Probiotics: the guardians of the gut

  • By: Tiana Rodrigues / Comments : 0

Soon after our birth, we have almost 1000 different varieties of guests that house our body or our gut forever. Depending on the invitations given, the guests vary. The invitations here refer to different physicochemical conditions as well as other factors such as use of antibiotics, stress, illness, aging, lifestyle practices and diet. Well our little guests are none other than microbes. The number of such microbes is ten times more than our own cells.

Factors that influence gut microbes

By and large, following are the different varieties of bacteria that inhabit different regions in the body.

Anatomical Location Predominant bacteria
Skin staphylococci and corynebacteria
Conjunctiva sparse, Gram-positive cocci and Gram-negative road
Oral cavity
teeth streptococci, lactobacilli
mucous mambranes streptococci and lactic acid bacteria
upper respiratory tract
nares (nasal mambranes) staphylococci and corynebacteria
pharynx (throat) streptococci, neisseria, Gram-negative rods and cocci
Lower respiratory tract none
Gastrointestinal tract
stomach Helicobacter pylori ( up to 50%)
small intestine lactics, enterics, enterococci, bifidobacteria
colon bacteroides, lactics, enterics, enterococci, clostridia, methanogens
Urogenital tract
anterior urethra sparse, staphylococci, corynebacteria, enterics
vagina lactic acid bacteria during child-bearing years; otherwise mixed

The bacteria that reside in the large intestine can be examined through stools.

The table below gives us a general idea of strains that reside in the large intestine along with the amounts in which they are usually present.

BacteriumRange of incidence
Bacteroides fregilis 100
Bacteroides melaninogenicus 100
Bacteroides oralis 100
Lactobacillus 20-60
Clostridium perfringens 25-35
Clostridium septicum 5-25
Clostridium tetani 1-35
Bifidobacterium bifidum 30-70
Staphylococcus aureus 30-50
Enterococcus faecalis 100
Escherichia coli 100
Salmonella enteritidis 3-7
Klebsiella sp. 40-80
Enterobacter sp. 40-80
Proteus mirabilis 5-55
Pseudomonas aeruginosa 3-11
Peptostreptococcus sp. ?common
Peptococcus sp. ?common

Gut microbes are also believed to have a genetic control over certain regions of the brain that further modulate behaviour. They are known to produce short chain fatty acids that have been recognised to play a role in improving conditions such as metabolic syndrome, disorders that affect the bowel, and even certain cancers. Gut bacteria also synthesize arginine and glutamine (conditionally essential amino acids) and vitamin K (plays a role in heart, cognitive and bone health). They prevent disease causing pathogens from forming colonies in the gut and boosts immunity.

In a randomized, double-blinded study with endurance trained athletes with a fixed diet regime, it showed that supplementation with probiotics improved gut immunity, reducing inflammatory markers.

As per clinical studies, the tested amounts of probiotics for effectiveness in children is 5-10 billion colony forming units (CFU) per day and for adults, it is 10-20 CFUs daily. Any form of probiotic strain that is taken in the form of a supplement should be resistant to the acidic environment of the stomach and bile salts and acids so that we actually derive benefits from the supplement. Lactobacilli and Bifidobacterium are commonly used species because they possess all the properties required to remain viable in the gut. These two are also one of the first bacterial forms that colonise the gut post delivery.

Kefir, cheese, wine and fermented products like rice, dosa, dhokla, tofu and tempeh along with fermented vegetables are few sources of probiotics. Along with these, to keep the heroes of our gut healthy and dominant over the villains, we need to provide prebiotics. Prebiotics refer to the fibre, which is found in plenty in vegetables and fruits. Feed your gut well, you never know when the enemy can strike!

References:

  1. Impacts of Gut Bacteria on Human Health and Diseases. Available from:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425030/
    [Accessed on 17 Nov 2016]
  2. The Normal Bacterial Flora of Humans. Available from:
    http://textbookofbacteriology.net/normalflora_3.html
    [Accessed on 18 Nov 2016]
  3. Microbial regulation of microRNA expression in the amygdala and prefrontal cortex. Available from:
    https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0321- 3
    [Accessed on 18 Nov 2016]
  4. The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism. Available from:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3735932/
    [Accessed on 18 Nov 2016]
  5. Gut Bacteria in Health and Disease. Available from:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983973/
    [Accessed on 18 Nov 2016]
  6. Good bacteria, gut health and exercise. Available from:
    https://www.precisionnutrition.com/research-review- gut-health
    [Accessed on 18 Nov 2016]
  7. Probiotics. Available from:
    http://www.aafp.org/afp/2008/1101/p1073.html
    [Accessed on 18 Nov 2016]
  8. Microorganisms with Claimed Probiotic Properties: An Overview of Recent Literature. Available from:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053917/
    [Accessed on 18 Nov 2016]

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