Almonds a possible prebiotic?
Mandalari G, Nueno-Palop C, Bisignano G, Wickham MS, Narbad A. 2009. Potential prebiotic properties of almond (Amygdalus communis L) seeds. Appl Environ Microb 74:14;4264-70.
Prebiotics are currently defined as nondigestible substances that provide a beneficial physiological effect on the host by selectively stimulating the favourable growth or activity of a limited number of indigenous bacteria.
The nutritional benefits of almonds include cholesterol lowering effects and protection against diabetes. They are a good source of minerals and vitamin E but are not thought of as prebiotic. This study investigated the potential prebiotic effect of almond seeds in vitro by using mixed fecal bacterial cultures.
Two almond products, finely ground almonds and defatted finely ground almonds, were subjected to a combined model of the gastrointestinal tract which included in vitro gastric and duodenal digestion. The resulting fractions were subsequently used as substrates for the colonic model to assess their influence on the composition and metabolic activity of gut bacteria populations.
The finely ground almonds significantly increased the populations of bifidobacteria and Eubacterium rectale, resulting in a higher prebiotic index (4.43) than was found for the commercial prebiotic fructooligosaccharides (4.08) at 24 h of incubation.
Conversely no significant differences in the proportions of gut bacteria groups were detected in response to the defatted ground almonds. This indicates that not only may almonds possess prebiotic potential but that it is linked to the lipid content of the nuts.
The authors noted the differences between almonds and the established or traditional prebiotics of inulin and oligofructose. These fibres are resistant to the gastric and small intestinal environments but do change on the way through the stomach and small intestine. There are still a lot of nutrients present when the almonds reach the large intestine including lipids and polysaccharides. It is considered that as much as 60% of the nutrients are still potentially available by the time the almond reaches the large intestine.
More detailed studies on the digestibility of almonds and the role played by lipids in the potential prebiotic effect need to be performed using human volunteers.
Kim Hunter MNHAA
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|Publication:||Australian Journal of Medical Herbalism|
|Date:||Sep 22, 2009|
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