Here's a wonderful, if faintly disturbing, fact: your guts are home to a parallel world, a tiny, bustling population of more than 100 trillion individual bugs, each invisible to the naked eye, but together accounting for about 3 per cent of your entire body weight.
Welcome to your personal “microbiota”, an internal United Nations of more than 1,000 species of bacteria, working together in perfect harmony to keep the peace in your insides.
That complex, still poorly understood balance is vital for good "gut health" – an efficient digestive process unimpaired by infection or disease. Disrupt that balance, by introducing alien bacteria or inadvertently bumping off some of your "friendly" bugs, and the results can be swift and unpleasant. One unintended consequence of taking broad-spectrum antibiotics, for example, can be the destruction of "good" as well as "bad" micro-organisms, which can quickly trigger a debilitating bout of diarrhoea.
Poor gut health, says Maria Abi Hanna, a clinical dietitian at the Right Bite nutrition centre in Dubai, can also manifest itself in bloating, mental-health issues such as anxiety and depression, a weakened immune system, weight problems, type 2 diabetes and skin complaints, such as acne and eczema.
The good news is that there is increasing evidence that we can strengthen the defences of our microbiota, and even combat existing conditions, by introducing reinforcements – live micro-organisms in the form of “probiotic” foods and supplements.
Faced with a rising tide of products being marketed with increasingly ambitious claims, in 2000, the Food and Agriculture Organisation of the United Nations and the World Health Organisation settled on a definition of probiotics as “live micro-organisms which when administered in adequate amounts confer a health benefit on the host”.
It’s a definition that survives to this day, but buyer beware – not all probiotics are equal. There are many different strains of micro-organisms marketed as probiotics and, while some doubtless confer specific or even general benefits, not all product claims are backed by reliable evidence.
In Europe, for example, even the use of the term “probiotic” is banned on products by the European Food Safety Agency because, it says, it implies a positive health benefit where, in the view of the agency, none has been proven. So in the US and here in the UAE, where Japanese company Yakult opened its first office in March, supplying supermarkets across the GCC, its product is marketed as “a probiotic drink, that when consumed daily may help balance your digestive system and maintain overall health". In the UK and the rest of Europe, however, it’s merely "a fermented milk drink full of bacteria that are scientifically proven to reach the gut alive”.
In the past decade not one of hundreds of health claims by a range of manufacturers has been approved in Europe.
Regardless, there is some evidence that taking probiotics can play a part in controlling or even preventing a range of conditions, says Maria Abi Hanna: “There seems to be good evidence that probiotic supplements may be a convenient way of managing gut health, especially when it comes to treating irritable bowel syndrome, acne and eczema."
But increasingly probiotics are being proposed as the solution to a broader and more complex range of medical conditions. So far this year alone published research has suggested a role in conditions including high cholesterol, diabetes, obesity, autism, Attention-Deficit Hypersensitivity Disorder and neurodegenerative diseases, such as Parkinson's and Alzheimer’s. In June research published in the Journal of the American College of Nutrition even suggested that a multi-species probiotic supplement could prevent osteoporosis – a chronic progressive bone disease – in menopausal women.
A study published in the journal Gastroenterology in May suggested that, in addition to improving physical symptoms, the probiotic Bifidobacterium longum NCC3001 can also alter brain activity and reduce depression in patients suffering from irritable bowel syndrome. This was, however, only a small study, involving only 44 people, half of whom were taking the probiotic while the rest were given a placebo, or dummy drug. In fact, many trials resulting in big claims for probiotics are similarly under-powered – too small to draw incontrovertible conclusion.
In 2015 scientists working for The Cochrane Collaboration, an international organisation devoted to the promotion of high-quality evidence-based medical treatments, set out to discover if there was any real evidence backing claims that regular use of probiotics prevented acute upper respiratory tract infections, such as the common cold and sore throats. After reviewing 13 random-controlled trials, involving 3,720 participants, they concluded they showed that probiotics were almost 50% better at preventing infections than a placebo.
That made headlines, but there was an under-reported caveat: more and better trials were needed to confirm the finding, said Cochrane, because of “the quality of the evidence ... low or very low mainly due to poorly conducted trials” or the small numbers taking part.
Regardless of the more exotic and as yet unproven claims for probiotics, at the very least they can be trusted as “a means to help with gut health”, says Mary Ellen Sanders, executive science officer of the US-based International Scientific Association for Probiotics and Prebiotics. “If a person is experiencing minor digestive symptoms, many probiotics might be able to help.”
On the other hand, if you don't have any symptoms or compelling reason to use probiotics, such as to avoid the unpleasant side-effects of antibiotics, “then it is harder to determine how important a daily probiotic might be”, she says. In fact, research proving that healthy people get fewer digestive symptoms when taking probiotics has not been done. Such studies, says Sanders, “would be hard to do, as it’s really tough to design a study to show that healthy people stay healthy”.
But if you do decide to take probiotics, which one to choose? Suck it and see, says Sanders. “People can give a probiotic a try for a month and decide for themselves if it is working.” In reality, identifying the right probiotic for you almost calls for a degree in biochemistry.
Many strains of nine genera of bacteria – Lactobacillus and Bifidobacterium are two of the most common – are associated with probiotic health benefit. In April, however, a working group set up by the European Society for Paediatric Gastroenterology, Hepatology and Nutrition called for “improved quality control” in the production of probiotic products, increasing numbers of which, it said, were flooding the market. Regardless of whether or not the microorganisms truly offer the benefits claimed for them, to stand any chance of working they first “have to be present in a sufficient number by the end of the shelf-life, [be able] to pass through the gastrointestinal tract, resisting acid and bile, to colonise the gut and retain functional properties required to obtain the suggested beneficial effect”.
Unfortunately, concluded the society’s review of available evidence, studies around the world had shown that “inconsistencies and deviations from the information provided on the product label are surprisingly common”. Probiotic strains were “frequently … misidentified and misclassified, products are occasionally contaminated, strains are not viable, the labeled number of colonies cannot be verified, or the functional properties are diminished to the extent that preclude the proposed health benefit”.
That, says GP Dr Shefali Verma, medical director of the Institute for Biophysical Medicine in Dubai, is why it is important not to self-medicate but to “always work with someone who has experience in using probiotics. Not all supplements are the same and won't have the same therapeutic outcome.” In her practice she recommends “only a handful of probiotic supplements, ones I have had good results with and have a good track record”, and only for specific conditions – she is loathe to recommend the use of probiotics as a general preventive supplement.
“Too much of a good thing doesn't always have positive benefits,” she says. “Knowing why you are taking something is crucial and it shouldn't just become a habit.”
Popping an expensive probiotic pill should rarely be necessary, insists Amita Attlee, assistant professor in the Department of Clinical Nutrition and Dietetics at Sharjah university’s College of Health Sciences, who warns against “getting entangled in the trap of ‘quick-fixes’”. Instead, we should “invest in gaining correct scientific and nutrition information” and make sure our diet includes naturally occurring probiotics and “prebiotics” – natural food components that promote the growth of “good” bacteria.
Common sources of prebiotics include bananas, onions, garlic, leeks, asparagus, artichokes, soybeans and whole-wheat foods. Probiotics can be found in fermented dairy foods including yogurt, kefir products and aged cheeses which contain live cultures and some non-dairy foods, including kimchi, sauerkraut, miso and tempeh.
“There is still a controversy in terms of the efficacy and potential side-effects of probiotic supplements,” says Attlee. “Therefore, considering the health benefits and available sources in natural foods, it is best to encourage the consumption of prebiotics and probiotics through our daily diets rather than wasting money on supplements.”
Those 100 trillion tiny passengers you're carrying around inside you will only thank you for it.