I know this sounds very bizarre but I think I may have something called pica. As a child I would eat burned matchstick ends, which I craved, and this craving persists – even though I know it is potentially very harmful. I still also have a craving for soil, and I eat raw potato skins and coffee grounds. I'm 25 and have had benign colon polyps for five years. Could they be related to the pica?
You certainly have all the symptoms of pica, the condition where people eat bizarre items the rest of us find odd, which usually starts in childhood. Many, but not all, pica sufferers are deficient in iron stores, which can make them anaemic, and the unusual eating pattern appears to relate to the need to provide more iron than normal food can supply. Colonic polyps can, by bleeding tiny amounts each day, lead to iron deficiency, so theoretically there could be a link between them and your symptoms. Do please see your doctor; you may find that all you need is iron replacement – but the treatment may be a bit more complicated.

My husband ridicules me for my use of sun block all year round. For cosmetic reasons I started using factor 15 in autumn and spring, and factor 50 in summer. Is this too much?
He is not right to ridicule you, but he is right that you are overdoing the sun protection. It's good to feel the sun on your skin, not just because it makes vitamin D, but also because it is so enjoyable. So a few minutes in the sun every day without block is fine and pleasant and will make all the vitamin D you need. Recently we have begun to realise that vitamin D isn't simply the key to making strong bones: it also may protect against some internal cancers. The trick is to limit your exposure to avoid getting burned. In the autumn and spring you probably don't need block, except on exceptionally hot and cloudless days around noon. That's pretty rare in our climate.

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