Galacto-oligosaccharides (GOS) are amongst the most widely studied prebiotics until now. They are generally obtained from cow’s milk lactose through a trans-galactosylation process that allows to branch galactose molecules together. However GOS obtained from cow’s milk lactose generally contain residual amounts of cow’s milk products and then are generally not suitable for use in products aimed at people suffering from cow’s milk allergy or lactose intolerance. Lactose-free prebiotic alternatives to lactose-based GOS such as inulin or fructo-oligosaccharides (FOS) are available but do not display similar fermentation patterns in the gastrointestinal tract.
To fill this gap, new patented plant-based GOS have been recently introduced under the brand name AlphaGOS® and offer an interesting alternative to lactose-based GOS as they do not contain any trace of dairy product.
The microbiome, a key organ
Healthy adults harbor more than 1000 species of bacteria that live inside and on the Human body (1) . It is considered that 90% of cells in the human body are bacterial, fungal, or otherwise non-human (viruses) (2). The collective genome of these microbes is called microbiome, while the probiome is defined as the autochtonous beneficial bacteria that can be modulated through dietary manipulations.
Microbiome and probiome have attracted particular attention in recent years due to their probable implication in the regulation of a wide variety of physiological functions and potential impact on the risk of diseases. Emerging evidence suggest that dysbiosis (microbial imbalance or maladaptation on or inside the body) affects the maintenance of immune defense, cardiovascular health, glucose metabolism, weight management or digestive health (3) and that microbiota has an implication in the pathogenesis of auto-immune and neurodegenerative diseases (4-5).
Modulating the probiome and consequently the microbiome as well as the metabolome (i.e the metabolites produced in situ) can have positive impacts on the well-being of individuals, at all life stages.
GOS, a gold standard prebiotic to promote the growth of bifidobacteria
Among the vast gut bacterial community, bifidobacterium is probably the most widely studied genus which colonizes Human gastro-intestinal tract at all life stages. While it is dominant in healthy breast-fed infants its levels decrease but remain relatively stable in adulthood (30-40%) and then drop in elderly (10%) (Figure 1) (3). The abundance of bifidobacteria has been linked to a series of diseases or conditions such as Irritable Bowel Syndrome (IBS), obesity, asthma, cystic fibrosis or allergies (6).
Specific stimulation of the presence and activity of bifidobacteria within the human can be achieved through different methods but the two most studied are the direct supplementation with bifidobacterium strains or the supplementation with prebiotics that can selectively stimulate their growth. Prebiotics are selectively fermented ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon the host health (7).
Galacto-oligosaccharides (GOS) are amongst the most widely studied prebiotics until now (8). They have been studied for decades for their effect on gastro-intestinal transit, on mineral absorption or on immunity and allergies (7). In this context they are considered as the gold standard prebiotic substance in infant formulas (8) but their use in adults is also widespread. The bifidogenic action of GOS has been studied in multiple clinical trials in infants and adults and is now well established.
AlphaGOS, the unique plant-based, allergen-free and lactose-free GOS
GOS are generally obtained from cow’s milk lactose through a trans-galactosylation process that allows to branch galactose molecules together (9). However GOS obtained from cow’s milk lactose generally contain residual amounts of cow’s milk proteins and/or lactose and then are generally not suitable for use in products aimed at people suffering from cow’s milk allergy or lactose intolerance. While cow’s milk allergy prevalence decreases with age (from 1-17.5% in preschoolers to 1-4 % in adults), the frequencies of self-reported adverse reactions to cow’s milk are much higher than the medically confirmed diagnoses, not only in children but also in adults (10). Regarding tolerance to lactose, it is highly dependent on the persistence of lactase trait in adulthood and on geography: while 90% of the population in Scandinavia and Netherlands save this lactase persistent trait in adulthood, only half of the population does so in Southern Europe and Middle East (around 50% in Spain and Italy) and a very low proportion of the population presents it in Asia and Africa (around 1% in Chinese, around 5-20% in West African agriculturalists) (11).
Lactose-free prebiotic alternatives to lactose-based GOS such as inulin or fructo-oligosaccharides (FOS) are available but do not display similar fermentation patterns in the gastrointestinal tract. To fill this gap, new patented plant-based GOS have been recently introduced under the brand name AlphaGOS® and offer an interesting alternative to lactose-based GOS as they do not contain any trace of lactose or allergen.
Prebiotic effects similar to those of classical GOS
The potential of AlphaGOS® to display similar fermentation pattern to lactose-based GOS has been tested in an in vitro screening platform allowing to simulate the gastro-intestinal effect of the addition of prebiotics on the fermentation profile and regulation of microbiota.
To do so, both prebiotics (4 mg/mL) or a control (no prebiotic addition) were co-cultured in triplicates with stools of lean or obese adults during 20 hours, and measurements were performed at the end of the incubation period.
The results obtained demonstrate that AlphaGOS® and lactose-based GOS display a similar pattern with regards to the stimulation of the bifidobacteria population when compared to a control. This pattern was observed regardless of the weight profile of the stools donor (lean or obese) as shown in Figure 2.
Figure 2: Comparison of bifidogenic effects of AlphaGOS® and lactose-based GOS. Rows with a different letter are significantly different (p<0.001)
Similarly AlphaGOS® and lactose-based GOS exhibit similar patterns with regards to the production of short chain fatty acids (SCFAs) by the microbiota as illustrated in Figure 3.
Both AlphaGOS® and lactose-based GOS favor the production of propionate, acetate and butyrate in stools from both lean and obese subjects.
SCFAs are known to mediate important physiological functions in Humans such as increasing the absorption of certain nutrients, maintaining the integrity and function of the gut barrier, inhibiting the adhesion of pathogens or shifting energy metabolism (12).
Figure 3. Comparison of Short-Chain Fatty Acids production with AlphaGOS® and lactose-based GOS
AlphaGOS® exerts prebiotic effects both in lean and obese subjects by increasing levels of bifidobacteria and modulating SCFAs production. Furthermore these effects are similar to those of lactose-based GOS which are well-established prebiotics extensively studied in a variety of conditions. AlphaGOS® is then a suitable candidate to fight dysbiosis (imbalance of the gut microbiota in lean and obese adults). It positions as a unique alternative to lactose-based GOS, suitable for vegans, allergic and lactose-intolerant people, for various applications both in foods, supplements and beverages applications.
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