The Importance of Gut Bacteria for Our Physical and Mental Health

It's the engine that drives our digestive system. The gut microbiome is a dynamic ecosystem that can be kept in balance by adopting a healthy lifestyle, especially when it comes to diet. We asked Dr Thomas Killian, a specialist in micronutrition for 15 years, for his advice. MonacoSanté has the lowdown with everything you need to know. 

The gut microbiome: a digestive jack-of-all-trades

We each have our own unique gut microbiome. Found in the digestive tract - which consists of the stomach, the small intestine and the colon - your gut microbiome contains an estimated 100 trillion micro-organisms, including bacteria, viruses, parasites and fungi. It accounts for between one and two kilograms of your total body weight. Each adult’s gut microbiome is home to around 800 to 1,000 different species of bacteria, most of them beneficial. The microbiome performs a range of functions that are vital to keep us healthy, such as digesting food, protecting the body, and developing the immune system. “Everything you eat gets broken down and sorted. The useful parts become your fuel, providing the physical and mental energy you need every day. Anything your body doesn't need is rejected,” explains the doctor. The microbiome also helps the immune system to function properly by acting as a protective barrier against harmful invaders and substances like pollutants, pesticides, viruses, “bad” bacteria, and allergens. And it helps regulate your metabolism including how your body processes sugars and fats. “So it can reduce the risk of diabetes and obesity.” 

Looking after your gut microbiome

Another major benefit is that it helps regenerate the cells lining your gut, protecting against increased intestinal permeability. “Nearly 60% of our immune cells are found in the gut,” the doctor points out. But that’s not all. Dr Killian also explains that your microbiome allows the body to produce certain vitamins, such as vitamins K and B12. It supports bone growth and helps maintain the body’s iron balance. And last but not least, scientific studies have also shown that the microbiome plays a role in producing neurotransmitters - chemical messengers that are vital for brain function. “For example, serotonin, often called the ‘happiness hormone’. That’s why people refer to the gut as the second brain,” the doctor explains. “To look after your gut microbiome, start by avoiding anything that could damage or destroy it,” advises Dr Killian. There are many things that can upset the delicate balance of your gut bacteria. “They include taking antibiotics and other medications, chronic stress and anxiety, lack of sleep, artificial sweeteners, and toxins like alcohol, drugs, or tobacco. Not to mention pollutants, bacterial infections, and overexercising,” the doctor continues. Other factors beyond our control, such as age, menopause and pregnancy, can also negatively affect the microbiome. Subheader

How an unbalanced gut microbiome can put you at risk of illness

“It's said that your gut reflects your diet.” We can help our gut bacteria by making changes to our eating habitats, cutting down on foods that are high in fat, sugar, and animal proteins. Good news for those living in southern climes: the Mediterranean diet is believed to be excellent for maintaining a health gut balance. “It’s proven to promote a diverse bacterial community as it’s high in fibre and prebiotics, found in fresh fruit and vegetables, whole grains, and legumes.” But what are the risks of having an imbalance in the gut microbiome, and what illnesses can it cause? “The most common symptoms are repeated digestive issues: constipation, chronic diarrhoea, or alternating between the two,” explains Dr Killian. “You may also experience bloating, stomach pain or abdominal discomfort cramps, or acid reflux.” And even certain rheumatic diseases, inflammatory conditions, and depressive symptoms. ““I see many patients who come to me with skin problems like psoriasis or eczema. And since our gut is our second brain, it can also play a role in chronic anxiety or low mood.” Subheader

Fibre: a precious ally for your gut bacteria

“To maintain or restore your gut bacteria, aim for a fibre-rich diet, with plenty of fruit, raw and cooked vegetables, legumes, and whole grains,” recommends Dr Killian. Fibre - found in plant-based foods - cannot be digested by the human body. “That means from the moment it’s eaten until it’s passed out of the body, fibre comes into contact with the bacteria living in the digestive tract. Friendly bacteria can feed on the fibre, and are able to grow and develop,” explains the doctor. There’s another important benefit too: fibre helps to prevent constipation. The ideal intake is between 30 and 45 grammes of fibre every day. “I recommend eating raw vegetables mostly at lunchtime, and cooked vegetables for dinner in the evening. That way, they can be more easily digested overnight. The top sources of fibre include prunes, bran cereals, wholemeal bread, almonds, walnuts, as well as dried fruits and green beans.” Probiotics can also be a useful addition to a balanced diet. They are found in certain supplements and foods that have undergone a natural fermentation process, like yoghurt, kefir, or miso. Subheader

Diagnosis and probiotic treatment

Probiotics are live bacteria that develop gradually in the intestine if fed properly. For some patients with functional bowel disorders, the doctor recommends taking probiotics year-round. However, this isn’t necessary for everyone. “I like to think of the microbiome as a garden that needs tending every day. If the soil is good, you don’t always need to add fertiliser. But if you’re stressed, have a poor diet, not getting enough sleep, or taking medications or antibiotics, every day you destroy a few more of the friendly bacteria in your gut. That’s when you need to take probiotics regularly, to balance things out,” he argues. As a preventative measure, the doctor recommends two one-month probiotic courses each year: one in April to prepare for summer, and another in September to boost your immune defences before winter. With the wide variety of probiotic products available on the market, it’s strongly recommended to seek advice from a doctor specialising in micronutrition or a trained pharmacist. Dr Killian also points out that in some cases, micronutrition has its limits. “It can deliver very good results, but it cannot replace conventional medicine. It should be used alongside conventional treatment, or sometimes as an alternative in specific cases where conventional medicine doesn’t provide a complete solution,” he concludes.