(CNN)Mounting evidence suggests that the richer and more diverse the community of microbes in your gut the lower your risk of disease. Diet is key to maintaining diversity and was strikingly demonstrated when an undergrad student went on a McDonald’s diet for ten days and after just four days experienced a significant drop in the number of beneficial microbes. Similar results have been demonstrated in a number of larger human and animal studies.
Fast food vs. the African diet: The bacteria battle waged in your gut.
Your gut microbiome is a vast community of trillions of bacteria that has a major influence on your metabolism, immune system and mood. These bacteria and fungi inhabit every nook and cranny of your gastrointestinal tract, with most of this 1kg to 2kg “microbe organ” sited in your colon (the main bit of your large intestine). We tend to see the biggest diet-related shifts in microbes in people who are unhealthy with a low-diversity unstable microbiome. What we didn’t know is whether a healthy stable gut microbiome could be improved in just a few days. The chance to test this in an unusual way came when my colleague Jeff Leach invited me on a field trip to Tanzania, where he has been living and working among the Hadza, one of the last remaining hunter-gatherer groups in all of Africa.
A Hadza man hunting with bow and arrow, Lake Eyasi, Tanzania. My microbiome is pretty healthy nowadays and, among the first hundred samples we tested as part of the MapMyGut project, I had the best gut diversity — our best overall measure of gut health, reflecting the number and richness of different species. High diversity is associated with a low risk of obesity and many diseases. The Hadza have a diversity that is one of the richest on the planet.
The research plan was devised by Jeff who suggested I should have an intensive three days of eating like a hunter gatherer during my stay at his research camp. I would measure my gut microbes before heading to Tanzania, during my stay with the Hadza, and after my return to the UK. I was also not allowed to wash or use alcohol swabs and I was expected to hunt and forage with the Hadza as much as possible — including coming in contact with the odd Hadza baby and baboon poo lying about.
To help us record the trip I was accompanied by Dan Saladino, the intrepid presenter and producer of BBC Radio 4’s The Food Programme, who was preparing a Hadza microbe special.
After a long tiring flight to Mount Kilimanjaro Airport in Tanzania, we stayed overnight in Arusha, a city in the north of the country. Before setting off the next morning, I produced my baseline poo sample.
After an eight-hour journey in a Land Rover over bumpy tracks, we arrived. Jeff beckoned us to the top of a huge rock to witness the most amazing sunset over Lake Eyasi. Here, within a stones throw of the famous fossil site of Olduvai Gorge and with the stunning plains of the Serengeti in the distance, Jeff explained that we were never going to be closer to home as a member of the genus Homo, than where we were standing at that moment….
Massive increase in microbiome diversity
Twenty-four hours later Dan and I were back in London, him with his precious audio tapes and me with my cherished poo samples. After producing a few more, I sent them to the lab for testing.The results showed clear differences between my starting sample and after three days of my forager diet. The good news was my gut microbial diversity increased a stunning 20%, including some totally novel African microbes, such as those of the phylum Synergistetes.The bad news was, after a few days, my gut microbes had virtually returned to where they were before the trip. But we had learnt something important. However good your diet and gut health, it is not nearly as good as our ancestors’. Everyone should make the effort to improve their gut health by re-wilding their diet and lifestyle. Being more adventurous in your normal cuisine plus reconnecting with nature and its associated microbial life, may be what we all need.