If you listen to the health chatter on the TV news, in magazines and on the internet you will have heard about the importance of gut bacteria to health. Gut bacteria seem to be responsible for everything from gastrointestinal health to mental health to reducing high blood pressure. Modern “western” diets which are typically low in fibre and high in processed foods are are being linked to the rise of obesity and Type 2 diabetes because of the deleterious effect they have on gut bacteria.
I have been researching and thinking about the microbes in my gut for over a year. I started to read the research, then switched to a mostly plant based diet, deliberately increased the amounts of probiotic and prebiotic foods that I am eating and generally trying to be nice to my gut bugs.
This time, I have put my body (and dignity) forward in the interests of science and bought a uBiome Test kit to check out what is actually living in my gut. It took 3 weeks to get the package from the US and then another 6 weeks to get the results.
The results are very comprehensive and frankly a bit of science-jargon-babble. I am a scientist and I found the data a bit overwhelming and not easy to interpret. I think they could provide a bit more help in unraveling the numbers.
I have become a bit obsessed with the amazing microbiome that is present in our gut. The billions of microorganisms that live inside us and have the potential to do so much good if we look after them.
Gut Microbes and Health.
More and more research shows that this microbiome is essential to our physical and mental health and many of the health problems facing those in industrialized economies could be solved by paying closer attention to what bugs are in your gut.
When your bug population get out of balance (dysbiosis) your whole body is in trouble.
The gut biome has been linked to
Synthesis of vitamins and amino acids in the gut
Digestion of “non-digestible” carbohydrates which therefore affects the amount of energy that is released from some foods
Protection from “bad” bacteria
Irritable bowel syndrome and inflammatory bowel disease
Obesity and Type 2 Diabetes
Eczema and asthma
Most studies of overweight and obese people show a dysbiosis characterised by a lower diversity.
Translation: Obese people have an imbalance of microorganisms with not enough variety present
It’s much better to have a good variety of microorganisms in your gut because:
The association between reduced diversity and disease indicates that a species-rich gut ecosystem is more robust against environmental influences, as functionally related microbes in an intact ecosystem can compensate for the function of other missing species. Consequently, diversity seems to be a generally good indicator of a “healthy gut.”
Translation: Having lots of different species of bacteria makes your body better able to withstand challenges because what one bug can’t do another type can. They can cover all bases by working together.
Fibre is the answer!
So how do you get a good mix of bugs in your gut? The key is consuming a goodly amount of dietary fibre and reducing the amounts of highly processed foods that we eat.
The idea is that we need to feed our gut bugs. Highly processed foods are easily digested and absorbed and don’t make it to the large intestine where most of the bug action is happening. By eating foods high in undigestable fibre, we give the bugs a meal as well.
How much is enough? Australia’s CSIRO recommend between 25 – 35 g per day. Having said that; too much fibre can reduce the diversity of your microbiome and if you suddenly change from a low fibre diet to a high fibre diet you can suffer from abdominal discomfort and flatulence. You should spread fibre consumption throughout the day and drink plenty of water to keep it moving through your intestines.
Types of fibre
There are different types of fibre which have different properties. The main types are insoluble, soluble and resistant starch.
Insoluble fibre found in whole grains, legumes, vegetables, nuts and seeds provides bulk and can help control blood sugar levels.
Soluble fibre found in legumes, veggies and fruits give the bugs something to eat so they stay happy
Resistant starch, which is found in cooked, cooled and reheated rice, potato and pasta, as well has whole grains, legumes and under ripe bananas. Resistant starch increases the amounts of butyrate in the gut. Butyrate, a byproduct of microbial metabolism, is important in keeping the gut walls healthy as well as keeping bad bacteria at bay.
What are probiotics and prebiotics?
Probiotics are foods or supplements that contain living organisms such as yogurt and other fermented foods. Prebiotics on the other hand are foods that help the microorganisms in your body thrive.
A good analogy is that if you think of your gut as a garden, the probiotics are the seeds and the prebiotics the fertiliser.
Some chemicals and medications will damage your gut bugs.
Antibiotics kill bacteria. That’s their job, so they kill the bacteria in your gut too. You may need to take some extra special care of your gut bugs after antibiotics. There is some evidence that the appendix acts a reservoir for the microbiome and in time will help repopulate the gut with good bugs.
Emulsifiers are added to food to make oily and watery components stay mixed together. If you mix oil and vinegar together, they will after time, separate into layers unless you add an emulsifier. Some artificial emulsifiers have been linked to damaging the gut microbiome because they lead to a thinning of the mucous layer in the gut which in turn leads to leaky gut syndrome. This causes inflammation in many areas of the body. The answer? Prepare your own food from scratch as often as possible and avoid things your grandparents would not have considered as food. Be wary of foods with lots of numbers in the ingredient list and not many recognisable as food.
Omnivore vs vegan?
There does not seem to be much evidence that a well balanced omnivorous diet is any better or worse than a vegan diet. (see The BMJ article referred to below) Michael Mosley and others wholeheartedly recommend a “Mediterranean diet“. This type of diet is mostly plant based but does include meat, eggs, some dairy, healthy oils and nuts.
Further reading on gut microbes and health.
This post is only a very short summary of the growing volume of information available. Here are just a few of the articles you could read to if you want to know more.
Atkins – only Generation X’ers and before will remember this one!
There are so many variations on how to eat healthily! The array of information available these days is overwhelming. Even with my background in food science I find it hard to keep up.
Food as more than fuel
In my late teens and in my early 20’s, I was anorexic and for a short time bulimic. I ate very little. I weighed about 47 kg and got annoyed if I went over 50kg. My BMI was less than 17. (A Healthy BMI is between 19 an 24) I exercised hard and stayed very fit but perhaps not healthy. I used to replay the words from the Ford Pills Diet ad over and over in my head. It was on TV when I was only 7 but it obviously had left its mark!
Before intermittent fasting was a “thing”, I used to fast all day Saturday, with the idea I could eat what I liked on Sunday. I remember waking up in the middle of the night, dizzy and light headed. I had frequent hypoglycaemic events not because I was diabetic but because I didn’t eat often enough. I was an absolute pain in the neck when it came to eating out!
I did a Food Technology degree at University and on reflection, this was no doubt my way of becoming a “food expert” and validating what I was doing. After Uni, I went on to work in the food manufacturing industry for a few years before moving into laboratory equipment sales. It is not uncommon for people with eating disorders to work with food in one form or another. Apart from my day job I had a side hustle – being a fitness instructor. More reasons to exercise and stay thin.
Once I was married, I would cook hugely elaborate meals. My husband also enjoyed cooking and we would often spend almost the entire weekend planning, shopping, preparing and cooking fabulous menus which I didn’t eat much of. Food was always on the agenda as a hobby, and as a fuel.
I am pleased to say that as I have gotten older I have become more sensible with my diet although it is still a balancing act of energy in vs energy out.
I still enjoy cooking and now that I am cooking only for myself (and I’m past the wine and wedges phase) I make it an intentional act to cook a decent meal a few times a week. There are always leftovers, so I have enough for those nights when I have less time. I plan my weekly meals (let’s say that again: I aim to plan my weekly meals because sometimes I don’t!!) – mainly because it means I don’t waste so much food or have to face the decision of what to cook each night.
I remain interested in nutrition and have considered returning to study in this field. When I was doing my first degree, issues like antioxidants and gut bacteria weren’t even on the horizon. Coconut oil was a BAD thing!
Nowadays, I also look out for foods that will have a protective factor against the diseases of older age. There is some talk (but little evidence) that turmeric will reduce the inflammation that contributes to arthritis and dementia. I am now taking turmeric tablets. It can’t hurt, and it might help. In a previous post I spoke about good mood food, food that feeds your gut bacteria and is thought to contribute to positive physical and mental health.
Finding the right food balance.
In the end I think we all know that no fad diet will work. There is no magic bullet. If you want to lose weight you need to use more energy than you consume. If you want to be healthy you need variety. You need to be flexible and not place any unnecessary restrictions on what you can and can’t eat. Get your advice from reputable sources that don’t have a vested interest and are not trying to sell you something. I have not fact checked any of the websites I have linked to in the above list – so do your own research. I think you need to be careful if someone is making money out of selling you a fad diet.
The best dietary advice I have heard recently is summed up in seven words from Michael Pollan:
The little imaginary fellow on my other shoulder keeps telling me how bourgeois this line of reasoning is. A great many people on our Earth will find this concern about he best way to eat to stay healthy ridiculous because they have NO food.. We should be grateful we have the food in the first place and do our best not to waste it and distribute it more equitably – but that’s a whole other topic for a different blog post!