The digestive system is home to a complex community of microorganisms, including bacteria, yeasts and other microbes. Together, these are often referred to as the gut microbiome.
The gut microbiome is an active area of scientific research and is thought to be influenced by a wide range of everyday factors, including diet, lifestyle, age, travel, stress, sleep patterns and the use of certain medicines.
Live cultures, sometimes described as friendly bacteria, are selected microorganisms that may be found in fermented foods or included in food supplements. Commonly used types include Lactobacillus, Bifidobacterium and Saccharomyces boulardii. Different products may contain different strains, and each strain should be clearly identified on the product label.
A varied and balanced diet, including a range of fibre-containing foods, remains one of the most important foundations for general wellbeing.
What Are Live Cultures?
Live cultures are microorganisms that can be present naturally in fermented foods or added to food supplements. They are usually listed by genus, species and strain. For example, a product may refer to Lactobacillus acidophilus or Bifidobacterium lactis.
This level of detail is useful because different strains have different characteristics. Some supplements contain a single strain, while others contain a blend of several strains.
Live culture supplements are available in a variety of formats, including capsules, tablets, powders and liquids. They may also be combined with other ingredients, such as fibre, vitamins or minerals.
Where a product makes a health claim about an added vitamin, mineral or other nutrient, that claim should be authorised and used in line with the relevant conditions of use.
The Gut Microbiome
The gut microbiome is a naturally occurring community of microorganisms found in the digestive tract. Everyone’s microbiome is different, and it can vary depending on many factors, including diet, lifestyle and environment.
Research into the microbiome continues to develop, and scientists are still learning more about how different microorganisms interact with the body and with each other.
Because this is a complex area, it is important that product descriptions remain clear, factual and not overstated. Consumers should look for products that provide transparent information about their live culture content, including strain names, serving size and storage instructions.
Of these, possibly the best-known is the impact of live cultures on digestive problems, with a particular emphasis on irritable bowel syndrome (IBS).
Irritable Bowel Syndrome
IBS is recognised as the most common functional digestive order, believed to affect up to 25% of the population. It is characterised by digestive problems such as stomach pain, bloating and gas, often associated with persistent diarrhoea. IBS research suggests that the condition may disappear from time-to-time, only to return with a vengeance.
As yet, scientists have not conclusively proven the cause of irritable bowel syndrome but bacteria in the gut - often referred to as “microfauna” or “microbiota” - are believed to be implicated. This belief stems from the fact that scientists have discovered significant differences in the bacterial loads of individuals suffering from IBS, when compared with non-sufferers.
Furthermore, there is growing evidence that supplementing gut bacteria through the use of probiotics demonstrates clinical improvements in many people.
One study enrolled 50 IBS sufferers, and provided them either with a probiotic supplement or a placebo for a period of four weeks to assess any impacts. The probiotic group reported a 52% improvement in stomach pain whilst the placebo-takers only saw an 11% improvement.
On a wider scale the same study looked at a combined metric for all commonly-experienced symptoms of irritable bowel syndrome and reported a 49.6% improvement with friendly bacteria formulas. This positive data shows strong improvement in IBS symptoms in response to improved gut flora. However, this is far from the only such study…
As has been previously stated, not all strains of friendly bacteria necessarily have a positive impact on all outcomes. Another study therefore tried comparing two different strains. Volunteers with IBS were split into three different groups. One group received Lactobacillus salivarius, the second Bifidobacterium infantis, and the third a placebo. What was notable from the results were that after an 8 week dosing period it was Bifidobacterium that showed far superior results, demonstrating significant improvements in measures of stomach pain, bloating and bowel movements when compared to either the placebo or the other bacterial culture.
A “meta-analysis” is the name given to a scientific analysis where the results from numerous past experiments are gathered, collated and studied. The intention is to provide an overview of the scientific discoveries to date, adding detail to the subject in question. The benefits of probiotics for IBS have undergone a number of meta analyses in recent years. One of the most extensive included the results of twenty different studies, covering 1400 different patients. Their findings confirm that the use of live cultures in supplements is associated with improvements in all general IBS symptoms.
Diarrhoea
It might seem odd to separate diarrhoea from IBS bearing in mind that it tends to be one of the most common symptoms, but there is good reason for this. Namely, diarrhoea may also be caused by a range of other factors. Most notable of these is the use of antibiotics.
By their very nature antibiotics are designed to kill off bacteria, but are often not specific in their effect. As a result, antibiotics have been shown to equally reduce the helpful colonies of bacteria in the digestive system. This frequently results in bouts of diarrhoea, and it is believed that up 30% of people undergoing antibiotic treatment end up experiencing diarrhoea.
Not only is diarrhoea an unpleasant condition for the patient, but of course rapid expulsion of gut contents can also mean that the antibiotic treatment itself is less effective, as it remains in the body for a shorter period of time.
Fortunately there is a growing body of evidence to suggest that friendly bacteria supplements may help to establish the optimal balance, thus eliminating antibiotic-associated diarrhoea (often known by the acronym of AAD).
A study involving 766 children being prescribed antibiotics found that when combined with friendly bacteria supplements the risk of suffering from diarrhoea fell from 28.5% to just 11.9%. Other studies have shown that once diarrhoea is experienced the impacts tend to be lessened. One study investigating the effects of five different “healthy” bacteria on diarrhoea found that, on average, they reduced diarrhoea duration by a day or more.
It is therefore believed by many scientists that it may be wise to take probiotics alongside any antibiotics, but that live culture based supplements may also offer benefits for people suffering from more general diarrhoea, whether this is persistent or not.
Constipation
This is where the probiotic story really started to get interesting. While the research here is rather thinner on the ground, some studies have indicated that friendly bacteria formulas may also be beneficial for constipation.
As an example, twenty children suffering from constipation were provided with a daily dose of high qualtiy gut friendly bacteria supplement or a placebo. The experts in question then recorded the frequency of bowel movements to identify the impact. In the live bacteria group bowel movement frequency more than doubled, while stomach pain halved.
The obvious question is how friendly bacteria could potentially both assist in cases of diarrhoea and constipation - surely the actions are opposed?
Up until recently it was believed that the primary method of action by the friendly bacteria was to improve digestion, out-compete less beneficial bacteria and to control the permeability of the gut lining. This finding, however, suggests that something else might be at play.
Indeed, if recent studies are to be believed then it seems there is increasing evidence that the live gut friendly bacteria supplements may actually help to impact the immune system directly.
The white blood cells that fight infection are not uniform; a range of different cells are involved in mounting an immune attack. One such type is known as a “T cell”. T cells respond to messages from other parts of the immune system - a bit like calling in the army. Studies have found that IBS sufferers can experience very different levels of t cell activity than those not affected.
This process - that has been referred to as “immune activation” - suggests that the bacterial growth stimulated by these supplements don’t just have a physical impact on the gut but may also help to modulate immune responses. It is in this way that supplements may simultaneously be able to assist with diarrhoea or constipation, as the mode of action is rather deeper and more complex than initially realized.
Eczema
The potential impact of probiotic bacteria on immunity is given further weight by reports that they may improve allergies such as eczema.
A study in Finland gave expectant mothers a friendly bacteria supplement each day for two months leading up to the expected birth date and during the first two months of breastfeeding. At this point, probiotic supplementation was ceased and the incidence of eczema was tracked in the children for a period of two years. The results showed that children who had been exposed to probiotics - thanks to their mother’s intake - were significantly less likely to develop eczema.
These hopeful results were expanded further in another study, where babies showing symptoms of eczema were weaned off breast milk and onto a formula enriched with friendly bacteria. Two months later, the group of babies ingesting the formula saw significant improvements in their condition when compared to non-supplemented infants.
The scientists responsible pointed out that these results once again indicate that the potential benefits may be much greater than initially thought. There is now growing evidence that these supplements may help to reduce inflammation and modulate immune responses to allergens.
Sources of Friendly Bacteria
There are several different sources of gut friendly bacteria. A popular food source is a live-cultured yogurt and while there are many different brands available, try to avoid yogurts which are loaded with fructose corn syrup and artificial sweeteners.
Other food sources include sauerkraut (made from fermented cabbage and also rich in vitamins) and kefir (a fermented dairy product made from goat’s milk and fermented kefir grains). Always look for foods which are fermented, not pasteurised, because the pasteurisation process kills any good bacteria.
Friendly bacteria supplements also offer a convenient and cost-effective alternative. These often contain several different species of live bacteria, including the popular strain Lactobacillus acidophilus, so have the potential to offer a range of positive health benefits.
How Much Should I Take?
Bacteria are of course microscopic in size, so the obvious question is how much you should take. Most supplements are measured in either milligrams or micrograms but friendly bacteria supplements are rather different. Here the standard unit of measurement is a “colony forming unit” or CFU.
Scientists are still carrying out experiments to decide on the optimum intake for health, but most scientific studies which have shown positive results have provided between one billion and five billion CFUs.
One particular benefit of supplements over foods is that it is quite easy to tell what concentration of bacteria they contain. Dosing therefore becomes simple. When it comes to fermented foods made at home it can be very difficult to ascertain the CFU content and therefore how much should be consumed.
Side Effects of Gut Friendly Bacteria Supplements
Their excellent safety profile means that many people turn to these supplements at the first sign of digestive issues. It is important to always follow the dosage instructions on the label. For some people, they may result in mild side effects such as an upset stomach, diarrhoea, gas and bloating, particularly in the first couple of days. These symptoms should disappear as the digestive system rebalances itself, however if symptoms continue beyond that, discontinue use.
Some experiments have indicated adverse effects for those suffering from Crohn’s disease, so it is recommended that sufferers avoid supplementing with probiotics without suitable medical guidance.
These types of supplements are sold under food law in the UK and so are not heavily regulated. Therefore it is essential that you buy from a respected retailer. Look for high quality with live bacteria – the bacteria needs to be live when administered in order to be effective – and high potency levels.
Each person responds differently to different bacteria strains and strengths, and some find certain strains to be more effective than others. If one strain doesn’t work, you may find a different strain to be beneficial.
If you suffer from any serious underlying health conditions then consult your GP before taking supplements.
Summary
These supplements help to complement the existing colonies of friendly bacteria in your gut. In doing so, they may help improve common digestive problems like stomach pain, bloating and gas. Through a variety of means, they may also positively impact diarrhoea and, to a lesser degree, constipation. There is also growing - but not definitive - evidence that gut microbiota may actually modulate immune responses, leading to deeper improvements in overall health.
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