Most of us are well aware that health benefits come along with a diet rich in fiber and probiotics. Prebiotic fiber, however, is commonly lacking from the American diet . Adding prebiotics to your diet can bring improved digestive comfort, along with a long list of health benefits. Read on to learn more about prebiotics and how to take advantage of the benefits they offer.
Prebiotics are NOT Probiotics
Probiotics are living microorganisms that benefit the digestive system of their host.
Prebiotics are non-living types of indigestible fiber that pass through the human gastrointestinal system without significant change until interaction with the microflora of the gut. In other words, probiotic bacteria eat prebiotic fiber as fuel for a variety of health-promoting actions.
How do we get more prebiotic fiber? There are many natural, prebiotic-rich foods, which we will describe. If fitting more (both in quantity and diversity) of foods with prebiotics into your diet seems unreasonable, perhaps prebiotics supplements or prebiotic powder is a more convenient alternative.
What’s a Prebiotic?
Prebiotics are also known as “oligosaccharides” or small starch molecules (mostly fructans and galactans) that behave similarly to other forms of fiber. As with many high-fiber foods, the human gastrointestinal system cannot digest or absorb much nutrition from prebiotics alone.
However, once fermented by anaerobic bacteria in the large intestine, prebiotics cause beneficial change to the composition and activity of the gut microflora, allowing for improved digestion, higher immune function, better hormonal balance, reduced stress response, lower risk for obesity and weight gain, healthier cholesterol levels, and reduced inflammation [2-4].
Although all prebiotics are fiber, not all fibers are prebiotic. In order for an ingredient to be classified as prebiotic, it must show resistance to 1) the acidity of stomach acid, 2) hydrolysis by mammalian enzymes, and 3) absorption in the upper intestinal tract. It must be fermentable by microflora in the large intestine and also selectively stimulate the growth and activity of the probiotic strains of bacteria known to promote health in the host .
A few examples of fibers that qualify are inulin, oligofructose, lactulose, and resistant starch. Strains of lactobacilli and bifidobacteria are the probiotics targeted by most prebiotic fiber compounds, as these microbes exhibit a preference for oligosaccharides for consumption .
How Do Prebiotics Work?
The beneficial bacteria (probiotics) residing in the human gastrointestinal system consume prebiotic oligosaccharides for their own survival. As probiotic microflora thrive from the regular availability of prebiotic fiber, there is less opportunity for pathogenic bacteria to multiply.
Probiotic microorganisms ferment prebiotic fiber producing short-chain fatty acids (SCFAs) such as butyric acid, which is known to support the integrity of the intestinal lining . SCFAs metabolized in the liver help to regulate electrolyte levels in the body to improve digestion and support the regularity of bowel movements . SCFAs also help to stabilize blood glucose levels and decrease cholesterol synthesis . The process of fermentation lowers pH in the gut, which allows for increased absorption of dietary minerals, stimulates immune function, and further protects the bowels from harmful bacteria and other pathogens [8,9].
By fueling the beneficial gut bacteria, prebiotics have been associated with biomarkers of reduced inflammation, which is considered to be the root cause of many chronic diseases . Additionally, it has been documented that prebiotic consumption plays a role in both lipid and carbohydrate metabolism . They also have a reducing effect on cholesterol and triglyceride levels and an upregulating effect on satiety hormones . These benefits, along with effects on blood sugar regulation, make prebiotics an excellent supplement to add to a weight control regimen [1,2].
There is a growing body of evidence solidifying the link between gut health and mood, depression, and anxiety (referred to as the gut microbiota-brain axis). The gut is responsible for absorbing and metabolizing nutrients from both the diet and microbial fermentation. If digestion and absorption are more efficient due to prebiotic and probiotic supplementation, so will be the production and transmission of hormones and neurotransmitters that help to control mood (fear and other emotions) and relieve stress. A 2015 study published in Psychopharmacology concluded that prebiotics do indeed have a neurobiological effect on the brain, and can lower circulating levels of the stress hormone cortisol .
Sources of Prebiotics
Prebiotics can come from certain foods or supplements (powdered or encapsulated).
Foods with Prebiotics
According to a literature review published in the Electronic Journal of Biotechnology, the best food sources of prebiotics are vegetables, fruit, tubers, and roots. Specifically, the best vegetables are garlic (Allium sativum L.), Jerusalem artichoke (Helianthus tuberosus L.), leek (A. ampeloprasum L.), okra (Abelmoschus esculentus L. Moench), onion (Allium cepa L.), and shallot (A. cepa L. var. aggregatum); the best fruit sources are dragon fruit (Hylocereus species), jackfruit (Artocarpus heterophyllus Lam), nectarine (Prunus persica L. Batsch), and palm fruit (Borassus flabellifer L.); the best roots are chicory (Chicorium intybus L.) and yacon [Smallanthus sonchifoliu (Poepping and Endlicher) H. Robinson]; the best tubers are dahliya (Dahlia species) and gembili (Dioscorea esculenta (Lour.) Burk.) .
Aside from onions and garlic, many of these food sources of prebiotic fiber are sparse in the Western diet due to seasonality or cultural scarcity. Unless you are willing to make major changes to your diet around adding more probiotic foods, adding a prebiotic supplement is likely an easier solution.
Our Prebiotic Powder Supplement: BioMaintenanceTM Prebiotic + Fiber
A benefit to taking prebiotics supplements instead of relying on food sources of prebiotics is that you know exactly which types of prebiotic fiber are in your supplement, how much, and which probiotic species they nourish.
BioMaintenanceTM Prebiotic + Fiber supplement is an excellent option for nourishing your healthy microbiome. In only 12 calories and six grams of total carbohydrates, this supplement is jam-packed with five grams of dietary fiber, isomalto-oligosaccharides, alpha galacto-oligosaccharides, xylo-oligosaccharides, and fructo-oligosaccharides.
Isomalto-oligosaccharide is a naturally occurring, plant-based, dietary fiber. It is prebiotic, soluble, and low on the glycemic index. “Soluble fiber” means it dissolves in water as opposed to “insoluble fiber” which does not. Soluble fiber forms a gel-like consistency in the stomach that slows stomach emptying, allowing the body to feel satiated for a longer period of time (yet another reason why fiber is so important to weight management) . Soluble fiber also helps to reduce cholesterol absorption .
Derived from legumes, α-galacto-oligosaccharides (α-GOSs) are another variety of prebiotic, soluble fibers with anti-inflammatory properties . They may be effective for appetite regulation, as fermentation of these prebiotics by microbes promotes the secretion of gut peptides that are known to affect both appetite and food intake control .
Xylo-oligosaccharides (XOS) can be found naturally in bamboo shoots, fruits, vegetables, milk, and honey. Fermentation of XOS leads to acidification of the colonic contents and the formation of SCFAs that serve as fuel for the function of different tissues, regulating cellular processes. XOS supplementation has been shown to significantly decrease the abundance of 3 different harmful bacteria species associated with pre-diabetes in both healthy and pre-diabetic patients . Supplementation with XOS was also found to increase the abundance of beneficial bacterial species, Bifidobacterium lactis .
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