The billions of microorganisms that inhabit our digestive tract play a vital role in many of the body’s functions. The balance of this well-organized population, known as the gut flora or microbiota, depends on many factors.
As a result, an imbalance in the gut flora—or gut dysbiosis—can cause a variety of health issues. This article explores the signs of gut dysbiosis, its causes, and its major consequences. You’ll also learn more about ways to restore your microbiota to regain comfort in your daily life.
What is the gut microbiota?
Generally speaking, the term “microbiota” refers to the collection of microorganisms (nonpathogenic bacteria, viruses, parasites, and fungi) that live in a specific environment. There are various types of microbiota in our bodies, found on the skin, in the mouth, in the vagina, in the intestines, and so on.
The gut microbiota is the largest of these, containing 10¹² to 10¹⁴ microorganisms. That’s 2 to 10 times more than the number of cells in our bodies, weighing in at 2 kilograms!
This gut microbiota is primarily located in the small intestine and the colon (since gastric acidity renders the stomach lining virtually sterile).
Although its existence was discovered over a century ago, the means to study it remain limited, and the functions it performs in the body have only recently been elucidated.
It is now well established that, beyond its digestive functions alone (energy absorption, fat storage, appetite regulation, etc.), it plays a role in our body’s metabolic, immune, and neurological functions, including skin appearance and psychological well-being. This explains why gut dysbiosis can contribute to a wide range of diseases and represents a key avenue for prevention.
What is intestinal dysbiosis?
Intestinal dysbiosis is an alteration in the composition and function of the gut microbiota: the term often refers to an “imbalance in the gut flora.” Most often, this imbalance is caused either by a decrease in the diversity of the microbiota, a decrease in beneficial populations, or an overgrowth of pathogens.
Causes of an imbalanced gut flora
The most significant factors in the development of gut dysbiosis are believed to be diet and medications. However, there are many others(1):
- A diet high in sugars and low in fiber. Diets high in simple sugars can disrupt the intestinal barrier, promote intestinal inflammation, and alter metabolism.
- Medication and other xenobiotics. These substances can profoundly alter the composition of the microbiota and promote the proliferation of potentially harmful microorganisms.
- Food additives: preservatives, emulsifiers, and artificial sweeteners (such as sucralose, which is used in table sugar, processed fruits, chewing gum, salad dressings, etc.). These compounds have been linked to an increase in certain bacteria from the Proteobacteria group and to increased intestinal inflammation.
- Infections and inflammatory conditions. Infectious diseases (e.g., the COVID-19 virus), even when they do not directly affect the digestive tract, can induce dysbiosis.
- Host-specific factors (genetic predisposition, immunity, digestive secretions). For example, the role of gastric acidity, bile acids, defensins, lysozyme, and intestinal immunoglobulins (IgA), which normally help regulate the microbiota.
- Certain lifestyle habits and environmental factors (diet, hygiene, physical activity, etc.). A healthy lifestyle may help reduce the risk of chronic and infectious diseases.
What are the signs of dysbiosis?
The first signs of an imbalance in the gut microbiota are digestive in nature:
- Bloating and gas,
- Diarrhea or constipation,
- Abdominal pain.
However, its effects can be much broader and affect the body beyond the intestines. For example, an imbalanced microbiome can lead to chronic fatigue, mood disorders, skin problems, weight gain, or a weakened immune system.
The consequences of an imbalanced gut microbiome
While gut dysbiosis can cause daily discomfort, it can also lead to more serious consequences.
1. Digestive System Diseases
An imbalance in the gut microbiota can be responsible for digestive disorders ranging from simple, temporary diarrhea to inflammatory bowel diseases (IBD): Crohn’s disease, irritable bowel syndrome (IBS), ulcerative colitis, colorectal cancer… (2).
2. Infectious Diseases
The gut microbiota plays a crucial role in the proper functioning of the immune system. It is capable of identifying pathogenic species and destroying them, acting as a barrier at the level of the intestinal wall.
Dysbiosis can thus increase susceptibility to infectious diseases, such as Clostridioides infection or COVID-19, which affects the nasal mucosa and the respiratory system, as well as the digestive system. It is thought to contribute to severe forms of COVID-19 due to the mutual influence of the gut, lung, and airway microbiomes(2).
3. Obesity and Diabetes
A decrease in one group of bacteria (Bacteroidetes), coupled with an increase in another (Firmicutes), could lead to the microbiota’s ability to store energy from food more easily. This would thus result in an increased risk of obesity(3).
The gut microbiota also plays an essential role in insulin resistance and in maintaining normal blood sugar levels(4). Diabetes, however, is precisely a disease characterized by insulin resistance, which leads to excessively high blood sugar levels. Furthermore, studies conducted on diabetic patients have shown that most patients exhibit a significant decrease in butyrate-producing bacteria and an increase in opportunistic bacteria that cause chronic inflammation(4).
4. Cancers
A number of studies have concluded that certain tumors are linked to the presence of specific microorganisms or to intestinal dysbiosis. For example, it has been established that an imbalance in the microbiota favoring certain species (such as Fusobacterium) increases the risk of colorectal cancer (5), and that the presence of Helicobacter pylori promotes the development of gastric cancer.
Some studies also point to a correlation between regular antibiotic use (which disrupts the balance of the gut microbiota) in young women and the development of breast cancer (6).
5. Depression, anxiety, schizophrenia
The functioning of the human brain is influenced by the gut microbiota(7). In fact, the nervous system that controls the gut alone contains 200 million neurons. Its primary function is to regulate intestinal motility; however, 80% of these nerve cells transmit information from the gut to the brain... Thus, an imbalance in the microbiota is likely to alter the information transmitted to the central nervous system.
Some preliminary studies now suggest that dysbiosis is a risk factor for depression and anxiety, among other genetic, epigenetic, environmental, and psychological factors (8). Imbalances in the gut microbiota are thus observed in patients with anxiety or depression.
In people with schizophrenia or bipolar disorder, the balance between various pro-inflammatory and anti-inflammatory cytokines (substances produced by the immune system) in the blood is disrupted. These cytokines are directly mediated by substances present on the surface of certain bacteria, which are naturally found in the gut microbiota(9).
6. Alzheimer’s and Parkinson’s Diseases
Gut dysbiosis may indeed be involved in the process of brain inflammation associated with Alzheimer’s disease, which is responsible for significant cognitive decline. Researchers have also demonstrated that a tailored diet—rich in probiotics and anti-inflammatory compounds—can slow the progression of the disease by combating intestinal permeability(10).
As for Parkinson’s disease, the severity of its symptoms appears to be correlated with the concentration of a particular species of bacteria (Enterobacteriaceae) in the gut microbiota(11). The various mechanisms underlying these two degenerative diseases may be mediated by neuroactive substances of bacterial origin.
7. Chronic Fatigue Syndrome, Fibromyalgia
It appears that the gut microbiota of people with chronic fatigue syndrome has higher concentrations of certain bacteria (Faecalibacterium, Roseburia, Dorea, Coprococcus, Clostridium, Ruminococcus, Coprobacillus) than that of people who do not have the condition(12).
Regarding fibromyalgia, increasing the intake of prebiotics and probiotics to rebalance the gut microbiota helps reduce pain (which is often extremely severe) and combat inflammation(13).
8. Asthma and Respiratory Allergies
Researchers have highlighted the role of four types of gut bacteria in the prevention and treatment of asthma. Acquiring these bacteria within the first 100 days of life may help protect newborns against this disease. One study showed that young patients had a deficiency in four bacteria (Faecalibacterium, Lachnospira, Veillona, and Rothia) that are normally acquired naturally by infants(14).
Another study shows that oral administration of a specific antibiotic capable of altering the composition of the gut microbiota can reduce symptoms in adults with severe asthma(15).
As respiratory allergies affect an increasing number of people, a link has been established between an imbalance in the gut microbiota—which influences immunity at a very early stage—and seasonal allergies. It appears that increased exposure to antibiotics starting in childhood, which disrupts the balance of the microbiota, reduces the effectiveness of the type 2 immune system—precisely the system that regulates our ability to fight off allergens that cause respiratory conditions (16).
What to eat if you have intestinal dysbiosis?
Diet plays an important preventive role in maintaining a healthy gut microbiome. Here are a few tips to effectively support it, preserve its diversity, and ensure it functions properly:
- Eat fiber: Gut bacteria feed on fiber (prebiotics), so it’s beneficial to increase your intake through whole grains, legumes (lentils, chickpeas, white beans, flageolet beans, split peas), vegetables (especially asparagus, artichokes, leeks, garlic, onions, green peas, cabbage…) and fruits (especially passion fruit, bananas, and berries).
- Avoid additives: Sweeteners in processed foods increase levels of Bacteroides and Clostridiales, which alter metabolic functions, leading to increased insulin resistance and contributing to diabetes and obesity. Emulsifiers, on the other hand, cause intestinal inflammation that disrupts the satiety signals sent to the brain.
- Include fermented foods: Fermented foods (kimchi, kombucha, miso, sauerkraut) and dairy products (kefir, yogurt, cheese) are rich in live microorganisms that enrich the microbiome.
- Opt for gentle cooking methods: Steaming increases the digestibility of fiber.
- Choose the right fats: Opt for raw, first-press cold-pressed virgin oils, such as camelina, walnut, canola, and flaxseed oils. Also consider fatty fish (salmon, tuna, sardines, mackerel). Omega-3s play an important role in the composition and metabolic activity of the microbiome.
- Eat foods rich in glutamine: Glutamine is an amino acid that helps restore the intestinal barrier. You’ll find it in fish, eggs, dairy products, cabbage, parsley, and more.
- Limit meat: Foods high in animal fats increase the proportion of Bacteroides and Firmicutes bacteria that produce metabolites. These bacteria promote local inflammation, which causes the vagus nerve to become less sensitive to satiety signals sent to the brain, resulting in reduced appetite regulation. It is therefore best to choose low-fat protein sources (fish, soy products, legumes).
- Consume sugar in moderation: Refined industrial sugar, as well as chemical sweeteners, disrupt the balance of gut flora, favoring harmful fungi such as Candida albicans.
- Avoid alcohol: Alcohol also tends to disrupt the balance of gut flora.
Which probiotic is best for dysbiosis?
After taking antibiotics, dealing with a gut infection, or even after the holidays or periods of stress that affect the gut flora, it’s essential to restore your gut microbiota.
To do so, you can choose Glutaform Digestive Comfort, which contains L-glutamine—an amino acid that acts on the cells of the intestinal mucosa—along with Maxi-Flore Comfort+, a probiotic complex that supports digestive comfort.
Probiotics have three major effects:
- They modulate the activity of the intestinal immune system(17). They strengthen immunity when it is weak and reduce overactivation of the immune system, particularly in cases of allergies or intestinal inflammation.
- They enhance the barrier function of the intestinal mucosa.
- Finally, they have direct antimicrobial effects by displacing pathogenic bacteria and preventing them from adhering to the intestinal walls.
In this way, they help the microbiota regain its diversity of “good bacteria” that are beneficial to the body and assist it in combating excess harmful bacteria that interfere with the proper functioning of our immune system, our metabolism, and gut-brain communication.
After an initial one-month course of treatment, it is recommended that you follow a maintenance regimen of one to two doses per week and take probiotic supplements when you are not in a “high-risk” period.
Finally, keep in mind that the leading cause of microbiota imbalance is antibiotic use. Take antibiotics only when absolutely necessary, as prescribed by your doctor.
