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.

Voices
voicesGood for Lana Del Rey for helping kill that myth, writes Grace Dent
Sport
The Pipes and Drums of The Scottish Regiments perform during the Opening Ceremony for the Glasgow 2014 Commonwealth Games at Celtic Park on July 23, 2014 in Glasgow, Scotland.
Commonwealth GamesThe actor encouraged the one billion viewers of the event to donate to the children's charity
Sport
Karen Dunbar performs
Entertainers showcase local wit, talent and irrepressible spirit
Sport
Members of the Scotland deleagtion walk past during the opening ceremony of the 2014 Commonwealth Games at Celtic Park in Glasgow on July 23, 2014.
PROMOTED VIDEO
Arts and Entertainment
The Tour de France peloton rides over a bridge on the Grinton Moor, Yorkshire, earlier this month
film
Life and Style
fashion Designs are part of feminist art project by a British student
News
Very tasty: Vladimir Putin dining alone, perhaps sensibly
news
Life and Style
Listen here: Apple EarPods offer an alternative
techAre custom, 3D printed earbuds the solution?
Arts and Entertainment
Top guns: Cole advised the makers of Second World War film Fury, starring Brad Pitt
filmLt-Col Steven Cole is the man Hollywood calls when it wants to borrow a tank or check a uniform
News
The University of California study monitored the reaction of 36 dogs
sciencePets' range of emotions revealed
News
Snoop Dogg pictured at The Hollywood Reporter Nominees' Night in February, 2013
people... says Snoop Dogg
News
ebookA unique anthology of reporting and analysis of a crucial period of history
Arts and Entertainment
A scene from Shakespeare in Love at the Noel Coward Theatre
theatreReview: Shakespeare in Love has moments of sheer stage poetry mixed with effervescent fun
News
Joining forces: young British men feature in an Isis video in which they urge Islamists in the West to join them in Iraq and Syria
newsWill the young Britons fighting in Syria be allowed to return home and resume their lives?
Arts and Entertainment
The nomination of 'The Wake' by Paul Kingsnorth has caused a stir
books
News
i100
Life and Style
food + drinkZebra meat is exotic and lean - but does it taste good?
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
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

BI Manager - £50,000

£49000 - £55000 per annum + competitive: Progressive Recruitment: My client is...

BI Project Manager - £48,000 - £54,000 - Midlands

£48000 - £54000 per annum + Benefits package: Progressive Recruitment: My clie...

VB.Net Developer

£35000 - £45000 per annum + competitive: Progressive Recruitment: If you're pa...

SAP Business Consultant (SD, MM and FICO), £55,000, Wakefield

£45000 - £55000 per annum + competitive: Progressive Recruitment: SAP Business...

Day In a Page

Screwing your way to the top? Good for Lana Del Rey for helping kill that myth

Screwing your way to the top?

Good for Lana Del Rey for helping kill that myth, says Grace Dent
Will the young Britons fighting in Syria be allowed to return home and resume their lives?

Will Britons fighting in Syria be able to resume their lives?

Tony Blair's Terrorism Act 2006 has made it an offence to take part in military action abroad with a "political, ideological, religious or racial motive"
Beyoncé poses as Rosie the Riveter, the wartime poster girl who became a feminist pin-up

Beyoncé poses as Rosie the Riveter

The wartime poster girl became the ultimate American symbol of female empowerment
The quest to find the perfect pair of earphones: Are custom, 3D printed earbuds the solution?

The quest to find the perfect pair of earphones

Earphones don't fit properly, offer mediocre audio quality and can even be painful. So the quest to design the perfect pair is music to Seth Stevenson's ears
US Army's shooting star: Lt-Col Steven Cole is the man Hollywood calls when it wants to borrow a tank or check a military uniform

Meet the US Army's shooting star

Lt-Col Steven Cole is the man Hollywood calls when it wants to borrow a tank or check a military uniform
Climate change threatens to make the antarctic fur seal extinct

Take a good look while you can

How climate change could wipe out this seal
Should emergency hospital weddings be made easier for the terminally ill?

Farewell, my lovely

Should emergency hospital weddings be made easier?
Man Booker Prize 2014 longlist: Crowdfunded novel nominated for first time

Crowdfunded novel nominated for Booker Prize

Paul Kingsnorth's 'The Wake' is in contention for the prestigious award
Vladimir Putin employs a full-time food taster to ensure his meals aren't poisoned

Vladimir Putin employs a full-time food taster

John Walsh salutes those brave souls who have, throughout history, put their knives on the line
Tour de France effect brings Hollywood blockbusters to Yorkshire

Tour de France effect brings Hollywood blockbusters to Yorkshire

A $25m thriller starring Sam Worthington to be made in God's Own Country
Will The Minerva Project - the first 'elite' American university to be launched in a century - change the face of higher learning?

Will The Minerva Project change the face of higher learning?

The university has no lecture halls, no debating societies, no sports teams and no fraternities. Instead, the 33 students who have made the cut at Minerva, will travel the world and change the face of higher learning
The 10 best pedicure products

Feet treat: 10 best pedicure products

Bags packed and all prepped for holidays, but feet in a state? Get them flip-flop-ready with our pick of the items for a DIY treatment
Commonwealth Games 2014: Great Scots! Planes and pipers welcome in Glasgow's Games

Commonwealth Games 2014

Great Scots! Planes and pipers welcome in Glasgow's Games
Jack Pitt-Brooke: Manchester City and Patrick Vieira make the right stand on racism

Jack Pitt-Brooke

Manchester City and Patrick Vieira make the right stand on racism
How Terry Newton tragedy made iron men seek help to tackle their psychological demons

How Newton tragedy made iron men seek help to tackle their psychological demons

Over a hundred rugby league players have contacted clinic to deal with mental challenges of game