Most people are somewhat familiar with the concept of probiotics, on the other hand prebiotics are not quite as well known by the general population. The most utilised definition of prebiotics is “a substrate that is selectively utilized by host microorganisms conferring a health benefit”. (Carlson et.al., 2017).

Some of the key functional characteristics of prebiotics include the ability to:

• resist the low pH of the stomach, 

• resist hydrolysis (breakdown) by mammalian enzymes, 

• resist absorption in the upper gastrointestinal tract, 

• the ability to be fermented by intestinal microbiota and selectively stimulate the growth and/or activity of intestinal bacteria associated with host health and overall well-being

The purpose of this article is to focus on one of the less known prebiotics available, xylooligosaccharides (XOS).  XOSs are mixture of oligosaccharides like xylobiose, xylotriose, and xylotetrose containing xylose residues linked by α1–4 bonds, naturally found in various food sources like milk, honey, vegetables, fruits, and bamboos shoots.

Xylooligosaccharides Effects on the Microbiome — 

Lin et.al., (2016) looked into the effects of XOS supplementation on Lactobacillus spp., Bifidobacterium spp. and Clostridium perfringens.   The researchers divided subjects into 2 groups, test group and control group. Over a 6 week period  test subjects received XOS-enriched rice porridge while the others (control group) received placebo rice porridge. Fecal samples were collected at the end of weeks 0, 1, 3, 4, 6, and 7 for microorganism examination.

The results showed that 6-week daily ingestion of the XOS-enriched rice porridge induced significant increases in fecal bacterial counts of Lactobacillus spp. and Bifidobacterium spp., as well as decreases in Clostridium perfringens. 

What’s quite important to note with these findings is the preferential feeding of beneficial microbes such as lactobacillus and bifidobacterium without increasing levels of opportunistic pathogens such as Clostridium perfringens which is known to cause food poisoning.

Finegold et.al., (2014) In a randomized, double-blind, placebo-controlled study, 31 healthy adult subjects were given 1.4 grams or 2.8 grams of PreticX™ XOS for eight weeks.

The bifidobacterium count increased significantly in the XOS supplemented groups with a greater increase seen in the higher dose (2.8g) group. 

They also found XOS was tolerated without significant gastrointestinal side effects.  No increases were seen in Lactobacillus and Clostridium species.

Yang et.at., (2015) in their pilot study looked more specifically on the impact of XOS supplementation on the microbiome of healthy individuals and Prediabetic (Pre-DM) individuals.  Both healthy and Pre-DM subjects were given 2 g per day of XOS for 8 weeks. They found that XOS had a clear impact on gut microbiota in both healthy and Pre-DM groups, and resulted in dramatic shifts of several bacterial taxa associated with Pre-DM. Among them, Dialister spp. and Slackia are pro-inflammatory , and were greatly reduced by XOS. Additionally, T2DM associated lactic acid bacteria Enterococcus, Streptococcus, and Lactobacillus were also greatly reduced by XOS. The inhibitory effect of XOS on other opportunistic pathogens, such as Clostridia, Streptococcaceae, and Subdoligranulum, further supports that XOS can potentially promote an optimal gut microbiota profile, and consequently reduce the risk of Type 2 diabetes.

XOS effects on constipation —

Tateyama et.al., (2005) took thirty constipated pregnant women and supplemented them with 4.2g XOS daily for 4 wk. Prior to commencement of XOS supplementation the mean number of bowel motions was 1.1 per week.  By the end of the first week the mean number of bowel motions was up to 5.3 per week, and by the end of the 3rd week it was upto 6.7 per week.

Of note no side effects were observed

The authors concluded XOS intake was highly effective for the reduction of severe constipation in pregnant women without adverse effects.

Xylooligosaccharides effect on Bifidobacterium —

Given the quite consistent findings that XOS promotes the growth of bifidobacterium species in the gut it’s worth covering the importances that these species have in the gut.

Bifidobacteria reside naturally in the gastrointestinal tract of healthy human adults.  Bifidobacterium is a unique genus of bacteria in that no gas is formed as an end product of metabolism.  Bifidobacteria also do not produce any known carcinogenic substances in vivo. Low Bifidobacteria concentrations have been negatively associated with obesity and weight gain.   Increases in Bifidobacteria have also been correlated with a decrease in blood lipopolysaccharides (LPS).  LPS are inflammatory reagents that play a role in the development of inflammatory metabolic disorders and conditions, and are primarily found in gram-negative bacteria. LPS induce the activation of Toll-like receptor 4 (TLR4), which leads to inflammation due to release of pro-inflammatory cytokines and chemokines.

In summary we can clearly see that XOS is a quiet achiever, with research showing it consistently improving the gut microbiome balance and appears to assist constipation in pregnant women all while having minimal to no side effects.  The fact it doesn’t appear to cause side effects put’s it in a bit of a league of its own when it comes to prebiotic fibres as they are notorious for causing unwanted flatulence and sometimes exacerbating bloating in those with irritable bowel syndrome.  Adding my own clinical experience working with patients utilising microbiome testing this is one of the prebiotics I have seen benefits with subjective symptoms and objective post testing outcomes, and mirrors that with the studies in that it is well tolerated even with sensitive patients.

Here are a few options we have available from our online store:

Microbiome Labs - MegaPre™™ & also comes in Capsules

Pure Encapsulations - Poly-Prebiotic

References

Carlson, J., Erickson, J., Hess, J., Gould, T. and Slavin, J., 2017. Prebiotic Dietary Fiber and Gut Health: Comparing the in Vitro Fermentations of Beta-Glucan, Inulin and Xylooligosaccharide. Nutrients, 9(12), p.1361.

Finegold, S., Li, Z., Summanen, P., Downes, J., Thames, G., Corbett, K., Dowd, S., Krak, M. and Heber, D., 2014. Xylooligosaccharide increases bifidobacteria but not lactobacilli in human gut microbiota. Food & Function, 5(3), p.436.

Lin, S., Chou, L., Chien, Y., Chang, J. and Lin, C., 2016. Prebiotic Effects of Xylooligosaccharides on the Improvement of Microbiota Balance in Human Subjects. Gastroenterology Research and Practice, 2016, pp.1-6.

TATEYAMA, I., HASHII, K., JOHNO, I., IINO, T., HIRAI, K., SUWA, Y. and KISO, Y., 2005. Effect of Xylooligosaccharide Intake on Severe Constipation in Pregnant Women. Journal of Nutritional Science and Vitaminology, 51(6), pp.445-448.

Yang, J., Summanen, P., Henning, S., Hsu, M., Lam, H., Huang, J., Tseng, C., Dowd, S., Finegold, S., Heber, D. and Li, Z., 2015. Xylooligosaccharide supplementation alters gut bacteria in both healthy and prediabetic adults: a pilot study. Frontiers in Physiology, 6.