Dysbiosis - by Dr. David Dowson
1. The Normal Human Intestinal Bacteria
Normally we think of bacteria as the cause of many diseases, and it seems surprising at first that there is a vast colony of bacteria within our bodies which are necessary for life, health and even the prevention of disease. These are the so called communal bacteria which live in the gut. Their relationship with the human host is complex and not fully understood, but it is clearly a symbiotic one, where both host and bacteria mutually benefit from each other.
The human intestine, in adults, contains approximately three and a half pounds of bacteria. The nature of these varies in different parts of the intestine, and there is also a marked racial variation which reflects different dietary habits. It has been estimated that as many as 400 different bacteria are normally present, some of which are permanent, where as others are temporary visitors. To make matters more complicated, each type of bacteria has many different strains, with one strain specific to humans and others to different animals.
In addition there are other organisms, mainly yeasts, present in smaller numbers. The development of these is kept to a minimum by the bacteria present.
Despite such a wide range of bacteria there are two forms which predominate and both are permanently present in the healthy intestine. These are the bifido-bacteria and lactobacilli. The latter predominate in western races, because of the relatively high intake of milk products whereas bifido-bacteria are the dominant form in those of eastern origin.
At birth the gastro-intestinal tract is sterile, with no organisms present. Colonisation slowly develops, with proliferation of bacteria taken in the diet. The proliferating types depends on the local ecological environment - particularly the acid levels - until a stable situation is achieved. The organisms enter by the mouth, and the diet is therefore important in dictating the balance of organisms present. Breast fed babies develop mainly bifido-bacteria, whereas babies fed on formula feeds predominantly lactobacilli develop.
2. The Function of the Normal Bacteria
The presence of these bacteria is essential to health, in that animals reared in sterile conditions and with sterile intestines rapidly succumb to infection when exposed to a normal environment. It appears that the normal bacteria probably have the following functions:-
They manufacture some of the essential B group vitamins, particularly biotin, niacin, pyridoxine and folic acid.
They control the development of other potentially harmful bacteria and yeast organisms. The is achieved by the production of antibiotics and the maintenance of an acid level which discourages other organisms.
By producing the enzyme lactase, they assist in the digestion of milk based foods.
They enhance bowel function by encouraging the normal peristalsis or contraction of the intestine. Without normal bacteria the duration of digestion is much increased.
There is evidence that cholesterol levels are reduced by the normal bacteria, and some authorities claim that they have an anti-cancer effect.
They enhance the absorption of essential nutrients by producing the correct acid/alkali environment for the maximum effect of bile acids and enzymes from the pancreas.
They play a role in maintaining an adequate immune system.
3. Dysbiosis
Dysbiosis is the disturbance of the normal bacteria in the gut, with reduced levels of the essential bacteria. The concept of dysbiosis is largely ignored by the medical profession in the UK, but is widely accepted on the continent, particularly in Germany. Veterinary practitioners also recognise the significance and importance of the bowel bacteria, and preparations containing these are commonly added to animal feeds. Much evidence exists to show that dysbiosis is the underlying cause of considerable illness, not just those associated with the intestine. These conditions may be caused by the result of the dysbiosis rather than being a direct effect.
4. The Causes of Dysbiosis
The most common cause of dysbiosis - and the reason why it is so common in the west is the inappropriate use of antibiotics. Infective illnesses, even when caused by viruses, against which they are ineffective, are commonly and immediately treated with antibiotics. Whilst this may be effective in dealing with an acute bacterial infection, these so called wide spectrum antibiotics kill off a large range of bacteria, including the normal healthy bugs in the gut. This is why disturbed bowel action, particularly diarrhoea, commonly follows a course of antibiotics. Ironically the overuse of antibiotics increases the need for future antibiotics, as the dysbiosis induced by them suppresses the immune system.
Other medications enhance the development of dysbiosis. Hormones, particularly those taken to treat menopausal symptoms, appear to encourage dysbiosis and make it more difficult to treat. This only applies to hormones taken by mouth, and not those administered by an adhesive patch.
Stress, too, has a role in increasing the development of dysbiosis. This may not be a direct effect but one which results from poor dietary intake and inappropriate eating habits. Convenience foods, together with rapid and infrequent meals do not help normal bacteria to develop.
5. The Symptoms of Dysbiosis
The main symptoms of Dysbiosis are disturbed bowel action - which may be either diarrhoea, constipation or a combination of both - together with excessive wind and abdominal distension. Other symptoms may be present which are a result of the dysbiosis and which may be sufficiently sever that the underlying dysbiosis is ignored.
6. Conditions Associated with Dysbiosis
Bowel problems, such as irritable bowel, colitis and sometimes Crohn’s disease are commonly, at least partially, associated with a dysbiosis. In addition clinical experience with patients suggests that it is an important factor in other conditions, such as rheumatism, post viral fatigue, eczema, urticaria and asthma. It appears that with these non-digestive problems, the dysbiosis causes food and other allergies to develop. This probably occurs because in the presence of an imbalance of the bacteria the bowel wall becomes leaky allowing the absorption of proteins, prior to their digestion into amino-acids, which are then allergenic. As a consequence full treatment involves not only the management of the allergies, but treatment of the dysbiosis if the full cure is to be achieved.
One important and very common condition associated with dysbiosis is the incorrectly termed candidiasis. Incorrect because it is not just candida organisms, but a range of yeasts which are overdeveloped. These yeasts are normally present, but are kept under control by the healthy bacteria. In addition to the usual symptoms, as described, of dysbiosis, patients with this yeast overgrowth syndrome also complain of fatigue, a craving for sweet foods and intolerance of alcohol. Management of the condition involves firstly correction of the yeast overload with anti-fungals and dietary modification, and then the correction of the underlying dysbiosis.
7. The Treatment of Dysbiosis - The Role of the Probiotics
Clearly treatment of dysbiosis involves the replacement of the correct bacteria into the gut, but this is not as easy as it appears. Many bacteria taken by mouth do not even reach the intestine as they are killed by the stomach acid. In addition, as there are trillions of bacteria in the gut a large dose - and over a prolonged period - is necessary. The type of bacteria is also important, and depends on the patient's race and dietary habits. In these formulations the bacteria are in a dormant state, and only become active on exposure to a moist environment.
Preparations which attempt to replace the bowel bacteria are collectively know as probiotics, as they encourage, rather than discourage (as with antibiotics). To be successful a probiotic must therefore fulfil several criteria:-
1. It must contain sufficient numbers of bacteria to ensure that enough reach their destination (passing through the stomach without too great a loss)
2. The bacteria must be of types applicable to the individual, and in the correct ratio. If possible they should also be strains which are specific to the human.
3. They should be presented in an acceptable and palatable form.
4. Acid/Alkali additives should provide the optimum conditions for the bacteria to successfully colonise the gut.
Clearly a preparation which is suitable for all is an impossibility, as individuals vary in their needs according to their lifestyles and dietary habits. |
