A recent study showed that very low-cal diets could considerably impact the gut microbiome, provoking increased levels of Clostrosidiodes difficile, a pathogenic bacterium known to be one of the causes of severe diarrhea.
Though the study’s subjects didn’t present any traces of the health problems, the presence of an increased amount of C. difficile poses some fundamental questions regarding how the human intestinal microbiome is linked to weight loss.
The study monitored 80 overweight and obese women for 16 weeks, half of whom followed a very-low-cal diet – an extreme diet, sometimes managed medical, limiting individuals to only 800 calories per day in liquid form.
The other half of the women kept their current body weight.
Peter Turnbaugh, a microbiologist of the University of California San Francisco, said:
“Our results underscore that the role of calories in weight management is much more complex than simply how much energy a person is taking in. We found that this very-low-calorie diet profoundly altered the gut microbiome, including an overall decrease in gut bacteria.”
For the following part of the research, the scientists transplanted faecal samples from five individuals who had lost the most weight into mice with no microbiome and compared the results to mice that got transplants of pre-diet samples.
Though the mice diets remained constant, those who received post-diet samples lost 10% of their overall body bass on average, while others registered no change.
Sequencing on the mouse microbiomes showed a very high amount of C. difficile.
Though the bacterium naturally occurs in the human gut, it is usually kept under control by the fat metabolism process that takes place when we eat.