Glossary - G

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. 

Gardnerella vaginalis

This is a predominantly pathogenic (harmful) bacteria that lives in the vaginal tract. If populations of friendly bacteria in the vaginal tract deplete e.g. strains of Lactobacillus, then this allows space and nutrients for Gardnerella vaginalis to overgrow and cause symptoms of Bacterial Vaginosis (BV)Gardnerella vaginalis can be treated with antibiotics, but often the infection will return within a few months. The natural way to promote a healthy balance of the vaginal microflora and keep Gardnerella vaginalis at bay, is to increase the levels of friendly Lactobacillus bacteria in the vagina.


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.

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.


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.


Gluten is a family of proteins found in grains like wheat, spelt, rye and barley. These proteins form a sticky substance when flour is mixed with water and is what makes dough elastic. The two main proteins are glutenin and gliadin, the latter of which can have negative effects on health.

Gluten-free diet

This is a diet which advocates avoiding all gluten, a protein found in wheat, barley, and rye. Gluten causes an autoimmune reaction in those with coeliac disease and is believed to cause sensitivity and gut inflammation in many other people.

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.


This group of bacteria is known as ‘gram-positive’ as they change colour when coming into contact with a staining method known as Gram’s method. This method is used in order to classify different types of bacteria. ‘Gram-positive’ bacteria have a thick cell wall (made out of peptidoglycan) which take on the purple stain.

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.

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.


The gullet, or oesophagus is the tube connecting the mouth (or pharynx) to the stomach. The transit of food down the gullet is aided by muscle contractions, or peristalsis.

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.

Find out more about gut flora.

Gut integrity

Gut integrity refers to the health of the structure of the intestinal lining. An impairment of this gastrointestinal lining increases the risk of developing GI diseases, food intolerances, inflammation in the body and infections. Gut integrity can be damaged by a number of things prominent in modern life such as antibiotics, parasites, unhealthy diet, and sugar.