“Huge knowledge gaps”: Ethnicity-microbiome link could impact infant formula to personalization
07 Jul 2020 --- Microbiome-based diagnostics and therapeutics must take the ethnicity of the individual into account, warn researchers from APC Microbiome Ireland. Their study revealed that Irish Travellers – an ethnic minority who have long lived on the fringes of Irish society – have a gut microbiome “strikingly” different to that of the non-Traveller settled community. The researchers flag that this investigation could have major implications on everything from the design of infant formula to the outlook for personalized nutrition.
“This kind of research is revealing huge knowledge gaps and showing that we know a lot less about the microbiome than we thought. Possible implications include difficulties defining the optimal diet for societies with diverse microbiomes, difficulties deciding what is the ideal donor for fecal transplants when such treatment is needed, and difficulties interpreting microbiome tests in any given situation, which must now be reconciled with knowledge of ethnicity,” Professor Fergus Shanahan, a study investigator, tells NutritionInsight. 
Published in Nature Medicine, the study discovered that whereas the settled or non-Traveller Irish have an industrialized type of microbiome with a relatively increased risk of chronic disease, most of the Travellers retain an ancient or non-industrialized type of microbiome, which may protect from many chronic inflammatory disorders, including Crohn’s disease and ulcerative colitis. This microbiome was strikingly more similar to people living in non-industrialized countries than to the settled Irish.
“The distinctiveness of the microbiome of the Irish Travellers is remarkable because they live in parallel with the non-Traveller Irish on a tiny island that is modern and industrialized. This challenges our concepts of what is normal in a multi-ethnic society and challenges the promise of the microbiome for personalized therapeutics and diagnostics,” says Shanahan.
He continues that determining how the Travellers have retained their unusual microbiome will be of huge benefit to the rest of society. “Likewise, determining how the non-Travellers lost the microbes that the Travellers have retained will have obvious implications for the future. The findings could have implications for the choice of foods, design of infant formula and even whether we should control the composition of the microbiota that colonize infants.”
The degree to which the Traveller lifestyle was adapted to that of the settled community, the more their microbiome changed.A microbiome closer to that of Mongolians than of non-Traveller Irish
Irish Travellers represent nearly 1 percent of Ireland’s population and are distinct from other nomadic groups in Europe, variously referred to as Romani and Roma, note the researchers. However, this group is very genetically similar to the non-nomadic settled Irish population. Their lifestyle drastically changed in 2002 when new legislation effectively ended nomadism and altered their living conditions.
A total of 118 adult Irish Travellers with a mean age of 39 years participated in the study, which compared their fecal microbiota with that of the settled background population in the same geographic locality, as well as with samples from individuals in other industrialized and non-industrialized countries.
The research found that the greater the degree to which the Traveller lifestyle was adapted to that of the settled community, the more their microbiome changed from the non-industrialized type to the industrialized type associated with disease. However, Shanahan explains that non-Travellers who adopt a Traveller lifestyle would not see their microbiome change. “Much more work is required to determine how non-Travellers might re-wild their microbiome with the missing microbes that have been lost due to decades of modernization.”
He continues that ethnicity is linked with culture, which has a profound influence on the microbiome. However, the degree to which each ethnic group differs from others is variable. For example, some ethnic groups have similar microbiomes, whereas others have highly distinct microbiomes.
“The reason why the [case of the] Irish Travellers are so informative is that confounding variables such as genetics and geography were excluded in the present study. Notably, the Travellers were found to have a microbiome that is closer to that of Mongolians than it is to the non-Traveller Irish. This is a remarkable finding and is testimony to their robust and distinctive ethnicity,” says Shanahan.
The study represented the shared efforts of clinicians and scientists working in partnership with the insight, wisdom and input of Cork Travellers who not only participated in the study, but also influenced its design and planning.
An eye on the future
The researchers will now study mother and baby pairs.
Notably, the global diversity of the microbiome is far greater than once thought. “As more ethnic groups are studied, the diversity at bacterial strain level seems vast. Most of what we know about the human microbiome is based on studies of affluent modern societies of the first world. Much less is known of the non-industrialized world,” details Shanahan.
The researchers now intend to investigate whether the Traveller microbiome is passed down genetically, or is just a result of lifestyle. They will study mothers and babies longitudinally to determine which is more important: vertical transmission or horizontal transmission from the environment.
Other research endeavors include conducting a more detailed epidemiological study to confirm that the Travellers have reduced risk of autoimmune and immuno-allergic disorders. They also hope to determine if the Travellers might be at particular risk of metabolic disorders since their microbiome is not suited to an obesogenic environment.
Research into the microbiome has been rapidly progressing in recent months, as highlighted by World Microbiome Day. Last week, probiotics start-up Sun Genomics raised US$8.65 million in its Series A funding to build “the world’s largest longitudinal data set.” Meanwhile, other researchers developed whole-body computational models to further propel research into personalized medicine, including the role of diet on the microbiome.
By Katherine Durrell
