Definition: In 2001, the WHO defined probiotics as “live microorganisms that, when administered in sufficient quantities, are beneficial to the health of the host”. Since then, work has been done on the definition, but it is still not accepted by the European Food Safety Authority because the definition contains a health claim that is not measurable.1
Weight: The body contains around 1.5 kilograms of probiotic bacteria, which together weigh more than our brain at around 1.36 kilograms.2
Quantity: In a healthy person, there are around 100 trillion (and certainly between a trillion and a quadrillion) microorganisms in the gut that play an important role in our health. There are about 10 trillion cells in the body in total.3,4
Tribes: There are more than 500 million probiotic bacterial strains in the body. Some of the strains live there permanently, while others are in transit. The most common strains are Lactobacillus, Bifidobacterium, Streptococcus and Saccharomyces boulardii. The strains behave in different ways and act in different ways in the body.5
Market: In 2018, the global market for probiotic foods and supplements amounted to around USD 50 billion. This is expected to increase to around USD 70 billion by 2023.6
Habitats: Probiotic bacteria live in many parts of the body, not just in the gut as you might think. The bacteria are also found in the mouth, nose, esophagus, rectum, joints and more.
Appendicitis: Although the function of the appendix has been unknown for many years, several new studies suggest that it may act as a repository for probiotic bacteria. Among other things, researchers have noted that the appendix is found in many different mammals that have evolved in very different directions, yet it has been preserved in virtually all mammals, including humans. This may indicate that it has a function, as it should otherwise disappear over time.7,8,9
Diseases and illnesses: In recent years, there has been a lot of focus on probiotics as dietary supplements and the resulting commercial interest in the supplements has also led to a number of claims that they can prevent certain diseases. These include constipation, colds and cancer. However, it should be emphasized that all these claims remain claims and that there is no scientific evidence of these effects yet.10,11,12,13,14
Immune system: Probiotic bacteria are known to have an impact on the immune system, but the exact relationship between the two is unknown. There are numerous studies on the effects of probiotics on the immune system and many proponents are clearly convinced that probiotic supplementation can help improve immune function. However, as with disease prevention claims, the beneficial effects of probiotic supplementation on the immune system remain claims until proven otherwise by science.15,16,17
The birth: All babies are born with a sterile intestinal system, they get their first probiotic bacteria through breast milk or formula, and later through the food they consume.18
