All About Prebiotics

Introduction

There is an increasing interest in dietary strategies to modulate microbiota, considering the popularity of supplements that contain and nourish "good bacteria." One such nutritional strategy is the inclusion of prebiotics in the diet. Prebiotics are nondigestible food ingredients such as dietary fibre, that promote the growth of beneficial bacteria in the digestive tract. This blog on prebiotics will cover their types, food sources and their benefits to our health.

What are Prebiotics?

Prebiotics are referred to as "a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improving host health." Glenn R. Gibson and Marcel Roberfroid were the first to introduce and elaborate on the concept of prebiotics.

Since then, there has been an increase in the number of scientific studies as well as industrial interest owing to its enormous potential for modifying the gut microbiota.

Prebiotics can be found in a variety of foods, including chicory, chia seeds, dandelion greens, flaxseeds, onion, garlic, almonds, artichoke, oats, barley, and many others, but they can also be synthesised through the enzymatic digestion of complex carbohydrate foods.

The majority of identified prebiotics are carbohydrates. Carbohydrates, such as dietary fibre, are potential prebiotics. Prebiotics may be dietary fibre, but dietary fibre is not always prebiotic. On the market are some common prebiotics, such as fructooligosaccharides (FOS), guar gum, galactooligosaccharides (GOS), and inulin. We shall learn more about the types of prebiotics in the upcoming section.

How do Prebiotics Work?

The main function of prebiotics is to stimulate the growth and activity of beneficial bacteria in the gastrointestinal tract, which is beneficial for human health. Prebiotics have these beneficial effects through the following mechanisms:

• Prebiotics act as barriers to pathogens and toxins by preventing their adhesion to epithelial cells.
• Prebiotics are fermented and metabolised into mostly short-chain fatty acids (SCFAs), which are subsequently used by the human body as a source of energy.
• After the fermentation, SCFA’s stimulate the immune system and inhibit pathogenic microorganisms. Since SCFAs can diffuse into blood circulation through intestial cells, prebiotics have the ability to affect not only the gastrointestinal tract but also distant site organs.

Considering the above favourable effects, here are a few health benefits of prebiotics:

• They provide energy to the gut microbiota and influence the microbial community's function and composition.
• Enhance antibody responses to viral vaccines like influenza and measles, including an increase in antibody responses toward viral vaccines.
• Reduce your risk of cardiovascular disease (CVD) by lowering inflammation and improving your lipid profile.
• Induce apoptosis (cell death) to reduce the risk of colorectal cancer and its progression.
• It decreases the risk of allergic skin diseases such as atopic dermatitis.

Types of Prebiotics and Their Health Benefits

There are many types of prebiotics, the majority of which are oligosaccharide carbohydrates (OSCs) such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS). Inulin is also a prebiotic which is a combination of of oligo- and polysaccharides.

1. Fructo-oligosaccharides (FOS) or Fructans

Fructo-oligosaccharides, or fructans are a type of short-chain sugar molecules that help healthy microflora flourish in your intestines. Since they are not easy to digest, they are fermented in the colon by beneficial bacteria. They are low in calories and are considered soluble dietary fibre.

Natural sources of FOS

• Chicory root
• Onions
• Garlic
• Jerusalem artichoke
• Asparagus

Uses of FOS

• Increasing your intake of dietary fiber.
• It encourages the growth of good bacteria in your gut.
• Activate the immune system
• Improved gastrointestinal health and mineral absorption
• Protection against colon cancer
• Lowers the risk of obesity-related disorders.

2. Inulin

Inulin is a long-chain oligosaccharide which is less soluble than FOS. Like FOS, it is not digested in the upper gastrointestinal tract, which is why it has a reduced caloric value. It is used to replace fat in food products due to its smooth, creamy texture and a fat-like mouthfeel.

Natural sources of Inulin

• Leeks
• Asparagus
• Onions
• Wheat
• Garlic
• Chicory
• Oats
• Soybeans
• Jerusalem artichokes

Uses of Inulin

• Inulin can be fermented by gut commensal bacteria, providing a nutrient source for the bacteria that produce short-chain fatty acids. This in turn can suppress infection by acid-sensitive pathogens by creating an acidic environment.
• Stimulates the growth of health-promoting intestinal bifidobacteria and decreases the growth of health-deteriorating bacteria such as Bacteroides.
• It regulates blood sugar levels as it does not lead to a rise in serum glucose or stimulate insulin secretion.
• It is used for reducing LDL cholesterol.

3. Galactooligosaccharides (GOS)

Galacto-oligosaccharides (GOS) are non-digestible carbohydrates derived from lactose, a naturally occurring sugar in milk. Adults and infants have been shown to benefit from them. GOS is a good source of food for beneficial bacterial species that promote our gut health, including Bifidobacteria, Lactobacilli, and others.

Natural sources of GOS

• Lentils
• Chickpeas
• Beans
• Green peas

Uses of GOS

• Increasing the health and numbers of bifidobacteria
• Help with stool frequency and consistency
• Increasing the levels of good bacteria in your gut
• Impacts the immune system by positively affecting some markers of immune function
• It helps increase calcium absorption, which may be mediated by the gut microbiota, specifically bifidobacteria

The Last Word

When selecting a prebiotic supplement, make sure it is safe and look for a Good Manufacturing Practices (GMP) certification. Although prebiotics are good for your health, taking supplements might need a green signal from your healthcare provider depending upon your area of target and dosage.

We hope this article has helped you learn more about prebiotics, the positive impact they can have on your health, and a few of the best prebiotic foods to add to your diet for a healthier you!

References:

• Dorna Davani-Davari, Manica Negahdaripour, et al. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. 2019 Mar 9.
• doi: 10.3390/foods8030092.
• Michele Pier Luca Guarino, Annamaria Altomare, et al. Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders in Adults, 2020 Apr 9. doi: 10.3390/nu12041037.
• Kaur, Amrit Pal et al. “Plant Prebiotics and Their Role in the Amelioration of Diseases.” Biomolecules vol. 11,3 440. 16 Mar. 2021, doi:10.3390/biom11030440
• Monteagudo-Mera, Andrea et al. “Adhesion mechanisms mediated by probiotics and prebiotics and their potential impact on human health.” Applied microbiology and biotechnology vol. 103,16 (2019): 6463-6472. doi:10.1007/s00253-019-09978-7
• den Besten, Gijs et al. “The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism.” Journal of lipid research vol. 54,9 (2013): 2325-40. doi:10.1194/jlr.R036012
• Le Bourgot, Cindy et al. “Fructo-oligosaccharides and glucose homeostasis: a systematic review and meta-analysis in animal models.” Nutrition & metabolism vol. 15 9. 25 Jan. 2018, doi:10.1186/s12986-018-0245-3
• Sabater-Molina, M et al. “Dietary fructooligosaccharides and potential benefits on health.” Journal of physiology and biochemistry vol. 65,3 (2009): 315-28. doi:10.1007/BF03180584
• G. Chen, C. Li, K. Chen, Chapter 6 - Fructooligosaccharides: A Review on Their Mechanisms of Action and Effects (2016). Studies in natural products chemistry volume 48 (pp. 209-229). Elsevier. ISBN 9780444636027. https://doi.org/10.1016/B978-0-444-63602-7.00006-0.
• Marín-Manzano, María Del Carmen et al. “Prebiotic Properties of Non-Fructosylated α-Galactooligosaccharides from PEA (Pisum sativum L.) Using Infant Fecal Slurries.” Foods (Basel, Switzerland) vol. 9,7 921. 13 Jul. 2020, doi:10.3390/foods9070921
• Kao, A C C et al. “The Influence of Prebiotics on Neurobiology and Behavior.” International review of neurobiology vol. 131 (2016): 21-48. doi:10.1016/bs.irn.2016.08.007
• Davis, L M G et al. “A dose dependent impact of prebiotic galactooligosaccharides on the intestinal microbiota of healthy adults.” International journal of food microbiology vol. 144,2 (2010): 285-92. doi:10.1016/j.ijfoodmicro.2010.10.007
• Cardelle-Cobas, Alejandra et al. “Bifidogenic effect and stimulation of short chain fatty acid production in human faecal slurry cultures by oligosaccharides derived from lactose and lactulose.” The Journal of dairy research vol. 76,3 (2009): 317-25. doi:10.1017/S0022029909004063
• Vulevic, Jelena et al. “A mixture of trans-galactooligosaccharides reduces markers of metabolic syndrome and modulates the fecal microbiota and immune function of overweight adults.” The Journal of nutrition vol. 143,3 (2013): 324-31. doi:10.3945/jn.112.166132
• Le Bastard, Quentin et al. “The effects of inulin on gut microbial composition: a systematic review of evidence from human studies.” European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology vol. 39,3 (2020): 403-413. doi:10.1007/s10096-019-03721-w
• Rao, Mingyue et al. “Effect of Inulin-Type Carbohydrates on Insulin Resistance in Patients with Type 2 Diabetes and Obesity: A Systematic Review and Meta-Analysis.” Journal of diabetes research vol. 2019 5101423. 27 Aug. 2019, doi:10.1155/2019/5101423
• Liu, F et al. “Effect of inulin-type fructans on blood lipid profile and glucose level: a systematic review and meta-analysis of randomized controlled trials.” European journal of clinical nutrition vol. 71,1 (2017): 9-20. doi:10.1038/ejcn.2016.156