How can our food choices affect bacteria in our digestive system and our health?

Heather Campbell
 min read

How can our food choices affect bacteria in our digestive system and our health?

How can our food choices affect bacteria in our digestive system and our health?The consumption of food is one of the essential activities for both us (humans) and bacteria.

As a general rule, eating food allows a living organism to function, live, grow, and renew itself. Not only us as humans, but also the bacteria in our digestive system. This is why we must weigh our nutritional decisions, because it directly affects the gut and hence the rest of our body.

Read on to learn how you can make sure that you’re consuming the right nutrients for your gut health.

How can our food choices affect bacteria in our digestive system and our health?

Food can be consumed because it contains nutrients, the compounds necessary to cover the physiological needs of the person who consumes it.

Bacteria in digestive system and us benefit from food

The nutrients that make up food are either assimilated directly without further modification, or after transformation through digestion (for humans) or fermentation (for bacteria and indirectly for us humans).

They meet the various needs of the cells by ensuring energy supply, metabolic regulation or even the molecules necessary for maintenance and renewal.

We usually talk about the necessary nutrients for our eukaryotic cells in all their diversity.

They are also useful for bacteria because if we are fine, then the bacteria are fine, especially through the reciprocity and complementarity of cooperation between bacteria and humans.

Feeding that bacteria well will also be beneficial to many of our organs, especially those that are the target of our collaborations and, therefore, indirectly responsible for our vitality.

How can our eating habits affect bacteria in our digestive system and our health is an important subject and merits your attention.

The food needs of bacteria

Recognizing the dietary needs of the huge and diverse population of bacteria that live in our bellies is important.

These nutrients must resist digestion and absorption in the upper part of our gastrointestinal tract (from the mouth to the small intestine) to fall into this category.

And these nutrients must be adapted to the specific needs of the bacteria and hence, must be non-digestible.

To satisfy the needs of the bacteria, 2 categories of these nutrients are necessary:

  • General colonic nutrients
  • Specific/selective colonic nutrients

General colonic nutrients

General colonic nutrients are able to quantitatively feed a large majority (if not all) of our bacteria in our colonic microbiota and maintain them.

This is the role traditionally assigned to so-called fermentable dietary fibers.

Specific/selective colonic nutrients

Their food value is reserved for a limited number of species of our colonic bacteria which are the only ones able to feed on them since they have the metabolic capacity to consume them.

Offering these privileged bacteria a nutritional advantage promotes their selective proliferation, and reinforces the functions associated with them in our microbiota.


In this second category, bacteria find the prebiotics that maintain their biodiversity in our own microbiota, respecting the symbiosis in the singular dialogue that a human maintains with bacteria.

The first nutrients of this category, to which we were exposed, were present in very large numbers, in our mother’s milk.

They played a key role in the postnatal implantation of bacteria in our colon and, therefore, awakened our immunity.

But, many prebiotics are also present in different fruits, vegetables, legumes, etc. In short, in all the foods preferred by bacteria.

Some of them are available in the form of commercialized food supplements. Our colonic microbiota can therefore benefit from their effects throughout our lives.

Prebiotics are essential to maintain the intrinsic biodiversity of our colonic microbiota.

They act on the pre-existing biodiversity of our microbiota, they maintain and strengthen it, but they do not increase it.

This requires the regular consumption of a wide variety of natural and sometimes prebiotic nutrients from all available plant food resources.

The prebiotic character must be understood as a constitutive property of these resources used in all their diversity.

High biodiversity is the primary quality of the colonic microbiota. This is the one to be maintained by our food. All our bacteria have their role to play because there is no argument to favor one over the other (except for those identified as pathogens that must be avoided).

Any nutrient that can support their growth and activity is good to take. All our gut bacteria deserve the best nutrition.

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Edible plants

On the other hand, bacteria love edible plants such as vegetables, legumes, fruits, whole grains, dry or sprouted seeds.

When they are the product of germination and then growth on living soil, they bring a wide variety of both categories of colonic nutrients into their natural matrices (the plant cells).

Therefore, bacteria prefers those that come from an organic farming practice or seasonal agroecology and consumed raw or cooked at a mild temperature.

When possible, they should be eaten with the skin or peel on, as the outer layer often hosts a large part of our colonic nutrients.


The different varieties of seaweed are often available dried and are rich in non-digestible and often fermentable nutrients.

Together, and in all their diversity, bacteria loves seaweed because it is the most efficient, the most adequate and the best adapted to the needs of the bacteria.


A final food completes this menu, pollen (frozen), sometimes identified as a super-organism, is rich in a wide variety of nutrients including probiotics and prebiotics.

Pollen is the male seed of flowers produced by the stamens. The bees collect a part of it which they mix with their salivary secretions and transport in the form of balls to the hive.

As the biodiversity of bacteria is the condition of their fundamental qualities, its maintenance can only come from a diversity of colonic nutrients, in particular prebiotics.

Tips for good vitality

If you want to have a good digestive system and enviable vitality, it is not enough to eat every day, and in all seasons, a few tomatoes, a little salad, a few potatoes (often in the form of chips or fries), an apple, a banana and occasionally carrots, some leeks, strawberries, grapes, etc.

To ensure the bacteria in our body a balanced diet, it would be good to include, in your daily life, and following the rhythm of the seasons, the greatest possible diversity of all available foods at every meal!

Every fruit, every vegetable, every legume, every grain, every seed, every seaweed, etc should be a part of our daily diet.

But also each of their varieties. something which is often overlooked given the preference of industrial producers, to bring different and complementary colonic nutrients.

Eating 5 servings of vegetables, legumes, fruits, whole grains and dry or sprouted seeds daily cannot be enough if this dietary practice does not take advantage of the great biodiversity that nature offers to cover all the needs of bacteria, whether general or selective/specific!

They are all necessary to feed the bacteria properly, stabilize and strengthen the biodiversity of the bacteria, and optimize the functionality of the intestinal bacteria for our health.

Beyond their specific qualities, these foods are also the best sources and guarantee the most effective supply of all the minerals, vitamins, and other molecules essential to bacteria and to us in general.


Probiotics do not belong to either of the two categories of nutrients that are required to properly feed the bacteria.

Probiotics would have two benefits for our colonic microbiota:

  • Bring in new species that are potentially beneficial for some of its functions.
  • Reintroduce bacterial species that would have existed there and would have disappeared or that would be threatened with extinction.

As knowledge stands at the moment, the number of bacterial species available for the first benefit is limited compared to the biodiversity of bacteria. The effectiveness of probiotics is therefore limited.

How can our food choices affect bacteria in our digestive system and our health? Conclusion

Given the importance of our microbiota to the functionality of our colon, the lack of thought and recommendations for our diet is surprising.

Hence the concept of colonic nutrients.

Even though they are only prokaryotes, we cannot ignore the needs of the majority of cells in the body, especially knowing about the importance of the functions with which they are closely associated in the small intestine and especially the colon.

The nutrients needed to meet the requirements of such a diet are of 2 types:

  • Generals
  • Specific/selective

They constitute what is classically grouped under the term dietary fiber.

In this spirit, the best colonic foods are all edible plants and plant products, including seaweed, to be consumed in every season, in their greatest possible variety.

They alone can provide the multitude of bacteria in the microbiota of our digestive system the nutrients necessary to maintain their immense biodiversity, which is the only guarantee of the quality of the multiple functions of which they are partners.

Eat as many edible plants (including seaweed) from agroecology as possible every day.

If you cook them, do so at low temperature while keeping them al dente. Enhance this consumption with fermented food preparations that you can easily prepare yourself.

It may seem a little daunting at first, but with time and patience you will be able to make the best choices for you and your body.

About Heather Campbell

As a nutritionist, my field of specialization is science-based nutritional advice but more importantly, it is my goal to share capturing and inspiring stories, examples and solutions which can help plus-size individuals overcome their specific difficulties. Read More