- High protein consumption from red and/or processed meat is associated with the production of metabolites that increase the risk of colorectal cancer.
- Amino acid fermentation can have both beneficial and negative effects.
- Adequate fiber intake reduces the harmful effects of high protein consumption.
Gut bacteria and gut microbes: the inner ecosystem
In biology, the term microbiota refers to all the micro-organisms living in a specific environment, called the microbiome, in an animal or plant host.
The body is home to several microbiomes.
Unsurprisingly, the intestinal microbiota plays the most important role in digestive health but is also a pillar of the immune system . It contains over 100,000 billion - yes, we didn't add too many zeros - microorganisms, 99% of which are made of various species of bacteria, the remaining 1% being a mix of viruses, parasites and yeasts.
Each individual has his or her own microbiota, a bit like having his or her own fingerprints. That said, there are commonalities between people, with around 10% of the microbiota common to the human species.
A further 30% comes from our genetic heritage and individual evolution, with things like:
- Our gender.
- The way we came into the world (natural way or C-section).
- Where we live.
- Our age.
The rest is influenced by eating habits and physical activity. There is therefore a fixed proportion, but also plenty of room for adaptability.
Geography of the human gut microbiota
The gut microbiota is not evenly distributed, in quantity and quality, throughout the digestive tract. The stomach, for example, because of its highly acidic environment, contains very few bacteria. And that's a good thing, because it's what allows us to kill off various pathogens before they can make us sick. In contrast, the large intestine is the most densely populated area. By far. It's the site of bacterial fermentation, nutrient metabolism, the production of certain vitamins and so on.
How our diet affects our gut microbiome
To date, no particular diet stands out in terms of microbiota health. But some major trends have been identified.
A varied diet rich in fruit, vegetables, whole grains and legumes (and therefore fiber) is a constant among populations with the healthiest gut.
Conversely, a diet leaning too much towards fats and proteins is associated with poor microbiota health and diseases such as type 2 diabetes or colorectal cancer. The good news is that it can take as little as 24 hours of better nutrition to start producing beneficial effects.
The essential thing here is to understand how the bacteria of the gut develop, live and die. Whatever we do, we have and will always have a microbiota. It's not something that disappears, but something that evolves. And it evolves according to what we feed it. Let's take a look at the main influencers of this field.
Carbohydrates
- Complex carbohydrates, fiber and resistant starch are associated with good bacterial diversity.
- Replacing refined carbohydrates with less or unprocessed sources feeds the production of bacteria and metabolites beneficial to health.
- Reducing complex carbohydrate intake or total carbohydrate intake leads to a decline in bifidobacteria.
- Insufficient fiber intake is associated with thinning of the intestinal wall (which can allow toxic compounds to pass into the body: this is endotoxemia), disruption of biogeography, and suppression of the beneficial effects of physical exercise.
Fats
- A high-fat diet (>40% of total calories) reduces bacterial diversity and is linked to low-grade inflammation.
- Saturated fats may sharply increase the levels of lipopolysaccharides, responsible for low-grade inflammation too.
- Omega-3s, on the other hand, do not cause this rise, and may increase the number of good bacteria.
- High fat consumption at the expense of carbohydrates and fiber is associated with reduced bacterial diversity and proliferation of pro-inflammatory bacteria.
Protein
Alcohol and coffee
- In observational studies, moderate consumption of red wine is associated with greater bacterial diversity.
- The chlorogenic acid contained in coffee is thought to have a positive effect on intestinal microbiota.
Gut health and immunity
As mentioned above, a healthy microbiome plays a major role in the functioning of the immune system. And this is true from the very first days of life.
Birth and childhood: a key period for establishing a solid immune base
The way in which a baby is born, whether naturally or by C-section, has a significant influence on the development of its intestinal microbiota and, consequently, its immune system.
- During vaginal delivery, the baby is exposed to micro-organisms present in the mother's vagina and perineum. This allows early colonization of the gut by beneficial bacteria such as Lactobacillus, Bifidobacterium and other commensal bacteria.
- This early microbial exposure plays a crucial role in the maturation and development of the infant's immune system. It helps distinguish beneficial microorganisms from pathogens, thus contributing to a balanced immune response.
- Conversely, babies born by C-section do not benefit from direct contact with the maternal vaginal microbiota. Their initial intestinal colonization is therefore delayed and often dominated by environmental bacteria present in the hospital, such as Staphylococcus, Corynebacterium and Clostridium, which are not necessarily the most favorable for the development of infant health.
- This difference in microbiota composition can affect the development of the immune system. Babies born by C-section have an increased risk of developing certain health conditions linked to microbiota imbalance, such as asthma, allergies , eczema and inflammatory bowel disease.
Then, during childhood, the immune system continues to mature and develop. Even if they are not all related to the microbiota, the key factors to support immune resistance in children are:
- A diet rich in prebiotics, probiotics and fiber to maintain intestinal health.
- Exposure to diverse foods and environments to boost immune responses.
- Regular physical activity, which positively influences the composition of the intestinal microbiota.
Adolescence and adulthood: lifestyle, diet and immune resistance
In adolescence and adulthood, various factors can have an impact on intestinal health and immune function:
- A balanced diet and regular physical activity optimize immune function.
- Stress management is essential to maintaining a healthy intestinal-immune axis.
- Increasing consumption of some fermented foods (more on this later) is beneficial for the intestinal microbiota.
Ageing: reducing chronic inflammation and supporting immunity
With age, changes in the intestinal microbiota can have an impact on immune function:
- Ageing often reduces microbial diversity, which can be compensated for by a diverse and fiber-rich diet.
- Fermented foods, prebiotics and anti-inflammatory nutrients boost immune resistance in the elderly.
- Targeted nutritional interventions can help mitigate the effects of immunosenescence.
By understanding the vital link between the gut microbiome and the immune system, we can develop targeted strategies to support immune health throughout life. From innovative infant nutrition to lifestyle interventions for adults and the elderly, maintaining a healthy gut-immunity axis is essential for promoting overall health and preventing disease.
Feeding your gut
There are many ways to support your health through what you eat.
Your food supplies energy, vitamins, minerals and a combination of dead or live microbes and their metabolites are associated with health. Scientists study bacterial strains to understand more about the specific benefits of different ones.
For example:
- Saccharomyce boulardii, Lactobacillus casei, Lactobacillus acidophilus help with traveler's diarrhea (Tourista!) or after antibiotics
- Lactobacillus rhamnosus GG, Saccharomyce boulardii are useful in case of diarrhea in young children
- Irritable bowel syndrome can be alleviated by Bifidobacterium infantis, Lactobacillus plantarum, Lactobacillus rhamnosus, or Bifidobacterium breve
- VSL-#3, a patented blend of 8 bacterial strains, helps claming down inflammatory bowel diseases
- A for pre-biotics, nutrients that nourish the intestinal microbiota, a varied diet rich in fruits, vegetables, and complex carbohydrates (and therefore fiber) is recommended.
The gut microbiome: a new world of possibilities waiting to be discovered
The human gut microbiome has emerged as an area of research with immense potential to revolutionize our approach to diet, disease prevention and personalized healthcare.
Each individual microbiome is complex, as it is made up of unique patterns of microorganism populations. This calls for advanced research techniques. Thus, the integration of artificial intelligence and machine learning has become essential to identify specific bacterial strains useful (or harmful) to each individual, and to understand their functions. These technological advances pave the way for more targeted and effective solutions based on the microbiome.
The future of microbiome science
As research progresses, several key areas are emerging as particularly promising:
Personalized nutrition
The unique nature of each individual's microbiome opens the door to highly personalized nutritional solutions. By analyzing a person's gut microbiota, scientists could potentially develop tailored dietary recommendations to optimize health outcomes. This approach could revolutionize how we think about nutrition, moving away from one-size-fits-all diets to truly individualized plans.
The gut-brain axis
The connection between the gut and the brain is becoming increasingly clear as convincing studies show a gut-brain interaction where microbes play a very important role. This research could lead to breakthroughs in managing mental health and neurological conditions through dietary interventions.
Immune system boosting
With a significant portion of our immune system located in the gut, understanding the microbiome's role in immunity is crucial. Future research could lead to the development of foods that support our immune cells and strengthen our natural defenses against disease.
Obesity and metabolic health
The microbiome's influence on metabolism and satiety could provide new avenues for addressing the global obesity epidemic. By modulating gut bacteria, it may be possible to develop foods that naturally promote weight management.
OneBiome: a new era in nutrition
Research on the gut microbiome has revolutionized our understanding of how diet, health, and gut bacteria interact. Today, this scientific progress is translating into concrete solutions, such as those developed by Danone Research & Innovation , which explores how nutrition can positively influence the microbiome to enhance overall well-being. Among these innovations, OneBiome stands out as a major breakthrough in personalized dietary recommendations. This expertise was founded on a collaboration between our microbiome and digital services experts based in Singapore. Our goal is to translate complex microbiome data into actionable health insights for consumers, making microbiome science more accessible and impactful.
Using advanced DNA sequencing and artificial intelligence, OneBiome provides individuals with tailored insights into their gut health. The process follows four key steps:
- Sample collection: users provide a stool sample for microbiome analysis.
- Microbiome profiling: the sample is analyzed to identify bacterial diversity and detect imbalances.
- Data interpretation: AI-driven algorithms assess microbiome composition and its impact on health.
- Personalized recommendations: a customized report offers dietary and lifestyle guidance based on the individual’s unique microbiome profile.
The journey into the world of the microbiome has only just begun, but the promise of transforming human health is undeniable. As science continues to unravel the mysteries of our gut inhabitants, we're moving closer to a future where nutrition isn't just about calories and nutrients, but about fostering a thriving internal ecosystem that contributes to our overall well-being.
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- The Science of Gut Health: What the Research Really Says About Your Gut Microbiome. Dr. Gabrielle Fundaro and Dr. Jessie Hoffman. Renaissance Periodization Editions. 2021.
