Microbe of the Month: Reinforcing a gutsy resistance fighter: The more bifidobacteria in our intestine, the better. Bernard Dixon explains how it can be encouraged

An adequate intake of fibre - once disregarded by nutritionists and eaters alike - combats constipation, helps some people with irritable bowel syndrome and may also prevent diverticulitis. Now another neglected feature of our bowels is attracting the attention of scientists seeking means of improving resistance to intestinal disease, this time infections such as enteritis.

Glenn Gibson and colleagues at the Medical Research Council's Dunn Nutrition Centre in Cambridge believe it may be possible to alter the huge population of microbes growing in the large intestine so that disease-causing invaders cannot become established there.

One starting point for the research was the discovery that the mixture of bacteria in the intestines of breast-fed babies differs significantly from that of bottle-fed ones, and indeed adults. The main difference is that some 95 per cent of the intestinal flora of breast-fed babies consists of bifidobacteria (so called because their cells are often bifurcated - Y-shaped). The percentage is lower in babies given bottled milk. It also declines on weaning, and falls to some 25 per cent in the adult, when bacteria such as Escherichia coli predominate.

The full significance of bifidobacteria was not recognised, because unlike E coli they grow in the absence, rather than the presence, of oxygen. This meant that laboratory techniques for culturing bacteria from faeces tended to underestimate the numbers of bifidobacteria. Now, however, there are good reasons to believe that their presence contributes to the health advantages of breast as against bottle-feeding.

There are several possible reasons for this. Bifidobacteria produce lactic and acetic acid, which impair the growth of bacteria such as Clostridium perfringens, the agent of one type of food poisoning. They produce several vitamins and enzymes that play a role in digestion. And they are powerful stimulators of the body's immune defences.

Dr Gibson and his colleagues are now investigating the possibility of stimulating the growth of beneficial organisms such as bifidobacteria in the large intestine, so that they comprise a greater fraction of the population. By manipulating the microbial flora in this way, they believe they may be able to replicate the sort of health benefits observed in breast-fed babies. Their hopes are enhanced by reports that the bacterial community in the gut, which may be impoverished in patients receiving intensive antibiotic therapy, can be restored if they are given cultures of bifidobacteria to swallow.

The strategy being developed is to administer not the bacteria themselves but substances which, after passing unchanged through the stomach, arrive in the large intestine and stimulate the growth of bifidobacteria already there. Two of these substances are inulin and oligofructose, types of sugar that occur naturally in vegetables and other plants. Dr Gibson and his colleagues have used them in two sets of experiments. First, they prepared 'faecal slurries' from human volunteers and demonstrated that when they incubated these in the presence of inulin or oligofructose the bifidobacteria in the samples grew vigorously, while other bacteria, including those capable of causing disease, remained at low levels. Tests with pure cultures confirmed that bifidobacteria directly inhibited the growth of E coli and C perfringens.

Very recently, these results in laboratory glassware have been augmented by successful experiments in human volunteers. They were given a diet enriched firstly by ordinary sugar, followed by either inulin or oligofructose, and finally by sugar again. The experimenters monitored the bacteria in the volunteers' faeces. In each case, there was a marked shift in the bacterial flora, bifidobacteria becoming dominant during the period when the subjects were consuming the diet supplemented by inulin or oligofructose.

The lesson is clear. It is feasible, as Dr Gibson hoped, to alter the balance of bacteria in the human large intestine in such a way as to favour bifidobacteria, which are known to confer health benefits. This raises the possibility of adjusting the human diet by replacing ordinary sugar with inulin or oligofructose as a means of reducing, in the long term, the toll of intestinal infection. Inulin and oligofructose are safe and acceptable as sweeteners, though somewhat less sweet than ordinary sugar.

The upshot could, therefore, be a combination of health benefits conferred by an altered microbial population in the large intestine, and a simple means of avoiding the obesity, dental caries and other health hazards associated with over-consumption of sugar.

Start your day with The Independent, sign up for daily news emails
Life and Style
love + sex A new study has revealed the average size - but does that leave men outside the 'normal' range being thought of as 'abnormal'?
Arts and Entertainment
TV
Voices
The Palace of Westminster is falling down, according to John Bercow
voices..says Matthew Norman
Sport
Steve Bruce and Gus Poyet clash
football
News
Graham Norton said Irish broadcaster RTE’s decision to settle was ‘moronic’
TV
Arts and Entertainment
Jake and Dinos Chapman were motivated by revenge to make 'Bring me the Head of Franco Toselli! '
arts + ents Shapero Modern Gallery to show explicit Chapman Brothers film
Arts and Entertainment
Kurt Cobain performing for 'MTV Unplugged' in New York, shortly before his death
music Brett Morgen's 'Cobain: Montage of Heck' debunks many of the myths
ebooks
ebooksA special investigation by Andy McSmith
Life and Style
life
Sport
Brendan Rodgers
football The Liverpool manager will be the first option after Pep Guardiola
News
Amazon misled consumers about subscription fees, the ASA has ruled
news
Arts and Entertainment
Myanna Buring, Julian Rhind-Tutt and Russell Tovey in 'Banished'
TV Jimmy McGovern tackles 18th-century crime and punishment
Arts and Entertainment
Paul Whitehouse as Herbert
arts + ents
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Lettings and Sales Negotiator - OTE £46,000

£16000 - £46000 per annum: Recruitment Genius: This is an opportunity to join ...

Recruitment Genius: Home Care Worker - Reading and Surrounding Areas

£9 - £13 per hour: Recruitment Genius: This is a great opportunity to join a s...

Recruitment Genius: Key Sales Account Manager - OTE £35,000

£25000 - £35000 per annum: Recruitment Genius: Have you got a proven track rec...

Recruitment Genius: Sales Executive - OTE £40,000

£15000 - £18000 per annum: Recruitment Genius: This is a great opportunity for...

Day In a Page

Syrian conflict is the world's first 'climate change war', say scientists, but it won't be the last one

Climate change key in Syrian conflict

And it will trigger more war in future
How I outwitted the Gestapo

How I outwitted the Gestapo

My life as a Jew in wartime Berlin
The nation's favourite animal revealed

The nation's favourite animal revealed

Women like cuddly creatures whilst men like creepy-crawlies
Is this the way to get young people to vote?

Getting young people to vote

From #VOTESELFISH to Bite the Ballot
Poldark star Heida Reed: 'I don't think a single bodice gets ripped'

Poldark star Heida Reed

'I don't think a single bodice gets ripped'
The difference between America and Israel? There isn’t one

The difference between America and Israel? There isn’t one

Netanyahu knows he can get away with anything in America, says Robert Fisk
Families clubbing together to build their own affordable accommodation

Do It Yourself approach to securing a new house

Community land trusts marking a new trend for taking the initiative away from developers
Head of WWF UK: We didn’t send Cameron to the Arctic to see green ideas freeze

David Nussbaum: We didn’t send Cameron to the Arctic to see green ideas freeze

The head of WWF UK remains sanguine despite the Government’s failure to live up to its pledges on the environment
Author Kazuo Ishiguro on being inspired by shoot-outs and samurai

Author Kazuo Ishiguro on being inspired by shoot-outs and samurai

Set in a mythologised 5th-century Britain, ‘The Buried Giant’ is a strange beast
With money, corruption and drugs, this monk fears Buddhism in Thailand is a ‘poisoned fruit’

Money, corruption and drugs

The monk who fears Buddhism in Thailand is a ‘poisoned fruit’
America's first slavery museum established at Django Unchained plantation - 150 years after slavery outlawed

150 years after it was outlawed...

... America's first slavery museum is established in Louisiana
Kelly Clarkson: How I snubbed Simon Cowell and become a Grammy-winning superstar

Kelly Clarkson: How I snubbed Simon Cowell and become a Grammy-winning superstar

The first 'American Idol' winner on how she manages to remain her own woman – Jane Austen fascination and all
Tony Oursler on exploring our uneasy relationship with technology with his new show

You won't believe your eyes

Tony Oursler's new show explores our uneasy relationship with technology. He's one of a growing number of artists with that preoccupation
Ian Herbert: Peter Moores must go. He should never have been brought back to fail again

Moores must go. He should never have been brought back to fail again

The England coach leaves players to find solutions - which makes you wonder where he adds value, says Ian Herbert
War with Isis: Fears that the looming battle for Mosul will unleash 'a million refugees'

The battle for Mosul will unleash 'a million refugees'

Aid agencies prepare for vast exodus following planned Iraqi offensive against the Isis-held city, reports Patrick Cockburn