Lost Microbes: The Foundation of Our Starter Cultures

Modern lifestyles have caused many microbial species that were once common in humans to disappear almost completely from the Western gut microbiome. These lost species play essential roles in metabolism, immune balance, gut barrier integrity and even the gut–brain axis. Traditional populations still carry these microbes in abundance. In the industrialised world, however, they are often missing entirely.

Our starter cultures are therefore built around the strains that current research identifies as the most depleted and the most physiologically important for restoring a resilient, balanced microbiome.

Below you will find a clear overview of which of our strains qualify as true lost species and why they matter so much.

Nr.	Bacterium	Lost Species Status	Main Functions	Included in Sets
1	L. reuteri	⭐⭐⭐⭐⭐ strongly lost microbe, often >80 percent depleted in Western microbiomes	Inflammation regulation, oxytocin pathway, metabolism, small intestine balance	Happy Gut, SIBO, SIBO Stable, Light Gut, Protect Gut
2	B. infantis	⭐⭐⭐⭐⭐ strongly lost microbe, often >80 percent depleted in Western microbiomes	Inflammation, gas reduction, barrier function, immune balance	Happy Gut, SIBO Stable
3	B. longum	⭐⭐⭐⭐⭐ strongly reduced microbe, often >70 percent lower than in traditional microbiomes	Gut brain axis, metabolism, inflammation	Light Gut
4	L. gasseri	⭐⭐⭐⭐ clearly reduced, around 40–60 percent less common in Western populations	Fat metabolism, small intestine flora, inflammation	SIBO, SIBO Stable, Light Gut
5	L. rhamnosus	⭐⭐⭐⭐ clearly reduced, often 40–70 percent lower prevalence	Gut barrier, stress, mood, immune regulation	Happy Gut
6	L. brevis	⭐⭐⭐⭐ culturally lost microbe, reduced due to lack of fermented foods	GABA production, stress regulation, immune support	Protect Gut (exclusive in the 5 set bundle)
7	B. subtilis	⭐⭐⭐⭐ formerly common, now rare, reduced due to hygiene and lower environmental exposure	Microbiome stability, resilience, biofilm regulation	SIBO Stable
8	L. helveticus	⭐⭐⭐ reduced but not a classic lost species	Stress, mood, immune modulation	Protect Gut (exclusive in the 5 set bundle)
9	B. coagulans	⭐⭐⭐ functionally useful but not primarily lost	Small intestine tolerance, digestion, inflammation modulation	SIBO
10	B. clausii	⭐⭐ not a lost species therapeutic complementary strain	Immune resilience, overall stability	Protect Gut (exclusive in the 5 set bundle)

The Three Most Important Lost Species

Limosilactobacillus reuteri

Common in traditional populations, almost absent in Western microbiomes
Function: calms the gut lining, regulates inflammation, supports metabolic balance and influences oxytocin pathways
Reuteri is one of the key microbial species needed to rebuild a modern gut ecosystem

Bifidobacterium infantis

Severely reduced in Europe and North America
Function: lowers inflammation, strengthens the gut barrier, reduces gas formation and plays a central role in immune modulation
Considered one of the most important lost species

Bifidobacterium longum

One of the most significantly depleted microbes worldwide
Function: modulates the gut–brain axis, regulates inflammation and supports metabolic balance
A core strain for a stable and regulated gut environment

Additional Valuable Lost Species

Lactobacillus gasseri

Clearly reduced in many studies
Supports fat metabolism, helps regulate the small intestine and reduces inflammatory signals

Lactobacillus rhamnosus

Often diminished in Western populations
Important for gut barrier function, mood regulation, stress resilience and immune health

Lactobacillus brevis

Abundant in traditional fermented foods, now rarely consumed
Known for GABA production and supporting stress regulation

Bacillus subtilis

Historically obtained from soil, plants and traditional foods; now almost absent
Contributes to microbial stability and a resilient gut flora

Functional Complementary Strains

These strains are not classic lost species but remain valuable in specialised formulations:

Lactobacillus helveticus

Supports mood, stress regulation and immune balance

Bacillus coagulans

Highly acid resistant, supports digestion and small intestinal balance

Bacillus clausii

A robust spore forming strain that supports immune resilience and overall stability

Why We Use These Specific Strains

Our starter cultures are formulated to directly replenish the microbial species most affected by modern living. The key lost species appear across several of our sets. Strains that are functionally important but not severely depleted complement more specialised formulas such as our complete 6 month programme.

This gives you a clear, scientifically grounded combination of microbes designed to rebuild the gut microbiome in a way that reflects how it naturally exists in populations with higher microbial diversity.