Greater than the Sum of its’ Parts: Inulin Plus XOS is a Powerful Combination

Prebiotic Biome Fuel

Prebiotics are special types of fiber/carbohydrate that humans cannot digest. They pass through the gut intact and are used as fuel by the good bacteria that live in your intestine, where they make products that acidify (a good thing!) and feed the cells lining your colon.



Prebiotics have immense potential to benefit human health and are subject to increasing interest by the scientific community.

Number of Research Papers Published on Prebiotics




In a study published in the British Journal of Nutrition, European researchers found that adding XOS to inulin boosted the effectiveness of the prebiotic 2X!


The randomized, parallel, double-blind, placebo controlled study (the gold standard of studies) monitored 60 healthy volunteers (34 women and 26 men) over a period of two months.


The sixty volunteers were randomly assigned to one of three groups:


  1. Placebo: Received a daily dose of 5 g maltodextrin,
  2. XOS: Received 5 g XOS
  3. INULIN + XOS: Received a combination of 1 g XOS + 3 g Inulin


The products were taken in two daily doses, before breakfast and before the evening meal.


The researchers monitored the gut microbiomes of the volunteers and took regular blood samples to monitor markers of inflammation and short chain fatty acids.


Prebiotic Scientists

What did they find?


Microbiome analysis:

  • There were significantly more Bifidobacteria in the XOS and INULIN + XOS groups than the placebo and slightly more Lactobacilli.
  • Total short chain fatty acid production was significantly increased in the INULIN + XOS group compared to placebo and XOS only.
  • Bacterial enzymatic activity increased in both XOS and INULIN + XOS groups.


Immune analysis:

  • 70% increase in secretory IgA in the INULIN + XOS group.
  • Significantly decreased circulating LPS (LPS is a component of bacteria and believed to be a trigger for systemic inflammation).
  • System-wide decrease in the pro-inflammatory pathway and stimulation of the anti-inflammatory pathway.


The researchers concluded without any doubt that both XOS and INULIN + XOS have strong prebiotic effects after 2 and 4 weeks of intake.


The ability of prebiotics to stimulate the growth of healthy Bifidobacteria has been demonstrated in a number of studies. However, the researchers found that (under similar experimental conditions) the stimulation of Bifidobacteria growth using 5g of INULIN + XOS in this study was much more effective than previous studies using 10g of individual prebiotics.


The combined INULIN + XOS formulation was at least twice as effective as individual prebiotics for stimulating the growth of healthy bacteria!


XOS alone or INULIN + XOS both increased short chain fatty acid production. Interestingly they affected the ratios differently, suggesting that they promote the growth of different bacterial populations in the gut microbiome.


Finally, only the combination of INULIN + XOS had an effect on the immune system of the healthy volunteers (a healthy test group makes this more difficult to assess) and stimulated anti-inflammatory mechanisms.


The next steps for this exciting research will be to assess the effects less healthy populations, such as obese individuals with low-grade systemic inflammation.


The authors see the INULIN + XOS combination as having great potential for weight-loss and improvement of metabolic disturbances when added as part of a moderate low-energy, low-fat diet.