Glossary - I


Short for irritable bowel syndrome. A widespread condition involving recurrent abdominal pain and diarrhoea or constipation, often associated with stress, depression, anxiety, or previous intestinal infection.

Immune support

Immune support is a general term used to describe a nutrient, food, or supplement that confers benefits to the human immune system. Our immune system is comprised of complex interactions between our organs, hormones, gut bacteria, and other substances.

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.


The ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells.


Immunomodulatory is where something such as a supplement, medication or chemical is capable of changing or modifying the immune response.

Infectious diseases

Caused by pathogens, which include bacteria, fungi, protozoa, worms, viruses, and even infectious proteins called prions. Pathogens of all classes must have mechanisms for entering their host and for evading immediate destruction by the host immune system. Most bacteria are not pathogenic.

In vitro

In vitro is Latin for ‘within the glass’. When something is performed in vitro it is carried out outside of a living organism

In vivo

In vivo is Latin for ‘within the living’. It refers to work (studies) being carried out within a whole, living organism.

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. Increased intestinal permeability plays a key role in leaky gut syndrome.


Inflammation is part of a complex bodily response to infection or injury. This could be a mechanical, chemical, viral, bacterial, or biological cause of damage. The body reacts with reddening, swelling, heat, pain and loss of function. The term inflammation is usually used with a specific area of the body in mind but is now often used to refer to the general increase in a chronic ‘inflammatory state’ in the body. Inflammation is a natural and healthy response, however persistent, systemic inflammation can lead to illness.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is the umbrella term for ulcerative colitis and Crohn’s disease; both of which cause intestinal inflammation and symptoms such as abdominal pain, vomiting and diarrhoea.


Interleukins are a family of cytokines, naturally-occurring proteins that are responsible for signalling between cells. Interleukins may regulate cell growth but they are particularly important in stimulating immune responses, such as inflammation.


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.

Additions to our Probiotics Glossary

If you come across a term you feel should be within our Probiotics Glossary, please do not hesitate to reach out to us and we will endeavour to research and add them. Email us at: [email protected]/uk

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