Recent research is only beginning to unravel the mystery of living beings that cohabit our bodies, in particular the bacteria in our gut. The colonies, huge in number and comprising a variety of bacterial species, are unique to each of us, perhaps identifying us as distinctly as our fingerprints. In a paper published earlier this year in Nature, scientists have broadly classified this diversity into three types, and all of us carry one of these three types or eneterotypes of gut bacteria—Bacteroides, Ruminococcus, or Prevotella. A new study published in Science magazine provides greater understanding of these three types, suggesting that the presence of one or the other may be related to the kind of diet each individual consumes.
The team led by Frederic Bushman of the University of Pennsylvania asked ‘98 healthy volunteers to fill in two questionnaires, one asking about what they ate and drank recently, the other about their long-term dietary habits. The team also took stool samples from the subjects and analyzed their DNA content to determine the makeup of the gut flora.’ According to the study as reported in Science magazine, their results showed that ‘People who eat a lot of meat and saturated fat tended to have more Bacteroides in their flora; Ruminococcus prevailed in people who consumed lots of alcohol and polyunsaturated fats, whereas Prevotella favored a diet rich in carbohydrates. It’s not clear whether one type of microbial flora is healthier for the host than the other.’
The result immediately raises questions about whether one type of colony is healthier for the host than another. If that turns out to be the case, the study offers hope of new ways to improve health by changing diets, Bushman says. The results, though, also show that a short term change in one’s diet is not enough to change the type of gut bacteria. Ten volunteers were selected and half were fed a diet rich in fat and low in fibre, and the other half were put on a high-fibre-low fat diet for ten days. While the bacterial population began shifting with some species becoming more populous and others less so, the gut type remained the same.