Trillions of bacteria live in our digestive system. This microbiome is composed of 1000 different types of bacteria. It is defined during delivery and the first three years of life. Every human being has its own specific microbiome, like fingerprints. (1,2)
These bacteria living in our digestive system constantly interact with all our organs. When our guts are imbalanced, it impacts our bodies in various ways.
As this microbiome is linked to many of our body systems, it influences and is influenced by our overall health. A comprehensive approach is essential to rebalance it. The gut is a living organ, and it needs to be taken care of in a holistic way, a little bit like a plant that needs sun, water, nutrient, and love to grow. (3)
What are the most important factors influencing our gut's health?
Diet
Diet is, of course, the first step to improving your intestinal flora. It is a cooperation between our body and the microbiome. The bacteria living in our intestines digest our food, which helps the digestive system do its job, and it is a way for them to be nourished. We feed them, and they're allowing us to function better.
Which food is the best for our intestinal flora?
1/Fibers
Bacteria in our digestive system are mainly eating fibres. Fibre is composed of long molecules of carbohydrates. You can find fibre in fruits, vegetable wholegrain, nuts and seeds, beans, and lentils. Fibre is commonly classified as soluble, which dissolves in water, or insoluble, which doesn't dissolve.
Soluble fibre can help lower blood cholesterol and glucose levels. It is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium.
Insoluble fibre promotes bowel movement and benefits those who struggle with constipation or irregular stools. Whole-wheat flour, nuts, beans, potatoes, and cauliflower are good sources of insoluble fibre.
During food processing, fibre is removed, and white flour is relatively fibreless.
We need a certain amount of fibre to stay healthy. In our industrialised country where the food is processed, many people don't reach this quantity of fibre per day. People often need to reshape their diet completely to get this amount, introducing whole food and less processed food. (4)
2/Healthy fat
Healthy fats are not prebiotics, as the bacteria don't "eat" them. Fatty acids, especially omega 3, act as a booster for intestinal flora. They regulate the abundance and the type of microbes, enhancing healthy bacteria and promoting diversity. They also have an anti-inflammatory effect and regulate the production of short-chain fatty acids by the intestinal flora. These short-chain fatty acids are essential molecules produced by the intestinal microbiome and one of the ways our intestinal flora interacts with our organs. They are powerful antioxidants that promote our health in many ways. (5)
3/Hydration
Good hydration is critical for our body, particularly in our digestive system. Hydration impacts the gut lining, which corresponds to all the cells and membranes that pave the walls of our intestines. Hydration also affects PH in the intestines. These two actions have an indirect impact on the quality and diversity of the microbiome.
4/ Fermented foods
Fermented foods are made with the help of natural bacteria or yeasts, creating a beneficial change in the nutritional value of these foods. These natural bacteria are probiotics; they are part of the healthy bacteria of our intestinal flora.
There are many types of healthy bacteria in the gut. When we take probiotics, we add a kind of beneficial bacteria and increase their population. It also positively impacts other types of bacteria by reducing inflammation and creating a favourable environment for their growth.
The Holistic approach
"Stress and depression can reshape the gut bacteria's composition through stress hormones, inflammation, and autonomic alterations" (6)
Science has shown that intestinal flora is extremely sensitive to stress and hormonal imbalance during the past few years. To recreate a healthy gut, rebalancing the diet "only" is sometimes not enough. It is, therefore, a matter of having a more comprehensive approach to improving our lifestyles.
What factors can have a positive impact on our intestinal flora?
1 Exercise
Regular exercise is essential for the health of our intestinal flora. Any type of exercise is excellent. The most important thing is to do an activity that suits your body, health, and tastes. Practising a regular workout is more beneficial than practising intensively. The best exercise for you is the one you enjoy the most because it will be the one that you do the most regularly.
2/Stress management
The intestinal flora directly impacts our hormonal system and brain, but it also works the other way. When we are stressed, we produce some inflammatory molecules that damage our intestinal flora. It created then a vicious circle, where the imbalance of our gut decreases our ability to cope with stress, and stress decreases the quality of our guts.
There are a lot of techniques to cope with stress. Relaxation, meditation, visualisation, or crystals positively affect our ability to cope with stress and help protect our guts.
Essential oils and CBD are beneficial. CBD has been proven to be helpful for our guts. We have the same CBD receptors in our brain as in our digestive system, so somehow, CBD has the same relaxing effect on both organs. Studies have also shown that CBD directly impacts our microbiome by promoting specific types of healthy bacteria.
3/Sleep
Our digestive system and its microbiome are constantly working to digest the different foods we eat throughout the day. At night, they must take the time to regenerate and reset. If we eat late foods that need more time to digest, we fall asleep with a digestive system that continues to work and therefore does not rest properly. Eating early on a dinner low in saturated fat, sugar, and alcohol gives it time to regenerate adequately and better health.
Our gut microbiome is a living friend within us that protects us from the environment and improves the functioning of our bodies in several ways. Like any living thing, it also needs care and protection to stay healthy and robust, and it is our responsibility to take care of it as we take care of ourselves.
2. The emerging world of the fungal microbiome Gary B. Huffnagle1 and Mairi C. Noverr2
3. Mitsuoka T. Intestinal flora and human health. Asia Pac J Clin Nutr. 1996 Mar;5(1):2-9. PMID: 24394457.
4. Myhrstad MCW, Tunsjø H, Charnock C, Telle-Hansen VH. Dietary Fiber, Gut Microbiota, and Metabolic Regulation-Current Status in Human Randomized Trials. Nutrients. 2020;12(3):859. Published 2020 Mar 23. doi:10.3390/nu12030859
5. Costantini L, Molinari R, Farinon B, Merendino N. Impact of Omega-3 Fatty Acids on the Gut Microbiota. Int J Mol Sci. 2017;18(12):2645. Published 2017 Dec 7. doi:10.3390/ijms18122645
6 .Published in final edited form as:
Curr Opin Behav Sci. 2019 August ; 28: 105–110. doi:10.1016/j.cobeha.2019.01.011.
Stress, depression, diet, and the gut microbiota: human– bacteria interactions at the core of psychoneuroimmunology and nutrition
Annelise Madison1,2, Janice K Kiecolt-Glaser1,3