In David Attenborough’s book and movie “A Life on Our Planet” the famous biologist points out that we are living in a time of extinction. While Attenborough refers mostly to us humans being responsible for an unprecedented extinction of wild life, this holds also true to the extinction of bacterial life in and on our body.

While we are sentimentally attached to diversity in Nature whilst thinking of “cuddly” panda bears or cute dolphins, we tend to be much less sentimentally attached to bacterial species. Nevertheless, there are very good reasons for wanting to maintain diversity in our guts as well, or at least diversity of good bacteria.

A rich and healthy diet is good for our microbiome

Several studies have compared the microbiome of people in the US or Europe to the microbiome of people living in Africa following traditional hunter & gatherer lifestyle. The general conclusion is that the African microbiomes showed higher microbial richness and biodiversity and that this gut diversity is linked to a diverse diet containing many different fresh fruits and vegetables. In comparison, the gut of people consuming a less rich Western diet, with many processed foods and very low in fibre, were also less diverse.

 Fit & healthy people have a healthy gut, with a rich and diverse microbiome. Lack of bacterial diversity is linked to poor health.

Why is gut diversity important?

There is accumulating evidence from countless scientific and clinical studies worldwide showing that fit & healthy people have a healthy gut, with a rich and diverse microbiome. In contrast, lack of bacterial diversity is linked to poor health. In an unhealthy environment, where natural diversity has been destroyed, for example, by a poor diet or excessive use of antibiotics, harmful bacteria can take over causing disease. This situation is a bit like the destruction of the wonderful biodiversity of coral reefs.

Loss of diversity and why it matters

So why are we living in a time of extinction when it come to our gut microbiome? There are two main reasons, both related to so-called “modern” lifestyles:

1. increased levels of hygiene, sanitation and medical advances such as antibiotics. These without a doubt, have helped humanity to massively reduce the amount of harmful and dangerous infections. However, in this “fight against microbes” our modern societies have also slipped into an unhealthy “sterile environment”, with the unfortunate (and unintended) effect of also killing many of the good bacteria.
2. Loss of diversity in our diets. —  Modern “western” diets tend to depend on highly processed foods that are not very diverse and that contain just simple carbohydrates. These “unhealthy diets” contain very little complex-fibre and do not have the diversity of fresh food that is needed to feed and maintain a healthy gut microbiome. And an unhealthy gut is generally unhealthy for our health and wellbeing as a whole.

Diversity seems to be the key!

Diversity of your microbiome is good and prevents you from diseases. Diversity can be increased by eating many different fruits and vegetables and less simple carbohydrates. Try to avoid white flour or sugar. The more diversity of fresh, healthy plant material we eat, the more diverse the microbiome bacterias will be. Whilst antibiotics can be life-saving, oversue of antibiotics can also be harmful and our obsession with hygiene and the fight against microbes, can also be harmful. Therefore, occasionally exposing yourself to some dirt, like working in a garden, can be good and healthy, enlarging your microbiome diversity.

The closing sentence of the book “the diet myth” by scientist-clinician Tim Spector claims “And diversity seems to be the key!”. In the same way that a more diverse ecosystem is a healthier ecosystem…a more diverse microbiome is also a healthy microbiome!

Selected references

Attenborough, D. a. A life on our planet : my witness statement and vision for the future.

Spector, T. D. a. The diet myth : the real science behind what we eat. Updated edition

Microbiome diversity by geography:

O’Keefe, S.J.D et al (2015) Fat, fibre and cancer risk in African Americans and rural Africans.Nature Communications, Vol: 6:6342 . doi: 10.1038/ncomms7342

Schnorr, S.L., et al., Gut microbiome of the Hadza hunter-gatherers. Nat Commun, 2014. 5: p. 3654.

Pasolli, E., et al., Extensive Unexplored Human Microbiome Diversity Revealed by Over 150,000 Genomes from Metagenomes Spanning Age, Geography, and Lifestyle. Cell, 2019. 176(3): p. 649-662 e20.

De Filippo, C., et al., Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa. Proc Natl Acad Sci U S A, 2010. 107(33): p. 14691-6.

Yatsunenko, T., et al., Human gut microbiome viewed across age and geography. Nature, 2012. 486(7402): p. 222-7.

Obregon-Tito, A.J., et al., Subsistence strategies in traditional societies distinguish gut microbiomes. Nat Commun, 2015. 6: p. 6505. –