Effects of galactooligosaccharides (GOS) on the gut microbiota in lactose intolerant individuals
This research suggests that galactooligosaccharides (GOS) supplements might offer a new way to help lactose intolerant people better tolerate dairy products by promoting beneficial gut bacteria.
College of Health researcher(s)
College unit(s)
Highlights
- Galactooligosaccharides (GOS) may alleviate the lactose intolerance symptoms.
- GOS supplementation changed the microbiota in lactose intolerant humans.
- Significant increases in Actinobacteria and Firmicutes phyla in the GOS group.
- Considerable increase in the amount of genus Bifidobacteria in the GOS group.
- GOS enhances the presence of Bifidobacteria and potentially reduces LI symptoms.
Abstract
Lactose intolerance (LI), which affects approximately 75% of the global population, leads to symptoms such as abdominal pain, bloating and diarrhea. The primary management strategy for LI involves the avoidance of lactose-containing products. Although there is no cure for LI of genetic origin, the administration of prebiotics, including the consumption of galactooligosaccharides (GOS) and, potentially, the regular, low-level intake of lactose, may modify the gut microbiota to aid in symptom management. We conducted a six-week, single-blind trial on 14 participants who self-reported LI to examine the effects of GOS vs. low level lactose in the context of a normal diet on the gut microbiota. Fecal samples, gastrointestinal symptom reports and dairy consumption data were collected throughout the study. No significant changes in alpha and beta microbial diversity were observed within the GOS and lactose groups individually. There were significant increases in Actinobacteria (P < 0.0001) and Firmicutes (P = 0.0006) phyla in the GOS group. Additionally, a considerable elevation in amount of the genus Bifidobacteria (P < 0.0001) and a reduction in self-reported diarrhea incidents (P = 0.0085) were observed in the GOS group. The findings suggest that GOS enhances the presence of commensal Bifidobacteria and potentially alleviates LI symptoms.
FAQ: Galactooligosaccharides (GOS) and Lactose Intolerance
What is lactose intolerance (LI) and what causes it?
Lactose intolerance occurs when the small intestine doesn't produce enough of the enzyme lactase. Lactase is needed to break down lactose, a sugar found in milk and dairy products. When lactose isn't properly digested, it moves to the colon, where it causes symptoms like abdominal pain, bloating, and diarrhea. This is often due to lactase non-persistence (LNP), where lactase production decreases after weaning, which is a trait that affects about 75% of the world's population. Some people, however, have a genetic variation called lactase persistence (LP), where they continue to produce lactase into adulthood.
How do galactooligosaccharides (GOS) potentially help manage lactose intolerance?
GOS are prebiotics, meaning they are carbohydrates that can't be digested by human enzymes but can be fermented by bacteria in the colon. Specifically, GOS selectively encourage the growth of beneficial bacteria like Bifidobacteria in the gut. These bacteria have enzymes (β-galactosidase) that can break down both GOS and lactose without producing large amounts of gas. By increasing these beneficial bacteria, GOS might help the body process lactose more efficiently, thus reducing symptoms of LI.
What changes in the gut microbiota were observed with GOS supplementation in lactose-intolerant individuals?
The study found that GOS supplementation led to a significant increase in the relative abundance of Actinobacteria and Firmicutes phyla, as well as the genus Bifidobacteria. There was also a decrease in Bacteroidetes. These changes suggest that GOS supports a shift in the gut microbiome towards a more beneficial composition.
Did GOS supplementation affect gastrointestinal symptoms in the study participants?
Yes, the study showed a significant decrease in self-reported diarrhea among participants taking GOS compared to a control group consuming a low dose of lactose. However, there was also a significant increase in self-reported bloating during the supplementation period, suggesting a trade-off in symptom management.
Why was a low-lactose control group used instead of a placebo or lactase supplement?
The study used a low-lactose control group instead of a placebo to better simulate real-world management strategies for LI. Using a lactase supplement wouldn't have provided insight into the dietary effects of GOS in usual dietary conditions, whereas, low-lactose consumption is common method for those with lactose intolerance. This strategy allows assessment of GOS as a potential dietary option that could complement or even replace enzyme supplementation.
Are the changes in the gut microbiota and symptoms permanent after stopping GOS supplementation?
No, the study indicated that the positive changes in microbial composition and reduction in diarrhea symptoms were transient, subsiding after the end of the supplementation period. This suggests that consistent intake of GOS may be necessary to maintain benefits.
Did GOS supplementation lead to any adverse effects in study participants?
The primary adverse effect noted during GOS supplementation was a statistically significant, though not clinically severe, increase in bloating. However, the GOS dose used was well-tolerated, with no participants withdrawing from the study due to adverse effects and no observed increase in diarrhea.
What are the limitations of the study and what future research is needed?
The study had several limitations, including a small sample size, short duration, and the absence of a placebo control group. Future studies should include a placebo control group and larger, more diverse populations and investigate the long-term effects of GOS supplementation. Additionally, exploring combinations of GOS with other prebiotics or probiotics, and using functional analyses like metatranscriptomics and metabolomics is warranted.