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

Pectin is a polysaccharide present in virtually all plants where it contributes to the cell structure. Pectin is found in fruit, vegetables, legumes and cereals. The term pectin covers a number of polymers which vary according to their molecular weight, chemical configuration, and content of neutral sugars. Different plant types produce pectin with different functional properties. The word pectin comes from the Greek word ‘pektos’ which means firm and hard, reflecting pectin’s ability to form gels. Pectins contribute to the maintenance of normal blood cholesterol levels.

Phagocytes are a type of white blood cell which play a vital role in the functionality of the immune system. Phagocytes perform the specific role of ingesting and absorbing pathogens or toxins, and can also release enzymes to destroy them. Once a phagocyte has engulfed a pathogen, it can communicate to other immune cells, such as lymphocytes, to help identify the type of antibody needed to neutralise other invading pathogens.

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.

A pilot study is a small study, experiment, or set of observations which are undertaken in advance of a planned large-scale project. It is used specifically to test aspects of the research design and to evaluate feasibility in advance of the project. This allows adjustments and improvements to be made prior to its start.

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.

Plasma is one of the main components of blood. 55% of blood volume is made up of plasma. Plasma itself contains a mix of proteins (albumin, fibrinogen and immunoglobulins), salts and hormones.

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 four main groups: phenolic acids, stilbenes, lignans and flavonoids. Flavonoids are further classified into several groups. Flavanols, one of the groups of flavonoids most abundantly found in fruit and vegetables, are 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 and wine).
Research suggests that polyphenols, with their antioxidant properties, may play a role in the prevention of diseases, particularly related 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 a treatment for pouchitis, research shows that people with pouchitis have lower levels of beneficial bacteria in their system.

Prebiotics are compounds in food that induce the growth or activity of beneficial microorganisms such as bacteria and fungi. The most common example is in the gastrointestinal tract, where prebiotics can alter the composition of organisms in the gut microbiome.
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, stimulate the growth of probiotics from the Bifidobacteria genus.

Members of this gram-negative genus are closely related to Bacteroides, 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 live bacteria and yeasts that are good for you, especially for your digestive system. We usually think of these as germs that cause diseases, but your body is full of bacteria, good and bad. Probiotics are often called ‘good’ or ‘helpful’ bacteria because they help keep your gut healthy. You can find probiotics in supplements such as tablets, powder and some foods, like yoghurt.
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.

Most probiotics are sold as dietary supplements, which do not undergo the testing and approval process that drugs do. Manufacturers are responsible for making sure they are safe before they are marketed and that any claims made on the label are true. But there is no guarantee that the types of bacteria listed on a label are effective for the condition you are taking them for. Health benefits are strain-specific, and not all strains are necessarily useful, so you may want to consult a practitioner familiar with probiotics to discuss your options.

These are simple, single-celled organisms that do not have organelles or other internal membrane-bound structures. Critically they do not have a nucleus so only contain a single chromosome.

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.

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