About our body’s bacteria
Bacteria exist in all parts of your body – your skin, your blood, your mouth – and while there are some types that will do you harm, most live in harmony with your body and some even keep it alive and well.
Some bacteria in your mouth can make your breath smell – they digest food particles in there and produce hydrogen sulfide (yes, the same stuff that gives rotten eggs that smell), methyl mercaptan (the same stuff that makes faeces smell, well, like faeces), and there are others that produce putrescine, which is also released from rotten meat, and cadaverine, released when something has died.
Others, like Streptococcus mutans, also cause tooth decay, while similar-sounding Streptococcus salivarius is beneficial, helping to prevent bad breath, along with Lactobacillus sp. and others.
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Bacteria in the digestive tract
Researchers know even less about the bacteria in our digestive tracts because while it’s fairly easy to swab the inside of someone’s mouth and then look at the bacteria saliva contains, it’s not so straightforward to do the same with the digestive system. Which is why a lot of the figures relating to bacteria in your gut are estimates – for example, scientists estimate the gut contains between 300 and 1000 different types of bacteria, with over 3 million genes. In total the number of bacteria could be anything between 100 and 1000 trillion.
In fact, bacteria are so plentiful in your lower intestine that the dry mass of faeces is made up of around 60% bacteria. If anything those figures serve to show how little scientists know for certain about the bacteria in our digestive system – they don’t even know how many there are!
How your body’s bacteria helps you
What they do know is that the bacteria are absolutely essential for us to live – they work together with other bacteria to create neurotransmitters, they help produce antibodies to fight against invasive bacteria or viruses, they break down harmful substances in food so the body can excrete them, and they break down food so that the body can use the nutrients.
The problem is that in order to kill off bacteria that might be causing you to be ill – such as when you have a sinus infection, for example, something that is notoriously hard to treat with anything but antibiotics – the antibiotic you’re given also kills off bacteria in your digestive system.
So, taking the example of a sinus infection, you might be prescribed penicillins, macrolides, cephalosporins or fluoroquinolones, as all these fight sinus infections.
Penicillins, which come in a wide range of forms, some narrow spectrum, others broad spectrum (amoxycillin, which is often prescribed, is narrow spectrum), work by interfering with the way bacteria function, preventing them from building cell walls. This means that as the bacteria grow, they eventually burst their own cell walls, dying off.
Macrolides stop bacteria from making new proteins, so they can't multiply and eventually the remaining ones are killed off by the body's natural immune system. These are narrow spectrum antibiotics.
Cephalosporins, which are stronger, work in a similar way to penicillins, but for people who are allergic to penicillin are a useful alternative.
Finally, fluoroquinolone, broad-spectrum antibiotics, prevent bacteria from replicating.
How are antibiotics prescribed?
For any bacterial infection, a narrow-spectrum antibiotic is ideal as it will target more specific bacteria. But that’s not always possible. If your bacterial infection doesn’t improve with a narrow-spectrum antibiotic your doctor will likely prescribe a broad-spectrum one – some doctors might simply prescribe the broad-spectrum one to be certain it will be effective (this is true if you’re in an at-risk group, for example, with lower immunity).
There are other factors involved too, in what you are prescribed – cost, side-effects and previous research showing how effective a certain antibiotic is for a specific type of infection. But sometimes an antibiotic will be prescribed when it’s not needed.
Recent research, for example, suggests that patients with bronchitis, who are otherwise well, should not be offered antibiotics routinely (which is how it was in the past) because it appears not to be as effective as previously thought, and yet if you have bronchitis you may well find yourself clutching a prescription as you leave the doctor’s office. The downside of this is not only that bacteria become more resistant to drugs, which is a major concern, but also that you, as the patient, inadvertently kill off the good bacteria in your body while taking the antibiotics.
How antibiotics affect the balance of bacteria in your gut
While both good and bad bacteria will gradually regrow in your digestive system, the problem is that while you’re taking the antibiotics, and immediately after, the balance is dramatically upset. This means that yeasts grow unchecked, taking over where before they would have been held back by helpful bacteria such as Lactobacillus and Bifidobacterium.
When certain yeasts in your digestive system get out of control, unchecked by friendly bacteria, they can even push their way through your intestinal walls – and it’s thought this could be one of the causes of leaky gut, a term used to describe a group of symptoms including bloating, gas, and stomach cramps.
8 IBS remedies and lifestyle changes to make your life easier
And while that in itself is pretty bad news, it gets worse. “Not many people know that more than 60% of the immune system is based in the gastro-intestinal tract and a good balance between the various types of gut bacteria is essential for maintaining health,” says chief scientific consultant for Bimuno, Dr Paul Vandewalle.
In fact, it’s estimated that 70% of your immune cells are actually produced in the gut. So after you’ve managed to recover from a bacterial illness by using antibiotics, you’ve actually made your chances of getting sick again higher because now your gastro-intestinal tract is lacking in the bacteria it needs to function well. Add to this the fact that as you age your good bacterial numbers begin to dwindle and you can see how important it is to replace lost bacteria after a session of antibiotics.
Avoiding antibiotics and boosting your immune system
How can you help boost good gut bacteria
So what can be done about it? You can, of course, rebuild your stocks of good bacteria by eating live bacteria foods such as yogurt, and there are a myriad of ‘good bacteria’ products and supplements on the market now too. But what works best?
How to make yogurt
Best foods for gut bacteria
To begin with, your go-to foods are those that naturally contain good bacteria, or that promote the production of good bacteria, which means live yogurt (containing Lactobacillus, for example), but also sauerkraut, kefir, tempeh and miso. These last three foods work well because they’re fermented, so they already contain healthy beneficial bacteria making them ideal foods to focus on after antibiotic treatment.
How to make sauerkraut
How to make kimchi
The pros and cons of soy
But you should also look to add foods such as Jerusalem artichokes, which contain inulin a substance that helps good bacteria flourish in the digestive tract.
Cream of Jerusalem artichoke soup
Sea bass with Jerusalem artichoke puree
Bananas also help bring back a happy bacterial balance in your intestines, working on microbes called ‘phyla’. They should be one of your go-to foods for when you feel your stomach is upset too.
Sugar-free banana bread
Lightning-fast banana balls
Corn in the form of sweetcorn or polenta, for example, will also help because in your gut it ferments, creating strands of healthy gut bacteria as it does so.
Chilli pumpkin cornbread
Should you bother with probiotic supplements?
Finally, you can also take probiotic supplements and specially made drinks or foods with probiotics added. Don’t worry about overdoing it, unless you have a weakened immune system (in which case see your GP before taking probiotics as they can cause problems), as the bacteria have to go through your stomach to get to your digestive tract, where high levels of acid kill off many bacteria, you need to ingest a lot to redress the imbalance. So add probiotic supplements and specially made probiotic drinks and foods to your daily food intake, and within a few months your digestive flora should be back to near-normal.
The benefits of probiotics and prebiotics
How do you know if your gut bacteria is back to normal?
Not sure whether it’s time to relax or not? Check your stool – if you’re healthy, you’ll go to the bathroom regularly without any problems, and your stool itself will be softish (not hard), shaped like a sausage or snake, with or without cracks. That’s your clue to a successful treatment!
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