A search for the blog posts on our site about obesity will result in a list of posts discussing correlations between obesity and bacteria in the gut. People have hypothesized that by modulating the microbiome, you may be able to alter obesity levels in humans. Many studies have looked at how probiotics and prebiotics can modulate bacterial structure to control obesity and metabolic diseases, however little has been done to look at how herbs and fruits could modulate bacterial composition.
A recent study from Korea looked at Schisandra chinensis fruit (SCF), a fruit found most commonly in northern China, that has a long history of being used in East Asian culture as a therapeutic for conditions such as diabetes, obesity, cough, and other conditions. Previous studies of SCF in mice have shown that it modulates the microbiome, however no human trials had been previously conducted. To analyze this in humans, a clinical trial was conducted in Korea to look at the impact that SCF had on gut bacteria, body composition, and blood chemistry.
At the Dongguk University Ilsan Hospital in Korea, scientists recruited women who were obese (BMI over 25) who met other specific medical conditions. 28 women ended up participating in the study, 13 in the SCF treatment group and 15 in the placebo group. The study participants each took either SCF or placebo twice a day for twelve weeks and blood and fecal samples were taken before and after the treatment as well as a physical examination including heart rate, waist circumference, body weight, and blood pressure.
After twelve weeks, both the placebo and experimental group saw a decrease in waist circumference and fat mass, thought the SCF group saw a greater decrease in fat mass, blood glucose and other parameters. An analysis of the fecal samples before and after the twelve weeks saw greater clustering in the SCF group than the placebo group. At the genus level, there was significant differences between the two groups and the SCF group saw a greater abundance of genus levels (both groups saw similar levels of phyla changes). They saw specific clustering between patients in the SCF group despite dissimilar clustering prior to treatment. This showed that SCF had an influence on gut microbiota that was dependent on gut bacteria prior to treatment.
This study found differences between bacterial composition in patients who were given the Schisandra chinensis fruit and those in the placebo group. Many of the bacteria that saw an increase in the SCF group, including Akkaermansia, Roseburia, Prevotella, Bifidobacterium, and Bacteroides, had shown an association with reduced obesity levels in previous studies. While decreased waist circumference, body mass, and other weight loss parameters were seen in the SCF group, the results were not statistically significant. Much research has been done to look at ways of altering the microbiome and this study shows us that we should continue to investigate the effects of herbs and fruits on our microbiome.