The bacterial battle
going on in your gut.
What constitutes a healthy gut microbiome?
I understand why we’re all interested in how what we eat affects us. I find it scary that gut bacteria is still talked about as if we understand how it affects our health (beyond infections that is, cos we know they aren’t good). I see a lot of people talking about gut health as the key to curing and preventing diseases. Years ago, I read a magazine or an advert on the tube and bought some bacteria in a jar, from a health food shop in Chiswick, hoping it would make me healthier. We've all done it at some point. Here’s what you need to know and where we’re at with health and fitness.
What do the bacteria in your gut do?
You may have heard of some of these bacteria found in and on our bodies. Bacteroides, Lactobacillus, Streptococcus… Bacteria in our guts break down or combine molecules in food to make useful products that are either used in the body or removed as waste. Specific bacterial strains do things like break down carbohydrates, make vitamins and release energy from food we ingest. There is research that has shown certain strains of bacteria can prevent other bacterial infections and (in animals) that certain bacteria can prime the immune system response (T-cells) but that’s in animals. I haven’t given that much credence until a human study appears. (If you come across any, please send them my way).
But what about good and bad bacteria? What does that mean? Thousands of species are present in the gut. Unique combinations and quantities for each individual. Research from one study a couple of years ago, showed that no one in the test group had the same bacteria, although the same broad family and their functions were present. Well that makes things very complicated, yet again our uniqueness makes coming up with tangible evidence hard. More research is needed into which bacteria are beneficial, why and whether that’s true for everyone. Abundance or overwhelm of one type and you get an undesired infection, too few or low diversity has been linked to other diseases. It's a bit of a minefield.
Events such as taking antibiotics for infections disturbs this population dynamic. However, gut populations tend recover over time by themselves.
So do you need to worry about or try to change your gut microbiome?
There is lots of good evidence that suggests that what you eat affects your gut microbiome proportions. You have thousands of species in and on your body. If you eat a particular diet, then those bacteria best placed to make use of the nutrients within will flourish in your gut, the bacterial hunger games if you will. This effect is long term, one meal or short change in diet is unlikley to change bacterial populations. So parasite cleanses, 7 day juice diets, a supplement here and there are unlikely to make a difference, even if they feel like they do.
There is less evidence as to whether those bacteria are good for you and your body systems. Also, we know that the food we eat contains bacteria, fungii and viruses - not all killed by washing, cooking and digestion. So we’re adding to our microbiome all the time, sometimes harmlessly, other times, disasterously.
Advice at the moment is general. An increase digestive resistant carbohydrates is beneficial to gut bacteria, they love the stuff. That’s fibre to you and me and other advice is to eat things that are good for your body. Well, Duh. The really good and reasuring news is that your gut microbiome will do what it’s going to do unless you change things long term. If you need help in integrating those things into your eating, then perhaps see a nutritional therapist or dietician.