Scientists reviewed hundreds of research papers to understand how probiotics (good bacteria) and prebiotics (food for good bacteria) might help treat colorectal cancer. They found that most studies focus on prebiotics like fiber, while fewer studies test probiotics directly. The research suggests that gut bacteria play an important role in cancer treatment, but scientists need to do more studies to figure out the best ways to use these natural approaches. This review shows a growing interest in using food and natural compounds to support cancer therapy, though practical challenges still exist.
The Quick Take
- What they studied: How probiotics (beneficial bacteria) and prebiotics (food that feeds good bacteria) might help people being treated for colorectal cancer, based on what scientists have already published
- Who participated: This wasn’t a study of patients—instead, researchers reviewed 116 scientific papers published between 2020 and 2025 about gut bacteria and colorectal cancer treatment
- Key finding: Most research focuses on prebiotics like dietary fiber (70% of studies), while fewer studies test probiotics directly (24%). Only a small number of studies (3%) looked at using both together, even though combining them might work better
- What it means for you: While gut bacteria appear important for cancer treatment, we don’t yet have enough evidence to recommend specific probiotic or prebiotic supplements as a main cancer therapy. These may be helpful additions to standard treatment, but talk to your doctor first
The Research Details
This research is called a ‘bibliometric analysis,’ which means scientists didn’t conduct their own experiments with patients. Instead, they searched through thousands of published research papers and carefully selected 116 that met their specific criteria. They focused on papers published between 2020 and 2025 that were written in English and found through Google Scholar and PubMed (major scientific databases). From those 116 papers, they deeply analyzed 37 studies to understand trends in the research.
The researchers looked for papers using specific search terms like ‘colorectal cancer,’ ‘colon cancer,’ and ‘gut microbiota.’ They followed strict guidelines (called PRISMA guidelines) to make sure their review was organized and fair. This approach helps scientists understand what other researchers have discovered and identify gaps in our knowledge.
This type of review is valuable because it shows us the ‘big picture’ of what scientists around the world are studying. Instead of looking at one small study, we can see patterns across many studies. This helps identify which research areas are getting attention and which ones need more work. For colorectal cancer and gut bacteria, this review reveals that most scientists are studying fiber and prebiotics, but fewer are testing actual probiotic bacteria—which might be an important gap to fill.
This review has some strengths: it followed established scientific guidelines and reviewed papers from respected databases. However, readers should know that this is a summary of other people’s research, not original research with patients. The quality depends on the quality of the 116 papers reviewed. Also, the review only included English-language papers, so important research published in other languages might have been missed. The declining number of publications in recent years (only 3 papers from 2025) suggests this research area may be slowing down.
What the Results Show
The analysis revealed that research on gut bacteria and colorectal cancer is concentrated in China, which leads global research efforts in this area. The overwhelming majority of studies—about 70%—focus on prebiotics, which are foods or compounds that feed beneficial bacteria in your gut. Common prebiotics studied include dietary fiber from plants. These studies suggest that feeding your good bacteria might help support cancer treatment.
In contrast, only about 24% of studies directly tested probiotics, which are actual beneficial bacteria supplements. Scientists identified several reasons for this gap: probiotics are harder to study because they’re living organisms that can die or change, they’re more expensive to research, and it’s complicated to figure out which specific bacteria strains work best.
Very few studies (only 2.7%) looked at combining prebiotics and probiotics together, even though scientists think this combination might work better than either one alone. Among the probiotic studies that did exist, one specific bacteria called Clostridium butyricum appeared most frequently, suggesting it might be particularly important for cancer treatment.
The review found an interesting trend: there’s growing scientific interest in traditional medicine and functional foods (foods with health benefits beyond basic nutrition) for cancer treatment. This reflects a shift toward natural and preventive approaches. However, the number of new papers being published each year has actually declined recently, which suggests research momentum in this area may be slowing. The researchers noted that while scientists recognize the importance of having diverse types of bacteria in your gut, the actual number of studies testing different probiotic species remains surprisingly small.
This review fits into a larger scientific conversation about the gut microbiome’s role in cancer. Previous research has suggested that gut bacteria influence how our immune system works and how our bodies respond to cancer treatment. This analysis confirms that scientists are increasingly interested in this connection, but it also reveals that we’re still in early stages of understanding exactly how to use probiotics and prebiotics as cancer treatments. The focus on prebiotics over probiotics is somewhat different from other areas of medicine, where probiotic supplements are more commonly studied.
Several important limitations exist: First, this review only looked at papers published between 2020 and 2025, so older research wasn’t included. Second, only English-language papers were reviewed, meaning important studies published in Chinese, Spanish, or other languages were excluded. Third, the review analyzed what other scientists published but didn’t evaluate whether those studies were well-designed or had strong evidence. Fourth, because this is a review of reviews rather than a study with actual patients, we can’t draw firm conclusions about whether these treatments actually work in real people. Finally, the declining number of recent publications makes it harder to understand current trends.
The Bottom Line
Based on this review, here’s what we can say with different levels of confidence: (1) Eating more fiber and plant-based foods appears safe and may support gut health during cancer treatment—moderate confidence. (2) Taking probiotic supplements specifically for colorectal cancer treatment is not yet proven effective—low confidence, needs more research. (3) Combining prebiotics and probiotics might be beneficial, but we don’t have enough evidence yet—very low confidence. Always discuss any supplements or dietary changes with your cancer care team before starting them.
This research matters most to people with colorectal cancer and their doctors who are looking for ways to support standard cancer treatment. It’s also relevant to people interested in cancer prevention through diet. However, this review should NOT be used as a reason to replace standard cancer treatments (surgery, chemotherapy, radiation) with probiotics or prebiotics alone. People with weakened immune systems should be especially careful about probiotics and should consult their doctors first.
If someone were to increase their fiber intake or take probiotics, changes in gut bacteria composition might begin within days to weeks. However, any effects on cancer treatment would likely take much longer to measure—probably weeks to months. This is why we need long-term studies with many patients to understand if these approaches actually help fight cancer.
Want to Apply This Research?
- Track daily fiber intake (target: 25-30 grams per day) and note any digestive changes. Users can log fiber sources like vegetables, fruits, whole grains, and legumes, plus record digestive symptoms to identify patterns.
- Users can set a daily goal to eat one additional high-fiber food (like beans, berries, or whole grain bread) and track completion. This builds the habit gradually without overwhelming dietary changes.
- Create a weekly summary showing fiber intake trends and digestive wellness notes. Users can share this data with their healthcare provider to discuss whether dietary changes are helping their overall health during cancer treatment.
This review summarizes published research but does not provide medical advice. Probiotics and prebiotics should never replace standard colorectal cancer treatments like surgery, chemotherapy, or radiation. If you have colorectal cancer or are at risk, consult with your oncologist or gastroenterologist before starting any supplements or making major dietary changes. Some people, especially those with weakened immune systems, should avoid probiotics without medical supervision. This analysis reflects research trends through 2025 and may not represent the complete scientific evidence on this topic.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.