Probiotics: eat your bugs
by Peter Lavelle

Australian researchers say probiotics can help some common bowel
conditions. But how do you know what you're buying?

Published 06/03/2008

The human gut is a crowded neighbourhood - if you're a micro-organism,
that is. There are 500 species of bacteria resident in the adult
gastrointestinal tract, mostly in the large bowel.

Not only do they live there in peaceful coexistence with us, they may
actually help - keeping out disease-causing bacteria, keeping our
immune system healthy and maintaining the lining of the bowel.

But under some circumstances, the normal mix of these microbes gets
disrupted.

It might be because of foreign organisms in our bowel, such as
bacteria from contaminated water, or viruses spread from person to
person or hand to mouth. Or some of the normal micro-organisms may
killed by broad-spectrum antibiotics taken for a range of common
infections.

When this happens, it upsets the normal function of our bowels and we
may get symptoms like diarrhoea, abdominal cramps and bloating.

What if we could minimise these effects by swallowing preparations
containing large doses of the micro-organisms normally found in our
gut?

That's the thinking behind probiotics, the name given to preparations
containing live micro-organisms that, when administered in large
enough amounts, confer a beneficial health effect.

Probiotics have become more popular over the last 10 to 20 years,
along with vitamins, wheatgerm, and various other alternative and
complementary medicines. The idea of restoring our normal intestinal
flora and putting us back into balance, without using drugs, makes
them seem natural and safe.

They're classed by the Therapeutic Goods Administration as
complementary medicines. You can find them in supermarkets in
fermented milk drinks and some yoghurts, and in health food stores and
pharmacies as capsules and powders.

The most commonly used probiotics are yeast, particularly
Saccharomyces, and bacteria, particularly Lactobacillus (lactic acid
bacteria) and Bifidobacterium. These micro-organisms are found in
large numbers in the normal healthy intestine.

Until recently there hasn't been a lot of good scientific evidence
that they work, so GPs don't often recommend them, and may not even
know much about them. It hasn't helped that they're aggressively
marketed with claims that are vague and unscientific - that they 'help
maintain your body's natural balance', or 'maintain inner digestive
health and aid overall wellbeing'.

Some claims are particularly far-fetched: for example, that they cure
bad breath, high cholesterol, chronic fatigue and menstrual
complaints. (They do everything, it seems, except put a shine on the
duco of the Commodore.)

Still, there is some scientific evidence that they work, at least for
some conditions.

That's the conclusion of a group of Australian gastroenterologists who
did a review of the literature on probiotics and their effects on
disease, and reported their findings in the latest Medical Journal of
Australia. They found there's good evidence that they work in three
different conditions causing diarrhoea.

One is acute viral infectious diarrhoea, especially rotavirus, a
common cause of severe diarrhoea in children. When given with
rehydrating fluids, probiotics reduced the duration of the diarrhoea
by an average of 1.2 days. Probiotics are most effective if given
early in the course of illness; Lactobacillus rhamnosus was the
probiotic found to be most effective. Probiotics were ineffective
where the diarrhoea was caused by bacteria.

Countering antibiotics
Probiotics also helped reduce the likelihood of diarrhoea after
antibiotics, the reviewers found. About one person in four gets
diarrhoea after taking broad-spectrum antibiotics by mouth - it can
happen after a single dose. But Lactobacillus rhamnosus and
Saccharomyces boulardii reduce the chances. One study of 269 children
found that taking Saccharomyces boulardii reduced the chance of
diarrhoea by 10 per cent. Another study of adults over 50 found
diarrhoea a third less likely in those taking a mixture of
Lactobacillus casei, Lactobacillus bulgaricus and Streptococcus
thermophilus.

Probiotics also helped traveller's diarrhoea, they found. On average
people taking probiotics, especially Lactobacillus rhamnosus, reduced
their risk by 15 per cent.

But probiotics weren't much help for other bowel conditions. While
they're often used to help treat chronic inflammatory bowel disease
(Crohn's disease and ulcerative colitis), irritable bowel syndrome,
and various allergies including eczema, there wasn't much evidence one
way or another that they work in these conditions (though they may
help some symptoms, like bloating and passing wind in irritable bowel
syndrome).

This isn't the first evidence that suggests the benefits of
probiotics. A review of 34 well-designed studies published two years
ago in The Lancet Infectious Diseases found probiotics reduced
antibiotic-associated diarrhoea by 52 per cent, reduced the risk of
traveller's diarrhoea by 8 per cent, and of diarrhoea of any cause by
34 per cent. They found the most protective strains were Saccharomyces
boulardii, Lactobacillus rhamnosus, Lactobacillus acidophilus and
Lactobacillus bulgaricus.

Are you getting what you paid for?
Before you rush down to the supermarket or health food store, it's
worth bearing in mind that there's a limit to how useful this research
is going to be when it comes to actually buying probiotics.

The researchers point out that commercial preparations of probiotics
vary a lot in the dose of yeast and bacteria, and in the strains they
contain.

Choice magazine did a survey in 2006 of probiotics and found that
while some products were labelled with the type of yeast and bacteria
they contained, most weren't. Nothing has changed since then, says
Choice.

Then there's the issue of whether there's enough micro-organisms in
the product to be really effective. Under the Food Standards Code,
probiotic yoghurts and drinks must contain at least one million live
bacteria per gram to supply the required 10 billion colony-forming
units (CFU) per day needed to have an effect.

But most preparations don't tell you how many live bacteria they
contain, Choice found. Manufacturers do their own measurements, and
some UK studies have found that many products on the market contained
doses of bacteria too low to be effective.

Some nutritionists argue that most people can get by without
probiotics - they can keep their bowels regular and healthy just by
eating foods with plenty of fibre, such as fruit and vegetables,
legumes (peas, beans, and lentils), wholegrain breads and cereals.

On the other hand, if you're prone to diarrhoea when you travel
overseas, or you take antibiotics, or you or your child has bouts of
winter diarrhoea, then probiotics might help, and won't do any harm.
The evidence shows they're safe in normal healthy people. But make
sure the dose is high enough and the preparation contains the right
strains.

Article Link:
http://www.abc.net.au/health/thepulse/stories/2008/03/06/2181923.htm

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