Gut health. There is a good reason this is a nutrition ‘hot topic’. It really does have an important role in health and performance!
What do we mean by gut health?
The gut is everything from your mouth to the exit at the other end :P. When we talk about ‘gut health’ we usually mean the health of your intestines.
So, what makes your intestines healthy?
1. A healthy population of bacteria. Your gut is home to many different bacteria. For your gut to be healthy these need to be in balance – not too many ‘bad’ bacteria, but also not too many of any one ‘good’ bacteria (you can have too much of a good thing!).
2. A lining that lets stuff through, but not too much! Food must pass through the lining of the gut and into the body so it can be used for fuel and to make tissue. However, if the gut is ‘leaky’ too much can get through. This can include the bacteria themselves, bits of undigested foods, and artificial chemicals in food.
3. It’s immune system. The lining of the gut has a role not just in keeping the gut free from infection, but also the rest of the body. If gut immunity is not tip top, we are at higher risk of infection.
The gut microbiome impacts the leakiness of the gut and the effectiveness of the gut immune system. This is why the focus of ‘gut health’ is the health of the gut microbiome.
What is gut health related to?
So many things. The gut really is our second brain! A healthy gut microbiome is important for:
1. Effective digestion and absorption of food. And therefore, access to the fuel and building blocks we need for life!
2. Vitamins! Our gut bacteria can also produce certain vitamins to supplement those obtained from our food. And vitamins are needed for pretty much everything in our bodies to work effectively.
3. Energy metabolism and weight control. In addition to helping digest food effectively, the ‘good’ bacteria of the gut produce chemicals that appear to help ensure our metabolism works effectively.
4. Stress and anxiety. The gut and brain are closely connected. The chemicals produced by the bacteria send signals to our brain. And there are nerves that directly connect the brain and the gut. When our gut is unhealthy, chemical and nerve signals are sent to the brain that can increase stress and anxiety. A side note: this works both ways. You know when you are nervous, or anxious, you feel it in your gut? That is your brain signalling to your gut!
5. Immune function. We touched on this above. A healthy gut microbiome directly supports immune function in the whole body – especially how we fight throat and chest infections.
How does this impact exercise performance?
1. Gut issues. We all know that a gruelling or long workout can make even the best of us want to vomit and / or make our bowels a little more active than usual!! And this slows us down. If you suffer from gut issues without exercise, you are typically at higher risk of this.
2. Sick people can’t train, or at least not effectively. The odd sick day and missed training session has little impact, but if you are you getting sick multiple times a year for days or weeks on end, your training is going to suffer.
3. Training adaptations. Now this is the interesting one! Training adaptations need the fuel and building blocks that food provides, plus an effective inflammatory process. A healthy gut microbiome has a role in this. So, it seems a healthy gut has a role in helping us adapt effectively to our training, i.e. to get fitter, faster and stronger!
What to eat for a healthy gut?
Our diet impacts the bacteria that live in our gut. In addition, certain foods contain bacteria that might help top up the amounts in our gut. So, what to eat?
1. Load up on ‘Microbe accessible carbohydrates’. Otherwise known as fibres and resistant starches. We can’t digest these, but they are vital foods for the ‘good’ bacteria in our guts. These are found in fruits, vegetables, wholegrains, pulses and beans. Eat a range for the full variety of foods our different bacteria need.
2. Include polyphenols. These are small molecules found in certain foods that seem to help increase the good bacteria in the gut and limit the bad bacteria. Rich sources of polyphenols are good quality olive oil, spices such as cumin and cinnamon, nuts, seeds, and dark berries.
3. Limit refined sugars. In other words, the stuff added to biscuits, cakes, candy, ice cream and other processed foods (including savoury ready meals!). These appear to be the favourite food of many species of ‘bad’ bacteria. Limit these to help limit the amount of these bacteria.
4. Limit certain emulsifiers and artificial sweeteners. There is some evidence that these may disrupt the good bacteria in the gut, and – if the gut becomes leaky because it is unhealthy – get into the blood and cause problems. There are not yet enough studies to be certain, but perhaps it is prudent to limit these until we know more.
5. Probiotics. Certain foods contain bacteria. These foods are called probiotics. Live yoghurt, kefir, kimchi, sauerkraut, unpasteurised cheese, sourdough, miso and other fermented foods. Except wine and beer … the alcohol content and pasteurisation of these kills the bacteria (sorry!). Eating these might help top up the ‘good’ bacteria in the gut, although it is not clear if the bacteria in these foods always reach the gut alive. You can also buy probiotic supplements, but I would take care here. Most supplements contain a lot of a limited types of bacteria. Even if these are ‘good’ bacteria, you don’t want your gut to be overrun by just a limited number. You need the full range. So I would not recommend probiotic supplements unless you are under the guidance of a medical practitioner who knows the bacteria you might need a boost of!
So there you have it. Gut health matters!! This is what we know so far. But it is a very new area of research, so expect much more to be understood in the coming years.