How to incorporate vitamin D through foods or supplements without adding unnecessary sun exposure or compromising skin health.
The search for vitamin D often raises an uncomfortable question: how can one obtain it without exposing the skin too much? The answer does not lie in abandoning sunscreen. Nutrition, medical evaluation, and supplementation when indicated allow you to care for both needs.
Sunscreen does not block vitamin D completely
Although sunscreens reduce the UVB radiation that reaches the skin, numerous studies have shown that habitual use does not prevent the production of vitamin D.
Recent research observed that daily application of very high-SPF sunscreens can moderately lower vitamin D blood levels. However, this does not justify exposing oneself to the sun without protection, since there are other safe ways to obtain it, such as through diet and supplementation when indicated.
Each November 2 marks the World Vitamin D Day, a date that invites us to learn about its functions, the available dietary sources, and when it is necessary to resort to supplements.
What functions does vitamin D serve and how to incorporate it
Vitamin D contributes to bone health and to the regulation of the immune system. It also has hormonal activity: the body converts it into an active substance that influences gene expression and the performance of immune cells.
It is fat-soluble —it dissolves in fats— and is stored in the liver and adipose tissue. There are three ways to obtain it: cutaneous production, activated by ultraviolet B radiation; certain foods; and supplements.
Salmon and mackerel are among the fish that provide vitamin D. It can also be incorporated through fortified products, such as some milks. In these cases, checking the label helps identify which contain it.
Needs change with age and can increase in older individuals. The usual diet and the characteristics of each patient help guide professional assessment.
Sun damage can advance without causing burns
Chronic and repeated exposure to ultraviolet radiation causes actinic damage, i.e., skin damage caused by the sun. That deterioration accumulates over time and promotes both skin aging and the development of skin cancer.
Damage can arise from small, everyday doses and progress without redness or visible burns. Therefore, deliberately extending time in the sun to boost vitamin D production adds radiation and dermatological risk.
Personal history and skin condition should be part of any assessment of sun exposure. In practice, it is prudent to reduce direct sun contact between 11 a.m. and 4 p.m., seek shade, and combine sunscreen with appropriate clothing, a hat, and UV-filter sunglasses.
It is recommended to use a sunscreen with SPF 30 or higher and to reapply every two hours and after swimming. The face, neck, décolletage, ears, and hands require special attention due to their frequent exposure. These measures should be maintained year-round, even on cloudy days.
Supplementation always requires medical indication
Taking more sun exposure does not guarantee correcting a vitamin D deficiency. A clinical trial published in the journal Clinical Nutrition, conducted in young adults with vitamin D deficiency in South Korea, showed that after eight weeks, 54.2% of those who received oral supplementation reached levels of at least 20 ng/mL. In the group that was advised to expose themselves to the sun, that proportion was 12.2%.
Both interventions raised the levels, but the supplement proved more effective under the evaluated conditions. The authors noted that adherence to the solar exposure regimen was relatively low, a limitation to consider when interpreting the results.
The approach needs to consider each patient’s medical history. In individuals with melasma, photodermatoses —conditions that cause an abnormal skin response to radiation— or a history of skin cancer, even brief exposure can be counterproductive.
In those cases, individualized oral supplementation provides a means to supply vitamin D without worsening preexisting conditions.
Why taking supplements on your own is not advisable
Avoid self-medication is essential. Excess vitamin D caused by improper use of supplements can raise blood calcium levels and lead to complications, including kidney damage. The dose and duration of treatment must always be determined by a professional.
Meeting vitamin D needs and preventing sun damage are not opposing goals: they must be addressed together. Increasing sun exposure to try to correct a deficiency adds risk that can be avoided with proper evaluation.
This information is for educational purposes and does not replace consultation with a licensed medical professional.
Source: Dr. Leisa Molinari, dermatologist, specialist in skin cancer and Mohs micrographic surgery. Founder of the Skin Medical Center and Leisa Skin Science, and developer of Piel Protec. M.N. 116.628. @dra.leisamolinari
