There are ten times more bacteria in your body than your own cells. This might seem scary, but really you wouldn't be able to function without most of them like the probiotics that help digest your food and fight invading microbes. There's good bacteria and bad bacteria, but the gut seems to be so diverse in its bacterial offering from person to person that scientists have always found it difficult to say "hey, this is what a healthy microbiome should look like." Analyzing thousands of bacteria species in your guy is challenging and we're still not there, but a recent effort involving 4,000 participants has some good hints as to what makes a healthy gut.
Researchers collected and analyzed feces from 4,000 individuals living in the U.S., the United Kingdom, Belgium and the Netherlands. They identified 664 different genera, although we're pretty convinced there are plenty more bacterial species which weren't tagged. Later, the stool samples were expanded to include some coming from Papua New Guinea, Peru and Tanzania. In this expanded version, the researchers found 14 genera of microbes that were common in 95% of the humans sampled.
“We compared all the microbiota we could get our hands on,” says Jeroen Raes at the University of Leuven (KUL) in Belgium, who led the study.
This bacteria diversity data was then correlated with the health and behaviour of the participants. The most important takeaway is having bacterial diversity in the gut offers health benefits, and the more the better. Those people who had less microbiome diversity were those with a higher body-mass index, which corresponds to being overweight or obese. Those who had the most gut bacteria diversity ate a lot of fruits and vegetables. Dairy-rich diets were also associated with a more diverse biome. Subjects who drank coffee and tea also saw an improvement, while soda reduced the diversity for unclear reasons.
To increase your gut bacteria diversity, the findings suggests, consume fruits, vegetables, dairy and probiotics-rich products like yoghurt.
The older the people involved in the study, the more diverse their biomes. More than anything, however, the use of medicine influenced the greatest variation among the people involved in this study. These include drugs like antibiotics, osmotic laxatives, medications for inflammatory bowel disease, benzodiazepines, antidepressants, antihistamines or hormones used for birth control or to alleviate symptoms of menopause.
Considering so few genera were shared by people across the world, the relationship between a certain bacterial biome and health benefits is debatable. We know for sure, however, that there are bacteria that cause a plethora of health problems like irritable bowel syndrome, and even as many as 23,000 deaths in the United States alone. Through careful analysis and more genetic sequencing of the bacteria that line our guts, many lives might be saved.