There are over 400 species of bacteria in your belly right now that can be the key to health or disease.
Probiotic supplements of exceptional quality and effectiveness that contains at least 10 billion CPU (colony-forming units) of several human strains of "friendly" intestinal micro-flora can actively prevent illness.
The genomes of the bacteria and viruses of the human gut alone are thought to encode 3.3 million genes.
Professor Tim Spector of the genetic epidemiology department at Kings College London has had a busy few years with his continuing work on the TwinsUK Registry -- the world's richest collection of genotypic and phenotypic information tracking 13,000 twins over two decades -- and the launch of the crowdfunded British Gut Project.
And what has Spector learnt from all this big gut data? That personalised probiotics not a one-strain-fits-all approach is the way forward for both gut health research and the gut health industry.
"Everyone is so unique," he told us. "That's the big challenge for industry -- waking up to this idea. You have to be more intelligent. Having one strain that will help everyone is very naive."
Spector's latest venture Map My Gut (MMG) makes this gut idiosyncrasy -- a headache for probiotic players investing millions in failed applications for population-wide health claims for single strains -- into a commercial opportunity.
Launched at the beginning of the September, MMG offers customers specialist gut microbiome analysis and personalised nutrition advice on how to improve both microbial balance and function.
By the end of the month the start-up was already at capacity for its metagenome test, forcing them to close orders until January.
What is a metagenome test?
Known as the â€˜Rolls Royce of genome testing', the metagenome test looks at genetic material recovered directly from environmental samples. In this case, faecal samples.
MMG decribes the test as a "state of the art method" that "fully sequences every gene in every living organism in your gut to the deepest level".
"It is a highly complex test that allows us to identify microbes not just to the family level (broad group of bacteria) like 16s but to the species and sometimes strain level (subtype of species). It provides accurate data on the functions of your microbes, as well as viruses, and fungi, virulence genes and antibiotic resistance."
"In five years this will be routine," he said. "You can tell more from gut microbes than you can from DNA, and I'm a geneticist."
The start-up wasn't yet asking people why they wanted to tests, but he said: "At the moment people have problems with their diet or gut health that GPs [general practitioner doctors] can't help them with like obesity, allergies or IBS [Irritable Bowel Syndrome]."
He said neglecting to measure gut microbe make-up in these kinds of patients was "like giving a heart check-up without taking their blood pressure".
The feedback on microbe makeup offered by MMG goes deeper, quicker than that given through the British Gut Project.
Launched in October 2014, the British Gut Project has seen over 2,000 people paying various fees to have their or their family's microbiome mapped.
Yet not everyone was happy with the level of feedback they got for their money four to six months later.
The British Gut Project taught them people were prepared to pay more for more detailed feedback provided within a shorter time frame.
Me me me
One study from the consortium involving 1,269 adults from seven European countries found after six months, people who received personalised nutrition advice did indeed have a healthier diet compared to those who received standard blanket advice based on national guidelines.
However, this positive result was regardless of whether the personalised advice was based on their diet alone, diet and phenotype or diet, phenotype and genotype.
At the time John Mathers, professor and director of the Human Nutrition Research Centre at Newcastle University in the UK and one of the Food4me researchers, told us he believed people just needed to feel advice was tailored to them and were less interested in the complex cogs -- like phenotype and genotypes -- behind this.
The next step for MMG will be to track the impact of interventions.
Just a few weeks ago the start-up signed a non-exclusive contract with an unnamed dairy food manufacturer.
Professor Tim Spector will be presenting a talk on the latest gut health research at next week's industry event Health ingredients Europe (HiE) in Frankfurt, Germany.