Over the last few years, I’ve noticed a striking trend when reviewing intake forms for new patients: approximately 70% are taking some form of probiotics. When I ask why, their answers range from promoting general wellness to treating specific conditions.
The public has been well educated about how microbiome health contributes to a wide constellation of health issues—not just digestive problems. While our understanding of the microbiome remains limited and evolving, one principle all experts agree on is clear: the healthiest microbiome is the most diverse microbiome.
The Reality About Probiotics
Although probiotic supplements can help promote diversity, what most consumers don’t realize is that these beneficial bacteria don’t actually colonize the intestine, as we might hope. Once you stop taking them, they disappear. A better way to understand probiotics is to think of them as tourists visiting your town. While they’re there, they exert positive influences, but eventually leave, and their impact fades as the permanent residents regain control.
Why don’t probiotics colonize permanently?
The reasons are multifactorial. First, they face colonization resistance from native microbes already established in your gut. Second, new probiotic strains often struggle to adhere to the intestinal wall and establish firm roots in this competitive environment.
What Are Prebiotics?
This is where prebiotics come in. To be classified as a prebiotic, a food ingredient must meet four criteria:
- Cannot be broken down or absorbed in the stomach or small intestine
- Selectively feeds certain potentially beneficial bacteria (not all bacteria indiscriminately)
- Promotes a healthier microbial ecosystem overall
- Induces local and systemic changes that improve human health
What Is NOT a Prebiotic?
It’s important to distinguish prebiotics from other beneficial fibers. Fiber supplements like psyllium, pectin, and flaxseeds are certainly microbiome-nourishing foods, but they are not technically prebiotics because they feed many bacterial species, rather than selectively nourishing specific beneficial strains.
Types of Prebiotics
There are generally three main categories:
Fructooligosaccharides (FOS): These are inulin-like fructans found naturally in garlic, onions, chicory root, and Jerusalem artichokes.
Lactulose: Better known as a laxative, lactulose is a semi-synthetic sugar manufactured through heating or processing lactose (milk sugar).
Galactooligosaccharides (GOS): These can be found in small amounts in boiled chickpeas, red lentils, red kidney beans, soybeans, and raw onions.
The Benefits of Prebiotics
Prebiotics do more than just promote colonization of beneficial microbes. Research suggests they may also:
- Enhance immune system function
- Improve absorption of calcium and iron
- Promote satiety and support healthy eating patterns
- Reduce blood glucose levels in people with type 2 diabetes
- Support modest weight loss (typically 2-5 pounds over 12 weeks)
- Inhibit yeast overgrowth
- Potentially prevent colon cancer
- Reduce recurrent urinary tract infections
- Relieve constipation
- Reduce systemic inflammation
- Lower cholesterol levels
- Help manage irritable bowel syndrome symptoms
- Prevent traveler’s diarrhea
A Word of Caution
Using prebiotics can be tricky. When not used correctly, they can cause abdominal pain, bloating, and even constipation—the very symptoms you may be trying to avoid. Rather than experimenting on your own, I strongly recommend finding an experienced practitioner to guide you.
At Naturopathic Family Health, our providers offer complimentary 10-minute consultations to help you learn more about our approach.
If you are interested in optimizing your gut health, we’d love to help you get started on the right path.
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Dr. Sherry Su, ND, FABNG
Naturopathic Doctor San Jose
408-356-1364
