What should you eat to keep your gut healthy? And can bacteria really be good for you? With the help of Holland & Barrett nutritionist, Isabel Tarrant, we delve into the science of digestion and reveal some of the best foods for gut health.
What happens in the gut?
The gut is a nine-metre-long tube that starts at the mouth, moves from the oesophagus to the stomach, through the small and large intestines, and ends at the back passage. It’s where digestion takes place, and this involves three important processes:
- Breaking down food into smaller pieces.
- Absorbing what our body needs from what we eat.
- Getting rid of the waste that can’t be used by our bodies.
The wellness benefits of a healthy gut
Within the gut exists a thriving community of bacteria. As well as aiding digestion, they provide essential support for immune functioning, your skin, and brain health.
“We have approximately 100 trillion live bacteria living inside of us – this equates to 2kg of our body weight,” says Isabel Tarrant, Holland & Barratt nutritionist. “These helpful bacteria thrive by feeding off the food we eat. So, food is essential not only to feed and fuel us, but also to feed and fuel our friendly gut bacteria.”
But how does what happens in our gut impact on our overall health and wellness?
Immune system functioning
A staggering 70% of our immune cells are in our gut.1 As a result, problems in your gastrointestinal tract can make you more susceptible to feeling run down or picking up illnesses.
“Friendly bacteria produce metabolites, such as short chain fatty acids. They play a crucial role in regulating T cells – the key peace-keeper cells of our immune system,” says Isabel. “Moreover, our gut bacteria produce compounds which support the healthy functioning of white blood cells, known as macrophages. They are key for fighting off infections and harmful germs.”
Mood and brain function
The health of your gut microbiome impacts on cognitive function and mood. This is down to a two-way relationship between the gut and the brain known as the gut-brain axis.
“Bacteria in the gut modulates the activity of various chemicals in the brain, known as neurotransmitters. For example, it’s estimated that 90% of the ‘happy hormone’, serotonin, is made in the gut,” Isabel explains “Research shows that individuals suffering with anxiety, depression and autism tend to have greater imbalance in their gut, with more negative bacteria than positive, compared to healthy individuals.”
There’s a strong relationship between the composition of your gut bacteria and sleep quality.
“Imbalances in the gut microbiome are associated with increased risk of sleep disturbances and poorer sleep quality,” says Isabel. “This is due to the interaction between gut bacteria and the regulation of sleep hormones.”
Gut bacteria produce compounds known as short-chain fatty acids (SCFAs), which influence the production of the hormones responsible for the feeling of hunger and fullness.
“Individuals with a healthy gut bacteria composition tend to also produce more SCFAs, which leads to reduced hunger and increased fullness,” Isabel says. “This has a direct impact on eating habits and weight.
Research shows a striking difference between the gut bacteria of overweight and lean individuals.”
What are the symptoms of an unhealthy gut?
It’s estimated that at any one time, about 4 in 10 people have at least one problematic digestive symptom.2 These symptoms typically come in the following ways:
How can I support normal gut health?
As a starting point, you may want to include these good gut foods in your diet:
High fibre foods such as fruits, vegetables, wholegrains, beans and legumes help to feed gut bacteria, allowing them to thrive and grow.
Eat the rainbow
The different phytochemicals found in coloured fruits and vegetables can help to encourage production of a diverse range of positive bacteria in your gut.
Prebiotic foods such as garlic, onion, chickpeas, beans, artichoke, banana and leeks are special fibres which good gut bacteria love to feed on.
The live bacteria in foods such as sauerkraut, live yogurt, kombucha, kefir and tempeh contribute to a healthy gut microbiome. Alternatively, look out for probiotic supplements with a variety of bacterial strains and a high potency of bacteria.
These antioxidants are found in certain plant foods, including berries, purple carrots, spinach, green tea, grapes and dark chocolate. They are broken down by gut bacteria to produce compounds that support immune functioning, brain health and digestion.
What are the three worst foods for your gut?
Unfortunately, not all foods have a positive effect on gut health. The following are some of the worst foods for gut health.
Alcohol strips the gut of positive bacteria and promotes the growth of negative microbial species. This results in an imbalance in gut bacteria that can have a negative impact on immune functioning, digestion, sleep, mood and weight.
Studies show that a high intake of sugar suppresses the growth of positive bacteria. As a result, you can expect a negative impact on your microbiome composition.
Artificial sweeteners and emulsifiers
Common sweeteners, such as saccharin, aspartame and sorbitol, can prevent the growth of friendly bacteria in the gut. This can cause negative harmful bacteria to thrive.
Summary: Eat mindfully to keep your gut healthy
The healthy, friendly bacteria in your gut need a constant supply of nutrients to multiply and flourish. Eating a wide variety of whole, unprocessed foods, including fibre, probiotics and a range of fruit and vegetables, is an important baseline for good gut health.
Last updated: 12 April 2021