Does Sunscreen Block Vitamin D?
Sunscreen can block UVB rays, which help the body produce vitamin D.
Experts say most people don't apply enough sunscreen for it to stop vitamin D production completely.
How much vitamin D you can get from sun exposure depends on factors such as where you live, the time of day, and how much time you spend outdoors.
If you're very diligent about applying sunscreen before you leave the house, will the sun protection prevent your skin from producing enough vitamin D?
A broad-spectrum sunscreen helps block ultraviolet B (UVB) light, which can cause skin cancer. But UVB rays are also what the body uses to make vitamin D naturally. This might mean that wearing sunscreen could lower vitamin D levels, but experts say that shouldn't be a concern.
“There are multiple studies that show that regular use of sunscreen would not affect vitamin D levels,” said Henry W. Lim, MD, FAAD, a board-certified dermatologist at Henry Ford Health in Detroit, Michigan.
According to a 2019 meta-analysis published in the British Journal of Dermatology, the bulk of the research suggests sunscreen use has little to no impact on vitamin D concentration in the body.However, the researchers acknowledged that clinical trials on the impact of high-SPF sunscreens were lacking.
The FDA recommends that most adults and children use at least one ounce of sunscreen to cover their entire body.
“None of us use that much,” Lim said, which he said means people are less protected from the sun and are still able to produce vitamin D.
Related:Should You Take Vitamin D Supplements for Bone Health?
Do You Need Vitamin D Supplements in the Summer?
Although sunscreen doesn't seem to reduce vitamin D production, some health experts recommend taking a daily multivitamin or vitamin D supplement year-round just to be safe.
However, most people can get enough vitamin D through sun exposure and diet, according to Melissa Ann Prest, DCN, RDN, CSR, a Chicago-based national spokesperson for the Academy of Nutrition and Dietetics.
Salmon, trout, and halibut are some of the best dietary sources of vitamin D and many food products, like milk and cereal, are also fortified with vitamin D.
Related:Not Getting Enough Vitamin D in Your Diet May Impair Muscle Function
Most adults need 600 IU of vitamin D per day, while adults over 70 years old need 800 IU daily. It's rare to have a vitamin D overdose, but vitamin D deficiency is more of a concern.
While vitamin D screening is not always covered by insurance, Prest said people who are at a greater risk for vitamin D deficiency should get screened at their annual physical exam. These include people who don't get a lot of sun exposure, older adults, people with darker skin, and people who might not absorb vitamin D well due to gastric bypass surgery or a condition like cystic fibrosis or ulcerative colitis.
"Depending on what that level is, that's when a supplement may or may not be needed," Prest said, adding that she wouldn't recommend a supplement if someone isn't vitamin D deficient.
Since vitamin D is fat soluble, it's important to take a vitamin D supplement with a meal to increase absorption. Vitamin D2 and vitamin D3 supplements are similar in function, but Prest said that people who follow a vegan diet might want to avoid vitamin D3 since these can be made from the lanolin oil found in sheep's wool.
Related:The 9 Best Vitamins and Supplements for Skin Health
How Much Vitamin D Are You Getting from the Sun?
Multiple factors—including how much time you spend outside, the season, the latitude where you live, and the amount of melanin in your skin—all affect how much vitamin D is produced from sun exposure.
A 2017 study in Spain looked at the amount of sun exposure needed for adequate vitamin D production in a northern mid-latitude region at midday and found that 10-20 minutes was enough during the spring and summer, but it would take two hours during the winter.
"The amount of vitamin D produced is directly related to how close the sun is," said Bess Dawson-Hughes, MD, a senior scientist and director of the bone metabolism team at Tufts University. "Those who like to walk along the beach in the late afternoon won't be making much because the angle of the sun is so wide at that time of day,"
Since vitamin D is stored in the body's fat tissues, it can remain in reserve until the body needs more. People who tend to their outdoor gardens, for example, might have more vitamin D in storage, while office workers might need to increase their vitamin D intake, Dawson-Hughes said.
Lim, who advises patients on skin health, recommends wearing a hat and walking in the shade in addition to wearing sunscreen. While vitamin D is essential, having proper sun protection can reduce the risk of skin cancer, wrinkle development, and skin discoloration.
Related:The Benefits vs. Side Effects of Vitamin D
Regular sunscreen use likely won't lead to vitamin D deficiency. If you are concerned about your vitamin D levels, consider asking a healthcare provider to conduct a screening. Once you have received your results your healthcare provider can help you determine if a vitamin D supplement is right for you.