We all know that probiotics are important for health, but do we ask ourselves – why is that? The human microbiome is made up of trillions of microorganisms and they are critical to maintaining the body’s overall health and well-being. In this article, we will look at the potential of probiotics to restore and maintain a harmonious balance within the human microbiome. Not only do beneficial bacteria have the ability to promote optimal gut health, but they also offer numerous other health benefits that you may not be aware of.
What is the human microbiome?
The human microbiome is one of the most interesting areas that has attracted the attention of the medical community in recent years. It is a collection of microorganisms that inhabit our bodies. It is important to note that this microbial world does not exist in isolation from us but, on the contrary, consists of bacteria, viruses, fungi and other microorganisms that coexist in our body.
The number of these microbial cells is phenomenal, as they inhabit various parts of the human body, including the skin, the oral and nasal cavities, the gastrointestinal tract and even the genital area. They are representatives of thousands of different species of microorganisms, and their community creates a complex microbial ecosystem. In practice, the estimated number of these microbial cells in the human body is around 100 trillion.
It is important to stress that this world of microorganisms and the human body exist in a symbiotic relationship. This means that microbes and humans jointly interact and influence each other. Microbes help in various processes that take place in our body, such as the absorption of nutrients, the support of the immune system and even our mood and mental health.
Therefore, the human microbiome plays an extremely important role. Studying this microbial world has the potential to expand our understanding of many aspects of human health and lead to new ways of treating various diseases.
What is dysbiosis?
Dysbiosis is a condition in which the normal balance of microorganisms in the microbiome of the human body is disrupted. This microbiome is a collection of different bacteria, viruses, fungi and other microorganisms that inhabit our gastrointestinal tract, skin and other parts of the body.
When the imbalance of microorganisms increases, this disrupted balance can lead to a number of unwanted symptoms and health problems. Some of the symptoms that can occur with dysbiosis include:
- Gas and bloating
- Poor digestion
- Leaky gut
- Systemic imbalances
- Mental health disorders such as anxiety and depression
- Immune system dysfunction
- Liver dysfunction
- Changes in blood sugar levels
- Hormonal imbalances
What are probiotics?
The term “probiotic” is derived from the Greek word and literally means “for life”. Probiotics are beneficial bacteria that normally inhabit the human gastrointestinal tract and have a positive impact on our health.
Probiotic food supplements provide specially processed bacteria or yeasts in the form of freeze-dried microorganisms that are resistant to living in the gastrointestinal tract. This precautionary process allows the micro-organisms to survive in the acidic environment of the stomach and reach the intestinal tract, where they can participate in the regulation of the balance of the microbial flora.
The intake of probiotics supports the health of the human microbiome and improve gastrointestinal tract function. These supplements also offer other potential benefits such as improving the immune system, reducing inflammation and keeping the digestive process in optimal condition.
Probiotics and gut health benefits
Probiotics have proven gut health benefits. They help promote gastrointestinal health and immune function, but are also used for other health purposes.
Probiotics improve the gastrointestinal environment and make it more inhospitable to unwanted microbes. They can prevent unwanted bacteria from adhering to the gastrointestinal mucosa by acting as ‘colonisation barriers’.
Probiotics produce antimicrobial compounds, such as bacteriocins, which modify the microbiome in a positive direction. In addition, they produce hydrogen peroxide and organic acids that maintain the optimal pH level in the intestine and provide energy to the cells lining the colon.
Probiotics and immune health benefits
Probiotics stimulate the immune response and support the defences of the immune system. They increase the secretion of immunoglobulin (Ig) A, an antibody that coats our gastrointestinal tract that acts as a first line of defense against infection. IgA is a non-specific antibody that can bind to and neutralize unwanted microorganisms. Some probiotics have also shown the ability to activate key cells of the immune system – natural killer cells, macrophages and T lymphocytes.
Probiotics and antibiotic-associated dysbiosis
One of the best documented uses of probiotic supplements is to prevent antibiotic-associated dysbiosis. Most antibiotics kill both disease-causing organisms (pathogens) and beneficial bacteria. This action leads to significant disruption of the microbiome and the development of diarrhea in about 35% of people who take antibiotics.
Probiotics can help by restoring balance and preventing imbalance. It is advisable to start taking probiotics in the first two days after taking antibiotics. Products with multiple strains and high concentrations (30 to 100 billion bacteria) are recommended for dysbiosis.
Recommendations when choosing probiotics
Dosing recommendations for probiotics are based on two main factors: the quality of the strains in the formulation and their viability when consumed. Viability depends on proper production and storage of the product.
When choosing probiotic supplements, it is important to look for products with a specific number of live organisms measured in colony forming units (CFU). For prophylaxis, an intake of between 5 billion and 30 billion CFU per day is most commonly recommended. Choose products carefully and make sure probiotics are appropriate for your individual needs and current health status.
- Colella M, Charitos IA, Ballini A, Cafiero C, Topi S, Palmirotta R, Santacroce L. Microbiota revolution: How gut microbes regulate our lives. World J Gastroenterol. 2023 Jul 28;29(28):4368-4383.
- Pramanik S, Venkatraman S, Karthik P, Vaidyanathan VK. A systematic review on selection characterization and implementation of probiotics in human health. Food Sci Biotechnol. 2023 Jan 10;32(4):423-440.
- Sanders ME. Impact of probiotics on colonizing microbiota of the gut. J Clin Gastroenterol. 2011 Nov;45 Suppl:S115-9.
- Rueda-Robles A, Rodríguez-Lara A, Meyers MS, Sáez-Lara MJ, Álvarez-Mercado AI. Effect of Probiotics on Host-Microbiota in Bacterial Infections. Pathogens. 2022 Aug 29;11(9):986.
- Liao W, Chen C, Wen T, Zhao Q. Probiotics for the Prevention of Antibiotic-associated Diarrhea in Adults: A Meta-Analysis of Randomized Placebo-Controlled Trials. J Clin Gastroenterol. 2021 Jul 1;55(6):469-480.
- Goldenberg JZ, Yap C, Lytvyn L, Lo CK, Beardsley J, Mertz D, Johnston BC. Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children. Cochrane Database Syst Rev. 2017 Dec 19;12(12):CD006095.
- Zhang L, Zeng X, Guo D, Zou Y, Gan H, Huang X. Early use of probiotics might prevent antibiotic-associated diarrhea in elderly (>65 years): a systematic review and meta-analysis. BMC Geriatr. 2022 Jul 6;22(1):562.
- Shen NT, Maw A, Tmanova LL, Pino A, Ancy K, Crawford CV, Simon MS, Evans AT. Timely Use of Probiotics in Hospitalized Adults Prevents Clostridium difficile Infection: A Systematic Review With Meta-Regression Analysis. Gastroenterology. 2017 Jun;152(8):1889-1900.e9.
- Collinson S, Deans A, Padua-Zamora A, Gregorio GV, Li C, Dans LF, Allen SJ. Probiotics for treating acute infectious diarrhoea. Cochrane Database Syst Rev. 2020 Dec 8;12(12):CD003048.
- McFarland LV, Goh S. Are probiotics and prebiotics effective in the prevention of travellers’ diarrhea: A systematic review and meta-analysis. Travel Med Infect Dis. 2019 Jan-Feb;27:11-19.