Scientists from the National Autonomous University of Mexico and the University of Reading and report that inulin extracted from Agave tequilana boosted the numbers of bifidobacteria and lactobacilli to a similar extent to other commercial inulins.
“This is the first study reporting of a potential prebiotic mode of activity for Agave fructans investigated which significantly increased populations of bifidobacteria and lactobacilli compared to cellulose used as a control,” wrote the researchers.
The study supports findings from the archaeological record, as highlighted by a recent report by archaeologist Jeff Leach, head of the Paleobiotics Lab in New Orleans, and Kristin Sobolik from the University of Maine.
Well-preserved coprolites (fossilised human faeces) from dry cave deposits in the northern Chihuahuan Desert showed that our ancestors from 10,000 years ago adhered to a plant-based diet in this area of the world, predominantly from agave (Agave lechuguilla), sotol (Dasylirion sp.) and onion (Allium drummondii). The faecal samples showed that our ancestors regularly consumed in excess of 100 grams per day of prebiotic fibres – considerably more than modern recommendations of between five and eight grams per day for inulin and oligofructose.
Then and now
Researchers led by Reading University’s Adele Costabile compared the fermentation properties and the potential prebiotic activity of fructans extracted from Agave with different commercial prebiotics: Orafti HP (inulin), Orafti Synergy1 (inulin plus oligofructose), Orafti Raftilose95, Actilight 950P (Beghin Meiji). Cellulose was used as a control.
“The results indicate that inulin derived from Agave has a potential prebiotic effect as it increases the growth of bifidobacteria and lactobacilli,” wrote Costabile and her co-workers. “This effect is similar to the one observed for established inulin-type prebiotics derived from chicory root thus justifying the potential of Agave as a prebiotic.”
The study merely shows a bifido- and lactobacillus-boosting effect and the actual prebiotic activity of the ingredients is still to be shown.
Prebiotics are defined as “non-digestible (by the host) food ingredients that have a beneficial effect through their selective metabolism in the intestinal tract” (Gibson et al. 2004).
Professor Glenn Gibson from Reading University and co-author on the paper, told NutraIngredients: "These are in vitro investigations and therefore the definitive test of a human study remains to be published.
"Based on these laboratory studies, it would seem that the Agave is a source of prebiotic effects. This is due to the inulin type fructans contained therein. This may not be especially surprising in that fructans are recognised to be useful prebiotics in that they selectively stimulate bifidobacteria in the gut. However, they have hitherto been sourced from a relatively restricted number of plants. These studies, should they be confirmed in humans, indicate a further source material," added Prof Gibson.
“Currently, there is an overproduction of Agave plants in Mexico, and there is a high interest in its high fructan concentration to explore this natural resource as fibre, sweeteners and supplement ingredients,” wrote the researchers.
“As Agave represents a very important agricultural resource in Mexico, industries could be encouraged to use it as a cheaper source of inulin compared with the derived from imported brands,” they concluded.
Source: Journal of Applied Microbiology
June 2010, Volume 108, Issue 6, Pages 2114-2121
“In vitro evaluation of the fermentation properties and potential prebiotic activity of Agave fructans”
Authors: E. Gomez, K.M. Tuohy, G.R. Gibson, A. Klinder, A. Costabile