By John Ellerman BSc, MASM, Consultant Microbiologist for ProGood Pty Ltd
The bacteria that live within our gastrointestinal tract have dramatic impacts on health. They make up 90% of the cells in our body (yes, we are only 10% human by cell count) and contain 99% of our genes! They help us digest our food and manufacture a range of compounds that can be either beneficial or bad for us. They also communicate with our immune system in ways that can be either good or bad, depending on the type of bacteria present.The overuse of antibiotics has led not only to the emergence of antibiotic-resistant pathogens but has also done considerable damage to our intestinal bacteria, with dire consequences for a vast and growing number of people.
The Small Intestine: Nutrient Absorption and Immune System
The small intestine, situated between the stomach and the colon, has an enormous surface area because of folds and the presence of villi which are finger-like projections into the lumen (the space inside). This surface, which can be the area of a tennis court, enables the absorption of small nutrient molecules such as sugars, amino acids, vitamins and minerals but is easily compromised if too many bad bacteria are present. A healthy small intestine is inhabited largely by streptococci and lactobacilli. These bacteria are closely related to yogurt cultures and are non gas-producing, relatively non proteolytic (i.e. non protein-splitting) bacteria that survive mainly by digesting various sugars. They also inhibit bacteria that try to invade their territory but are very sensitive to antibiotics. When we take an antibiotic we risk totally wipe them out and in many cases their place is taken by bacteria that normally inhabit regions either higher or lower in the gastrointestinal tract (GIT). This phenomenon is now know as Small Intestinal Bacterial Overgrowth (SIBO), though the yeast, Candidaalbicans, may also be involved in some cases. Unfortunately these invaders are often proteolytic gas producers and when we feed ourselves we feed them and they produce gas which manifests as bloating and often as gastric reflux as the gas forces stomach acid up the oesophagus throat). Their proteolytic enzymes attack the very fragile wall of the small intestine, destroying the villi and making the gut permeable to large food molecules and bacteria, both of which can translocate into the blood stream.
Food Sensitivities and Autoimmune Diseases:
When the surface of the intestine is damaged by bad bacteria it is as if a sledge hammer has been taken to a brick wall and the gut now becomes “Leaky”. When large protein molecules like gluten or casein translocate into the blood stream the immune system thinks we are being invaded by viruses or bacteria and produces an immune response which makes the person feel ill whenever they eat foods containing those compounds.
When bacteria go through the intestinal wall and into the bloodstream the immune system detects the invasion by sensing unique molecules called lipopolysaccharides in the bacteria cell wall. It then makes antibodies to structures that are on the outer surface of the bacteria as well as to internal cellular components. If these structures mimic structures somewhere in the individual’s body then these antibodies also attack them. The result is an autoimmune disease. In some cases the trigger molecules have been linked to certain bacteria. In heart disease, one of the chief suspects is Chlamydia pneumoniae which has a myosin mimic on its outer surface. Myosin is prevalent in the artery wall and antibodies to that molecule are thought by some to be the cause of the formation of arterial plaque. Ankylosing Spondylitis (arthritis of the neck) is possibly being triggered by the presence of a molecule on the surface of a bacterium called Yersinia enterocolitica and other bacteria that mimics a protein in the joints of the neck. And the anti-DNA antibodies that are responsible for Systemic Lupus cross-react with a part of the DNA of E. coli called the Lac7 gene, suggesting a possible causal link.
Situated between the villi are dome-shaped structures called Peyer’s Patches which are receptors for the immune system. If bad bacteria stick to them they increase inflammation and reduce resistance to infection. If good bacteria stick to them, the opposite happens. Inflammation is a major component of many disorders that people suffer from. It has even been discovered that if you have a chronic source of inflammation somewhere in your body then you are 50% more likely to suffer from major clinical depression (because the brain gets inflamed) or from lower back pain. Inflammation is also a major component of conditions such as asthma, hay fever, eczema and other skin conditions.
Inflammatory Bowel Diseases (Crohn’s and Ulcerative Colitis) are the combined result of the presence of a cluster of defective genes which render the sufferer unable to control inflammation and the inflammatory effect of certain gut bacteria that would be kept under control in a normal person.
Diarrhoea and Constipation:
Diarrhoea is the result of the body trying to flush out irritating bacteria by pumping in water. Constipation, on the other hand is often due to the presence of too many neurotoxin-producing bacteria such as E. coli and Clostridia. The neurotoxin paralyses the nerves responsible for controlling bowel motility, the peristalsis that pushes the food along in the intestine. Both these conditions can be controlled by the administration of probiotic cultures at an appropriate level. The direct physical effect of fibre in stimulating peristalsis is also a factor that is often involved.
Dysbiosis, Depletion of the Microbiome and the Probiotic Myth:
Dysbiosis is simply the presence, in the gut, of too many bad bacteria; an imbalance between good and bad bacteria. It is often the result of antibiotic use but can be caused by having been born by caesarean section because the baby does not pick up the bacteria present in the mother’s birth canal and these are basically gut bacteria and critical to the baby’s wellbeing.
The breast has been shown to harbour a range of bacteria that are also important for gut colonisation, hence the significance of breast feeding.
Antibiotics have been shown to permanently deplete the range of bacteria in the gut (the microbiome). And contrary to popular belief, it is not possible to replace, with a probiotic, those species that have been wiped out. There are two reasons for this. The first is that, shortly after birth, bacteria called “Segmented Filamentous Bacteria” set up residence on the Peyer’s Patches and suppress the immune system to prevent it from rejecting the bacteria that we have obtained from our mother. This makes the baby temporarily susceptible to infections but enables the immune system to educate itself as to which bacteria it should tolerate and nurture for the rest of that individual’s life. Unfortunately this means that it will, in the future, reject probiotics too. The second reason is that the good bacteria that have been wiped out are usually not the types that have been recognised as probiotics and they cannot be supplied by law. The only way to effect a change with probiotics is to administer them in overwhelmingly high cell numbers (in the trillions) and to continue to top them up on a daily basis.
Probiotics, Prebiotics and Synbiotics:
Prebiotics is another name for fibre and in particular, fibre that feeds probiotic (good) bacteria.
Combinations of probiotics and prebiotics are called “synbiotics” because of the synergy that occurs as the prebiotics feed the probiotics and cause them to multiply to higher levels in the GIT.
I was on the Management Committee of a Federally funded Cooperative Research Centre (CRC) for Food Industry Innovation which was directed by Professor Noel Dunn at the University of NSW. It included CSIRO scientists, led by Dr Martin Playne at the Division of Dairy Research, as well as industry scientists from Mauri Laboratories (producer of the cultures and led by me) and Starch Australasia (producers of prebiotic Hi-maize resistant starch and led by Dr Ian Brown).
The CSIRO scientists were isolating and screening large numbers of probiotic cultures and a major criterion was the ability of the cultures to inhibit bad bacteria such as E. coli, Salmonella, Listeria, etc. This gave rise to a range of probiotics including Lactobacillus acidophilus LAFTI strain L10 and Bifidobacterium lactis LAFTI strain B94. Their work has also been mirrored by a group at the NSW Department of Primary Industries, led by Dr James Chin in collaboration with Kevin Healey at International Animal Health Products which confirmed the superior efficacy of these strains but also demonstrated one particularly unexpected result: About a third of the strains of so-called “probiotics” on the Sydney market actually stimulated pathogens, rather than suppressing them. “Oils definitely ain’t oils”!
In parallel to the work at the CRC work on prebiotics was being conducted at CSIRO Division of Human Nutrition under Dr. David Topping. In an experiment conducted by Dr Anthony Bird, pigs were fed normal starch, resistant starch or fructooligosaccharide (FOS), or combinations thereof. It was found that the level of Bifidobacteria in the pigs (as measured in their faeces) was increased five-fold when FOS was fed to them and more than ten-fold when resistant starch was fed to them but the interesting thing was that when they were fed a combination of both, the levels of Bifidobacteria increased nearly 50-fold! Dr Bird told me personally that if the same experiment was conducted in humans he would expect that there could be as much as a 200-fold increase! A good source of FOS is inulin.
This experiment supports rather emphatically the potential efficacy of a product which combines various prebiotics with the best probiotics. If, for example, one combines a dose of 30 billion probiotic cells with these two prebiotics, one would anticipate that this would result in an effective dose equivalent to taking a trillion or more cells. Trehalose has also been found to boost acidophilus numbers and there are a range of other prebiotics such as arabinogalactan which boost bifidobacteria in the same way as resistant starch does. A combination of all these factors in the one formula could be called a “Super Synbiotic” The effect is dose-dependent and there is just not enough room in a capsule to fit an efficacious dose of prebiotics so the best answer is to take it in powder form, a spoonful at a time in a drink.
One word about taking probiotic preparations containing a lot of different strains: Many strains will fight each other so more is not better and why would you dilute the best strains with others that may even stimulate pathogens. Some manufacturers boost the numbers of cells in their products by adding cultures such as yogurt starters (Streptococcus thermophilus and Lactobacillus bulgaricus) and even silage starters such as Lactobacillus plantarum, just because they are cheap and make the product sound good, even though the particular strains used may not have significant probiotic properties.
However, considerable anecdotal evidence suggests that many of the conditions alluded to earlier can be positively affected by the administration of a suitable super synbiotic on a continual, daily basis.