What Exactly Is Alpha-Galactosidase?
Alpha-galactosidase is an enzyme that is essential for breaking apart the bonds found in certain types of carbohydrates, such as galacto-oligosaccharides (GOS).1
GOS are found in legumes like beans and lentils, but also in a few other plant foods like certain grains and broccoli (see table below).
Galacto-Oligosaccharides (GOS) content of 19 popular foods
Sources
* = Measurement of short-chain carbohydrates in common Australian vegetables and fruits by high-performance liquid chromatography (HPLC)2
+ = Quantification of fructans, galacto-oligosacharides and other short-chain carbohydrates in processed grains and cereals (2011) Biesiekierski3
Why Might Alpha-Galactosidase Enzymes Be Needed?
Our bodies can’t absorb carbohydrates until they’ve been fully broken down into single sugar units (a.k.a. monosaccharides), which makes enzymes essential for getting the energy we need from our foods.
What’s different about α-galactosidase, though, is that it isn’t actually made by the cells in our digestive tract.
Because of this, when carbohydrates such as those containing GOS come down our gastrointestinal tube, they go undigested and end up getting fermented by microbes in our colon. Fermentation produces end-products such as short chain fatty acids (SCFAs), as well as gasses such as carbon dioxide, hydrogen, and methane.
Some People With IBS Struggle With Galacto-Oligosaccharides (GOS)
With that said, for reasons that aren’t completely understood just yet, some people experience pretty intense symptoms after eating foods that contain a lot of GOS that go far beyond the occasional semi-annoying passing of gas.
Because of this, GOS is one of the categories of carbohydrates initially restricted on a low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (a.k.a. “FODMAPs” ) diet. This “diet” is one of the best-known treatments for IBS, significantly reducing symptoms in 52-86% of people struggling with IBS.56
However, since these fermentable carbohydrates are known to be super healthy (not to mention super tasty), it’s really not ideal to have to avoid them completely. So to counteract the negative effects, a potential solution for those who are specifically very sensitive to GOS is to supplement with α-galactosidase.
Can Alpha-Galactosidase Enzymes Help Your IBS Symptoms?
The short answer? Most likely it can help relieve GOS-related symptoms, but so far only 3 studies have looked at α-galactosidase supplementation in adult IBS patients, and the results are mixed. To better understand the current state of the evidence and figure out who might be helped by supplementing, let’s do a bit of a deep dive into each of these studies.
2016 Study from Finland
The first of these 3 studies was published in 2016 by a group from Finland. 7 They found 125 IBS patients who’d reported that abdominal bloating and flatulence were their most disturbing symptoms, and randomized them into 2 groups: 1 group that took a capsule containing 1200 galactosidase units (GALU) of α-galactosidase or a placebo 3 times a day with meals. What were the results?
After 12 weeks, the treatment group receiving α-galactosidase had a trend towards better improvement in their IBS symptom severity score (IBS-SSS) compared to placebo, but the difference wasn’t statistically significant. Treatment also didn’t show that it improved quality of life. The only significant outcome they found was that after the 4-week follow-up period, the rate of people who qualified as successful responders was higher in the α-galactosidase group.
One notable point about this study was that significantly more people withdrew from the enzyme treatment group than the placebo group (18 vs 7). Of the people in the treatment group, 4 said they dropped out because of abdominal pain, and 2 said it was because of diarrhea. It’s totally normal and expected that people withdraw from studies, but it definitely does raise some eyebrows when the differences in the number of withdrawals are significantly higher in the treatment group like they were in this study.
Overall, the authors postulated that the less than ideal results were due to an insufficient sample size because of dropouts, as well as the significant placebo response.
2018 Study from Australia (Monash University)
The next study that tested α-galactosidase on IBS patients was published in 2018 by a group of researchers from Monash University in Australia. 8 In a valiant effort to minimize confounding factors, they used a crossover study design with a rather complex protocol involving all participants going through 3 different 6-day intervention periods.
The first 3 days of each period consisted of a low FODMAP and low fiber diet, followed by 3 days of meals that were high in GOS ( ~6.5-6.7 g of GOS per day). On the last 3 days of each 6 day period, when they were consuming foods high in GOS, all participants were also given either 150 GALU of α-galactosidase, 300 GALU of α-galactosidase, or a placebo with each meal.
Complicated, I know, but that is kinda what you have to do to try and isolate what’s going on when it comes to studying food.
31 participants completed this study, of which 21 were found to be GOS-sensitive (68%), meaning they had significantly worse symptoms when receiving a placebo on the high GOS-diet days. Of those that were GOS sensitive, the full 300 GALU dose significantly reduced bloating and abdominal pain compared to placebo. These results were only seen for this sub-group, not for all the participants together, when symptom scores were corrected for baseline values.
Also, considering the issues from the first study we talked about, it’s worth mentioning that the only adverse event reported in response to α-galactosidase during this study was with 1 person who had an episode of dizziness while on the half-dose dose (150 GALU/meal).
2021 Swedish Study
The most recent study done on IBS patients was published in 2021, and included 20 participants who specifically complained of frequent bloating, abdominal distention, and/or flatulence.9
Like the second study, this had a crossover design, so all the participants were put on the placebo and the 1200 GALU dose of enzyme at one point or another. The study happened over two separate study visits, where participants were given a breakfast and lunch high in GOS and fructans (0.9 and 0.4 g GOS, respectively), followed by a low FODMAP dinner. So what were the conclusions of this study?
Sadly, when compared to placebo, α-galactosidase didn’t significantly improve symptoms based on any of the outcomes they measured. Why such unexciting results? Well, unfortunately the study design had some significant issues. One issue is they didn’t check to see if the participants were sensitive to GOS. If they had, it’s possible they may have found a subgroup that did respond to the enzyme treatment, like they did in the previous study.
Another issue is that the test meals were high in both fructans and GOS. It’s possible sensitivity to fructans masked any benefits that could have been seen from taking α-galactosidase. The good news is that there weren’t adverse events reported, so even though they couldn’t show that α-galactosidase helped, it also didn’t seem to hurt, even at this higher dose of 1200 GALU per meal.
The Takeaway From The 3 Studies
So what can we take away from all this? Based on what evidence we have, it is probably safe to say that α-galactosidase is only going to help in people that have done the low FODMAP diet and found that they are sensitive to GOS.
How To Take Alpha-Galactosidase Enzymes Supplement For IBS
How Much To Take (Dosing)
As far as dosing goes, 300 GALU did seem to relieve symptoms of GOS-sensitivity in IBS patients. Similarly, studies in non-IBS people have shown that significant reductions in symptoms can be found with lower doses such around 300 GALU, but that 1200 GALU showed better results.1011
One of the two IBS studies that did test out this higher 1200 GALU did report some adverse events such as diarrhea and abdominal pain though, so you may want to work up to this amount slowly if 300 GALU isn’t providing adequate relief.
When To Take (Timing)
Timing of dosing may also be important. Most studies had participants taking the whole dose of α-galactosidase just prior to eating, but in the 2nd IBS study by the Monash group, they had participants split the dose, 1 capsule taken at the beginning and 1 during the middle.8
This technique may help with making sure as much of the GOS-containing foods are being exposed to the enzyme, giving it a chance to break apart the galactosydic bonds we talked about earlier.
Other Experiments To Consider
Figuring out the right mix of conditions to optimize the effectiveness of α-galactosidase is likely going to require some trial and error.
This means not only experimenting with different doses depending on the amount of GOS you are eating, but maybe even different brands.
It may be worth trying a version that states it is enteric coated if you’re finding that the regular kind doesn’t seem to be doing much, as this may help prevent the super acidic stomach acid from deactivating the enzyme before it reaches the small intestine.
You might also want to pay special attention to the additives in the enzyme supplements, as they sometimes contain ingredients that fall under the umbrella of FODMAPs, such as mannitol and sorbitol.
Who Should Not Take It (Side Effects)
Last but most certainly not least, always check with your doctor before starting and stopping a supplement of any kind. While α-galactoside is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA), it may not be appropriate for everyone.12
For example, α-galactosidase may result in blood sugar changes due to the increased availability of simple sugars as a result of more complete carbohydrate digestion. It also has been found to make certain diabetes medications less effective.13 Those with galactosemia also may need to avoid this enzyme, as it will increase the amount of galactose that needs to be digested. Those with mold allergies should also be extra cautious, as enzymes like this are often sourced from a fungus known as Aspergillus niger14
Summary & Verdict
- A-galactosidase is a digestive enzyme that helps break down a specific type of bond in certain galactose-containing carbohydrates, such as the galactooligosaccharides (GOS) found in some plant foods like beans.
- This enzyme is not made and released by the cells in our gut, so normally, these types of carbohydrates go undigested and eventually are fermented by microbes in the colon
- Although, in general, it is normal and even healthy that some carbohydrates go undigested, some people experience abnormally severe symptoms from eating foods high in fermentable carbohydrates like GOS
- A-galactosidase has been shown to be effective at improving symptoms after eating foods high in GOS, however, is likely only effective in people that have identified themselves as GOS-sensitive
- Doses of around 300 GALU of α-galactosidase per meal have been shown to significantly improve some symptoms. However, a higher dose of 1200 GALU per meal may be more effective, based on the wider research on non-IBS subjects.
- A-galactosidase is generally recognized as safe (GRAS) by the Food and Drug Administration (FDA), and has been tolerated well by the vast majority of participants in research studies. However, one of the few studies done on IBS did report that a significant number of dropouts in the group taking 1200 GALU per meal. Reasons for dropping out included worsened diarrhea and abdominal pain. These issues were not seen in a later study on IBS patients taking this same dose.
- Always check with your doctor before starting or stopping a supplement. A-galactosidase may not be appropriate for every person, especially in people with diabetes, galactosemia, or mold allergies.
