Is it true that if you have asthma and go to live on a mountain, your condition could be cured? How high up the mountain would you have to go? And is it the pure mountain air that does the trick?

You would have to go above 5,000ft, so the nearest mountains for someone in Britain are probably the Alps. The mountain air isn't the main reason. Most asthma in Britain is caused by a reaction to house dust mites - and they don't live at altitudes above 5,000ft. So if house dust is the cause of your asthma, it's a fair bet that you would improve by living at altitude. Don't go too far up, though: above 10,000ft you may well have trouble with low oxygen levels and cold air, both of which may stimulate your asthma.

Does eating fish really help the brain?

A few years ago I would have said that we really don't know. Then a Chicago study claimed that if you eat two or more fish meals a week, your rate of decline in brain power with age is slower than the usual by between 10% and 15%. Fish-eaters' heart rates were slower, too, than those of non-fish-eaters. How much reliance can you put on one study? I'm not sure, but I don't know of other studies that suggest the reverse - that eating fish harms the brain - unless the fish are caught in places where the sea contains a lot of man-made pollution (such as mercury in the Sea of Japan).