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Glossary of Probiotic Terms


AB-Life® collectively refers to three specific strains of Lactobacillus plantarum; including CECT 7527, CECT 7528, and CECT 7529. These three specific strains of probiotic bacteria have been extensively studied for their potential in helping to reduce blood cholesterol levels. In one notable clinical trial, total cholesterol levels were reduced by an average of 14%, when the probiotics were taken over a 3 month period. Read more about that trial here.

The AB-Life® strains can be found in OptiBac Probiotics 'For your cholesterol'.

Acidophilus (Lactobacillus acidophilus)

Acidophilus is one of the more well-known species of probiotic.  As it belongs to the Lactobacillus genus, acidophilus is generally situated in the small intestine within the gut.  Acidophilus is known especially for its beneficial effects in preventing traveller’s diarrhoea, Candida overgrowth, and antibiotic-associated diarrhoea or thrush.

For further information read more on Probiotic Strains.


Acne is a skin condition characterised by spots. Acne and spots are caused by inflammation of the sebaceous glands, often due to infection from pathogenic bacteria. Acne is therefore often linked to dysbiosis.


Actinobacteria belong to a group of Gram-positive bacteria, many of which are found in the soil, and play an important role in decomposition. All species of Actinobacteria are aerobic which means they do not require oxygen for growth, and a few are known pathogens, such as Mycobacterium. 

Alpha Linolenic Acid (ALA)

Alpha-linolenic acid, or ALA, is one of the fats that makes up Omega 3 polyunsaturated essential fatty acid and is found in plant oils such as flaxseeds, pumpkin seed and walnut oils. ALA is converted into EPA & DHA by the body. Some studies have shown Alpha-linolenic acid may help maintain normal cholesterol levels.

Antibiotic - associated diarrhoea

Antibiotic-associated diarrhoea, or ADD, refers to diarrhoea that occurs as a result of an antibiotic course. Because antibiotics do not distinguish between good and bad bacteria, in many cases they kill off significant amounts of the body’s natural friendly bacteria, often leading to an upset stomach.

Recent research shows that up to 1 in 5 people stop their course of antibiotics early because they have antibiotic-associated diarrhoea.


Antibiotics are substances that kill or inhibit the growth of bacteria and similar microorganisms. Antibiotics are often prescribed by doctors to treat bacterial infections. As they work against all bacteria in the body, antibiotics destroy good bacteria in the system as well as bad.


Antioxidants are nutrients that decrease or slow oxidation, thereby protecting cells from free radicals which can cause degeneration to the body's cells. Antioxidants are therefore thought to protect the heart, arteries, and other tissues, as well as to boost the immune system.


This is a common disorder that is characterised by joint inflammation and stiffness. A number of factors can contribute to this condition including infection, trauma and age.  Examples of arthritis include osteoarthritis, which involves degeneration of the joints, and rheumatoid arthritis which is a type of autoimmune condition.


A neural development disorder which affects the way in which a person relates to, communicates with, and views other people and the world around them.  Autism is a spectrum disorder, meaning that the condition will affect different people in different ways; some autistic people will live relatively 'normally' whilst others will have accompanying learning disabilities and require more support.

Asperger's Syndrome is a form of autism; typically associated with fewer learning difficulties, and above average intelligence.  The range of related disorders including autism and Aspergers is called the 'autism spectrum' and people with the disorder are often referred to as having 'Austim Spectrum Disorder' (ASD).  Autism is thought to affect up to 1 in 100 children, and is four times more common in boys than girls.  

It has been suggested, and somewhat documented, that children and adults with autism have a higher than average number of gastrointestinal problems. 

Autoimmune condition

An autoimmune condition occurs when the immune system mistakenly attacks and destroys healthy body tissue. The reason for the immune system developing an inability to recognise the difference between healthy body tissue and harmful substances is unknown, but many health practitioners believe a Leaky Gut could be to blame.

It is possible for an autoimmune disorder to affect one or more organ or tissue in the body, and a person may suffer from more than one autoimmune disorder at the same time.

There are more than 80 different types of autoimmune disorders, including arthritis, Hashimoto’s Disease, Type 1 Diabetes etc. 

Bacillus coagulans

A member of the Bacilli genusBacillus coagulans is a type of lactic acid producing bacteria which is similar to Lactobacillus. Unlike members of the Lactobacilli genus though, it reproduces via spore formation. Some strains of this bacteria have been described as a probiotic, although good clinical evidence investigating its therapeutic uses in humans is lacking, so it may be more correct to refer to them as live cultures. It is able to withstand extreme conditions and is thought to improve functioning of the immune system in humans. 

Bacillus subtilis

Commonly found in soil, this type of bacteria has also be shown to be a normal constituent of human commensal bacteria. Also know as the hay or grass bacillus, members of this genus have a protective coating which allows them to tolerate extreme conditions. Natto is a Japanese breakfast food which consists of soybeans that have been fermented with Bacillus subtilis.


Bacteria are unicellular (single cell) microorganisms belonging to the "prokaryote" kingdom of organisms. They are characterised by their lack of specialised internal organs or any organised nucleus. Bacteria are not visible to the human eye and are able to reproduce asexually, growing and dividing their cells at incredible speed. Bacteria can be pathogenic, commensal (unaffecting human health) or beneficial for human health i.e a PROBIOTIC!


A bacteriocin is a substance expressed by certain species of bacteria to kill or inhibit the growth of other bacteria of the same family. Examples include Staphylococcin produced by Staphylococcus aureus and colicin, produced by Esherichia coli.


These are a genus of gram- negative bacteria which makes up a significant proportion of the gastrointestinal bacteria in mammals. They are involved in many important metabolic activities in the human digestive system including helping to break down complex carbohydrates into more simple ones. Bacteroides are beneficial to the host as long as they reside in the gut, although they may cause infections and abscesses if they move to other parts of the body.


The Bacteroidetes group (or phylum) of bacteria is composed of three large classes of gram-negative, non-spore forming, anaerobic, and rod-shaped bacteria. They are widely distributed in the environment, including in soil, sediments and sea water as well as being found in the guts and on the skin of animals.

The Bacteroidia class is the most well studied and is present in the digestive tract of most mammals, and includes the Bacteroides genus.

Barrier Effect

Probiotics such as Lactobacillus acidophilus adhere to the epithelial cells that cover the gut wall lining. The good, probiotic bacteria decrease the amount of available space for pathogens (harmful bacteria) to bind, effectively creating a protective barrier against pathogens; resulting in what is known in microbiology as the 'Barrier Effect'.  The Barrier Effects is one key way in which probiotics are thought to be good for immunity.

Bifidobacteria / Bifidobacterium

Bifidobacterium (singular) or Bifidobacteria (plural) is a genus, or family, of bacteria generally found in the large intestine. Types, or species, of Bifidobacteria include bifidum, infantis and breve. Over the age of 60, levels of Bifidobacteria in particular are thought to largely deplete in the gut.

Bifidobacterium bifidum

bifidum is a probiotic species belonging to the Bifidobacterium family. Bifidobacterium bifidum will naturally reside in the large intestine. Different strains of Bifidobacterium bifidum will have different properties, for example Bifidobacterium bifidum Rosell-71 is β-galactosidase positive (β-galactosidase is an enzyme required for the digestion of lactose.) It is particularly resistant to gastric acidity at a pH over 4, which is why it is recommended to take it at mealtimes.

Bifidobacterium breve

Bifidobacterium breve is a probiotic species believed to have particular benefits in the inhibition of pathogens. Different strains of breve are sourced from different mediums and can have different qualities.  The strain Bifidobacterium breve Rosell-70 for example is a strict anaerobic, gram-positive rod of human origin. This specific strain is both β-galactosidase positive and a-glucosidase positive.

Bifidobacterium infantis

'infantis' is a probiotic species belonging to a family of bacteria called Bifidobacteria. Bifidobacterium infantis can be found in the microbiota of infants, children and adults, although it is found in higher concentration in infants and is thought to be beneficial for  childrens' wellbeing and immunity. Interestingly, breast-fed infants have shown higher volumes of Bifidobacterium infantis in the faeces than children who were bottled-fed.

As for all probiotics, it is important to look at the specific strain within the infantis species in order to determine its qualities. Bifidobacterium infantis Rosell-33 for example is an anerobic, gram-positive rod isolated in pairs or short chains.

Bifidobacterium lactis

Bifidobacterium lactis is a species from the Bifidobacterium genus (family) of probiotics. Bifidobacterium lactis is one of many types of probiotic bacteria in the large intestine that makes up the human microbiota. Different strains of probiotics have been tested for different properties, so as with all all probiotics, it is worth being aware of the specific strain. 

For example, Bifidobacterium lactis BB-12® has been scientifically researched to help maintain regular bowel movements, and is probably the most researched strain of the B. lactis probiotic in the world. 

Bifidobacterium longum

'longum' is a probiotic species from the Bifidobacteria genus, residing in the large intestine. Different strains of Bifidobacterium longum have different properties, for example Bifidobacterium longum Rosell-175 has been found in in-vitro tests to resist gastric acidity at a pH over 3. This particular strain seems to show ability to modulate some immunological parameters of inflammation; in vitro tests on human epithelial cells show Bifidobacterium longum Rosell-175 to downregulate TNF-β and Rantes.


The term 'bifidogenic' describes substances with stimulate the growth of probiotics, in particular Bifidobacteria.  Prebiotics should therefore be Bifidogenic in order to fulfil their role. The action of prebiotics on probiotics in the gut is often referred to as the 'bifidogenic effect' or sometimes as the 'bifidus effect'.


A biofilm is a collection of microorganisms that have adhered to each other upon a surface. The formation of biofilms can occur on living and non-living surfaces and is often a reactionary response to the microorganisms environment. Biofilms are thought to be responsible for most microbial infections in the human body.

Blind Trial

A blind trial is an experiment in which the participants do not know certain information about the experiment in which they are participating. This may include such information as to whether they are in the experimental group or the control group. 


Bloating is a feeling of tightness and fullness in the abdomen, often causing a visible protrusion of the abdominal region or tummy. Bloating affects both men and women, and can be caused by excessive intestinal gas, the menstrual cycle, or overeating.  It is also thought to be a symptom of dysbiosis.


BM or BMs is the acronym used to shorten the words Bowel Movement/Bowel Movements.  Also known as a stool or feces, a bowel movement takes places as food moves through the digestive tract and passes out of the body through the rectum and anus. 


This is a severe, serious and sometimes fatal form of poisoning caused by a type of bacteria known as Clostridium botulin. It can be contracted from ingesting affected food, wound contamination and can also be found in the soil. It affects the central nervous system and is typified by a range of symptoms including nausea, vomiting, disturbed vision and muscle weakness. 

Broad Spectrum Antibiotics

Broad Spectrum Antibiotics are antibiotics that work on both gram-positive and gram-negative bacteria. These can therefore be used for a variety of bacterial infections.

Caesarean Section

Also known as a Cesarean section (American spelling) or a C-section (abbreviation), a caesarean section is the name given to the procedure in which the baby is delivered by surgical extraction from the uterus, as opposed to vaginal birth. C-sections are normally performed when complications arise in pregnancy or labour meaning that vaginal birth is no longer the safest option for mother and/or baby.

Interestingly, a direct positive correlation has been shown between babies born by caesarean-section and babies and infants with digestive problems; possibly due to the fact that caesarean babies do not absorb friendly bacteria from the mother's birth canal during the birthing process.

Candida albicans (C. Albicans)

Candida albicans (often simply referred to as Candida) is a yeast-like fungus which feeds on sugar.  It can be found in the flora of the mouth, skin, intestinal tract and vagina; many people have small amounts of Candida albicans in the body without experiencing any negative side effects or symptoms. When allowed to overgrow however, Candida albicans can cause inflammation and itching, leading to infections such as thrush.  Candida overgrowth cannot be treated by antibiotics as it is fungal, therefore doctors often prescribe anti-fungal medicines, or opt for natural supplements including probiotics.


Capsules consist of an outer casing that is filled with a powder or liquid, whereas tablets are manufactured by compressing and compacting ingredients together. Capsules usually contain less excipients or fillers than tablets, and are easier to swallow because of their shape. 


Cholesterol is a fatty substance produced by the body, in the liver. It can also be found in some foods. Cholesterol is carried around the body by two lipoproteins, LDL & HDL. LDL (known as the ‘bad’ cholesterol) carries cholesterol from your liver to your cells, and HDL carries cholesterol back to the liver for excretion from the body. Too much LDL in the blood can cause a build up in the arteries and can increase the risk of heart disease and raised blood pressure. 


Members of this ancient genus of bacteria are found throughout the environment in places such as soil, and includes some species which are pathogenic to humans. They are responsible for causing tetanus and some forms of food poisoning. Clostridium difficile is a member of this genus. 

Clostridium difficile

Also called C. diff or C. difficile, Clostridium difficile is a bacteria that occurs in small amounts in many people's large intestine. If the number of Clostridium difficile bacteria increases greatly however, it can lead to infection. People suffering from C. difficile infection experience varied symptoms, from mild or severe diarrhoea to severe inflammation of the bowel. In some cases, particularly amongst the elderly, it can cause death. C. difficile infection is often thought to be caused by antibiotics, which can diminish probiotic levels in the gut and allow for overgrowth of C. difficile. The bacteria can be contagious and is often referred to as a superbug.

For more information, see http://www.cdiff-support.co.uk/


Infant Colic is a general term for a condition where the baby cries very often, for long periods of time, with no obvious reason as to why. Colic is often associated with digestive problems such as indigestion, food allergies, gas or intestinal cramps.

Commensal bacteria

These non- pathogenic types of bacteria naturally coexist with humans in a non- harmful symbiotic relationship, which does not impact negatively on the health of the human host.

Competitive exclusion

This principle refers to the idea that when two different organisms which require the same resources exist in the same environment, eventually one of them will be eliminated or displaced by the more dominant organism. 


Constipation is defined as having difficulty in passing stools, or having hard and dry stools.  Many people now define constipation as having less than 3 bowel movements per week. Constipation is thought to be caused by factors such as lack of fibre in the diet, lack of physical activity, lifestyle changes such as pregnancy, stress and ageing, and by dysbiosis.

Crohn's Disease

Crohn's is an inflammatory bowel disease (IBD) in which parts of the digestive tract become swollen and develop ulcers. Generally located in small intestine and/or colon, Crohn's can in fact develop anywhere in the gastrointestinal tract, from the mouth to the anus.


Cystitis is an infection of the bladder particularly affecting women, causing symptoms such as a burning sensation during urination as well as a frequent need to urinate. Cystitis is usually caused by pathogenic bacteria such as E. Coli entering the urethra and travelling to the bladder. Evidence suggests that maintaining healthy levels of friendly bacteria help promote balanced levels of vaginal flora.


Cytokines are cell signalling molecules that modulate the immune system response. Cytokines can either be peptides, proteins or glycoproteins, and they include the sub-groups: interleukins, interferon and growth factors. Their main purpose is to initiate the movement of cells towards sites of either trauma, infection or inflammation. 


Diarrhoea is defined as frequent, loose and watery stools or bowel movements.  Diarrhoea can be caused by numerous factors including food poisoning, IBS and Colitis.

(Diarrhea is the American spelling)

Dietary fibre

Dietary fibre refers to indigestible components of fruits and vegetables. Dietary fibre is often classified into two groups:

Soluble fibre (including prebiotics) - which is digested by the microbes of the body and fermented in the colon, creating gas and physiologically active byproducts.

Insoluble fibre - aids defecation by absorbing water as it passes through the digestive system.


Taking place in the gastrointestinal tract, this term refers to the mechanical processing and enzymatic breakdown of foods into smaller parts which are more easily utilised and absorbed by the body.

Digestive enzymes

Digestive enzymes are found in the digestive tract and aid in the breakdown of complex macromolecules such as carbohydrates and protein, into their smaller parts. These more simple molecules are then able to be absorbed and utilised by the body more easily. Digestive enzymes are secreted by glands throughout the digestive system including salivary glands which produce saliva and secretary cells in the pancreas and stomach.


Diverticulosis is a condition that can occur when the walls of the colon become weakened, sometimes due to long term constipation which exerts pressure on the walls of the gut. Diverticulosis refers to the formation of small pockets or pouches in weak points of the intestine; pouches known as 'diverticula'. Diverticulitis is the disease in which the diverticula (pouches) become inflamed or infected. Diverticulitis is much more common in older people.

Research suggests that having a healthy balance of friendly bacteria in the gut can reduce the risk of diverticulosis and diverticulitis.

Double-blind trial

A double-blind trial refers to a scientific experiment in which both the test subjects and the research team are prevented from knowing certain pieces of information (i.e which control group is taking a placebo) that may lead to conscious or subconscious bias - which would invalidate the results.


Dysbiosis, Dys-symbiosis, or dysbacteriosis is the condition which describes an imbalance of beneficial and pathogenic bacteria in the body. (ie. too few beneficial bacteria in the gut.) Dysbiosis can be caused by factors such as travel, ageing, or taking antibiotics, which kill off both good and bad bacteria in the system.  It is possible for people to take a particularly long or strong course of antibiotics at some point in their lives, and still suffer from dysbiosis many years later.  

Dysbiosis is thought to contribute to a number of health issues including, but not limited to, IBS, food intolerances and allergies, weight gain, poor skin health, poor immunity, low energy levels, Candida and/or thrush.

E. coli

The full name of this rod- shaped bacteria is Escherichia coli, and it is found commonly in the lower intestine of humans. The harmless strains of this bacteria are normal residents of the gut, although some serious strains can cause food poisoning. diarrhoea and  meningitis. 


Eczema is a type of dermatitis (inflammation of the upper layers of the skin.) The symptoms of eczema include itching, scaling, dryness and redness of the skin.  Eczema has been linked to food allergies and dysbiosis.


The term 'endogenous' means to originate or develop internally within an organism, tissue or cell. Endogenous bacteria are those which reside within a closed system such as bacterial gut flora which live in the gastro-intestinal tract.

Enteric Nervous System

A subdivision of the autonomic nervous system, the enteric nervous system is responsible for innervating and controlling the gastrointestinal tract and digestive processes. Also known as the intrinsic nervous system, it has been described as the 'second brain' and can function autonomously, although it does require communication with the central nerovus system to function effectively.


The word 'enterotype' refers to a category of bacterial organisms, based on the balance of various kinds of bacteria in the human microbiome.  A study published in Nature¹ in April 2011 announced the discovery of three human enterotypes; defined by the bacterial family which dominates within the group, whether that be Ruminococcus, Bacteroides, or Prevotella bacteria.  

Further research published in September 2011² has now suggested that one's dietary habits may affect one's enterotype.


1. Arumugam, Manimozhiyan, Raes, Joroen, et al. (April 2011). Enterotypes of the human gut microbiome.  Nature. doi: 10.1038/nature09944.

2. Wu, G.D., Chen, J., Hoffman, K., Bittinger, Y, Chen, Y., et al Linking long-term dietary patterns with gut microbial enterotypes' Science. doi: 10.1126/science.1208344


Lining most internal and external surfaces of an animal’s body, this type of tissue consists of one or more layers of tightly packed cells. It encloses and protects parts of the body including the organs.


American spelling for Oesophagus.

Fatty acids

A fatty acid is a molecule made up of a long hydrocarbon chain with a carboxyl group (known as COOH). A collection of these molecules makes up fat. It is the combination of fatty acids making up a type of fat which control many of the fat's specific characteristics, such as its appearance, and whether it is liquid or solid at room temperature.  Fatty acids are found in different forms such as unsaturated, saturated and essential fatty acids. 


Firmicutes are a phylum, a large family, of bacteria. The Lactobacilli and Clostridia generas both belong to this phylum.


Also known as linseeds, flaxseeds are the seeds from a herbaceous plant typically grown in cooler regions of the world. They are either brown or golden in colour, and are rich in fibre and Omega 3 essential fatty acid Alpha Linolenic Acid (ALA). 

Free Radicals

A free radical is an unstable and highly reactive molecule which can do damage to cells in the body. They are thought to contribute to a range of diseases including cardiovascular disease, cancer as well as the aging process. Free radicals can come from environmental factors such as smoking and air pollution but are also natural by-products of bodily processes such as metabolism. Free radical damage can be minimised by the use of antioxidants.

Fructooligosaccharides (FOS)

Fructooligosaccharides (FOS) is one of the most well-known prebiotics. Naturally occurring in foods such as chicory root, the prebiotic FOS has a slightly sweet taste and can be used as a natural sweetener instead of sugar. Unlike sugar however, prebiotics such as FOS cannot be digested or absorbed by the human body, and therefore pass through the digestive tract to the large intestine where they act as a food source for probiotics.  FOS has been shown to stimulate certain types of beneficial bacteria more than others, often those of the Bifidobacteria genus in particular.


A fungus is a member of a large group of spore-forming organisms that range from microorganisms such as yeasts and moulds to the more familiar mushroom. They play a vital role in the decomposition of organic matter and the nutrient cycle.

GALT (Gut Associated Lymphoid Tissue)

The Gut-Associated Lymphoid Tissue, or GALT, comprises of several types of lymphoid tissue that work to protect the body from invasion. These lymphoid tissues include Peyer's patches, tonsils and adenoids.

Gamma-aminobutyric acid (GABA)

GABA is an amino acid found in the brain, that functions as an inhibitory neurotransmitter. It has a calming effect on nerve impulses in the brain, making it a natural 'relaxation agent'. A deficiency of GABA can lead to feelings of anxiety, tension headaches and even reduced cognitive function as the nervous sytem becomes over-stimulated and agitated. 

Gastro-intestinal tract

The gastro-intestinal tract, or simply 'gut', refers to the entire passage between a human's mouth and anus, including the oesophagus and stomach. This system of organs takes in food, digests it to extract energy and nutrients, and expels the remaining waste.

Gastro-oesophageal reflux disease (GORD)

Gastro-oesophageal reflux disease (GORD), or simply acid reflux disease, is caused by stomach acids escaping the stomach into the oesophagus, causing mucosal damage of the oesophagus lining or chronic symptoms; the most common being frequent heartburn.

The condition usually occurs due to a spontaneous and unnecessary opening of the barrier muscles between the stomach and oesophagus. Possible reasons for this have been cited as; a hiatal hernia or abnormal relaxation of the lower oesophageal sphincter.


Gastroenteritis, or gastric flu, is an infection of the gut (usually the stomach or intestines). The infection can be viral, bacterial or parasitic; and is often caused by consumption of contaminated food or drinks. Symptoms include diarrhoea, abdominal cramping, bloating, nausea and vomiting.

Having a healthy balance of friendly bacteria in the gut is thought to lessen the risk of gastroenteritis, as well as relieving symptoms and quickening recovery.


A genus is a group of related or similar organisms, and can be referred to as a 'family'. A genus contains one or more species. Examples of probiotic genera include Bifidobacterium and Lactobacillus.

Gram- negative bacteria

This group of bacteria are known as ‘gram-negative’ as they don’t change colour when coming into contact with a staining method known as Gram’s method. This method is used to classify different types of bacteria. Gram- negative bacteria usually have thin cell walls and include members of the E. coli genus.

Grape Seed Extract

Grape Seed Extract is made up of natural derivatives from whole grape seeds, usually containing the antioxidants oligomeric proanthocyanidins, (OPCs). Grape Seed Extract has been linked to numerous possible benefits, including lowering blood pressure and destroying cancer cells.

For further information on Grape Seed Extract, please see this article by the BBC: - http://news.bbc.co.uk/1/hi/health/7803619.stm

Green Tea Extract

Green Tea Extract is a powerful antioxidant, thought to be more than 200 times more potent than vitamin E in tackling free radicals. Many people take Green Tea Extract to reduce the risk of cancer or infection, or to maintain normal cholesterol and to support slimming.

Gut Flora

'Gut flora' refers to the microorganisms that live within the body's digestive tract, mostly comprised of bacteria, including both probiotics and pathogenic bacteria.


Haemorrhoids, or piles, are swollen veins in the anal canal and rectum. Haemorrhoids can be external (occurring outside the anal verge) or internal (occuring inside the rectum). Symptoms of haemorrhoids include swelling, pain, itching, irritation, and bright red blood. Piles or haemorrhoids are thought to be caused by excessive straining during bowel movements; often due to constipation.

Factors such as increased fluid intake, more exercise, and eating high fibre diets are thought to help prevent the development of haemorrhoids.


HDL (high-density lipoprotein) allows the transportation of fatty substances such as cholesterol and triglycerides around the bloodstream. HDL is small and dense and contains the highest ratio of protein to cholesterol. It is often referred to as the 'good cholesterol' as people with higher levels of this lipoprotein tend to be at lower risk of heart disease. HDL carries cholesterol away from the organs to the liver where it is mixed with bile, broken down and passed out of the body in the stool

Helicobacter pylori

Helicobacter pylori, usually just referred to as H. pylori, is a pathogenic bacteria that grows in the stomach and is the main cause of many ulcers and stomach inflammation. H. pylori can weaken the protective coating of the stomach, leaving it vulnerable to digestive acids and consequent irritation. Many people carry small amounts of the bacteria in their system to no ill-effect but lifestyle factors such as consumption of alcohol, coffee and smoking increase the risk of a H. pylori instigated ulcer.


A hormone is a chemical messenger that is released by a gland or cell in one part of the body, which has an action on cells in another part of the body. Hormones work by controlling and regulating bodily functions such as metabolism and digestion.

Immune system

The human immune system is a complex system of cells, processes and biological structures that protects the body from pathogenic microorganisms. The mucosal lining of the gut, which is maintained by probiotics, plays an important part in this system and is considered the front line against disease.

In vitro

Commonly known as ‘test tube’ experiments, these types of studies usually isolate components of an organism in an artificial laboratory environment so that certain factors can be more easily controlled. An example of this is in vitro fertilisation, whereby the egg is fertilised by sperm in equipment outside the body.

In vivo

In vivo experiments involve complete living organisms such as animal studies and clinical trials involving humans. In vitro experiments are another type of research.

Increased intestinal permeability

This occurs when the tissue lining the gut wall becomes damaged and allows certain substances such as toxins, microbes and undigested food to leak through the gut wall and into the blood stream. A healthy gastrointestinal system usually allows certain substances to pass through the gut wall such as water, vitamins and minerals but provides a barrier against other substances passing through. Increased intestinal permeability plays a key role in leaky gut syndrome.

Inflammatory Bowel Disease (IBD)

Inflammatory Bowel Disease (IBD) refers to both ulcerative colitis and Crohn's disease; both of which cause intestinal inflammation and symptoms such as abdominal pain, vomiting and diarrhoea.

For a unique probiotic with anti-inflammatory properties, see Saccharomyces boulardii.


Insulinemia is the term used to describe high levels of circulating insulin in the blood. Insulin is a hormone produced by the pancreas, and its role is to help the liver, muscle and fat tissue to take up glucose from the blood and convert it to glycogen that is stored in the liver and muscles.  A diet high in sugar may cause insulin resistance, when the cells of the body become less sensitive to insulin, therefore increased quantities of insulin are found in the blood. Insulin resistance is seen as a risk factor for Type 2 Diabetes and heart disease.  

Intestinal failure

This occurs when a large portion of the small intestine does not function normally or is not present. It usually occurs due to surgical removal or infant’s can also be born with abnormal intestines. Symptoms of intestinal failure include diarrhoea, weight loss, bloating and vomiting and if left untreated, digestion can be compromised and may lead to dehydration, malnutrition and small intestinal bacterial overgrowth.


Inulin is a prebiotic, and a natural polysaccharide (several simple sugars linked together) occurring in the roots and tubers of certain plants such as chicory.

Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome (IBS) is a functional disorder of the gastrointestinal tract characterised by varying symptoms such as bloating, abdominal pain or discomfort; accompanied by diarrhoea or constipation or alternation between the two.

For further reading, see the FAQ, which probiotics are for IBS?


The jejunum is part of the small intestine which lies between the duodenum and the ileum. The jejunum alone is roughly 9 feet in length, and is key in the absorption of nutrients during digestion.


Kefir is a thick, fermented milk originating from the Caucasian mountains, made with kefir grains; a combination of bacteria, yeast and polysaccharides. Kefir is often referred to as a 'probiotic' as it is thought to contain bacteria and yeasts that are beneficial to the body. Officially a probiotic or not, we would say that it is certainly a rich source of natural live cultures


'Lacidofil' is a probiotic blend of two well-researched strains from the Institut Rosell; Lactobacillus acidophilus Rosell-52 and Lactobacillus rhamnosus Rosell-11.  The two strains together have been researched and praised for a few various health applications, including; antibiotic-associated diarrhoea, H. pylori eradication, acute gastroenteritis in children and digestive health support.  Where can you find 'Lacidofil' ? Right here at OptiBac Probiotics of course! In 'For those on antibiotics'.


Lactobacillus  (singular) or Lactobacilli (plural) is a genus, or family, of bacteria including probiotic species such as acidophilus or rhamnosus. Species of the Lactobacillus genus naturally tend to reside in the small intestine. Lactobacilli produce lactic acid and are key in the production of fermented foods such as yoghurt and cheese.

Lactobacillus casei

The probiotic species 'casei' belongs to the Lactobacillus genus; like acidophilus or rhamnosus. Lactobacillus casei is a probiotic species widely found in dairy products such as yoghurt and cheese.  As always, one should look at a probiotic strain and not simply  the species; an example of a strain of Lactobacillus casei is Rosell-215.

Lactobacillus paracasei

Lactobacillus paracasei is a species of probiotic that belongs to the Lactobacilli genus. Lactobacillus paracasei will naturally reside in the small intestine and different strains of L. paracasei will have different properties. For example, L. paracasei Lpc-37 has shown particular strength in inhibiting pathogens such as Salmonella typhimurium, Staphylococcus aureus, Escheria coli and Listeria monocytogenes. L. paracasei Lpc-37 has shown to stimulate a specific immune response of the cell wall lining of the gut known to ward off viruses and support anti-allergy responses.

Lactobacillus plantarum

A versatile member of the Lactobacillus family of bacteria, this probiotic species is commonly found in fermented foods such as sauerkraut, and was first isolated from saliva. It is a natural resident of the human gastrointestinal tract.

This species has been connected to IBS (although we would always stress the importance of strain-specificity) - in that a certain strain of Lactobacillus plantarum has been well researched in IBS sufferers.   Other strains of the plantarum species have been researched in other groups of people, for example the strains CECT 7527, CECT 7528 and CECT 7529 have been tested and shown to help maintain healthy cholesterol levels.

Lactobacillus rhamnosus

Lactobacillus rhamnosus is a naturally occurring probiotic species of the intestinal and vaginal microbiota.  It is thought to reside primarily in the small intestine with similar species such as acidophilus. One specific strain of rhamnosus is Lactobacillus rhamnosus Rosell-11, which has shown strong capability to adhere to intestinal cell linings.

Lactococcus lactis

Lactococcus lactis is a probiotic species of bacteria that has been used for many years in the meat industry thanks to its ability to inhibit the growth of the pathogenic bacteria which degrades meat. Rosell 1058 is a specific strain of Lactococcus lactis which has been isolated from a kefir culture. It is both β-galactosidase positive and a-glucosidase positive.


LDL, or low-density lipoprotein, is a lipoprotein that carries cholesterol around the body. As cholesterol is a fatty substance and cannot dissolve in the blood, it requires a carrier to transport it around the body. LDL particles tend to be less dense than other lipoproteins and as a result are also known as 'bad cholesterol' due to their ability to deposit fat molecules in cells walls. This then attracts white blood cells, which can cause a build-up, leading to blocked arteries (atherosclerosis). 

Leaky gut syndrome

This is a term which is used to describe increased intestinal permeability in the lining of the digestive system. Leaky gut syndrome is a condition where the lining of the digestive system is impaired and damaged and therefore lets substance such as microbes, undigested food and toxins leak through the gut wall. This condition can impact negatively on digestion and is also thought to play a role in the development of certain autoimmune conditions. Although leaky gut syndrome is not completely understood, it is thought that factors such as stress, alcohol consumption, dysbiosis and the overuse of certain pharmaceuticals may play a role.

Live cultures

Often used interchangeably with the term probiotics, live cultures refer to beneficial microorganisms which are commonly found in foods such as yogurt. Due to new European legislation, 'live cultures' may replace the term probiotic to describe friendly bacteria such as Lactobacillus acidophilus.


In biology, a lumen refers to the space inside of a tubular structure such as the oesophagus, arteries, veins or intestines.


Lyophilisation is a sophisticated form of freeze drying cell structures without harming them. The process is used for materials such as; food, blood, human tissue, pharmaceuticals or, in our case, probiotics.

Here at OptiBac all of our probiotics are lyophilised and it is partially this process that makes them shelf stable with no need of refrigeration.


The first few stools or faeces of a newborn infant are known as meconium. Unlike adult stools, meconium is almost odourless and is often dark olive green in colour and sticky like tar.


The term metagenome refers to the genetic material which is present in a sample taken from the environment, and is made up of the genomes (genetic information) of an array of individual microorganisms.

Methane- producing bacteria

Also known as methanogens, these types of organisms produce methane as a by- product of their metabolism, which among other things, contributes to flatulence production in humans. They thrive in low oxygen environments such as the human gut and have also been found in extreme conditions such as deep glaciers and in hot desert soil.


A microscopic organism, such as a bacterium, fungus or virus.


A microbiome encompasses the entirety of microbes in a defined habitat, including all of their genetic make-up and their environmental interactions. For example; a human microbiome (all of the microbes that we share our body with) includes approximately 100 trillion microbes, outnumbering our own cells by 10 to 1.


'Microbiota' refers to the microorganisms (both probiotic and pathogenic) residing in the gastrointestinal tract. An imbalance in the microbiota is known as dysbiosis.


Microflora generally refers to the microorganisms (including both good and bad bacteria) that reside in the digestive tract. As the term 'flora' refers to plants, however, the term microbiota is now considered to be more correct than microflora.


Mucosa, also known as the mucous membrane, refers to the moist lining of internal, hollow organs such as the mouth and gastrointestinal tract.

Necrotising Enterocolitis

Necrotising enterocolitis is a condition occurring when part of the intestine is swollen or inflamed due to damage of the lining, often due to obstructed blood or oxygen flow during the perinatal period. Necrotising enterocolitis is the most common gastrointestinal surgical emergency in premature babies.

Nosocomial Diarrhoea

Nosocomial diarrhoea is diarrhoea occurring due to an infection acquired in hospital. Nosocomial diarrhoea is specifically not present prior to the patient's admittance to hospital, but occurs within 72 hours of being in hospital. C. difficile is recognised as the biggest cause of nosocomial diarrhoea.


This acronym refers to non-steroidal anti-inflammatory drugs which are a class of pharmaceuticals that are prescribed for their pain- relieving and anti- inflammatory effects. Examples include aspirin and ibuprofen and these drugs are often used for conditions such as arthritis, headaches and period pain. A range of side effects are associated with their use such as nausea and gastric ulceration.


The oesophagus is the passage in the body where food passes from the pharynx to the stomach, aided by peristalsis - muscle contractions through the digestive tract.

Omega 3

Omega 3 is a type of polyunsaturated essential fatty acid which cannot be made by the body therefore we rely on dietary sources for our required intake. Omega 3’s are needed for many of the body’s processes, and are important for brain and heart health. They are made up of 3 types of fat known as EPA (Eicosapentaenoic acid), DHA (Docosahexaenoic acid) and ALA (Alpha Linolenic acid). EPA and DHA can be found in fish and some plants oils, and ALA is found only in plant oils. 


A remedy that encompasses all

Pathogenic bacteria

Pathogenic bacteria, or pathogens, are harmful bacteria that cause disease or illness. Well-known pathogens include Salmonella or most types of E. coli.


This is one of the categories used in the biological classification of organisms and is ranked below kingdom and above class. It is a scientific hierarchy used to help arrange similar types of organisms together. For example, members of the genus known as Lactobacilli belong to the Firmicutes phylum. 

Pine Bark Extract

Pine Bark Extract is a derivative specifically extracted from bark of the pine tree, usually of the Pinus Maritima. Pine Bark Extract is often classified as a superantioxidant, and is believed to have numerous benefits on the body including improved circulation, reduced period pain, as well as anti-ageing properties.

For further information, see antioxidants.

Placebo-controlled study

A placebo-controlled study is a clinical experiment in which the test subjects are split, usually, into two different control groups. One group will receive the medicine or supplement being trialled and the other will simply receive a placebo (a capsule, tablet, powder or liquid identical in appearance to the medicine or supplement being trialled but designed to have no measurable health effect). In most cases, placebos are used in blind trials where the control groups do not know if they are receiving the placebo or the real treatment.


Polyphenols are naturally occurring compounds, some of which are known to protect cells against the damaging effects of free radicals (therefore giving them antioxidant properties). They are broadly categorised into 4 mains groups; phenolic acids, stilbenes, lignans and flavanoids. Flavonoids are further classified into several groups. Flavanols, one of the group of flavonoids most abundantly found in fruit and vegetables, is made up of catechins and proanthocyanins, such as Grape Seed Extract.

Certain polyphenols are either specific to a particular food (e.g flavanones found in citrus fruit, resveratrol in red wine) and others are found in all plant foods (e.g quercetin is found in fruit, vegetables, cereals, legumes, tea & wine).

Research suggests that polyphenols, with their antioxidant properties, may play a role in the prevention of diseases, particularly relating to cardiovascular health and cancer prevention.


Pouchitis, with symptoms such as diarrhoea and abdominal pain, is an inflammation of the ileoanal pouch, a bowel pocket created to hold bowel movements in patients with ulcerative colitis who have had their large intestine or colon removed. Whilst antibiotics are often used as treatment for pouchitis, research shows that people with pouchitis have lower levels of beneficial bacteria in their system.


Prebiotics such as Fructooligosaccharides (FOS) can be found naturally in certain foods such as leeks and chicory root. Prebiotic fibres are a food source for probiotics to grow, multiply and survive in the gut; in particular stimulating growth of probiotics from the Bifidobacteria genus. For further detail into prebiotics, see What are Prebiotics?


A premature, or preterm, baby is one that is born before 37 weeks of pregnancy.


Members of this gram- negative genus are closely related to bacterioides, and are commonly a cause of wound infections in cat and dog bites.  In humans, they exist as opportunistic organisms which are implicated in periodontal disease and anaerobic (absence of oxygen) respiratory tract infections such as pneumonia.


Probiotics are microorganisms, usually bacteria, that have proven health benefits - for the digestive and immune systems in particular. Different probiotic strains have been shown to demonstrate different beneficial effects on the body.  Although probiotics are commonly referred to as 'friendly bacteria', probiotics can be other microorganisms, for example the probiotic yeast, Saccharomyces boulardii.

For more information, see What are Probiotics?


This is a preventative measure used to help protect against or avoid a disease or condition occurring. For example, probiotics can be taken prophylactically to prevent food poisoning when travelling to a high risk area.


Also known as ‘purple bacteria’, this term refers to a major phylum of gram- negative bacteria which include pathogens such as E.coli and salmonella. 

Pseudomembranous Colitis

Pseudomembranous Colitis is an infection of the colon commonly, but not exclusively, caused by an overgrowth of Clostridium difficile in the large intestine. An overgrowth of C. difficile is commonly attributed to the taking of antibiotics. Known symptoms of Pseudomembranous Colitis include diarrhoea, abdominal pain and a severe inflammation of the inner lining of the colon.


Probiotic bacteria that either directly or indirectly influence the gut-brain axis and confer a benefit to mental health.

Randomised controlled trial

When referring to clinical trials, randomised refers to a trial which is set up in a deliberately random or unpredictable way. Known as the gold standard of clinical trials, randomised controlled trials ensure that the participants in the study are allocated randomly to the study groups.


The rectum is the space between the colon and the anus, where faeces are stored before bowel movements.


Belonging to the Clostridia class, this genus of bacteria is found in the human digestive tract and ferments ingested plant material.

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 acidophilus. Saccharomyces 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.

Saccharomyces boulardii can be found in For bowel calm (5 billion microorganisms of pure S. boulardii per capsule) and For travelling abroad (1 billion microorganisms of S. boulardii per capsule, combined with other strains).


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. 


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.

For more information, see Our Probiotic Strains.


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. 


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.


Thrush is a fungal infection almost always caused by the overgrowth of Candida albicans. Symptoms of thrush include white spots in the mouth, sometimes accompanied by pain. Alternatively, see Vaginal Thrush.


'Transient' refers to something that is temporary; remaining for a short period of time. A transient probiotic strain is therefore one that passes through the gut without adhering to the gut wall lining.

Adhesion to the gut wall lining is often considered an important factor in determining probiotic quality, as a probiotic that adheres can in turn colonise the digestive tract and have a longer lasting effect on the body. Probiotic strains such as Lactobacillus acidophilus Rosell-52 and Lactobacillus rhamnosus Rosell-11 undergo tests with the Institut Rosell to ensure their adhesion to the epithelial cells of the gut.  

Certain probiotic species are, however, transient by nature. For example the unique Saccharomyces boulardii probiotic.  A probiotic can be transient, and yet still have a positive effect on the human body.


Triglycerides are a type of fat found in the blood, which are usually measured alongside cholesterol as a risk factor for heart disease. The body uses triglycerides for energy production, however when levels are too high it can pose certain health problems. Triglyceride levels above 200 are considered high, with an increased risk affecting women. Factors affecting triglyceride levels in the blood include being overweight, smoking, excessive alcohol use as well as some genetic disorders. 

Ulcerative Colitis

Ulcerative Colitis is an inflammatory bowel disease (IBD) which provokes inflammation and sores, or ulcers, in the rectal and colonic lining. Symptoms of ulcerative colitis include abdominal pain and diarrhoea.

Urogenital tract

The urogenital tract (also referred to as the ‘genitourinary system’) combines all the organs of the reproductive system and the urinary system. Namely the kidneys, ureter, bladder and urethra, plus the ovaries, fallopian tubes, uterus and vagina in women, and testes, prostate, seminal ducts and penis in men.

Vaginal Thrush

Thrush, also known as Candidiasis or a yeast infection, occurs due to an overgrowth of yeast in the body, usually Candida albicans. Symptoms include mild to severe itching and soreness in and around the vagina.


A virus is a very small infectious microbe that can only replicate itself inside the living cells of an organism. Viruses on average are about 1/100th of the size of an average bacterium cell.


These one- celled microorganisms belong to the Fungi kingdom and are commonly used in the alcohol fermentation process and in baking. Some yeasts such as Candida albicans are mildly pathogenic to humans and others such as Saccharomyces boulardii have therapeutic uses.

Yogurt Starter Kits

A Yogurt Starter Kit is a combination of specific bacteria strains, known as yogurt cultures, selected for their ability to change milk into yogurt. The yogurt cultures (usually in powdered form) are added to the milk and allowed to incubate. The bacteria consumes the lactose in the milk, and uses it to produce lactic acid which cause the milk proteins to coagulate, resulting in yogurt.  The yogurt culture bacteria strains each have certain properties and are selected for their effect on the finished yogurt. For example, some types of bacteria produce more lactic acid which will result in a sour tasting yogurt & some bacteria strains create different textures in the milk, resulting in a thicker or more solid yogurt.