A gut feeling… Microbiome is the complex of trillions of living organisms that live in
(digestive tract) and on (skin/hair/nails) the human body. An estimated 100 trillion
microorganisms live in the gut alone, that is actually close to ten times the number of cells
that make up the body itself! These organisms help the regulation of the immune,
endocrine, digestive and metabolic systems.
Being that said, it is important to acknowledge that bacterium diversity, and
overall balance are connected to our states of health and disease. If we imagine that in
terms of cells, our gut has a surface of around 20’000 squared meters, we can also guess
that promoting health here is essential for longevity and for keeping diseases at bay. More
than 70% of the human immune system is found in the lining of the gut.
Among the different classes of bacteria, bifidobacteria are the most important and
beneficial bacteria of the gut microbiome. These are the responsible bacteria for digesting
fibre and other complex carbs, producing vitamins of the B group and K and short chain
fatty acid, which have an important role for general health.
When we are babies, we have mostly Bifidobacteria populating the microbiome, as children,
our bodies have an abundance of bifidobacterial, but as we age, factors such as poor diet,
stress and antibiotic use, decrease the levels of these good organisms.
According to research, the proportion of healthy bifidobacteria in the human gut is
about 60% in infancy, 30%-40% in adulthood,10% in late middle age, and less than 5% by
advanced age. Keeping levels as high as during infancy, allows the microbiome to perform
its health benefits, such as fighting allergies, drecreasing high cholesterol levels, aiding
respiratory diseases, relieving stress, and anxiety.
Less Bifidobacteria means more room for unhealthy, dangerous bacteria to take over. On
my practice, I see 90% of adults having too much of Clostridia Cluster I on their stools and
almost 20% only of Bifidobacteria, confirming research that the level tends to decrease over
time.
The gut microbiota is in constant evolution, varies greatly among individuals, and modulates
metabolism, allowing a window to predict individual responses to particular foods as part of
personalized medicine interventions.
The microbiome can become imbalanced through poor diet (high protein + high fat), drugs
(antibiotics), unhealthy lifestyle (smoking, sedentary), and toxins (heavy metals). This leaves
a state in which a relatively small number of microorganisms attain an unhealthy
dominance, often squeezing out the beneficial ones. This imbalance has direct connections
with practically every chronic metabolic disease in humans.
Like everything else in our body, Bifidobacteria need the right type of nourishment to grow
and multiply. Keeping in mind that we all have our own individual microbiome and
therefore should consult a physician for an individual diet, there are some general
guidelines that can be followed by all of us.
A Western-type diet in particular high in animal proteins and fat especially one including
large amounts of saturated fatty acids (vegetable and trans-fat oils), and low in fiber, has
been shown to induce gut dysbiosis, intestinal permeability, and inflammation.
A diet high in fiber and complex carbohydrates, on the other hand, supports the growth of
microbial populations that are efficient carbohydrate fermenters. These bacteria produce
short-chain fatty acids and other fermentation products that support the health of the
intestinal lining and have positive effects on immune and metabolic functions.
Bifidobacteria love complex carbohydrates (flaxseed meal), resistant starch (tapioca, sweet
potatoes), and fiber coming from legumes, fruits and vegetables, nuts, and whole grains.
These foods are the main ingredient of a healthy diet.
Omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and
docosahexaenoic acid (DHA) appear to improve the microbial balance and increase antiinflammatory
immune activity in the gut and throughout the body.
Fermentation, mainly by lactic acid bacteria, has been used to preserve and enhance
nutritional aspects of foods for thousands of years. Fermented foods are a source of
vitamins, minerals, enzymes, and a range of biologically active, health-promoting peptides
produced by microbes during fermentation.
The trick is keeping a varied and whole diet with no processed foods. Our microbiome needs
bacteria from all phyla and giving preference to one diet or another will lead to a
microbiome unbalance. An adult body needs no more than 60 net protein grams per day
from different animal origin such as eggs, meat, chicken and fish. The rest can be covered by
vegetable, resistant starch, whole grains, nuts, healthy fats (avocado).
Gut microorganisms have been shown to play a role in a wide range of human diseases,
including obesity, psoriasis, autism, and mood disorders. By modulating diet and helping the
good bacteria to thrive, we also decrease the risk of developing metabolic disorders, such as
obesity and diabetes. Together, these findings demonstrate the important role of gut
microbiota in maintaining host metabolic integrity.
Flint HJ, Duncan SH, Scott KP, Louis P. Interactions and competition within the microbial
community of the human colon: links between diet and health.
Walker AW, Ince J, Duncan SH, Webster LM, Holtrop G, Ze X, et al. Dominant and dietresponsive
groups of bacteria within the human colonic microbiota.
Topping DL, Clifton PM. Short-chain fatty acids and human colonic function: roles of
resistant starch and nonstarch polysaccharides.