Here the benefits of dark skin are outweighed by the need for bone-strengthening vitamin d, produced through exposure to UV rays.

这个地区人们通过照射紫外线来获取骨骼生长所需要的维他命d，所以深肤色的优势已凸显不出。

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The irony is that the same UV rays that trigger vitamin D production in your body also produce chemical changes in the skin's DNA.

具有讽刺意味的是，紫外线在你身体里产生维他命D时候同样也会改变你皮肤的DNA结构。

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She said that the use of sun creams and moisturisers with a sun protection factor also reduces UV absorption and so vitamin D production.

她说，使用含有防晒因子的防晒霜和保湿露也能减少紫外线的吸收和维生素D的合成。

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High pollen counts and - as you'd expect - high UV levels will be a feature on most days.

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Vitamin D is incorporated in the body when skin is exposed to sunlight of a certain wavelength but in the UK, during winter months, UV-B radiation can be insufficient to properly support vitamin D synthesis in the body.

BBC: Pregnant women 'ignoring vitamin D advice'