Do you ever stop to think about the bustling community inside you, one that plays a vital role in your health and wellbeing? I’m not talking about a trendy neighbourhood or a bustling city. I’m referring to your microbiome – the busy metropolis of microorganisms that call your body home sweet home. Unless you have digestive problems, you probably don’t give this a second’s thought – but you should. The “microbiome” is the guardian of your health and your gut environment could be the reason you have anxiety or low mood, painful periods, terrible menopause symptoms, or difficulty losing weight.
What is the microbiome?
Think of it as your very own ecosystem, but on a microscopic scale. It’s made up of trillions of bacteria, viruses, fungi, and other microscopic critters that live in various parts of your body, from your gut to your skin and everything in between.
You might be thinking, “bacteria? That doesn’t sound healthy”. Although we are used to hearing about bacteria as the “bad guys” – not all bacteria are bad. In fact, many of them are crucial for keeping you in good health. They help with digestion, support your immune system, and even play a role in regulating your mood, hunger levels, sleep, stress, and hormones.
That’s because what happens in the gut doesn’t stay in the gut.
The microbiome and mental health
There is a constant two-way communication with your brain and your digestive system. You may have heard me mention the gut-brain axis. It’s been the subject of a lot of research in the last decade and there is increasing evidence that your gut bacteria heavily influence your mood.
Your gut bacteria make chemicals that affect your brain. They produce neurotransmitters, chemical messengers that help transmit signals in the brain. One of these neurotransmitters is serotonin, often referred to as the “happy hormone” because it plays a crucial role in regulating mood and emotions.
A whopping 90% of your body’s serotonin is produced in your gut. The balance of bacteria in your gut can directly impact your serotonin levels, and subsequently, your mood. When you have a healthy and diverse microbiome, it’s like having a team of cheerful little helpers churning out serotonin to keep your spirits high.
But here’s where it gets interesting: your brain can speed up your gut (very simply, how quickly food moves through your body) and change what microbes are present.
And when your gut bacteria are out of whack, it can throw this delicate balance off-kilter. Imbalances in the microbiome have been linked to conditions like depression and anxiety.
The microbiome and immunity
If you’re the kind of person who catches every bug going, consider this might be down to what’s happening in your gut. The microbiome and your immune system are heavily linked.
Imagine your immune system as your body’s very own security team, constantly on the lookout for intruders and ready to spring into action at a moment’s notice. The microbiome plays a crucial role in training and coordinating this defence force.
The bacteria are like the teachers in an elite military academy, helping to educate and train your immune cells to distinguish between friend and foe. Your gut bacteria also produce molecules called metabolites, which act as messengers in the intricate dance between your microbiome and your immune system. These metabolites help regulate the activity of your immune cells, ensuring they respond appropriately to threats without going overboard and causing inflammation.
Inflammation is a bit like setting off a fire alarm – it’s a necessary response to danger, but too much of it can cause chaos and damage. Luckily, your gut bacteria are there to keep things in check, helping to maintain a delicate balance between fighting off invaders and keeping the peace within your body.
But the relationship between your microbiome and your immune system is a two-way street. Your immune system also plays a crucial role in shaping the composition of your microbiome, keeping the peace by promoting the growth of beneficial bacteria and keeping harmful bacteria in check.
The microbiome and your hormones
Your gut bacteria aren’t just masters of digestion and immunity; they also have a hand in regulating your hormones. One of the key players is cortisol, often referred to as the “stress hormone”.
When you’re feeling stressed out, your body releases cortisol to help you cope with the situation. Your gut bacteria can influence the production and regulation of cortisol, potentially shaping how your body responds to stress.
Certain types of gut bacteria can affect the HPA (hypothalamic-pituitary-adrenal) axis, a complex network of hormones involved in the stress response. By producing metabolites that interact with this system, your gut bacteria can influence the production and regulation of cortisol, potentially impacting how your body responds to stressors.
But that’s not all – your gut bacteria can also influence other hormones, like insulin, which plays a crucial role in regulating blood sugar levels. Studies have shown that imbalances in the microbiome can lead to insulin resistance, a condition where your cells become less responsive to insulin, potentially leading to high blood sugar levels and type 2 diabetes.
How to improve the health of your microbiome
Some foods are really good for supporting your digestive system
Fibre
Fibre is one of the best things to eat to support healthy digestion. Fibre is described as being either insoluble or soluble.
Insoluble fibre is part of the plant wall in fruit and veg. It’s indigestible so it passes right through your system, sweeping up toxins and other waste products as it goes, and keeping you regular. The undigested fibre is also fermented by gut bacteria, producing the beneficial short chain fatty acids I mentioned earlier.
You can find insoluble fibre in:
- Fruit and veg
- Beans and lentils
- Oats
- Wholegrain foods like brown rice and wheat
Soluble fibre can be partially digested and is well-celebrated for its ability to reduce cholesterol in the blood and normalise blood sugar levels.
You can find soluble fibre in:
- Oats
- Veg
- Fruit (especially apples, pears, berries and citrus fruits)
- Beans and lentils
Cruciferous vegetables
These smelly veg bring amazing health benefits on a number of different levels. Since we’re talking about foods that are helpful for your digestion, you should know that they contain compounds called glucosinolates, which are fermented by bacteria and used as fuel. They are prebiotic.
Examples are:
- Bok choy
- Broccoli
- Brussel sprouts
- Cabbage
- Cauliflower
- Kale
- Rocket
- Spring greens
- Watercress
Anti-microbial foods
Some foods exert a natural antibiotic or anti-fungal effect and can be useful for keeping nasties like pathogenic bacteria or unwelcome yeasts at bay.
These include caprylic acid found in coconut. Coconut oil is also a very good oil to use in cooking, especially at high temperatures.
Garlic contains the ingredient allicin, which has historically proven itself to be an effective killer of both bacteria and viruses, making it a great immune-boosting ingredient. Use it raw wherever possible.
Olive oil – the oleic acid has anti-bacterial properties. Use it generously to dress salads and veg.
WHAT TO AVOID
In the same way there are things your digestive system loves, there are things it will not love you for.
Sugar. That’s the number one thing to avoid, plus anything that contains added sugar.
Other things your tummy is not fond of include highly refined products like white rice, pasta, pastry and snacks like crisps and biscuits.