One expert reviews the benefits of prebiotics for better gut health.
Due at least in part to all of those famous yogurt commercials, consumers are quite familiar with the benefits of probiotics. They are, however, far less aware of the benefits of prebiotics, or prebiotic soluble fiber.
Prebiotic soluble fiber, a concept that gained traction more than two decades ago, is now defined as a selectively fermented substance that results in specific, healthful changes in the composition and/or activity of the gut flora. Research on the effects of prebiotic soluble fiber supplementation indicate beneficial impacts, including:
This article will focus on the last three of these health benefits: an increase in healthy bacteria, better immune function and regulation, and improvements in symptoms associated with GI disorders.
An Increase in Healthful Bacteria
Supplementation with prebiotic soluble fiber creates what is known as “the prebiotic effect”-changes in the makeup and/or activity of certain health-promoting bacteria. These beneficial effects are related to prebiotic soluble fiber’s metabolism and ability to produce vitamins, antioxidants, and bacteriocins. (Bacteriocins are narrow-spectrum natural antibiotics that help keep their bacterial competition at bay while, at the same time, inhibiting some “bad” bacteria that cause colonic disease.)
Prebiotic soluble fibers have several common features:
A sizeable body of research, both on humans and animals, demonstrates that supplementing with a variety of dietary soluble fibers types results in increases in Bifidobacteria, Lactobacillus, or both. These and other healthful bacteria improve health in a variety of ways. By feeding on prebiotic soluble fiber, their primary food source, they increase in number and metabolic activity, which as a result produces short-chain fatty acids, vitamins, antioxidants, and bacteriocins.
Short-chain fatty acids do a number of significant things. One type of short-chain fatty acid feeds the cells that make up the gut lining, helping to keep the cells healthy and thus supporting their barrier function. This type of short-chain fatty acid also regulates these cells’ growth and differentiation-factors that may contribute to the fatty acid’s role in helping to reduce the risk of colon cancer. Other short-chain fatty acids are absorbed and transported to the liver, where they favorably affect glucose metabolism and also appear to inhibit cholesterol synthesis and regulate the deposit of fat.
There are many different kinds of immune-system cells. These cells perform a variety of functions and create a variety of molecules that affect how the immune system functions. Although no single immune marker accurately reflects overall immune function, examining many markers in different situations can paint a picture of immune function and modulation in both hyper-immune conditions (such as autoimmune disorders) and hypo-immune ones (such as infection).
Adding prebiotic soluble fiber to the diet benefits the immune system in many ways. For instance, in infants who were not breastfed, prebiotic supplementation has been shown to create a significantly higher concentration of immune antibodies. In elderly adults, supplementation helped to increase natural killer cell activity, increase production of an anti-inflammatory substance, and decrease production of two pro-inflammatory substances. In infants with a high risk of allergies, prebiotic supplementation reduced blood levels of antibodies that cause allergic reaction and reduced the incidence of atopic dermatitis. Experimental data from animal studies of prebiotic supplementation showed similar benefits.
According to the author of one review article on prebiotic soluble fiber, many animal and human studies suggest that some aspects of innate and adaptive immunity of the gut and the entire immune system are positively affected by prebiotic supplementation. Additionally, a number of studies have shown that prebiotics play a role in helping to overcome infections. This body of work, along with other studies, strongly suggest that prebiotic supplementation improves the body’s response to certain infections and improves inflammatory conditions.
Help for Serious Bowel Conditions
Research demonstrates that prebiotic soluble fiber may help to improve the symptoms of gastrointestinal disorders and may help decrease the risk of colorectal cancer. People with irritable bowel syndrome (IBS) experience chronic recurring abdominal pain or discomfort coinciding with diarrhea, constipation, or both. In these cases, prebiotic supplementation has been shown to significantly reduce the incidence and severity of symptoms while increasing quality of life.
An imbalance of pro-inflammatory and immune-regulating substances in the gut’s mucous membranes causes inflammatory bowel disease (IBD), a chronic disorder characterized by intestinal inflammation, ulceration, and narrowing of the intestines. Symptoms include diarrhea, urgency and incontinence, and severe abdominal pain and rectal bleeding, and can have a profound negative impact on the ability to absorb nutrients as well as on the patient’s quality of life. Studies on patients with ulcerative colitis, a type of IBD, have shown significant reductions in inflammation following prebiotic supplementation, with increased mucosal Bifidobacteria and decreased pro-inflammatory substances. Similar changes have been seen in patients with Crohn’s disease, another type of IBD, with patients seeing a significant reduction in disease activity and with 40% of the treated patients entering disease remission.
Evidence from a number of studies suggests that changes to the colon’s bacteria may be a factor that leads to cancer. It follows, then, that improving the numbers and activity of healthful gut bacteria may interfere with the process of carcinogenesis., Animal studies have shown evidence of decreased pre-cancerous lesions and decreased tumor incidence following prebiotic supplementation.,,,,,,, Human studies examine changes in biomarkers of colon cancer, such as DNA damage and cell proliferation in the colon’s mucous membranes. A randomized, double-blind trial of prebiotic supplementation in patients with resected polyps or colon cancer showed favorable changes in multiple colon cancer biomarkers. 
A vast body of research tips the scale in favor of the benefits of prebiotic supplementation. Prebiotic supplementation can offer significant help to people who face serious gastrointestinal conditions and may help to improve symptoms implicated in multiple bowel issues such as IBS, IBD, and colorectal cancer. In addition, prebiotic soluble fibers improve inflammatory conditions and the body’s response to certain infections. These “prebiotic effects” make this natural, non-invasive supplementation a smart choice.
Peter Swann, MD, FAAFP, FACOEM, Chief Medical Officer of ISOThrive LLC, is a subject matter expert in the fields of prebiotics, probiotics, and the microbiome. He is a board-certified family physician with a focus on patient health, wellness, and prevention. A graduate of Dartmouth College and Tufts University School of Medicine, Dr. Swann is also a Fellow of the American Academy of Family Physicians and the American College of Occupational and Environmental Medicine.
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