Did you know that if you look after your gut, you’re (quite literally) looking after you? Gastroenterology Dietitian Dr Sammie Gill shares five reasons why your gut is way more important than you think. Spoiler: There’s a reason it’s often called the “second brain”.
1. Your gut microbes are mentors to your immune system
The largest part of your immune system is gut-associated lymphoid tissue (GALT). It sits along the full length of your gut and makes up around 70% of your entire immune system.
Your gut microbes are constantly communicating with GALT. They help shape immune responses by teaching and training GALT to respond appropriately – to remain tolerant to things that are harmless and to mount an attack to things that are harmful.
Without microbes, your immune system suffers. In fact, results from studies in germ-free mice (without any exposure to microbes at all) show that the immune system malfunctions resulting in impaired responses.
2. Your gut microbes have far-reaching effects
It’s well known that gut microbes are important for the health of your gut. But gut microbes don’t just serve your gut. They have far-reaching effects way beyond that.
Your gut microbiome is like a little factory of workers building and pumping out thousands of different compounds – from neurotransmitters to hormones and vitamins.
Many of these compounds can cross the gut wall into the bloodstream. Once in the bloodstream, they are free to travel around body and have effects elsewhere. For example, studies have shown that compounds produced by gut microbes can impact brain health (e.g. depression), heart health (e.g. cholesterol levels), and skin health (e.g. eczema).
3. Your gut microbes are responsive
Gut microbes can steer your health in different directions – both positive and negative. This is because they are responsive to their environment and their environment is dictated by you.
What you eat, how you sleep, how active you are, how you’re feeling, and medication use all shape which gut microbes thrive and what they do.
For example, studies have shown that the type of gut microbes can change dramatically within 24 hours when switching from a meat-based diet to a plant-based diet. In other words, you can have profound effects on your gut microbiome in a short period of time.
For ways to support your gut microbiome, check out 12 small changes that can make a big difference and 5 ways to 30g of fibre a day.
Sources
Cardiovascular diseases and the heart–gut cross talk. Indian Heart Journal. (2024). Link.
Diet rapidly and reproducibly alters the human gut microbiome. Nature. (2014). Link.
Exercise and the gut microbiome: a review of the evidence, potential mechanisms, and implications for human health. Exercise and Sport Sciences Reviews. (2019). Link.
Feeding gut microbes to nourish the brain: unravelling the diet–microbiota–gut–brain axis. Nature Metabolism. (2024). Link.
From microbes to mind: germ-free models in neuropsychiatric research. American Society for Microbiology. (2024). Link.
Gut microbiome diversity is associated with sleep physiology in humans. PLos One. (2019). Link.
Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases. Gut Microbes. (2022). Link.
The interplay between diet and the gut microbiome: implications for health and disease. Nature Reviews Microbiology. (2024). Link.
