by Matt Weik, BS, CSCS, CPT, CSN
I think it’s fair to say that we all can agree that exercise is great for the body. But what many fail to realize is that it can also take a toll on gut health — especially for those who engage in any sort of endurance training.
Many athletes unfortunately (and unexpectedly) experience gastrointestinal (GI) issues, and researchers are constantly looking for ways to minimize gut damage.
A new study from Swansea University’s Applied Sports Science Technology and Medicine (A-STEM) Research Centre in the UK took a deep dive into how dietary supplements impact exercise-induced gut damage and symptoms.
In this article, we are going to take a deeper dive into what this new research is showing regarding exercise-induced gut health and if the supplements we’re taking are actually helping prevent and fix this issue.
If you have the stomach for it, keep reading. Ok, I promise no more poor humor in this article. Let’s dive into it.
Disclaimer: This article is for informational purposes only and is not meant to treat or diagnose any condition. It is recommended that you speak with your doctor before starting any exercise program, making changes to your nutrition plan, or adding any new supplements into your current regimen.
The Link Between Exercise and Gut Health Issues
A 2014 study in Sports Medicine found that 30-50% of athletes deal with exercise-induced gut health issues.
High-intensity and endurance workouts (especially those in hot conditions) can actually weaken your intestinal barrier. This can lead to increased gut permeability, allowing bacteria and toxins to leak into your bloodstream (no bueno).
The result? Inflammation and gut issues.
With this in mind, researchers are looking at different nutritional strategies that might help you fix this issue.
The Swansea University team analyzed 26 studies that looked at different supplements and their effects on gut symptoms, intestinal fatty acid-binding protein (i-FABP, a marker of gut damage), and exercise performance.
Supplements Studied
The study examined several supplements that claim to support gut health and reduce GI symptoms. Many of these supplements are touted to improve gut health, which you and I may take regularly.
These supplements included:
- Probiotics
- Glutamine and cysteine
- Bovine colostrum
- Carbohydrates
- Curcumin
- Flavonoids
- Sodium nitrate
- Collagen peptides
- Capsaicin
- Sodium bicarbonate
What Did the Research Find? Can They Improve Gut Health?
These studies seemed to consistently show that i-FABP levels increased after exercise, indicating some sort of gut damage. However, most supplements that we all use did not significantly lower i-FABP levels, meaning their effects were not clinically significant.
So, are they all bad? Let’s look at each individually and dig a little deeper.
1. Probiotics: Some Potential, but Limited Impact
Probiotics (something many of us use) had the most promising results, showing a moderate reduction in GI symptoms during endurance exercise.
However, while they helped with symptoms, they did not significantly reduce gut damage biomarkers like i-FABP.
Dr. Shane Heffernan, a senior researcher, mentioned that “While probiotics appear to have the best evidence at the moment, their real-world impact is likely limited.”
2. Glutamine and Cysteine: No Significant Benefit
Glutamine and cysteine supplements were tested at different dosages and exercise conditions to see their effects on gut health.
The result? No significant improvements in gut symptoms or damage markers.
3. Bovine Colostrum: Possible Benefits, But More Research Is Needed
Bovine colostrum (which used to be extremely popular but has died off over the years) is believed to strengthen the gut lining and prevent bacterial toxins from entering the bloodstream.
Some studies showed it blunted i-FABP levels, but these studies were not done in extreme heat. So, whether bovine colostrum can help athletes who train in harsh conditions remains unclear.
4. Carbohydrates: Mixed Results
Carbohydrate supplements had inconsistent results.
Some research suggests that hydrogel solutions might be more effective than other forms in improving gut health, but more studies are needed to confirm this.
5. Flavonoids: No Impact on Gut Damage Markers
Flavonoids are known for their anti-inflammatory and antioxidant properties. But in this analysis, they didn’t make a noticeable difference in gut damage biomarkers.
6. Capsaicin: A Definite No-Go
Capsaicin, which we normally find in weight loss supplements, was the only supplement found to make GI symptoms worse.
Perhaps this will make you rethink taking any sort of fat burner or weight loss supplements that include this ingredient. After all, the effects are minor at best.
Athletes should avoid it before or during exercise.
7. Other Supplements: More Studies Needed
Single studies looked at curcumin, sodium nitrate, collagen peptides, and sodium bicarbonate.
Curcumin showed the biggest impact on reducing i-FABP levels, while collagen peptides showed some promise in reducing inflammation-related GI symptoms. However, the research is still too limited to draw firm conclusions on whether or not you should use them for gut health purposes.
What This Means for Athletes and Supplement Companies
The findings absolutely highlight the need for more research in sports nutrition. While probiotics show potential, there’s still no definitive solution for preventing exercise-induced gut damage.
Dr. Heffernan emphasized the need to explore new alternatives, including algae-derived prebiotics for gut health.
That said, there has been a recent uptick in these types of gut health supplements as I have been hearing more and more about them from the various supplement companies (more along the lines of holistic supplements) I work with on creating content and copy.
Lead researcher Robyn Aitkenhead recommended that supplement companies should focus on hydration and carbohydrate strategies to minimize gut issues and support improved gut health. She also noted that gel or liquid supplements might be better than whole-food forms for reducing gut stress.
Aitkenhead mentioned, “Poor use of carbohydrates can result in worse GI symptoms,” and urged manufacturers to develop better formulations for their supplements. She also said that she would like supplement companies to invest in research on new bioactive prebiotics.
Should You Give Up on Gut Health Supplements?
No. Not exactly.
This study confirms that while some supplements may help ease GI symptoms, most do not significantly reduce gut damage. Probiotics seem to be the most promising when it comes to gut health, but their real-world impact is still limited.
As research continues, athletes should focus on hydration, proper fueling, and avoiding known gut irritants like capsaicin, in particular.
But in the end, more studies definitely are needed to uncover better solutions for fixing issues and supporting gut health for all of us. Until then, paying close attention to diet, hydration, and supplementation choices remains key for gut health during exercise.