In order to study how human dietary practices influence the human gut microbiota and how a microbiota conditioned with one dietary lifestyle responds to a new prescribed diet, the researchers first took fecal samples from people who followed a calorie-restricted, plant-rich diet and samples from people who followed a typical, unrestricted American diet. The researchers found that people who followed the restricted, plant-rich diet had a more diverse microbiota.
They then colonized groups of germ-free mice with the different human donors' gut communities and fed the animals the donor's native diet or the other diet type. Although both groups of mice responded to their new diets, mice with the American diet-conditioned microbiota had a weaker response to the plant-rich diet.
To identify microbes that could enhance the response of the American diet-conditioned microbiota, the researchers set up a series of staged encounters between mice. Animals harboring American diet-conditioned human gut communities were sequentially co-housed with mice colonized with microbiota from different people who had consumed the plant-rich diet for long periods of time. Microbes from the plant diet-conditioned communities made their way into the American diet-conditioned microbiota, markedly improving its response to the plant diet.
Although the scientists are optimistic that their approach will help guide the development of new strategies for improving the effectiveness of prescribing healthy diets, they emphasize that more research is needed to identify the factors that determine the exchange of microbes between people.
Source: Science Daily