Prebiotic effect of fruit and vegetable shots containing Jerusalem artichoke inulin: a human intervention study

The biological and clinical importance of the human gastrointestinal microbiota is becoming increasingly recognised by consumers and healthcare workers. Although many disease states involve bacterial metabolism, the human gut microbiota may be considered extremely relevant for the maintenance and improvement in host health. For instance, bifidobacteria and lactobacilli may contribute to inhibit pathogenic bacteria, reduce blood cholesterol levels, improve the immune response and produce vitamins. Scientific concepts underpinning directed modulation of the human gut microbiota have been developed over several decades, with probiotics as the principal focus. In recent years, there has been an upsurge of interest in prebiotics, which selectively enhance beneficial components of the gut microbiota. Their use is directed towards favouring beneficial components within the gut microbial milieu such as bifidobacteria and lactobacilli. They are distinct from most dietary fibres like pectin, cellulose and xylan, which are not selectively metabolised by the gut microbiota. In contrast to probiotics, prebiotics can be added to many foods including those which are cooked or baked as they do not suffer from the survivability issues associated with probiotics.

The fructans (i.e. neosugar, oligofructose and inulin) are current market leaders for prebiotics worldwide. Most fructans are either synthesised from sucrose or prepared commercially from inulin-rich plant sources such as chicory root (Cichorium intybus). However, a number of alternative sources of inulin, such as Jerusalem artichoke (JA) (Helianthus tuberosus) and burdock (Arctium lappa) are now being commercialised, and there is growing scientific literature supportive of their equivalence to chicory-derived inulin. These emerging prebiotic candidates may eventually find their way into the global market. However, there is a need to confirm their prebiotic effectiveness using reliable methodologies in different formulations and in human studies.

Here, we report a human study designed to assess the prebiotic capability of fruit and vegetable shots containing inulin from JA root. The effect of JA inulin present in the fruit and vegetable shots upon relative numbers of intestinal microbiota was determined using fluorescent in situ hybridisation (FISH). Faecal concentrations of SCFA were measured, and digestive tolerance of the prebiotic shots was monitored over the course of the trial.

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