by placing the mushrooms gills side up.Fortified foods–including milk and nondairy milk alternatives, orange juice, and breakfast cereals–are another way that people commonly get vitamin D from diet.
But here’s the other thing that makes vitamin D a little different than any other nutrient I can think of is that food wasn't really meant to be our primary source of this nutrient. Sunlight was. Our skin produces this vitamin when it is exposed to UV rays.
This explains why people originating from different regions of the globe have varying skin colors. Those whose ancestors came from areas closer to the equator tend to have darker skin, which acts as a natural sunscreen against stronger UV rays while still allowing for sufficient vitamin D production. Conversely, those from northern or southern regions have lighter skin to allow more UV penetration, ensuring adequate vitamin D synthesis even with weaker sunlight.
Now, you might be wondering, if our bodies are so well-adapted to produce vitamin D from sunlight, why is vitamin D deficiency so widespread? Several factors contribute to this:
1. We spend more time indoors, limiting our sun exposure.
2. When we are outdoors, we often cover most of our skin with clothing.
3. We use sunscreen, which, while protecting against skin damage, also blocks vitamin D production.
4. Many dark-skinned individuals now live far from the equator, where they may not get enough UV exposure to produce sufficient vitamin D.
As a result, vitamin D deficiency has become increasingly common, particularly among children, the elderly, and those with dark skin. And research has linked low vitamin D levels to a variety of health conditions, including heart disease, diabetes, depression, autoimmune diseases, osteoporosis, several types of cancer, and even obesity.
However, it's important to note that the relationship between vitamin D and these conditions is not fully understood. In many cases, it's unclear whether low vitamin D levels cause these health problems or if the health problems lead to low vitamin D levels. Or, perhaps, whether our vitamin D levels serve as a proxy for other factors that influence our risk.
For example, people with high vitamin D levels may have lower levels of depression but that may be primarily due to the effect of sunlight on the amount of neurotransmitters produced in the brain and not the increased vitamin D production that the sunlight might also provoke. Increasing vitamin D levels (without sun exposure) would therefore not be very likely to help.
And this is why the results from a wave of large research trials on vitamin D supplementation as a hedge against everything from osteoporosis to cancer to cardiovascular and auto-immune disease have been a little disappointing, yielding only modest benefits or inconclusive results. Apparently, vitamin D pills are not the safe, cheap, and easy cure-all that many had hoped it might be.
All the more reason to find a way to find a reasonable balance between enabling natural vitamin D production in the skin and protecting our skin from damage and aging.
The amount of sunlight needed to produce adequate vitamin D varies greatly depending on factors such as time of year, geographic location, skin color, weather conditions, and time of day. For example, here in Baltimore, on a cloudless July day at noon, I'd only need to spend five minutes with my face, hands, and arms exposed to produce 25 mcg (1,000 IU) of vitamin D. If it were November, I'd need to stay out about half an hour. If it were November, and I were black, it would take an hour and a half.
To help determine your specific needs, you can use online calculators or smartphone apps that take these factors into account. I'll include links to some options in the show notes. These tools can help you balance skin protection and vitamin D production by estimating how much sun exposure might be beneficial before it makes sense to cover up.
Of course, the best way to prevent skin aging and skin cancer when you're older is to be diligent about protecting your skin when you're young. Although those wrinkles or basal cell carcinomas generally don't appear until the second half of life, most of the damage is done in the first half.
The risk of vitamin D deficiency, on the other hand, is much higher when we're older. So it might make sense to back off the sunscreen a bit more as we age, especially if we live in areas or have lifestyles that don't provide a lot of exposure.
The recommended dietary intakes for vitamin D actually assume that diet (as opposed to sun exposure) will be your primary source of vitamin D. Current recommended daily intakes for vitamin D are 600 IU for adults up to age 70, and 800 IU for those over 70. And recent dietary survey data suggests that fewer than 5% of American and Canadian adults are ringing that bell.
If you're concerned about your vitamin D levels, you can ask your doctor for a blood test. If your levels are low, your doctor might recommend supplements.
As for sunscreen being toxic, it sounds as if this listener’s Mom came across some sources that blew the dangers way out of proportion–as often happens online. Here’s the scoop: No toxic or other harmful effects have been observed in people applying sunscreen to their skin, even after decades of use. (Drinking it or injecting it into your body, on the other hand, are not recommended.)
The harms to wildlife and aquatic ecosystems, such as coral reefs, are certainly more of a concern and can be largely minimized by opting for mineral based sunscreens rather than chemical sunscreens. You can also opt for SPF-rated clothing in lieu of sunscreen.
To wrap up, while vitamin D may not be the cure-all that some have claimed, ensuring adequate levels is crucial for overall health. Whether you choose to get your vitamin D from sunlight, food sources, or supplements, it's important to find a balance that works for you. And remember, it doesn't have to be all or nothing when it comes to sunscreen use and vitamin D production. With a little knowledge and planning, you can protect your skin and maintain healthy vitamin D levels.
That's all for this episode. If you have any questions or topics you'd like me to cover in future episodes, you can email me at nutrition@quickanddirtytips.com You can also leave me a message at 443-961-6206
I’d also like to invite you to check out my other podcast. It’s called the Change Academy, where we explore the art and science of creating positive behavior change, both in our own lives, and in our workplaces and communities. You can find it on all the major podcast platforms. Just search for Change Academy.
Nutrition Diva is a Quick and Dirty Tips podcast. Our team includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings, and Morgan Christianson.
That's all for this episode. Thanks for listening! I'll see you next week.