Does wearing sunscreen cause vitamin D deficiency?

 Does wearing sunscreen cause vitamin D deficiency?

We use sunscreen to protect our skin from sun damage. Many people worry that it blocks the body’s production of vitamin D and weakens bones. Is this concern scientifically true? Or is it just a partial myth?

According to experts and recent studies, sunscreen provides strong protection against skin cancer, and regular daily use does not significantly reduce vitamin D levels. But in a country like Nepal, where sunlight is abundant but vitamin D deficiency is seen in 40-70 percent of the population, it is very important to maintain the right balance.

Vitamin D for bones

Vitamin D is an essential nutrient for the body. It is a key element in strengthening bone and tooth health, increasing the absorption of calcium and phosphorus,s and protecting against problems such as osteoporosis.

In addition, vitamin D strengthens the immune system, protects against infections, reduces muscle pain and fatigue, and improves brain health and mood.

When the skin is exposed to the sun's UVB rays, a substance called 7-dehydrocholesterol in the skin produces vitamin D3, which the body can actively use. In Nepal, this deficiency is more common in women, people who spend more time indoors, and those living in polluted cities.

Studies on whether vitamin D protects against cancer are mixed. Some studies have shown that vitamin D can help repair DNA damage from UV rays, reducing the risk of non-melanoma skin cancers, basal cell carcinoma, and squamous cell carcinoma.

Basal cell carcinoma is the most common type of skin cancer, while melanoma is the most dangerous. However, it is not yet fully proven that vitamin D completely protects against cancer, and more research is needed. Although some studies have linked high vitamin D levels to skin cancer, this may be primarily related to sun exposure.

The relationship between sunscreen and vitamin D

Understanding the relationship between sunscreen and vitamin D is twofold. When skin is exposed to sunlight, vitamin D is produced. Sunscreen blocks UVB rays, which can affect vitamin D production. In laboratory tests, the full application can block vitamin D production. But in real-life field trials and observational studies, its effect has been minimal. Many studies have shown that regular daily use does not significantly reduce vitamin D levels.

Because people do not apply sunscreen fully or correctly every time, some UVB rays reach the skin. Although some recent studies have shown that daily use of high SPF may slightly increase the risk of deficiency, experts emphasize that staying in the sun without sunscreen is the main risk factor for skin cancer.

Why is vitamin D deficiency so common in Nepal?

Despite the abundance of sunshine, studies have shown a deficiency in 42-70 percent of people. The main reasons include the modern lifestyle of staying indoors, the habit of covering the body with clothes and scarves, etc. Similarly, air pollution reduces UVB rays, and there are also reasons for eating less food, such as fish, eggs, and milk. This problem is even more severe in hilly and mountainous areas.

There are other options besides sunlight to meet the deficiency of vitamin D in the body. Short periods of safe sunlight help a lot. In Nepal, you can sunbathe by keeping your hands, face, and legs exposed for 10-20 minutes between 10 am and 3 pm. It is better to apply sunscreen after sunbathing.

Vitamin D can also be obtained from food. Fish, egg yolks, sun-dried mushrooms, milk, yogurt, and fortified foods. They are easily available in Nepal. Eating these foods 2-3 times a week will replenish vitamin D. If the deficiency is severe, supplements can be taken on the advice of a doctor. Supplements should only be started after a blood test.

Important things to note

When going out in the sun, you should wear sunscreen with an SPF of 30 or higher and reapply every 2 hours. Using clothing, hats, umbrellas, and shades can help protect against skin cancer.

You can get a short 10-20 minute morning sun exposure, but you should avoid prolonged sun exposure between 11 and 3 p.m. Especially women, the elderly, and those who live indoors should consult a doctor regularly to check their vitamin D levels.