The health and happiness of the trillions of bacterial cells that live in our digestive system is a topic that’s so hot right now, and only going to get hotter. That’s because, as understanding grows about the function of the 100,000,000,000,000 (that’s a hundred trillion to you and me) microbes inside us, we see that they have profound effects on our physical and mental health. Between them, these microbes contain around 3.3 million genes, making the human genome’s 23,000 look distinctly paltry. Some scientists suspect that it’s our ability to harness the power of these bugs that helps to explain human evolutionary success.
Honestly, the more I read about this subject (links to some great, entertaining books below), the more my mind is completely blown and I’ve been making a real effort to factor in gut-friendly food for the last few months.
Sadly for us, the health of the human microbiome has taken a pounding in the modern era, thanks to medical developments like antibiotics and c-sections, nutritional trends that see us eating more sugar, food additives and less fibre, and the move to more sedentary, more stressed and more tired lifestyles. Also, just the fact that we eat a much smaller range of foods than our ancestors has led to a much less diverse collection of bacteria in our ‘inner-garden’.
The host/bug exchange. We provide an all-inclusive food and accommodation deal so what’s the payoff?
- Protection for our digestive system. Not only do the gut bacteria make an additional physical barrier along the gut lining, they also produce fuel for cells making the mucous layer that keeps the gut wall lovely and healthy. I know this all sounds vaguely gross, but if erosion happens, and substances that aren’t supposed to get across this barrier start to get through, chronic inflammation and depression can result.
- Help to break down and absorb foods. This is a complex process and where the microbiome is thought to exert its influence over weight management. Some really interesting experiments on twins have highlighted that individuals with exactly the same genetic makeup, even when differences in calorie intake were taken into account, can have quite different weight outcomes; then when their microbes were tested, they showed quite different profiles with less varied bacterial colonies linked to greater weight gain.
- Support for our mental health. There are several processes via which this happens, but if you think about the ulterior motive for the bugs, namely, to help us be sociable so that we’ll hang out together and spread them around, this feels slightly creepy.
- Support for healthy immune systems. 70% of the immune system lives in the gut, so it initially seems weird that it’s happy to co-exist with several trillion bacterial cells in close proximity, but current thinking is that a good balance of gut bacteria ‘primes’ the immune system and prevents over- or under-activity. Some bacteria also produce specific antibacterial substances that fight harmful bugs.
- Manufacture of helpful substances. As well as making the butyrate to fuel mucous-making cells, gut bacteria also produce B vitamins and vitamin K, plus neurotransmitters, including serotonin. How good is that!
- Handling female hormones. A subset of the microbiome called the estrobolome assists in clearing oestrogen from the body. This is a vital part of maintaining a healthy hormone balance and therefore helps minimise the humongous list of issues associated with periods, the menopause, and all that fun stuff.
The fact that research in this field is in its infancy means that we can expect many more cool revelations to come. A slightly less appealing prospect is the fact that stool testing is likely to become much more common – so if you’re squeamish about your poo, it’s time to let it go!
Back in the day, supporting our health with probiotics meant eating a bit of extra yoghurt during a course of antibiotics, but now we know of lots of things that we can do everyday to nurture our little intestinal pals. Some are really straightforward, while others (making fermented foods) took me a bit of a run-in but turned out to be easier than expected and totally worthwhile. Here’s a quick summary of the main things that I’ve been doing.
- Eating more PREbiotics. These are fibres found in fruits and vegetables that we can’t break down ourselves, but can be feasted upon by our friendly bacteria. You can find lots of lists of great prebiotic foods online, but some of the more common ones that are easy to include in the diet include oats, apples, leeks, onions, garlic, asparagus and my much loved flax/linseeds. If you like unripe bananas, you’re onto a winner.
- Eating more PRObiotics. Probiotics are live, friendly microorganisms that challenge harmful bacteria, either by crowding them out, or stealing all of their food. You can get them in ‘live’ foods, like yoghurt, kefir, sauerkraut (not the usual stuff in jars in the supermarket) and kombucha. There’s also a whole swag of probiotic capsules on the market as well as the little drinks in the supermarket (which I would avoid due to sugar content and expense). I’ve started making my own kefir, sauerkraut and kimchi, and although they look like science experiments gone wrong when they’re percolating, and the sauerkraut does stink the cupboard out for a couple of days, they all taste good and I crave them if I have to go without for a day or two. If you are taking, or have just taken antibiotics, you really need to get some probiotics on board!
- Cutting back on processed food. As ever, sugar is a baddie here, along with emulsifiers (found in ice-cream, cakes, margarine, mayonnaise and…. chocolate) and artificial sweeteners These are all thought to basically act as fertiliser for harmful bacteria at the expense of our friendly bugs.
- Have a generally healthy lifestyle. You know the drill here: more sleep, reasonable exercise, addressing stress before it gets out of control. Very satisfyingly, the habits that look after your wellbeing are the ones that support a healthy gut profile.
Recipe: Homemade Sauerkraut.
Go on, give it a go! Just remember, don’t cook it or you’ll destroy all of the lovely bacteria (am I selling it to you??). It’s fantastic on top of a salad, or as a way to get your digestive juices going if you eat a tablespoon before a meal. I based this recipe on the instructions given here which you might want to check out. You’d need at least 3 litre-sized jars for this recipe though.
Warning: Ease your way into incorporating this into your diet, starting with a teaspoon before a meal, then if that goes okay, a tablespoon the next day and so on. I ignored this advice and the resulting biological warfare in my intestines was not particularly fun.
- 1 green cabbage
- 1/3 red cabbage
- 1/3 savoy cabbage
- 2 carrots grated
- 2 finely sliced garlic cloves
- Good salt
- (I also find celery juice a great addition to make the mix more ‘juicy’ and you can either blend about 4 sticks in a blender or nutribullet, or run through a juicer.) This is not essential though.
Method: Finely slice the cabbage (if you have a food processor, it will be very useful here), add in the other ingredients and then weigh. Once weighed, you can work out how much salt to use because for every 800g of vegetables, you need 1 tablespoon of good quality salt. Put all of the vegetables, plus the celery juice and salt into a large bowl and massage vigorously for about 10 minutes until the vegetables have released a lot of juice.
You can now pack the kraut into very clean large jars, it’s important to press down firmly to remove any air and ensure that there’s enough liquid to cover all of the vegetables and some space at the top because it will create some extra juice. If you save some of the large outer cabbage leaves, you can use these as a cover, and then weigh this down to keep everything submerged. There is a useful video guide to packing the jars on the video here (skip to 16:30 if you don’t want to watch the whole thing). Make sure to set the jars on a plate or something to catch any drips. On no account screw a lid on at this point – we don’t want any explosions! This part of the process is definitely the most fiddly and why I am lusting after one of these snazzy fermentation crocks. (what happened to my life…?)
Place your jars, covered with cloth/kitchen towel to keep contaminants out, into a warm dark place for 4 – 6 days, you can then add lids and keep them in the fridge for up to a couple of months at least.
Gut by Giulia Enders is hugely entertaining, quirky and really informative. The author is a gorgeous young German scientist who is just fascinated by our digestive system. You can watch her in action giving a TEDx talk about ‘Charming Bowels‘!
The Diet Myth by Professor Tim Spector is a bit meatier than Gut, but really accessible with practical advice as well.