Prebiotics are soluble nutrients (short-chain carbohydrates) that help promote the growth and reproduction of beneficial bacteria in our gut. These common substances naturally occur in food and include inulin, fructo-oligosaccharide (FOS), and galacto-oligosaccharide (GOS). Inulin and FOS are found in chicory root, Jerusalem artichokes, leeks, garlic, onions, soybeans, oats*, wheat*, rye* and bananas. GOS are found in beans, lentils, and large concentrations in human milk.
How do they work? Prebiotics such as inulin, FOS and GOS are not absorbed in the small bowel; thus, reach the colon unchanged. While in the colon, prebiotics are fermented by resident bacteria, particularly Bifidobacteria and Lactobacilli. The fermentation of inulin and FOS results in the formation of short chain fatty acids (SCFA) such as propionic acid, butyric acid and acetic acid, which are essential growth factors for GI mucosal membranes. These SCFAs serve as important regulators for local immune defense and nutrient absorption.
Since 70% of our immune system is located within our digestive tract, feeding our bacteria with prebiotic dietary fiber plays a crucial role in maintaining robust immunity. It is important to promote non-pathogenic intestinal bacteria because it can prevent overgrowth of pathogenic (or disease-causing) microbes. Some studies have shown evidence that certain prebiotics may have an effect in maintaining remission, especially in ulcerative colitis. Other studies on SCFAs have been shown protective effects against diet-induced obesity, insulin resistance, IBS, IBD, and colorectal cancer.
Some health benefits of Prebiotics
- Stimulates the growth of bifidobacteria and lactobacilli
- Serves as substrates for production of short-chain fatty acids, CO2 and H2
- Increases stool volume
- Reduces the penetration and growth of pathogenic bacteria
- Increases calcium absorption
- Decreased protein fermentation
- Decreases allergy risk
- Improves gut barrier permeability and therefore immune system defense
Note** Caution with gluten sensitivity when incorporating oats, wheat, or rye into diet.