Probiotics & Prebiotics

The human intestines contain an average of approximately 10¹⁴ microorganisms, made up of more than 400 different species. This microflora has a symbiotic relationship with the host organism and protects the body against infections, assists digestion, produces nutrients, and plays an important role in the immune system. A good microfloral balance in the intestines is essential for these functions and for the health of the host. When the intestinal flora is in balance, both beneficial and harmful microorganisms (pathogens) are present. This balance can be disturbed by factors such as the use of antibiotics, stress or an unbalanced diet. Disturbing the balance creates a risk that the beneficial intestinal bacteria will be suppressed and that the pathogenic bacteria will become dominant.

What are Probiotics?

The term probiotic literally means ‘for life’ and was first used in the 1960s, but not until the 1970s was the term used in the sense that it is used today. The simple definition is “a live microbial supplement which beneficially affects the host by improving the microbial balance”. With few exceptions, most probiotic products currently available contain lactic-acid-producing bacteria, which mainly belong to the genera Lactobacillus and Bifidobacterium.

The key here is the word ‘live’ and what they mean by beneficially affect. Probiotics are being heavily marketed through magazine and TV advertising particularly in yoghurt type drinks. Many question the ability of these preparations to benefit anyone never mind those suffering from conditions such as IBS. A recent study by the Foods Standards Agency suggested that few of the bacteria in the Probiotics studied could survive transit through the acidic contents of the stomach and of those that did get through there was little evidence that they changed the balance of bacteria in the gut.

There are a number of strategies available to get large numbers of active friendly bacteria into the gut for example taking in a highly active, freshly activated liquid preparation or taking a specially coated tablet or capsule which protects the bacteria in acidic environments. Yoghurt style drinks don’t offer any of these approaches. For those whose natural friendly bacteria have been disrupted by antibiotics or by some other trauma to the gut lining there is a clear benefit in getting the balance back to normal and there is a lot of evidence with IBS sufferers that good Probiotics supplementation can help.

The number and range of probiotic preparations are now staggering and it is very difficult for the average consumer to assess what products they should use. However, generally speaking taking a broad spectrum probiotic with a wide range of the important bacteria is most likely the best strategy. Usually a relatively high dose at the beginning and dropping the dose as the bacteria become established.

In certain cases specific bacteria such a Lactobacillus plantarum and a yeast strain Saccharomyces boulardii widely used in Germany have been shown to benefit digestive disorders such as IBS, however there is no evidence that they colonise the gut, only that they help the natural bacteria to re-colonise.

From a safety point of view there is little evidence of problems with occasionally some issues such as bloating due to the initial changes going on in the gut, however this usually settles down as balance is restored.

What are Prebiotics?

The term Prebiotic is a much later invention having first appeared in the mid 1990s. Simply by changing the pro for pre the literal meaning becomes, ‘before life’. More fully the definition for prebiotics is “a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one of a limited number of bacteria in the colon”. This definition is very similar to that of dietary fibre other than that prebiotics are selective for certain species. This selectivity was first shown for bifidobacteria which may be promoted by the ingestion of substances such as fructooligosaccharides and inulin, transgalactosylated oligosaccharides and soyabean oligosaccharides. A new prebiotic called Bimuno has recently come onto the market which a number of our members have found beneficial.