EAT LIKE THE HADZA TO DIVERSIFY GUT BACTERIA
For Tanzanian hunter-gatherers, porcupine and baobab are treats
They forage for berries, tubers and honey. They hunt birds and game with poisoned arrows. Porcupine is a favourite and baboon brain is considered a delicacy. They eat the way our ancestors ate before agriculture was introduced some 10,000 years ago. They have hardly any possessions, and no fixed place to live. They are the Hadza people of Tanzania, one of the world’s last remaining hunter-gatherer tribes. And they are of great interest to researchers because they appear to experience no diabetes, no colon cancer, colitis or Crohn’s disease. Obesity is unknown. One theory is that these conditions, which are rampant in the developed world, may be the consequence of a shifting balance in gut bacteria as a result of our modern diet.
Up to a thousand different varieties of bacteria inhabit our intestines, contributing up to two kilos to our body weight. Like other living organisms, bacteria eat and defecate. Their food is whatever we throw in their direction. They will digest the components we can’t, and then reward us for feeding them by releasing a variety of chemicals that can contribute to our health in their poop. Among these are vitamins B12 and K as well as short chain fatty acids that help keep our gut in good shape.
One way to gain insight into the connection between gut bacteria and health is to look for differences in the microbiome of dramatically different populations, and there can hardly be two populations as different as urban Italians and the Hadza. It turns out that bacteria in feces are a good reflection of bacteria that reside in the gut, and when researchers compared the bacteria in the poop of the Italians and the Hadza, they found a 40-per-cent greater diversity of microbes in the Hadza output.
Interestingly, the feces of the Hadza show an absence of Bifidobacteria, just the species that are thought to be important in the western diet and ones that are commonly included in “probiotic” products. Interestingly, the Hadza had lots of Treponema, a type of bacteria that in western populations is associated with diseases such as Crohn’s and irritable bowel syndrome, yet the Hadza do not suffer from these conditions. Another noteworthy finding was that Hadza men and women had significantly different bacterial populations, in all likelihood due to different diets. The men eat more meat and honey and the women eat more fibrous tubers.
In order to decipher the nuances of the relationship between our microbiome and disease, it would be of interest to know whether the microbiome can be altered by a change in the diet. That is just what Tim Spector, professor of genetic epidemiology at King’s College London, wanted to find out. For three days, he would live and eat the Hadza way and monitor the bacterial composition of his poop. He feasted on tubers, wild honey, Kongorobi berries, the fruit of the baobab tree and roasted porcupine. He accompanied the Hadza on their hunting and foraging forays to expose himself to all the microbes that the Hadza normally encounter and he refrained from washing. Lab tests showed a highly significant 20-per-cent increase in microbial diversity after three days and the presence of African microbes that had not been present before. But on returning to England, the microbial profile quickly returned to what it had been before the experiment. Still, the trial did demonstrate that the composition of the microbiota can be altered, albeit it takes a continuous change in diet to do so.
Of course, we are hardly going to make porcupine a dietary staple, and neither baobab fruit nor Kongorobi berries are going to show up in our supermarkets. However, we can eat more fruits and berries and high-fibre foods that should go some way to increasing the diversity of our gut bacteria. We must keep in mind, though, that the Hadza are also exposed to various bacteria from the local soil, from animals and from lack of western hygiene. Furthermore, the Hadza do not visit doctors, so we really can’t be certain to what extent they are protected from western diseases.
The intriguing research into the human microbiota has spawned numerous probiotic products, ranging from pills and fermented dairy products to various beverages. While probiotics may be of help in some intestinal disorders, there is no evidence that they offer any benefit to healthy people. Probiotics contain only a few types of bacteria and generally in numbers not significant enough to make an impact on the composition of the microbiome, even if they survive passage through the acidic environment of the stomach. The hope is that future research may be able to identify the specific bacteria that are beneficial to our health and find a way to deliver them to colonize the gut. Rear entry seems promising. Or we can just move into the bush in Tanzania and join the Hadza.