Our recent discussion in class about obesity and the microbiome has spurred my interested in the idea of the bacteria that are associated with obesity being more able to extract energy from the food that people eat. This study specifically speaks about this happening in mice, where the microbiota of an obese individual, where the ratio of Firmicutes to Bacteroidetes is higher, is better able to extract energy from a specific diet than lean mice. One piece of evidence they pointed to that showed this idea was the result of a bomb calorimetry test, which showed that the faeces of the obese mice had significantly less energy remaining in them than did the faeces of lean mice. In this study, the transplanted the microbiota from the caecum of either lean or obese mice into germ-free mice. After a 14-day period, there was no significant difference between the two groups of recipients in the measures of chow consumption, initial body fat, or initial weight of recipients. However, the results did show a statistically significant difference in increase in body fat over the two week period. These results suggest that an increased capacity for energy harvest in at least one type of obesity-associated gut microbiome.
This article was really interesting to read in that it does provide some evidence that shows that some types of gut bacteria are better able to extract calories from the food that we are taking in. However what I found equally interesting was that the gut microbiomes of the lean and obese mice were able to be transplanted to the germ-free mice. This made me think about the discussion we had about how similar our microbiomes can become to those people we spend a lot of time around. Is it possible that if someone lives with either a lean or obese person, their lean or obese gut microbes could influence the gut microbiome of the person they’re living with? The idea that the gut microbiome can be transplanted also leads me to wonder what type of treatment options are available to help shift the microbiome of people with obesity.
Turnbaugh, P.J., Ley, R.E., Mahowald, M.A., Magrini, V., Mardis, E.R., Gordon, J.I. (2006) An obesity-associated gut microbiome with increase capacity for energy harvest. Nature 44: 1027-1031.