The 'friendly' bug we all want to catch (Filed: 08/03/2005)

Bacteria straight off the shelf

Some bacteria are good for you, says the marketing, but is there any hard evidence of medical benefits? Bryony Gordon reports

Around 10 years ago, when I was a spotty, malnourished teenager, my mother returned from the supermarket with a stack of yogurt drinks. They were probiotics, she said, full of "friendly bacteria" that would do me the world of good. Yet when I asked her how exactly they would make me feel better, it soon became clear that she hadn't a clue.

Gut feeling: probiotics are said to promote a stable balance of bacteria in our intestines

A decade later, the probiotic market is worth £213 million in Britain alone, but we seem no clearer about how the products work and what they do; last month Tesco reported that customers were buying the supplements to cure hangovers, despite the fact that they do nothing of the sort.

They are said to contribute to a stable balance of good bacteria, known as gut flora, that live in our intestines. This balance helps to make vital nutrients and keeps our digestive systems healthy, but stress, antibiotics and illnesses that cause diarrhoea can upset levels of the flora. Hence the need for probiotics.

But does the average human being – when not suffering from such problems – need to increase his quota of friendly bacteria, as the makers of these products would have us believe?

"Topping up your bacteria with fermented milk – of which these drinks are essentially modified versions – has been part of our diet for thousands of years," says Professor Jeremy Hamilton-Miller, a microbiologist who has studied probiotic supplements. "So it's perfectly natural to incorporate these yogurts into your diet. But I think the manufacturers need to be a lot clearer about what the supplements actually do." In other words, general claims about "feeling good" have made consumers think that probiotics will help cure a variety of ailments.

There are, however, specific illnesses that probiotics have been shown to help. Lactobacillus GG, for instance, can help prevent diarrhoea, while others can ease constipation. Certain types have been found to relieve the effects of ulcerative colitis, and various strains have been shown to increase levels of Vitamin K, to decrease the risk of bowel and colon cancers and to cut cholesterol levels.

A Swedish study found that babies who were given the probiotic Lactobacillus Reuteri during the first six months of their lives were less likely to develop allergies and asthma.

Probiotics also have potential benefits for the elderly, says Jackie Lowden of the British Dietetic Association. "There is evidence that the levels of good bacteria in our bodies decline with age," she says. "And there have been studies that suggest other benefits; some probiotics are said to suppress quantities of Helicobacter Pylori, which has been linked with peptic ulcers and gastric cancers." Some research shows that probiotics may help with irritable bowel syndrome, she adds.

However, many have questioned how many of the good bacteria actually reach the gut, because acid and bile in the stomach are known to kill probiotics. Furthermore, when Prof Hamilton-Miller carried out a study into the effectiveness of probiotic supplements last year, he found that only a third of the products did what they claimed to do, and one was completely sterile. He will not name the unsatisfactory ones, because he has been threatened with legal action.

"I found that the range of probiotics was extraordinary," he says. "Some had billions of bacteria in them; one had nothing in it at all; others contained organisms that just shouldn't have been there."

But if we do want to take them, is there a way of doing so naturally? The answer is no, although we can ingest prebiotics, the micro-organisms on which probiotics live. These can be found in bananas, asparagus, onions, tomatoes, leeks, cucumber, chickpeas, peas and sunflower seeds, and some probiotic products now include them.

Prof Hamilton-Miller says the key to buying probiotics is to buy them long before their sell-by date and to keep them refrigerated. "If you don't treat bacteria properly, they will die." He adds that probiotics advertised on television or radio are likely to be of high quality, as they are vetted by advertising standards bodies.

"There is obviously a role for probiotics in the diets of certain people," says Lowden. "Yet there are huge issues over whether we all need to take them; the fact that they won't do us any damage means we carry on buying them." To many, however, £213 million might seem an awful lot of money to spend on something we may not even need.

Bacteria straight off the shelf

May be useful for constipation: Yakult

Yakult £2.60 for a pack of seven bottles

Yakult contains just one strain of bacterium, Lactobacillus casei Shirota, of which there are 6.5 billion in each bottle. Two studies – one in Holland, the other in Britain – have shown that the strain is resistant to stomach acid, although Prof Colette Short, the company's science director admits: "Not all of the bacteria survive, but a sufficient amount live to flourish within the gut."

Yakult, like all of the major probiotic brands, makes no specific claims about the health benefits of its product. "We are a quality probiotic which tops up the bacteria in the body," says Prof Short. "We are focused on the gut health environment, intestinal balance and the digestive health benefits that may bring." However, Lactobacillus casei Shirota has been shown to improve bowel regularity, so may be useful for constipation.

Danone Actimel £1.34 for four, or £2.48 for eight

"Feel the difference in two weeks," boasts the advert for Actimel. And what, exactly, is that difference? This is difficult to pinpoint. A spokeswoman says it is based on the months of September and October last year, when, of the 9.5 million consumers who bought Actimel, only 45 people asked for their money back, because they didn't feel any different.

More specifically, the Lactobacillus casei Imunitass strain – of which there are 10 billion in each 100ml serving – has been shown to reduce the duration, incidence and symptoms of diarrhoea in children, and reduce episodes of illness in people over 60. Like Yakult's bacteria, Lactobacillus casei Imunitass is resistant to gastric acidity; a spokeswoman claims that a 2002 study shows "that the bacteria reach the gut in viable quantities – although the exact number will, of course, vary from person to person."

Multibionta Advanced Formula £4.59 for 30 tablets; £8.19 for 60

Unlike most of the big probiotic supplements on the market, Multibionta is in tablet form – the bacteria are freeze-dried so that they remain alive. The advantage of having a probiotic in this form is that Seven Seas is able to put a special gastric-resistant coating on each tablet, ensuring that all 10 million bacteria reach the gut.

Multibionta contains Tribion Harmonis, which is a blend of three probiotic strains: Lactobacillus gasseri, Bifidobacterium bifidum and Bifidobacterium longum. The Lactobacillus is active in the upper part of the gastrointestinal tract, while the Bifidobacterium is active in the lower area, which means that the entire tract is protected against harmful bacteria.

Muller Vitality £1.48 for six

Muller contains 10 billion of the probiotics Lactobacillus acidophilus and Bifidobacterium which, like Multibionta, work on different parts of the gut, ensuring the whole area is covered. It also contains Inulin, a prebiotic which stimulates the effect of probiotics – Bifidobacteria, in particular.

Muller Vitality claims to "give balance to your digestive system". When pressed for more specific information, a spokeswoman said that "there is growing scientific evidence to support the concept that the maintenance of healthy gut microflora may provide protection against gastrointestinal disorders."

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