Do you suffer from London 'Disease'?

Do you constantly have a cold, eczema, psoriasis, flu or yeast overgrowth? If so, according to one body of opinion, you have "London Disease" (LD), a degradation of the immune system caused by London life.

It's the latest in a long line of "lifestyle syndromes" and, like chronic fatigue, burn-out, attention deficit disorder and stress, many medics believe the condition is non-existent. So are there minor body problems that naturally result from living at city pace, or is this a real illness that should be taken seriously?

Dr Gillian McKeith, a London-based nutritionist specialising in problems with the immune system, has " identified" LD and claims one in two of us has it. "The medical profession needs to take this seriously," she says. "I've seen the incidence of it increase in the past four years and it could cause major health problems soon." Those major problems, she says, include migraines, bowel disorders and arthritis, but the main worry is complete exhaustion.

She explains that the condition stems from a bad diet (eating too much cooked and/or processed food) and/or appendix removal, and both lead to poor digestion, which in turn leads to the reduction of enzymes required to support the immune system. When functioning at a low capacity, the immune system can't defend us against pollution and stress, and as a result we're more susceptible to infections; the immune system also attacks itself, which can cause eczema or psoriasis.

The cure, she says, is to eat more raw food and take supplements containing sulforaphane, a powerful antioxidant found in broccoli that stimulates the production of the enzymes that LD leaves us without.

Independent trials are now being carried out on the condition. "I've seen the results in my patients, so I know that the trials will prove I'm right," she says. "The medical profession ignores the immune system - the amount of research that's been done into it is small. I've done the work and hopefully can help people with it." She plans to do that by approaching the NHS with the results when the trials are completed, but will her findings be welcome?

"If the research stands up, then yes, of course, but I don't think it will," says Dr Richard Smith, editor of the British Medical Journal. "LD sounds like utter nonsense. First, if someone claims that a condition such as that affects half the city, I'd question it. I live in London and half the people I know don't regularly have colds, flu and eczema. Second, I'm not aware that Londoners have a particularly higher incidence of infection - if they do, it's because they're rammed together on the Tube and it spreads a lot quicker. Plus, immunology is not underresearched - it's very well investigated. One British medic won a Nobel Prize for research into it."

Despite this, Smith does accept that some of what McKeith says is correct. "Her argument is mixed," he says. "The appendix removal bit is nonsense. She's right that the wrong diet can lead to bad digestion, though I can't see how that would cause the problems she claims it does, and pollution isn't great either, though it's usually associated with respiratory, not immune, problems."

But nutritionist Ian Marber, author of Food Doctor in the City, thinks McKeith is on the right track. "I think her diet recommendations are good. However, none of this is new - we all know that an antioxidant supplement, backed by generous portions of fruit and vegetables and a balanced diet, is best. I think that saying one in two Londoners has the symptoms she describes is very excessive, but I do come across those problems in cities and think they often relate to bad diet, stress and pollution." The effects of stress and pollution on the body have not been extensively researched, he explains.

"The key point about LD is that it's not a disease," says Smith. "If it exists, it's a problem that results from city life. By saying those problems are illnesses, people like McKeith scare the public and play havoc with the health service. This sort of thing is happening increasingly. People are seeking medicine to solve the toils of everyday life, and that's wrong. We desperately need to establish a better definition of illness - the problems that should be taken to the doctor and those that shouldn't; the problems that should cause concern and those that shouldn't."