After this early beat the heart pauses for a fraction of a second and then produces a beat

After this early beat, the heart pauses for a fraction of a second and then produces a beat that is stronger than average. The combination of the pause and the extra strong beat produces the feeling that a beat has been missed and then the heart jumps within the chest. Your description of a cough that brings things back to normal is also quite common, although it is not usually mentioned in medical textbooks. I would be interested to know if other readers have had similar experiences.HAVE YOUR SAY: READERS WRITEJF from Devon has been suffering poor hearing and from blocked Eustachian tubes:For some years now I have been suffering from a progressive deterioration in hearing due, I suspect, to advancing age. However, my residual hearing is much adversely affected by almost continual blockage of my Eustachian tubes. I am almost permanently conscious of varying pressure upon the eardrums. Yawning produces improved hearing, but for only a few seconds or minutes.

I now have digital hearing aids for both ears, but I do not seem to be able to get anyone to take the Eustachian tube problem seriously. We seem to be tackling the symptoms rather than the underlying condition.Send questions and suggestions to A Question of Health, ‘The Independent’, Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182; or e-mail health independent.co.uk. Over the past three weeks, I have taken four separate tests for food intolerance. There was no agreement between the results, except that two tests identified a sensitivity to cow’s milk The other two told me cow’s milk was fine The cost of the tests ranged from £45 to £260.

The total number of foods I was told I had a significant intolerance to was 15. The head of Allergy UK, Muriel Simmons, told me that it was unlikely this was caused by food intolerance. Two of the testers (Ian Preston, on behalf of Health Screening UK, and John Graham, the chief executive of YorkTest) told me the opposite. I am exactly the kind of person who gets tested for food intolerance, having a chronic minor complaint and an open mind about alternative medicine. On the basis of this survey of the available tests, it is clear that the opportunities for wasting money and needlessly excluding foods are many. So is there a reliable test? Is there good advice somewhere?The problem is that food intolerance is medically still an “iffy subject”, as Dr Apelles Econs, the director of three allergy clinics (two private, one NHS) and a former GP, puts it. “There is currently no reliable test for food intolerance,” he says.

“There has been plenty of research, but so far all the tests fall short of the standards of accuracy that medical tests are expected to meet.” Of the four I tried, only the YorkTest has successfully completed a clinical trial, although this is yet to be published.There is no consensus about how many people suffer from food intolerance. The British Nutrition Foundation estimates that one to two per cent of adults and five to eight per cent of children are affected Dr Econs estimates 40 per cent. Neither is it fully understood what is happening within the body, when a problem food is eaten.By contrast, food allergy is well documented. It involves an immediate, often life-threatening, reaction by the immune system when a food is eaten.Food intolerance is a separate condition. It is rarely severe and causes symptoms such as migraines, bloating, nausea, diarrhoea and chronic fatigue. It involves several different mechanisms within the body, some to do with the immune system, some not. “In the midst of this sea of variations, every Tom, Dick and Harry can claim some kind of diagnostic accuracy,” says Dr Econs.The only reliable way to find out whether you are intolerant to a food is to exclude it from your diet for four to six weeks and then reintroduce it.