|
Pamela Mason, PhD, MRPharmS, is a freelance journalist
and author, based in Monmouthshire
|
Christopher Icha
Claims on probiotic products include helping to support the body’s
natural defences |
SUMMARY
Probiotics are live cultures of micro-organisms, usually bacteria, that,
when ingested, survive passage through the upper gastrointestinal tract
and have beneficial effects on the host.
The most common bacteria used
in probiotics include Lactobacillus species, bifidobacteria,
some streptococci and other gram-positive cocci.
These micro-organisms should resist gastric acid, bile salts and pancreatic
enzymes, and adhere to and readily colonise the bowel where they displace
potentially dangerous bacteria and create an environment that is unfavourable
for the multiplication of such pathogens.
In the UK, probiotics are available in foods or food supplements, sometimes
sold combined with prebiotics (see Panel 1), vitamins and minerals
and digestive enzymes. However, in Italy, one probiotic product, a
suspension
of Bacillus subtilis spores manufactured by sanofi-aventis,
has been available over the counter since 1999 for the treatment and
prevention
of gastrointestinal disorders. Increasingly popular, probiotics in
the UK are consumed as fermented dairy products, such as yogurts and
drinks,
fruit juices, and
dry preparations (ie, tablets, capsules and powders).
Uses suggested for probiotics include:
• To reduce the incidence and severity of diarrhoea
• To reduce the risk of allergic conditions
• To improve immune function
• To manage inflammatory bowel conditions, such as Crohn’s disease,
ulcerative colitis and irritable bowel syndrome
• To prevent Helicobacter pylori gastritis
• To reduce symptoms of lactose intolerance
• To reduce vaginal infections
• To decrease blood cholesterol
• To protect against bowel cancer
Full article PDF 170K
Panel 1: Prebiotics
Prebiotics are non-digestible food substances that promote the
growth of beneficial bacteria in the gastrointestinal tract. Chemically,
prebiotics are oligosaccharides and examples include inulin-type
fructans, fructooligosacharides and oligofructoses, which are
present
in many fruits and vegetables.
Prebiotics resist digestion in the upper part of the gastrointestinal
tract and are fermented by endogenous anaerobic micro-organisms
in the colon to produce lactic acid and short chain carboxylic
acids
(eg, acetic, butyric and propionic acid). This fermentation provides
metabolic substrates to the cells of the colon, stimulating growth
of the bifidobacteria population.
Prebiotics also promote the absorption of calcium and magnesium,
and possibly other minerals and trace elements within the colon.
Evidence is also emerging that they may reduce serum lipids,
particularly triglycerides. They are also being investigated
for a possible protective
effect in bowel cancer, constipation, inflammatory bowel conditions,
allergic dermatitis and lactose intolerance. |
|
The
Pharmaceutical Journal