The truth is a little more nuanced than that (as it tends to be when compared to 30 second TV advertisements) but that is the broad message. Probiotics are defined by the World Health Organisation (WHO) as ‘Live microorganisms which when administered in adequate amounts confer a health benefit on the host’. The most common forms are bacteria, but probiotics are not limited to bacteria.

The science surrounding the use of probiotics supplements for health reasons is still in its very early stages. Despite their use first being posited in the early 20th Century, it is only fairly recently that serious research has been dedicated to them. The evidence for their benefit is so far quite limited, but there have been encouraging studies pointing to their efficacy in managing IBS and other digestive conditions, reducing the recurrence of bladder cancer and managing eczema in children.

Probiotics are often said to promote general good health alongside the more specific uses described above. This is due mostly to the idea (originally from Chinese medicine) that a healthy gut leads to a healthy body. If the balance of microbes in the gut can be shifted towards the positive (probiotic) end of the scale, then we will be less susceptible to infection.

Current studies have demonstrated some support for this theory, although there is also an oft-reported placebo effect (not that this is necessarily a bad thing, as recent German studies supporting the widespread use of placebos attest) and probiotic research has not yet been standardised, meaning that it is hard to verify findings by comparing with existing studies.

Even so, this has not stopped scientists researching the future uses of probiotics. Going by the WHO definition of probiotics, we are not confined to the most common strains of ‘friendly bacteria’ currently in use and sold in supplement and yogurt form. Rather, probiotics are any microorganism that confer a health benefit on their host. This is a powerful idea that we may yet find to reach far beyond the current vogue for a ‘healthy tummy’.

There is already talk of ‘designer probiotics’ designed to produce specific effects, although this is harder than it might first appear. By all accounts the effects of microbes in our gut are far more complicated than a simple ‘bacteria X produces effect Y’ with the overall outcome being determined by a community of microbes rather than a single strain. What community achieves what is again determined by external factors such as diet and weight.

There has been much made of recent discoveries that probiotics may be helpful in reducing obesity by designing microorganisms that encourage the production of a particular polyunsaturated fat – t10, c12 Conjugated Linoleic Acid (CLA) – which has been shown to shrink the size of fat cells, decreasing overall body fat.

At the same time, other studies have shown that the communities of microbes naturally produced by the body are radically different in lean people to fat people, meaning that any ‘designer probiotic’ may need to be tailored if not to the individual, then to their body type, although it is not clear yet how much effect diet has. This could hinder the mass production of effective targeted probiotics.

That being said, there have already been some successes in production of ‘designer probiotics’, already being used to fight AIDS by mimicking HIV receptors. This approach is particularly fascinating and looks set to yield some of the most interesting applications of probiotics.

Part of the appeal of future designer probiotic features is that they don’t require trained medical staff to administer like other vaccines (if they were put to that use) and they are already being touted by some as the solution to antibiotic resistant bacteria (such as the kind that causes MRSA) as they are able to adapt just as quickly as the bacteria they are fighting.

The main problem at the moment is that probiotics tend to be physiologically fragile and have a very short lifespan, meaning that transport and storage can be difficult, before they face the challenge of our own physiological systems reacting against a foreign organism. However, huge advances have already been made in producing particular strains of probiotic that are, for example, bile resistant.

Although research into probiotic medicine is still in its very early stages, the preliminary signs are incredibly encouraging, and point to a highly successful future for probiotics in the growing field of biomedicine.

Many processes or exposures can increase the occurrence of abnormal cells. The precautions that minimize these exposures decrease the risk of cancer. Among the many potentially risky exposures are chemical exposures. Carcinogenic chemicals (carcinogens) can be ingested or generated by metabolic activity of microbes that live in the gastrointestinal tract.

It has been hypothesized that probiotic cultures might decrease the exposure to chemical carcinogens by:

1. Detoxification of carcinogens ingested
2. Altering the environment of the gut microbial populations and thereby decrease the metabolic activities of bacteria that may generate carcinogenic compounds
3. Producing metabolic products (eg butyrate) which improve the capacity of a death when delula must die (a process known as apoptosis or programmed cell death)
4. Producing compounds that inhibit the growth of tumor cells
5. Stimulating the immune system to better defend against the proliferation of cancer cells.

Research suggests that the consumption of probiotic supplements can reduce cancer risk. Researchers tested the effect of consumption of fermented foods or probiotic supplements have found:

• A reduction in the incidence of chemical induced tumors in rats.
• A reduction in faecal enzyme activity (ß-glucuronidase, azoreductase, nitroreductase, and one-dehydrogenase 7) that are created may play a role in colon cancer in humans and animals.
• Degradation of nitrosamines.
• A softening of the mutagenic activity of substances tested in the laboratory.
• Prevention of damage to DNA in certain colonic cells.
• Enhance immune system function.