Glossary - S

Saccharomyces boulardii

Saccharomyces boulardii (or S. boulardii) is a unique probiotic yeast originally extracted from lychee fruit. It has a different biological make-up and differing actions from other probiotics species such as Lactobacillus acidophilusSaccharomyces boulardii has undergone rigorous clinical research demonstrating its ability to bind to and flush out pathogens in the body. Newer research shows that Saccharomyces boulardii has strong anti-inflammatory properties.

Healthcare practitioners can find out more about Saccharomyces boulardii on the Probiotics Database. 


Serotonin is a neurochemical and hormone found in the brain, intestines, and blood platelets. It is believed to play a key role in emotional behaviour and moods, and is often attributed to happiness. Many people do not know that most of the body's serotonin is located in your gut.

Short Bowel Syndrome (SBS)

Short bowel syndrome (SBS) usually occurs when part of the small intestine has been removed for surgical reasons, such as to treat necrotising enterocolitis or Crohn's disease. On the other hand, infants can sometimes be born with a congenital short bowel. Symptoms include severe diarrhoea, cramping, bloating and fatigue. No cure is currently known for short bowel syndrome. As most absorption of food and nutrients occurs in the small intestine, people with short bowel syndrome are unable to absorb sufficient volumes of water & nutrients from food to sustain life.

We do not recommend probiotics containing Lactobacillus acidophilus Rosell-52 for infants for those with Short Bowel Syndrome.

Short Chain Fatty Acid

These are a type of fatty acid which are produced by bacteria in the large intestine by the fermentation or breakdown of substances such as dietary carbohydrates. They are used by the body to produce energy and are metabolised in the liver and muscles.

Small Intestinal Bacterial Overgrowth

Small Intestinal Bacterial Overgrowth (SIBO), also known as Small Bowel Bacterial Overgrowth (SBBO), refers to a condition in which abnormal amounts of pathogenic bacteria are present in the small intestine.   It is generally caused by a lack of muscular activity in and around the small intestine, meaning that bacteria is not swept away into the colon as it should be. SIBO is associated with various digestive or even muscular conditions, including diverticulosis.  Symptoms of SIBO include bloating, vomiting and diarrhoea.


'Species' refers to a type of microorganism existing within a genus or family. For example, acidophilus is the name of a species within the Lactobacillus genus. Different species within the same genus (eg. acidophilus and rhamnosus) are generally considered to be more closely related to each other than species from other genera (for example acidophilus is not closely related to the infantis species in the Bifidobacteria genus).

Various probiotic manufacturers use probiotics from the same genus and species, however one should always note the different strains used as well.


A group of prescription medicines that aim to lower the levels of LDL (‘bad’) cholesterol in the body.  Statins are often offered to those with a history of heart disease or genetically high cholesterol. There are several different statin brands, such as Lipitor and Lipistat. 

Statins are sometimes associated with a number of side effects so there may be advantages to trying to reduce cholesterol levels in other ways, such as by increasing intake of Omega-3 fatty acids in your diet. 

Statistically significant

Statistical significance in research is a measure used to determine the importance and relevance of data results. In research the p-value is used to determine if the result from the research is statistically significant or to determine the reliability of the findings. So if the p-value is <0.05 then the result/data is statistically significant.


This is another term for faeces, the solid waste produced in the colon, which is eliminated from the body through the rectum. Stool consists of undigested food, water, dead cells, bodily substances and bacteria.


A probiotic 'strain' is a specific biological variety of a species. For example, although many probiotic products contain the species Lactobacillus acidophilus, different manufacturers use different strains of acidophilus; and it is therefore important to select a robust, clinically-trialled strain. In the probiotic 'Lactobacillus rhamnosus Rosell-11' Lactobacillus is the genus, rhamnosus is the species, and Rosell-11 is the specific strain.


In probiotics, a strain refers to a certain variant within a species. An example of a species is 'acidophilus', and an example of an acidophilus strain is 'Rosell-52'. The strain tells you where a particular probiotic originated, what it was cultured on, and arguably the most important factor; what research has been conducted on that particular probiotic variant.  

Therefore 'strain-specificity' refers to the concept that the different effects of probiotics are variable right down to the level of the strains (and not just different families or species of bacteria).  This argument hence states that any health benefits from probiotics should be acknowledged right down to a particular strain. 


The dictionary definition of a supplement is ‘Something added to complete something else, make up for a deficiency, or extend or strengthen the whole’. Relating this definition to the field of natural health we can say that the goal of dietary supplements is to ‘make up’ for dietary deficiencies and ‘strengthen’ health. Food or dietary supplements can comprise either: vitamins and minerals, herbal extracts, essential fats, enzymes, amino acids or probiotics/live cultures.


Sutterella wadsworthensis, is a recently discovered bacteria which tends to thrive in low oxygen, or anaerobic conditions. Strains of these bacteria have been associated with gastrointestinal infections, and may also play a role in inflammatory conditions such as ulcerative colitis and Crohn’s disease. Sutterella has also been linked to autism, with levels detected in the gastrointestinal tracts of children with this condition. 


The term 'symbiotic' refers to the combination of more than one strain of probiotic. As different probiotic strains have different properties and settle in different areas of the gut, it is often beneficial to take more than one strain, unless seeking one specific probiotic strain in particular.

The word 'Symbiotic' should not be confused with 'Synbiotic', which refers to a combination of both probiotics and prebiotics. 


The term 'Synbiotic' refers to a combination of both probiotics and prebiotics in one supplement. Scientists have recently published an official definition for synbiotics as "a mixture comprising live micro-organisms and substrate(s) selectively utilised by host micro-organisms that confers a health benefit on the host".

Find out more about synbiotics

Systematic review

A systematic review is a literature review which analyses a collection of papers and research on a subject. They are usually based on questions which are set before the paper is written. A systematic review is designed to provide a complete and thorough summary of the current literature on a research subject.