20 facts you didn't know about diet, lifestyle and your gut
Section 3: What your gut bacteria actually do
15. Gut bacteria help digest fibre
Your body cannot fully digest many types of fibre. Gut bacteria can break some of them down in your large intestine.
16. This produces useful short-chain fatty acids
When bacteria ferment certain fibres, they produce substances called short-chain fatty acids. These ‘good’ fatty acids, including acetate, propionate and butyrate, can help ward off chronic inflammation linked to heart disease, as well as bowel cancer and inflammatory bowel diseases like ulcerative colitis and Crohn’s disease.
17. Your gut is a major centre for your immune system
The majority – 70-80% - of your immune cells are found in your gut. Given that the role of the gut is to absorb things you’ve swallowed into your bloodstream, it makes perfect sense that so much of your body’s first defence against infection is located here.
18. Gut bacteria can help make vitamins
Some gut bacteria contribute to the production of vitamin K and certain B vitamins. Obviously, there are a wide variety of other vitamins and nutrients, so a balanced diet is essential.
19. Your microbiome develops rapidly from the earliest stages of life
Before birth, your gut is sterile – in other words, it doesn’t contain any bacteria. Once you’re born, it’s a different matter. Your gut microbial community changes dramatically after birth as you encounter food, your environment and other microorganisms.
20. How you are born can influence your early microbiome
Babies born vaginally and by caesarean section can develop different early microbial communities. A vaginal delivery allows transmission of gut microbes from mother to child: this includes beneficial bacteria such as Lactobacillus and Bifidobacteria. These differences often become less pronounced as children grow.
21. Breast milk contains special sugars for beneficial bacteria
We’ve already heard that your gut microbiome develops rapidly after birth. Human milk contains human milk oligosaccharides, which babies cannot digest fully. They help feed particular beneficial bacteria, including Bifidobacterium.
Section 4: Diet and lifestyle surprises
22. Variety matters
While many vegetables and fruits are labelled ‘superfoods’ because of high levels of particular nutrients, no one food will fulfil all your body’s needs. Different plants provide different micronutrients and fibre, so aim for the wide variety you can of vegetables, fruit, wholegrains, beans, pulses, nuts and seeds.
23. Cooking and cooling can change carbohydrates
Cooking and cooling certain foods, like potatoes, pasta and rice, changes some of their digestible starch into resistant starch through a process called retrogradation. This makes them behave more like fibre, which isn’t readily broken down in the small intestine by enzymes and can be used to feed good gut bacteria.
24. Many UK adults do not eat enough fibre
Dietary fibre is good for your bowels and can support digestive health, yet as a nation we fall woefully short of the UK recommendation for adults of 30g of fibre a day. In fact, average fibre intake is just 18.3 grams.
25. Exercise can benefit your microbiome
Where exercise is concerned, every little helps your gut as well as your heart, lungs, joints and general fitness. Moderate activity and combining aerobic exercise and resistance training can improve gut microbial diversity, increase production of short chain fatty acids and boost your immune system.
26. Your microbiome responds to your diet
Your microbiome thrives on variety! 75% of the world’s food comes from just 12 plants and eating the same foods day after day offers less variety for your gut bacteria. Adding different plant foods can increase the range of fibres available to them.
27. Alcohol can affect your gut
Alcohol can affect both the balance and activity of microorganisms. This can predispose you to dysbiosis and increase the risk of chronic inflammation in the body.
28. Artificial sweeteners are not automatically “better for your gut”
It’s well known that sugar can have a negative effect on your gut microbiome. However, research suggests that artificial sweeteners too can affect the make-up of your gut microbiome and its production of short chain fatty acids. There’s still much we don’t know about how the effect of different sweeteners varies.
Section 5: Myths, misconceptions and surprises
29. Bloating does not always mean something is wrong
Gas, swallowed air, constipation, hormonal changes and normal digestion can all cause temporary bloating. However, if you’re suffering persistent or severe bloating, you should speak to your doctor.
30. Not every probiotic survives perfectly through your digestive system
In order to work, probiotics need to ‘arrive, survive and thrive’. They need to reach your system in enough numbers to have an effect, survive the hostile environment of your acidic stomach digestive enzymes and be able to multiply once they reach their destination. The evidence is that there is huge variation between different probiotics in this regard.
31. You do not need a “gut detox”
Your gut, liver and kidneys are working hard 24 hours a day to remove waste from your body. Not only do you not need ‘gut detoxes’, the very limited variety of food and drink they involve can have a negative impact on your gut.
32. Most bacteria are not your enemies
Your body is home to vast numbers of microorganisms, with most of them living in your gut. The vast majority are harmless or actively helpful, with only a relatively small proportion causing disease.
33. Antibiotics can change your microbiome for months
The discovery of antibiotics has revolutionised doctors’ ability to treat infections. However, they can also reduce beneficial bacteria. Recovery of the whole gut microbiome population can take weeks or even months after a course of antibiotics, with some strains of bacteria still absent 6 months after a single course.
34. A healthy gut does not mean never having symptoms
We all get gas, constipation, diarrhoea or bloating occasionally – whether down to a change in routine or diet or simply swallowing too much air with your meals. Getting occasional symptoms doesn’t mean your gut health is fundamentally poor.
35. Fermented foods and probiotic supplements are different
Foods such as live yoghurt and some fermented foods contain microorganisms and are referred to as probiotic foods. However, the number of microorganisms and the strains of bacteria can vary significantly from batch to batch. By contrast, probiotic supplements usually contain selected strains in specific amounts. It’s important to recognise that their effects are not necessarily interchangeable.
Section 6: Your gut through life
36. Your microbiome changes as you age
The bacteria living in your gut change throughout childhood, adulthood and older age. Not just your diet and lifestyle but also underlying health conditions and medications you’re taking can all have an impact.
37. Hormones can affect your gut
There has been a huge increase in awareness in recent years of the impact of hormone changes in the perimenopause and menopause on far more than hot flushes. These hormone changes during pregnancy and menopause, and even over the course of your menstrual cycle, can influence digestion, bowel habits and symptoms such as bloating and constipation.
38. Travel can disturb your gut rhythms
We all look forward to holidays but your gut can often struggle. Whether it’s changes to your diet, alcohol intake, exercise levels or sleeping patterns, your bowel habits can alter in response. That means constipation, diarrhoea, bloating and tummy pain can all become more prominent while you’re away – especially if you don’t take care of your microbiome.
39. Illness and medication can alter your microbiome
Infections, antibiotics and some other medicines can change the number and types of microorganisms living in your gut. Your microbiome may recover afterwards, although the process varies from person to person.
40. Small habits can make a big difference
The good news is that your gut is very forgiving and responds to what you do regularly. Eating a varied, fibre-rich diet, staying active, sleeping well, drinking enough fluid and avoiding unnecessary antibiotics can support your digestive health far more effectively than an occasional “gut cleanse”.
The bottom line
Your gut is an extraordinary ecosystem that is constantly changing and communicating with the rest of your body. You do not need expensive supplements, detoxes or a perfect diet to look after it. For most people, the best approach is surprisingly simple: eat a varied diet rich in plants and fibre, keep active, sleep well and give your gut time to adapt to changes.
And remember, your gut is not just a food-processing tube. It is a living community that plays an important role in digestion, immunity, metabolism and communication between your gut and brain.
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