Every other popular health book these days seems to contain the world "detoxification". We are urged to change our diet, fast or purge our systems to facilitate internal "cleansing".
In fact, recent scientific research suggests that many old ideas about the relationship between nutrition, the digestive system and disease, may be at least partly true.
The research centres on the role of the bowel flora the "'bugs" that live in the large bowel or colon in all of us. In a healthy bowel, billions of bacteria averaging a total of around four pounds in weight act as a kind of living sewage disposal system, breaking down the remnants of our food, and producing immune secretions and nutrients as by products of the process. In a healthy bowel, most of these bacteria are "good guys" such as those of the family known as "lactobacilli", holding the 'bad guys" including pathogenic bacteria, viruses and fungi in check.
The theory has it that if the balance of bugs in the bowel is knocked out for some reason, the "bad" guys can get the upper hand, leading to the production of harmful toxins in the bowel, and possible invasion of the body from an infectious "pool" of viruses and hostile bacteria resident in the gut all of which adds up to what could reasonably be described as immune deficiency.
Conventional concepts of immunity start at the bowel wall, and work inwards, not recognizing the contents of the bowel as a part of the immune system.
Nevertheless, Dr Alan Ebringer at the Middlesex Hospital has discovered that ankylosing spondylitis a painful arthritic disease resulting in progressive stiffening of joints is caused by a particular bacterium which lives in the bowel and feeds off carbohydrate residues. The bacterium resembles a particular type of body tissue, so when it enters the bloodstream an "auto immune" reaction in which the body attacks itself is triggered, causing inflammation and symptoms. Patients with this condition improve dramatically when put onto a low carbohydrate diet. Some doctors now believe that other "auto immune" diseases, such as motor neurone disease, myasthenia gravis, rheumatoid arthritis and some forms of diabetes, could be triggered in a similar way.
The example of ankylosing spondylitis lends powerful support of the notion that what goes on in the bowel can cause symptoms elsewhere in the body one which many doctors still find hard to accept.
Doctors at Addenbrooke's Hospital, Cambridge, have taken the first steps in redefining the term "food allergy" in terms of changes in the bowel flora. True food allergy is caused by a usually rapid immune mediated response to an offending food and is probably quite rare. Food intolerance, on the other hand, tends to be a much slower reaction hours or even days and may involve a food which is eaten regularly and in quite large amounts, like wheat or dairy products.
At Cambridge, a relationship has been established between food intolerance and the bowel flora particularly in patients with irritable bowel syndrome.
It is thought that symptoms may be brought on by shifts in the population of bacteria in the bowel, as particular foods favour the proliferation of particular bacteria.
The implications of this work are that if the reason for these imbalances in the bowel flora can be found, and the imbalances corrected, a whole range of chronic diseases previously though to be unconnected may be successfully treated.
Practitioners of natural medicine, including some today who use "fringe" methods such as colonic irrigation and enemas to wash out the bowel as part of the treatment of any chronic illness, believe that imbalances occur because the bowel quite simply becomes "clogged up" with mucous and old faecal debris and is unable to eliminate efficiently. As one famous naturopath put it: "death begins in the colon.
The author of The Allergy Handbook (Thorsons) and a forthcoming book about brain allergies.