Glossary - B

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!

Bacterial Vaginosis (BV)

Bacterial Vaginosis (BV) is an imbalance of the healthy microflora in the vagina. Bad bacteria e.g. Gardnerella vaginalis overgrow and cause a ‘fishy’ smell, and a thin white/ grey discharge. It is estimated that 1 in 3 women have BV, and many of these women will suffer in silence. The most common BV treatment is with antibiotics, but the effect is often only temporary and recurrence is high.

Find out more about Bacterial Vaginosis.


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.


The term ‘bacteriome' refers to the communities of bacteria that colonise the many epithelial surfaces in the human body, including the skin, intestines, sinus cavity, vagina etc. Whereas the term 'microbiome' refers to all the different micro-organisms (bacteria, yeasts, fungi) that inhabit a given environment, the term 'bacteriome' refers solely to the bacterial populations in the same habitat.


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 bifiduminfantis and breve. Over the age of 60, levels of Bifidobacteria in particular are thought to largely deplete in the gut.

Healthcare professionals can find out more about Bifidobacteria in the Probiotics Database.

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.

Healthcare professionals can find out more about Bifidobacterium breve in the Probiotics Database.

Bifidobacterium infantis

'infantis' is a probiotic species belonging to a family of bacteria called BifidobacteriaBifidobacterium 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.

Healthcare professionals can find out more about Bifidobacterium infantis in the Probiotics Database.

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. 

Healthcare professionals can find out more about Bifidobacterium lactis in the Probiotics Database.

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'.


The term Bifidus is a little controversial. It appears to be used as a shortened version of 'Bifidobacterium'; a well known family of bacteria thought to have probiotic properties. It is important to use the full and correct probiotic strain name, which includes 3 parts: genus (or family), species and strain. An example in this case therefore would be that Bifidobacterium lactis B1-07. Elsewhere this may be referred to Bifidus lactis. Shortening the name could make remembering and pronouncing the name easier, but we believe strongly in the importance of strain specificity. One strain is not the same as the other, as each has a different role and function in your body, therefore referring to all the various strains of Bifidobacterium with one word to cover all, does not differentiate between the bacteria.


Bile is the bitter-tasting, yellow to dark green alkaline fluid produced by the liver and stored in the gallbladder. It aids digestion of fats in the small intestine. Some foods can be helpful in stimulating bile production. 


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.

Bloating can be a symptom of serious illness such as bowel or ovarian cancer. Anyone with persistent bloating should see their GP. This site does not provide medical diagnosis or treatment.

Find out more about bloating.

Blood lipid

Blood Lipids is the term used for all the fatty substances found in the blood, including cholesterol and triglycerides. Lipids join with protein in your blood to form lipoproteins which make energy for your body, so they're important to the cells in your body. There are three types of lipoproteins (also known as cholesterol). High-density lipoprotein (HDL), low-density lipoprotein ( LDL) and very low-density lipoprotein (VLDL). HDL is sometimes called the “good cholesterol” because it keeps cholesterol from building up in your arteries. LDL can be thought of as the “bad” cholesterol because high LDL levels can increase your risk of heart attack or stroke. It is the balance between the two which is important when monitoring your cholesterol levels.


BM or BMs is the acronym used to shorten the words Bowel Movement/Bowel Movements. Also known as a stool or faeces, 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. 


Bowel is term for lower part of the digestive system, comprising of the small and large intestines. From the stomach, food passes through the small intestine where the majority of digestion and absorption of nutrients occurs. It then passes into the large intestine (colon) where water is absorbed and microbes salvage certain nutrients from the remaining indigestible food matter, before excreting the waste material through the rectum and anus.

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.