Consumer

Prebiotics and probiotics, microbiome and immune system

April 28, 2020

Covid-19 is credited with bringing to public attention the crucial role of the microbiome as a modulator of the immune system. Some insights on prebiotics and probiotics.

Microbiome, nature and functions

The microbiome is composed of billions of microorganisms of different species (bacteria, viruses, fungi, protozoa), transmitted matriarchally, which are found in the gut and live in symbiosis with our organism, effectively serving as ‘intermediaries’ between the external and internal environments. The billions of bacteria belong to more than 800 different species, mostly referred to as ‘commensals’ or ‘good bacteria’ (lactobacilli and bifidobacteria in particular). These, as a whole, constitute the bacterial flora by interacting not only with each other, but also with other microorganisms (fungi, archea, etc.) and the host.

The biofunctional activities of the microbiome are numerous:

– immunity. Influence of the activity and expression of agents involved in the immune response (cytokines, lymphocytes, dendritic cells, pro/anti-inflammatory agents, etc.),

– digestion. Modulation of the metabolism of certain nutrients, production of certain neurotransmitters (serotonin etc.), reduction of the possibility of developing allergies and/or intolerances,

– metabolism. The significant amount of vitamins and important short-chain fatty acids(Short-Chain Fatty Acids, SCFAs, e.g., butyric acid and propionic acid), which are developed by the fiber included in the diet, intervene in energy homeostasis. Namely, on modulation of body weight, disorders associated with obesity and overweight, and suppression of inflammatory signals,

– Bidirectional modulation of the gut-brain axis. Gut health affects neurotransmission and mental well-being. A gastrointestinal discomfort, conversely, sends signals that can translate into states of anxiety, stress or depression in the brain,

– Health and proper functioning of organs and systems. Respiratory, reproductive, liver, kidney, heart, bone and skin health, etc.

Gut dysbiosis, causes and effects

Gut dysbiosis is a state of imbalance in the intestinal microflora, manifested by an alteration in the quantity and variety of bacteria present there. Its first causes are identified in:

– Imbalanced diets, due to the consumption of junk food or nutritional deficiencies,

– medications (e.g., antibiotics, cortisone and anti-inflammatory drugs, laxatives),

– alcohol and smoking,

– contaminants. Residues of agrotoxics in food and the environment, endocrine disruptors and toxic substances, including in MOCAs (food contact materials and objects) and other everyday objects, fine particles in the atmosphere.

The effects of dysbiosis are increased intestinal permeability, weakened immune system and thus increased vulnerability of the body to the risk of infection.

Healthy microbiome, the role of prebiotics

The health of the microbiome depends on a varied and balanced diet in the context of a healthy lifestyle. Prebiotics in some foods also play an important role in promoting the balance of intestinal flora, or intestinal eubiosis. ABC:

A) proper diet rich in prebiotics. Polysaccharides (fructo- and galacto-oligosaccharides ‘non-digestible’, a specific subgroup of MACs(Microbiota-accessible carbohydrates) change the composition of the gut microbiota. Selectively promoting the growth of Bifidobacterium and Lactobacillus.

MACs are found in fruits, vegetables, whole grains and legumes, the cornerstone foods of the Mediterranean diet, in line with the ‘Healthy diets from sustainable food systems‘ model proposed by The Lancet‘s EAT Commission. (1)

Polyunsaturated fatty acids-such as linolenic acid, phytocompounds, and phenolic compounds-are also correlated with gut microbiota balance and qualified as prebiotics. They are found mainly in vegetables, fruits, fish and nuts.

Experimental clinical studies show that transient diet-induced changes in the microbiome are detectable in humans as early as 24-48 hours after dietary intervention.

B ) Adequate physical activity and rest. Recent guidelines from WHO(World Health Organization) and ISS (Istituto Superiore di Sanità) are recalled in this regard.

C) Possible supplementation of probiotics. Such live microorganisms, where administered in appropriate amounts and timing (> 1 billion per day, for treatment that can range from 3-4 weeks to 3 months), can actually exert beneficial functions for the body.

Probiotics

Probiotics are defined in FAO/WHO (2001) guidelines as ‘live microorganisms which when administered in adequate amounts confer a health benefit on the host‘ (2,3).

The Ministry of Health in its guidelines on probiotics and prebiotics (2018) requires that microorganisms used in foods and food supplements meet the following requirements:

A) tradition of use for supplementing human intestinal microflora (microbiota),

B) food safety. A useful reference is offered by the criteria defined by EFSA onQualified Presumption of Safety (QPS) status. In any case, microorganisms used for food production must not carry acquired and/or transmissible antibiotic resistance,

C) be active and viable when they reach the intestinal level in such quantities that they multiply there and exert a balancing action on the intestinal microflora through direct colonization (4,5).

Probiotics are therefore found in some dietary supplements and fermented foods that belong to the traditional cultures of different peoples. Where fermentation has been used as a method of food preservation since time immemorial. Some examples are Caucasian kefir (fermented milk), Korean kimchi (fermented cabbage with garlic, ginger, chili, Japanese miso (fermented soybeans with sea salt).

Research on probiotic products is in flux. To current knowledge, the mechanisms by which specific strains intervene in the prevention and possibly the treatment of certain diseases are still unclear (6,7,8,9). Lastly, some scientific studies are reported that show:

– Anti-inflammatory effect of a formulation with L. rhamnosus, B. lactis and B. longum, (10)

– Reduction in symptoms and severity of IBS(Irritable Bowel Syndrome) by administration of Bifidobacterium Longum BB536 and Lactobacillus rhamnosus HN001. Due to the restoration of intestinal permeability and microbiota balance in patients with IBS, (11)

Symbiotic products

Symbiotic products are the foods or dietary supplements consisting of the combination of prebiotics and probiotics.

Scientific evidence suggests the effectiveness of prebiotics-through a varied and balanced diet-and probiotics in improving our overall health. With a beneficial effect on gastrointestinal diseases, but also on strengthening the immune system. Through contributions to intestinal barrier structure and function, as well as to the well-being of the intestinal microenvironment.

Doses, route of administration, inter-individual variability, and strain-specific properties are just some of the variables that need to be investigated further before considering the results obtained from the studies as certain and reproducible.

Dario Dongo and Carlotta Suardi

Notes

(1) The Lancet Commissions. (2019).
Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems.
. The Lancet, Volume 393, Issue 10170, February 2-8, 2019, Pages 447-492 http://dx.doi.org/10.1016/S0140-6736(18)31788-4

(2) FAO, WHO. Joint FAO/WHO Working Group Report on Drafting Guidelines for the Evaluation of Probiotics in Food. London, Ontario, Canada. April 30 and May 1, 2002, https://www.who.int/foodsafety/fs_management/en/probiotic_guidelines.pdf

(3) Lorenzo Morelli, Lucio Capurso. (2012).
FAO/WHO Guidelines on Probiotics: 10 Years Later.
. Journal of Clinical Gastroenterology: October 2012 – Volume 46 – Issue – p S1-S2 doi: 10.1097/MCG.0b013e318269fdd5

(4) Ministry of Health. (2018)
Guidelines on probiotics and prebiotics.
, http://www.salute.gov.it/imgs/C_17_pubblicazioni_1016_allegato.pdf

(5) Dario Dongo (2018). Probiotics and prebiotics, Ministry green light. GIFT (Great Italian Food Trade). 5/15/18, https://www.greatitalianfoodtrade.it/salute/probiotici-e-prebiotici-via-libera-del-ministero

(6) Christopher L. Gentile, Tiffany L. Weir. (2018).
The gut microbiota at the intersection of diet and human health
. Science 362, 776-780 doi: 10.1126/science.aau5812

(7) Niels Banhos Danneskiold-Samsøea, Helena Dias de Freitas Queiroz Barrosb, Rosangela Santosc, Juliano Lemos Bicasc, Cinthia Baú, Betim Cazarinb, Lise Madsena, Kirsten Kristiansena, Glaucia Maria Pastorec, Susanne Brixf, Mário Roberto Maróstica Júniorb (2019).
Interplay between food and gut microbiota in health and disease
. Food Research International 115 23-31. https://doi.org/10.1016/j.foodres.2018.07.043

(8) Maria Gloria Dominguez-Bello, Filipa Godoy-Vitorino, Rob Knight, Martin J Blaser. (2019).
Role of the microbiome in human development
. BMJ Gut; 0:1-7. doi:10.1136/gutjnl-2018-317503

(9) Paola Palestini, Dario Dongo. (2019).
Microbiome and gut, the second brain.
. GIFT (Great Italian Food Trade). 14.2.19, https://www.greatitalianfoodtrade.it/salute/microbioma-e-intestino-il-secondo-cervello

(10) Marzia Sichetti, Stefania De Marco, Rita Pagiotti, Giovanna Traina, Donatella Pietrella (2018).
Anti-inflammatory effect of multistrain probiotic formulation (L. rhamnosus, B. lactis and B. longum).
. Nutrition 53 (2018) 95-102. doi I: 10.1016/j.nut.2018.02.005

(11) Bonfrate L, Di Palo DM, Celano G, Albert A, Vitellio P, De Angelis M, Gobbetti M, Portincasa P. (2020). Effects of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 in IBS patients. Eur J Clin Invest. 2020 Mar; 50(3):e13201. doi: 10.1111/eci.13201