Supplementing a high-fat diet with agavins, branched neo-fructans derived from Agave tequilana, led to a “normalization” in the ratio of Firmicutes to Bacteroidetes, according to scientists from Center for research and advanced studies of the IPN (Mexico) and Sejong University in Seoul (Korea).
The Firmicutes/Bacteroidetes ratio is reportedly a good biomarker for obesity, with data from a 2005 study indicating that obese mice had lower levels of Bacteroidetes and higher levels of Firmicutes, compared with lean mice.
Data published in the journal Nutrients also indicated that agavin supplementation was associated with weight loss and an increase in the production of short chain fatty acids (SCFA) at the start of the large intestine (cecum).
“These results could provide novel insight to develop a new supplementary strategy using agavins to modulate gut microbiota in overweight or obese individuals, which might have positive consequences on body weight loss,” wrote the researchers.
The potential gut benefits of consuming agave fructans has been reported previously, and prebiotic ingredients based on agave are commercially available from several companies, such as Mexico’s Bustar Alimentos and US-based The Tierra Group.
A 2010 study by scientists from the National Autonomous University of Mexico and the University of Reading (UK) reported that inulin extracted from Agave tequilana boosted the numbers of bifidobacteria and lactobacilli to a similar extent to other commercial inulins (Journal of Applied Microbiology, Vol. 108, pp. 2114-2121).
The new study is reportedly the first to show the global effects of a diet shift and supplementation with agavins on the microbiota composition in the cecum in overweight mice.
An expert panel convened by the International Scientific Association for Probiotics and Prebiotics (ISAPP) recently updated the definition of ‘prebiotics’ to be: “A substrate that is selectively utilized by host microorganisms conferring a health benefit”.
The researchers divided lab mice into two groups for five weeks: one group consumed a standard lab mouse diet while the other consumed a high-fat diet. Overweight mice from the high-fat group were then divided into three groups: The first group was shifted back to the standard diet, while the other groups were kept on high fat diets and supplemented with either agavins or oligofructose for another five weeks.
Results showed that mice the high fat diet for the first five weeks displayed a significant decrease in the diversity of the microbiota in the cecum, with an increased Firmicutes/Bacteroidetes ratio and lower SCFA levels.
Shifting these animals back onto the standard diet reversed these changes, with diversity and SCFA levels increasing.
Animals kept on the high-fat diet and supplemented with agavins or oligofructose showed a partial restoration in the microbiota, said the researchers. The Firmicutes/Bacteroides ratio was normalized, while SCFA levels also increased, they added.
Supplementation with agavins led to increases in Klebsiella and Citrobacter, which are members of the Enterobacteriaceae family. “Enterobacteriaceae have also been reported to increase during weight loss in obese mice and humans,” wrote the reseachers.
“[T]he enrichment of members of Enterobacteriaceae has not been reported previously under a prebiotic supplement, which opens opportunities to explore new probiotics,” they concluded.
2017, 9(9), 821; doi:10.3390/nu9090821
“Modulation of Gut Microbiota of Overweight Mice by Agavins and Their Association with Body Weight Loss”
Authors: A. Huazano-Garcia et al.