Gut Microbiota and Probiotics

Dr. Chirag Sethi^*, Dr. Swarna Anchal^**

^*Director, Classic Fitness Academy, New Delhi.

^**Technical Writer, Classic Fitness Academy, New Delhi.

 

Microbes are tiny microorganisms that cannot be seen by naked eyes but present all over the human body and include bacteria, archaea, and fungi. The anatomical areas where these microbes are found include skin, conjunctiva, gastrointestinal tract also called gut flora, urethra, and bladder, vagina, placenta, uterus, oral cavity, and lungs. As a whole, these microorganisms may weigh up to 1–2 kg, which is roughly equal to the weight of your brain. We can say, they function as an extra organ in your body and play a huge role in your health. Among these gut, micro-flora is of special interest as they live in the digestive tract of humans. Gut micro-flora is established one to two years after birth and the intestinal tract is also co-developed in a way that provides a barrier to pathogenic organisms. Gut micro-flora has the largest number of bacteria and the greatest number of species compared to other areas of the body.  Bacteria are usually viewed in a negative sense as some of them make us sick. However, we have two kinds of bacteria constantly in and on your body — good bacteria and bad bacteria.

On the other hand, 'Probiotics’ are live microorganisms which when administered in adequate amounts confer a health benefit on the host (World Health Organization, WHO). The term was first coined in the 1960s by Lilly and Stillwell. Probiotic products are having combinations of different strains of lactic acid bacteria, bifidobacteria, propionibacteria, and yeast known for their health benefits. Probiotics are the largest part of our gut micro-flora. The gut-flora and humans have not only a non-harmful coexistence, but having a mutually beneficial relationship also. Health benefits of probiotics are enlisted here below.

•          Digesting breast milk: Bifidobacteria are some of the bacteria that first start to grow inside infants' intestines. They digest the healthy sugars in breast milk that are important for the growth of babies.
•          Digesting fiber: Gut microorganisms benefit the host by fermenting dietary fiber into short-chain fatty acids which are absorbed by the host. They play an important role in the making of vitamin B and vitamin K, help to prevent weight gain, diabetes, and risk of cancer.
•          Helping control your immune system: The gut micro-flora also boosts your immune systems to fight against pathogens hence prevent infections.

•          Helping control brain health: New research suggests that gut micro-flora may also affect the central nervous system, which controls brain function. Certain species of bacteria can help to produce serotonin which is an antidepressant neurotransmitter that’s mostly made in the gut.
•          Resistance to pathogens: Gut micro-flora competes with pathogens for space and nutrients. Probiotics adhere to the cell surface hence providing less space for pathogenic bacteria and fewer nutrients are available for pathogens.

We cannot consider any microorganism as probiotics or fit for consumption. There are plethoras of researches that have shown the criteria for microorganisms to be considered as Probiotic and suitable for human consumptions. Survival of microbes under these gut conditions that are provided in research labs can determine whether a microbe should be considered as probiotic or not.

(1)       Survival to acid and bile: A microorganism culture must survive highly acidic and bile conditions as they have to pass the stomach and small intestine during digestion of foods.

(2)       Sensitivity to antibiotics: Microorganism must be sensitive to a large range of antibiotics hence giving fewer chances to antibiotic resistance.

(3)       Cell Surface Hydrophobicity: Bacterial cells must be having properties to adhere to the tissue cells in the gut hence compete with pathogens for space and nutrition.

(4)       Resistance to oxidative stress: they must have a great survival rate against oxidative stress produced in the body.

(5)       Health Benefits: These microorganisms must produce small fatty acids, bioactive peptides, and other bioactive components that are beneficial for health.

 

In our daily life, we consume a lot of products that are made up of probiotic cultures and are good for gut health. The following table shows the different kinds of food products made up of probiotics when applied to different food materials.

Approaches to Improve Gut Micro-flora

•                The diverse range of foods: Diverse micro-biome is an indicator of good gut health. To promote the growth of healthy gut flora one should include a diverse range of foods in the diet such as whole grains, legumes, beans, and fruit that contain lots of fiber.
•                Fermented Foods: Fermented foods having Lactobacilli that can reduce the number of disease-causing species. Fermented foods such as yogurt, sauerkraut, and kefir all contain healthy bacteria and they should be included in daily diets.
•                Limited intake of artificial sweeteners: Artificial sweeteners increase blood sugar hence increase the growth of unhealthy bacteria like Enterobacteria in the gut that cause diseases.
•                Prebiotic foods: Prebiotics are foods that stimulate the growth of healthy bacteria e.g. fibers of foods such as artichokes, bananas, asparagus, oats, and apples.
•                Breastfeed for at least six months: infants get most of the gut micro-flora developed by breastfeeding. The beneficial Bifidobacteria are developed in children who are breastfed for at least six months than those who are bottle-fed.
•                Eat foods rich in polyphenols: Red wine, green tea, dark chocolate, olive oil, and whole grains are good sources of polyphenols. When consumed they are broken down into their bioactive components by gut flora that stimulates healthy bacterial growth.
•                Take antibiotics only when necessary: Antibiotics should be taken only when necessary because they not only kill bad but also good bacteria in the gut and results in weight gain and antibiotic resistance.

Disruption in gut micro-flora causes by stress, parasites, antibiotics, and an unhealthy diet. The interrupted balance of the gut flora has been correlated with inflammatory, infectious diseases, and autoimmune conditions. The composition of micro-flora varies as a small number is present in the stomach and small intestine whereas the colon has the highest density of microbes. Among them 99% of the bacteria are anaerobes but in the cecum, aerobic bacteria are in high numbers. The composition of human gut micro-flora changes over time, when the diet changes, and overall health changes. 

The Bottom Line

The gut flora is significant for our health as it helps in controlling digestion and boosting the immune system with many other aspects of health. An imbalance of unhealthy and healthy microbes can be a cause for weight gain, high blood sugar, high cholesterol, and other disorders. To support the growth of healthy microbes, one should take care of his diet and should include a wide variety of fruits, vegetables, whole grains, fermented, and probiotic food products.

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