Controversy

Photoprotection and vitamin D: how can we sunbathe safely without falling short

Photoprotection is one of the most important measures for preventing cumulative sun damage, premature skin aging, and skin cancer.

But a reasonable question often comes up: if we protect ourselves a lot from the sun, can we develop vitamin D deficiency?

The practical answer is that it is possible to maintain good photoprotection without giving up adequate vitamin D levels. The key is understanding that we do not need to burn, tan, or spend a long time exposed to the sun in order to synthesize vitamin D.

Key point: the goal is not to avoid the sun at all costs, but to avoid sun damage. Exposure should be brief, gradual, adapted to skin phototype, and always avoid sunburn.

Why is photoprotection so important?

Ultraviolet radiation is one of the main factors involved in skin cancer. It also plays a very important role in photoaging: spots, wrinkles, loss of elasticity, and changes in skin texture.

That is why the current photoprotection message should not focus only on “putting on sunscreen.” Sunscreen helps, but it is neither the first nor the only measure.

Modern photoprotection is based on a combination of strategies:

1. Avoid intentional sun exposure. There is no such thing as a healthy tan.
2. Seek shade. Especially during the middle hours of the day.
3. Wear clothing, a hat, and sunglasses. Physical measures are very effective.
4. Apply sunscreen. Especially on areas that cannot be covered.
5. Adapt exposure. According to the ultraviolet index, the season, and skin phototype.

There is no such thing as a “healthy tan”

A tan is not a sign of health. It is a defense response of the skin against the aggression caused by ultraviolet radiation.

For this reason, both intentional tanning and UVA tanning beds should be discouraged. Repeated exposure increases cumulative skin damage and raises the risk of precancerous lesions and skin cancer.

In practice: if the skin has burned, exposure has been excessive. But even when there is no visible sunburn, cumulative sun damage may still occur.

What is the best way to protect yourself from the sun?

The first measure should not be sunscreen, but reducing direct exposure when the risk is high.

• Seek shade, especially during the middle hours of the day.
• Wear a wide-brimmed hat.
• Wear certified sunglasses.
• Use clothing that covers the skin, preferably made of dense fabric or with UPF protection.
• Apply broad-spectrum sunscreen to exposed areas.

Sunscreen should cover both UVB and UVA. In general, high or very high factors are recommended, such as SPF 30, SPF 50, or SPF 50+, depending on the context.

Practical guide to photoprotection

The ultraviolet index: a very useful tool

The ultraviolet index, or UVI, indicates the intensity of UV radiation at a given time and place.

It is a simple tool for deciding when we should increase protection. As a practical rule, when the UVI is equal to or greater than 3, photoprotection measures should be used.

The higher the UVI, the more important it is to reduce direct exposure and combine shade, clothing, and sunscreen.

In summer, the safety margin can be very narrow

With a high UVI, a person with a low phototype can burn in less than 20 minutes if they are not protected. That is why it is not advisable to wait until heat or redness is noticed before taking action.

The other factor: our skin type

The other factor to take into account is skin type: the lighter the skin, the more photoprotection it requires. The Fitzpatrick classification can help guide us.

What about vitamin D?

Vitamin D is important for bone health and has other functions in the body. Some of it can be obtained through sun exposure, since the skin synthesizes it when it receives UVB radiation.

The problem is that UVB radiation is also responsible for sunburn and contributes to skin damage.

Therefore, the question should not be “how much sun do I need to tan?”, but “how much brief and safe exposure may be enough?”.

Important point: the dose needed to synthesize vitamin D is significantly lower than the dose needed to produce a sunburn.

How much sun exposure would be enough?

There is no universal figure. It depends on skin phototype, season, time of day, latitude, age, exposed body surface area, and other factors.

As a general guide, when exposing small areas such as the face and hands during the middle hours of the day, approximate times vary greatly depending on phototype and season. Another recommended strategy is to expose areas of skin with less chronic sun damage (abdomen, thighs), to avoid accumulating more radiation.

Phototype	Usual response to the sun	Summer	Winter	Practical comment
I-II	Very fair or fair skin; burns easily	6-7 minutes	17-21 minutes	Higher risk of sunburn; physical measures should be emphasized
III	Intermediate skin; sometimes burns	8 minutes	25 minutes	Tanning should not be used as a goal
IV	Brown skin; rarely burns	13 minutes	38 minutes	Less sunburn does not mean absence of sun damage
V-VI	Dark or Black skin; burns very rarely	17 minutes	Up to 51 minutes	Higher risk of vitamin D deficiency; individualize

Important: these times are approximate and should not be interpreted as a universal recommendation. Sun exposure should be individualized and should never cause sunburn.

Does sunscreen cause vitamin D deficiency?

This is a common question.

Under ideal laboratory conditions, perfect use of sunscreen could reduce cutaneous vitamin D synthesis. But in real life, many people do not apply enough, do not reapply correctly, or leave areas uncovered.

Therefore, in most healthy people, regular sunscreen use is usually not the main cause of vitamin D deficiency.

In practice: if confirmed vitamin D deficiency exists, the safest approach is usually to correct it with diet or supplements, not by recommending more unprotected sun exposure.

When should supplementation be considered?

If vitamin D deficiency is confirmed, the most prudent approach is usually not to recommend more unprotected sun exposure. In general, it is preferable to correct it through diet, oral supplements, or the regimen indicated by a healthcare professional.

This is especially important in:

1. People with significant chronic sun damage, actinic keratoses, or a previous history of skin cancer
2. Patients at high risk of skin cancer: immunosuppressed patients (especially transplant recipients)
3. People with photosensitive diseases, especially lupus erythematosus.
4. Patients taking photosensitizing drugs

Recommended practical strategy

Step 1. Check the UV index

If the UVI is 3 or higher, protection is advisable. The higher the index, the more important shade, clothing, and reducing exposure time become.

Step 2. Prioritize shade and clothing

Clothing, hats, and sunglasses are very effective measures and do not depend on reapplication.

Step 3. Use sunscreen where clothing does not cover

The face, neck, neckline, ears, hands, and other exposed areas are often easily forgotten.

Step 4. Reapply if exposure continues

Sunscreen should be reapplied, especially after swimming, sweating, friction, or prolonged exposure.

Step 5. Avoid sunburn

Sunburn is a clear sign of excessive radiation. It should not be part of any health strategy.

Take-home message

Protecting yourself from the sun does not mean living indoors or being afraid to go outside. It means enjoying the outdoors with common sense: avoiding sunburn, using the UV index as a guide, prioritizing shade and clothing, and applying sunscreen to exposed areas.

Final summary

• There is no such thing as a healthy tan.
• Photoprotection begins with shade, clothing, a hat, and sunglasses.
• Sunscreen is an essential complementary measure on exposed areas.
• When the UV index is 3 or higher, protection is advisable.
• Vitamin D synthesis requires less radiation than the amount needed to burn.
• Exposure time depends on phototype, season, and time of day.
• In children and high-risk patients, protection should be maximized.
• In darker skin, photoprotection may also be important, especially if there are spots or hyperpigmentation.
• If there is vitamin D deficiency, it is usually preferable to consider supplementation before increasing unprotected sun exposure.

The key is not to avoid the sun, but to avoid sun damage.