Ötzi’s microbiome better than ours

Ötzi, the 5,000 years old men out of the ice, has been a window into the past for scientists of various disciplines, so far. Over the last years, we have learned how the hunter of the Neolithic Age dressed and what he had for his last dinner. Criminologists claim that he was killed on the run and friends of the acupuncture can tell from certain marks on his corpse that needling was a common therapy back then. So, it was only a matter of time, until microbiome scientists checked on Ötzi’s gut.

What is it good for?

A preceding study by a team of the University of Trento claimed a correlation between a low diversity in gut bacteria and an increase of civilization disease like allergies, obesity, and a number of autoimmune diseases. We have discussed a similar thesis in this article: „Immigration to US fosters obesity and changes microbiome“

The crucial factor seems to be a frequently found microbe, Prevotella copri. P. copri can be found in only 30% of today’s Western individuals, but in almost any non-Western sample. So, scientists focused on P. copri and found out that it is comprised of four so-called clades or branches. The studies prove that non-Western civilizations hold three to four of the relevant clades in their microbiome, whereas Western microbiomes usually hold only one.

Genes or way of life?

There are only two reasonable theories for this reduced appearance with Westerners: Either, people of Western heritage only have one of the four clades innately and are therefore generally more prone for the above-named diseases. Then, the gut microbiome would be like the skin: the lighter the complexion the more sensitive the reaction to sunlight. Or – and this is the hypothesis of the University of Trento and other scientific institutions doing research in that area – our Western lifestyle harms the microbiome in a way that already led to the extinction of three of the total four clades.

So, Ötzi turned out to be an ideal opportunity to scrutinize the Western microbiome of the past (on a random base and given that Ötzi has the microbiome of an average Western inhabitant from 5,000 years ago and is not the statistically possible exception to the rule). And the result proves the assumptions correct: Ötzi held three of the four relevant clades. The same clades were found in petrified excrements from Mexican people living some thousand years ago, by the way.

Things used to be better back then

What does this say about today’s way of life? Obviously, the Neolithic man from the Ötztal Alps and his Mexican contemporaries (contemporaries in a wider sense. What are a few hundred years in genealogy, anyway?) were in a much better constitution than we are today. And we claim to be highly developed in terms of medicine and technology; we believe to have a much more varied nutrition and the better living conditions, in general.

So, what is the reason? Is it the nutrition? Ötzi verifiably mainly lived on dried meat, or what we call the Paleo diet today. His Mexican counterparts presumably have subsisted on a diet high in starch and fibres based on corn meal. So, it cannot only be all about nutrition. Medical care should be at least more intense today with antibiotics, vaccinations, and surgical techniques. However, we should not assume that generations of previous millenniums completely lacked medical knowledge (on the contrary, when you look at surprising details as the previously mentioned acupuncture marks). Presumably, past generations had a lot more contact to nature and animals than we have today (in all possible forms of appearance like soil or pollen). And last, but not least, the exposure to chemicals, disinfectants and similar products today exceeds the past appearance, by far. All in all, we can assume that it is not only our diet but the total and complex way of life of today that harms Prevotella copri.

A small step for Ötzi, but a big step for microbiome research

Nevertheless, the findings prove that one or more factors of today’s way of life indeed impair our microbiome and make us sick. What factors that would be and what needs to be done to restore our microbiome, is pure speculation until now. But even more, the discoveries around the glacier man are highly important, as the new thesis is that indeed these three to four clades of a single bacteria are responsible for a change in our wellbeing and health for the better or worse. And that is a pretty specific statement in the complex galaxy of microbiome research. In any case, Prevotella copri and its clades should be the subject of interest in future research projects to minimize the effects of their disappearance.