On last week’s podcast, we talked with Erica and Justin Sonnenburg about how the food we eat, and specifically dietary fiber, is important for “feeding” our microbiomes. All of the variables that influence microbiome composition are not fully understood, however research is continually being conducted to better understand what factors affect the microbiome. To this end, a team of scientists from New York University School of Medicine set out to find how sex, body mass index (BMI), and dietary fiber intake impact the microbiome.

The scientists analyzed fecal samples from 82 individuals, 51 men and 31 women. They found that the women had different microbiome composition than the men, specifically a lower abundance of Bacteroidetes. They also found that BMI impacted microbiome diversity, specifically in women. Overweight and obese women had less diverse gut bacteria than normal weight women and women with a higher BMI also had less Bacteroidetes in their guts compared to the normal weight women.

The scientists also found that various sources of dietary fiber differentially impacted the microbiome of subjects. Fiber intake from fruits and vegetables resulted in higher levels of Clostridia and fiber intake from beans was associated with greater abundance of Actinobacteria. It is possible that dietary fiber is influencing the microbiome by reducing gut transit time and lowering the pH. It is also possible that it is influencing systemic levels of estrogen, which could alter microbiome composition.

As the microbiome continues to be implicated in diseases, the ability to identify variables that affect the microbiome are important and can potentially be used for altering microbiota composition to prevent or possibly treat disease.