• Vitamin D is created under the skin when we are exposed to sunlight
  • New study found too much sunbathing can lower levels in the body
  • Experts think pigment released when we tan blocks production of vitamin
  • Study found people exposed to sun with very brown skin were deficient 

Madlen Davies for MailOnline

We’re told to spend short bursts in the sun to top up our body’s levels of vitamin D.

But a new study has found sunbathing for too long could actually lower levels of the vitamin in the body.

Surprisingly, people exposed to the sun on a daily basis and who have very brown skin are deficient in vitamin D, researchers revealed.

They believe the pigment released when we tan – which turns our skin brown – may block the production of nutrient in the skin.

Sunbathing for hours might lower levels of vitamin D in the body, a study has found. Researchers said the pigment released when we tan - which turns our skin brown ¿ may block the production of nutrient in the skin

Sunbathing for hours might lower levels of vitamin D in the body, a study has found. Researchers said the pigment released when we tan – which turns our skin brown – may block the production of nutrient in the skin

Vitamin D is essential for healthy bones, and a deficiency can cause bones to become soft and weak, which can lead to bone deformities. 

In children, a lack of vitamin D can lead to scurvy, while in adults, it can lead to osteomalacia, which causes bone pain and tenderness.

While we get some vitamin D from some foods, including oily fish, meat and eggs, our body creates most of it from direct sunlight on our skin. 

And a 2010 British Medical Journal clinical review found that vitamin D deficiency can increase the risk of developing heart disease, bowel and breast cancer, multiple sclerosis and diabetes.

In light of this, in the UK, groups at risk of vitamin D deficiency are given supplements.

Researchers from the University of Pernambuco Medical School wanted to know if people with tanned skin were less likely to be deficient.

As part of the study, they examined nearly 1,000 people from Recife, Brazil, who were between 13 and 82 years old.

They all were exposed to the sun every day but did not use suncream and did not take vitamin D supplements.

Researchers used the Fitzpatrick skin phototype scale, a measure used by dermatologists to rate a person’s skin type and colour.

Using this scale they assessed how different skin types responded to the UV light found in sunlight.

Vitamin D is essential for healthy bones, and a deficiency can cause bones to become soft and weak, which can lead to bone deformities. Pictured is an X-ray of a child with scurvy

Vitamin D is essential for healthy bones, and a deficiency can cause bones to become soft and weak, which can lead to bone deformities. Pictured is an X-ray of a child with scurvy

Usually, higher scores on the Fitzpatrick scale indicate a person has a darker skin tone and is more likely to tan rather than burn in the sun.

The team also calculated a ‘sun index’ for each person – by multiplying the number of hours they spent in the sun every week by the amount of their body’s skin they exposed.

Then, researchers compared people’s ‘sun index’ score and their skin type with how much vitamin D they had in their blood.

Overall, 72 per cent of people were deficient in vitamin D.

Those lacking in this nutrient tended to be older and spend less time in the sun.

However, surprisingly, they found many people with very high daily exposure to the sun also had lower than average vitamin D levels.

The study’s lead author Dr Francisco Bandeira, of the University of Pernambuco Medical School, said the findings suggest skin tanning, which occurs to protect the skin against the harmful effects of UV rays, stops levels of vitamin D rising in the blood. 

The research was presented at the annual meeting of the Endocrine Society, in Boston. 

 

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