• Question: why do some people, when their sun bathing, go red and others brown? xxx

    Asked by sophiecousins to Vicki, Keith, Hywel, Emma, Alastair on 17 Jun 2010 in Categories: .
    • Photo: Alastair Sloan

      Alastair Sloan answered on 17 Jun 2010:

      Hi Sophie

      The redness is actual skin damage and burning. When you go brown or get a tan, it is the skin’s response to the UV from the sunlight. The UV causes the skin to make a brown pigment called melanin which protects the skin and gives you a tan. When you go red, you have burnt yourself, even if only slightly

    • Photo: Vicki Stevenson

      Vicki Stevenson answered on 17 Jun 2010:

      HI Sophie
      Your basic skin colour is dependent on the amount of melanonin in your skin – the more melanonin the darker your skin. The melanonin absorbs ultraviolet rays which cause sunburn (going red).
      Your skin can generate melanonin, but some generate more than others.
      The danger of having dark skin is that it cuts down asorption of vitamin D if you’re not in an area with very strong sun.
      I go red very easily which can be frustrating, but I just have to remember to put on sunscreen.

    • Photo: Keith Brain

      Keith Brain answered on 17 Jun 2010:

      Some of this has to do with the amount of melanin, or pigment, is our skins, which absorbs some of the light and so protects the skin. However, I think you’ve made a good observation – even in people with the same skin colour, some will go red, and some brown. You have me stumped!

      If I had to have an educated guess (lets call it a hypothesis!) I’d say that people’s immune systems differ, so that some will burn and others will tan. Could this be tested? Yes, I think so, but it would be very difficult. We could take people prior to a bone marrow transplant (where all of their immune cells are destroyed, ready to be replaced by a new set taken from a donor) … We could see whether they tan or burn … Then they have their transplant … then, once they’d recovered we could test them again and see what happens! We’d need to do this lots of times to be sure we had the right answer, but it give us answer. Of course, you’d have to wait until the people were going to have the transplant for a good reason – it wouldn’t be ethical to do the experiment otherwise.

      I’ll have to think about a simpler method!

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