The microbiome is a set of trillions of microorganisms (also called microbiota or microbes), containing thousands of different species that mostly inhabit the small intestine and colon of a healthy person, coexisting at the same time and helping us to perform many key functions in daily operations.


Today we bring you the top 10 facts about the microbiome & nutrition, which we hope will help you understand more about the role these “bugs” play in our bodies!


1. The gut microbiota is not a static thing. It changes throughout life after first colonising the gut shortly after birth and continuing to gather new members from the environment throughout life. Variation is highest during childhood, and it gradually decreases with age, illness, antibiotic use, fever, stress, injury, and dietary changes, all of which affect the blend of microbes that make up the microbiome.


2. Diet. The food we eat can have a significant impact on the gut microbiome. Many food ingredients are not absorbed by the body but rather are substrates for the metabolic activity of the intestinal microbiota, which can then produce other useful molecules for the host. A diet high in fibre and plant-based foods has been shown to support a diverse and healthy gut microbiome, while a diet high in sugar and processed foods can have the opposite effect. Read more about the influences of diet and gut health here.


3. Considered the most beneficial, the Mediterranean diet contains a high content of polyphenols. Although these molecules are not absorbed in the intestine, they are metabolised by the intestinal microbiota, giving rise to different phenolic acids. We can find them in foods of plant origin.


4. Relationship between peptides and the immune system. The peptides produced during the fermentation of some foods with microorganisms such as fermented milk or yoghurt, influence the immune system by maintaining the level of immunoglobulin IgA (a type of antibody). Different studies in experimental models show that the consumption of yoghurt or fermented milk can support greater resistance against infection.


5. There is an existence of the brain-gut axis, which connects the central nervous system with the intestinal microbiota through the vagus nerve, the parasympathetic system, bacterial metabolites (which can have actions as neurotransmitters), and the endocrine system associated with the digestive tract. Thus, in addition to the diseases that have classically been associated with alterations in the microbiota, such as obesity, type 2 diabetes, inflammatory bowel disease and allergies, other diseases of the central nervous system have also recently been associated, such as autism, anxiety, depression, and alcohol dependence.


6. Probiotics are live microorganisms that –administered in adequate amounts– positively modulate the composition and reinforce the barrier effect of the intestinal microbiota. Therefore, they constitute a complement of beneficial bacteria for health.

These bacteria or yeasts have a limited life in the intestinal microbiota (from a few days to 2 or 3 weeks).

Probiotics are present in food or available in the form of food supplements.

Foods that contain probiotics:

  • Sauerkraut
  • Plain live yoghurt
  • Kombucha
  • Miso or fermented soybeans
  • Kimchi
  • Kefir
  • Pickles
  • Buttermilk


7. Prebiotics are “food” for the microbes in your gut. Not being digested in the human stomach, they pass into the intestines and serve as a growth substrate for beneficial bacterial genera of the microbiota. On the other hand, the risk they have is that, if we eat them in large quantities, they can cause discomfort due to the production of gases as they are fermented by the microbiota.

Some foods that act as prebiotics are:

  • Vegetables: such as garlic, onions, artichokes, asparagus, leeks, and chicory
  • Fruits, especially bananas and berries
  • Whole grains: whole wheat and oats
  • Legumes and nuts


8. Foods that we should reduce or minimise from our diet for a strong microbiome and immune system:

  • Soft drinks
  • Processed and some frozen foods, have large amounts of sugar, salt, carbohydrates, and saturated fats (french fries, ready meals, pizzas…)
  • Alcoholic beverages
  • Refined carbohydrates, such as white pasta and white bread, even more so if we accompany it with sugary drinks such as soft drinks, fruit juices, or sweetened coffees
  • Although its use can be used for the flavour of food, its excessive consumption can lower our defences. Excess salt causes infections and immune deficiencies against some bacteria.
  • Although it’s completely fine to consume 1-2 cups a day, consuming large amounts of this drink could affect our health

Foods and drinks high in added sugars. The WHO recommends limiting your free sugar intake to no more than 10% of your overall energy intake, per day. Free sugars are those added to foods/drinks, or that found in honey, syrups and juices.


9. Hydration. The intestine is mucosa and therefore needs water to be hydrated.
Tips to stay well hydrated:

    • Drink water (approximately 8 glasses of water a day)
    • Eat foods rich in water (there are many fruits and vegetables with a high-water content. For example, watermelon, cucumber, tomatoes)
    • Avoid the consumption of alcoholic beverages because they dehydrate us


    10. Exercise and rest. Moving (walking, climbing stairs etc.) and exercising (patterned, structured sequences that make it harder to breathe when you do it) are very important since exercise increases anti-inflammatory bacteria species and reduces pro-inflammatory bacteria in the intestinal microbiota.

    Practicing it daily improves the microbial composition of the flora and prevents obesity and other diseases.

    On the other hand, rest is just as important. Rest refers to two important things:

    • Sleeping well at night and having a good night time routine
    • Having good management of stress and emotions

    We know that it is impossible to live without any stress, the key is to learn to manage it and get along with it.

    You might be interested in reading more in our blogs: Probiotics and Prebiotics: The Benefits of Gut Health, Zoe Diet Review

    We hope you enjoy these facts! By Nadia Pico, dietetic student, revised by Reema Patel, Registered Dietitian at Dietitian Fit & Co.



    1. J.R. Marchesi, J. Ravel. The vocabulary of microbiome research: A proposal. Microbiome., 3 (2015), pp. 31
    2. Cho, J. Martin, M.J. Blaser. The human microbiome: At the interface of health and disease. Nat Rev Genet., 13 (2012), pp. 260-270
    3. Arumugam, M., et al. Enterotypes of the human gut microbiome. 2011 May 12;473(7346):174-80.
    4. Ursell, L.K., et al. Defining the Human Microbiome. 2012 Aug; 70(Suppl 1): S38–S44.