Funded by the Almond Board of California, the researchers found that almond powder significantly increased levels of certain gut flora. As a result prebiotic effects were increased. The study, published in the July edition of Applied and Environmental Microbiology, found the prebiotic effect did not occur when the fat content was removed from the almond preparation, indicating lipid concentration is key to activating the prebiotic reaction. "We investigated the potential prebiotic effect of almond seeds in vitro using mixed faecal bacterial cultures," the researchers wrote. Institute of Food Research scientists led by Dr Guisy Mandalari used a Model Gut to simulate the physical and biochemical conditions of the gastro-intestinal tract so that the almonds experienced an environment similar to that of the stomach and the small intestine. Digested almonds were then mixed with an in vitro batch system to mimic the bacterial fermentation in the large intestine. The populations of intestinal bacteria were then monitored. "The results show a prebiotic effect of finely ground almonds (with lipid) but not with defatted almonds," Mandalari said. For the finely ground almonds with lipids, the study recorded a significantly increased population for bifidobacteria and Eubacterium rectale, "resulting in a higher prebiotic index (4.43) compared with the commercial prebiotic fructo-oligosaccharides (4.08) at 24h incubation." No such effect was recorded for the lipid-free almonds. "The increase in the numbers of Eubacterium rectale during fermentation of finely ground almonds correlated with increased butyrate production," the researchers wrote. "In conclusion, we have shown that addition of finely ground almonds altered the composition of gut bacteria stimulating the growth of bifidobacteria and Eubacterium rectale." Other research has indicated lipid content of almonds is reduced if almonds are not processed by grinding as in this case, or via mastication. The researchers noted the length of time the almond spends in the digestive system also affected the available quantity of lipids and proteins. They called for further research into almond digestibility, with prebiotic effects tested on human subjects. Source: Applied and Environmental Microbiology July 2008, published online ahead of print 23rd May 2008 doi:10.1128/AEM.00739-08 Investigation of the potential prebiotic properties of almond (Amygdalus communis L.) seeds. Authors: G. Mandalari, C. Nueno-Palop, G. Bisignano, M. S.J. Wickham, and A. Narbad.