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Gut bacteria and probiotics Part 3

How can we help our microbiome flourish and when do we need to help re-balance the digestive tract?

As explored in Part 2, our gut bacteria or microbiome need to be fed in order to not just survive, but to thrive. The food that the gut bacteria live off are called pre-biotics. Pre-biotics are essentially the breakfast, lunch and dinner of the probiotics/our gut bacteria. Pre-biotics are usually foods or parts of foods and include things like soluble and insoluble fibres. Usually the best sources are vegetables – raw vegetables generally supply the insoluble fibres and cooked vegetables generally supply the soluble types of fibres. Both are needed to feed the gut bacteria. You can also source Pre-biotic fibres as a supplement to further benefit the gut bacteria. And we know from part 2 that the bacteria then use a fermentation process in the digestive tract to break down these foods further and as a result produce SCFA (short chain fatty acids) that then feed our enterocytes or digestive tract cells…So perhaps there is reason to the rhyme when we are told to eat our greens!

Something else to be aware of when it comes to gut bacteria is that there is a delicate balance that needs to be maintained in our digestive tract. Too little of a ‘good bacteria’ is not enough to maintain a healthy gut environment. But did you know that too much of even a ‘good bacteria’ can be a problem. The ‘good guys’ can turn problematic if in too high concentrations and they can crowd out other good bacteria needed for balance.

And what happens to our microbiome when we take medications?

Many medications will unfortunately have a deleterious impact on our gut bacteria. For example PPIs (proton pump inhibitors) and antacids alter and reduce the acidity in our stomach which reduces our first line of defence against the wrong kind of bacteria coming into our digestive tract – with this defence barrier removed, our digestive tract bacteria inevitably begins to swing out of balance. Diabetic drugs such as metformin and laxatives are also know to make significant impacts on the gut microbiome. This can then begin a series of changes that leads to digestive issues and the increased presence of ‘bad’ bacteria.

Antibiotics are another series of medications that are commonly used (and often very much needed), that can wipe out our digestive tract microbiome. Antibiotics are basically anti-bacterial medications that aim to kill bacteria. Usually they are taken to eradicate bad bacteria (a very wanted and needed thing), however, the collateral damage is that they also kill the good bacteria. Sometimes we need to take antibiotics for a lung infection or a tick bite etc. and so the antibiotics are needed in the lungs or in the blood to get rid of bacteria that have taken over and are causing an infection. Classically we take the antibiotics as a tablet which enters our digestive tract and hence this is where it begins its antimicrobial role even though we don’t necessarily want it to act there, before being absorbed to act where actually needed.

Then of course you can have an infection of the digestive tract itself – an infection or infestation of bad bacteria in our bowels. This can range from specific pathogens such as salmonella, clostridium, staphylococcus or a more generalised SIBO (small intestine bacterial overgrowth) to name a few. In this case antibiotics may be warranted to wipe out the intruding bacteria in the digestive tract. Of course this will also kill off the good bacteria too – an unavoidable consequence.

Consider the car park theory – Imagine the digestive tract as a long, skinny, winding car park – and imagine that all these spots need to be occupied by cars (or bacteria symbolically). You really want them to be occupied by good cars/bacteria and not ‘bad’ cars/bacteria. But if there are free spots and not enough good cars/bacteria to go around, then the bad cars/bacteria will automatically take those spots. Sometimes the only way to get rid of the bad cars (or bacteria) is to take an antimicrobial agent or some antibiotics that clean out all the bacteria completely and then you need to start again by re-introducing the correct probiotics before the bad bacteria have a chance to come back.

This is where the correct probiotics come in handy – they can help to re-populate the digestive tract after a course of antibiotics or other medications or when there is a significant imbalance of bacteria for any other reason. So when there are digestive issues, allergies or other key conditions as mentioned above, taking probiotics to re-set the system can be very supportive. But a small note here that unless there is a specific condition that warrants you to take probiotics for longer term, it is not about taking them every day for ever!

Read on in Part 4 how not all probiotics are equal and how you can get probiotics from foods, but is this actually good or not?


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