Beyond the marketing promises made by supplement manufacturers and kombucha enthusiasts, what does the science say?
At the beginning of October of 2001, about a month after the 9/11 attacks on the Twin Towers, 11 experts from ten countries gathered at the Amerian Cordoba Park Hotel, a four-star establishment in Argentina, primarily targeted at business travellers. The experts represented the Food and Agriculture Organisation of the United Nations and World Health Organisation. The goal of this meeting, which took place over four days, was to evaluate “the scientific evidence available on the properties, functionality, benefits, safety, and nutritional features of probiotic foods”.
At the time, probiotics were starting to become a part of the popular conversation on nutrition, especially with regard to adding them to milk products for children and high-risk populations; there was “no international consensus on the methodology to assess the efficacy and the safety of these products”, according to a report from the meeting. A year earlier, in New York, another group of scientists had met to discuss fermented foods and health, and from that meeting, a multidisciplinary scientific organisation dedicated to advancing the field of probiotics and prebiotics was proposed. That group would eventually form the non-profit International Scientific Association for Probiotics and Prebiotics in 2002.
Back to that hotel in Argentina: out of that meeting, a working group was established to evaluate probiotics and test the health claims. Seven months later in 2002, that group would meet in London and Ontario to set the guidelines, eventually settling on the definition of probiotics as “live microorganisms which when administered in adequate amounts confer a health benefit on the host”.
To this day, bar minor grammatical variations, that remains the accepted definition of probiotics, which are part of the human microbiome – a diverse community of trillions of organisms including bacteria, fungi, viruses and protozoa – working together to maintain a healthy balance in our system. Various strains of probiotics in particular are mostly found in the gut, but they can also be found in the mouth, the vagina, lungs, skin, and the urinary tract. They are the good bacteria that among other things, balance out the bad bacteria, support the immune system, and control inflammation.
Besides naturally occurring in the human body, these strains, often with different functions, can be found in some fermented food and drinks. The rise in their popularity has also seen them bottled and sold as tablets, promising numerous health benefits. However, as published by the US’s National Institutes of Health’s (NIH) office of dietary supplements, “Expert bodies of health professionals make no recommendations for or against probiotic use by healthy people”. It is also worth noting that the definition of probiotics among professionals such as gastroenterologists, specifically states that probiotics need to be “administered in adequate amounts [to] confer a health benefit on the host.”
Regardless of the scientifically untested promises of supplement manufacturers and kombucha enthusiasts, what that adequate amount might be for different health benefits is also not a standard amount, nor is it even a standard probiotic strain, as revealed by the large body of research into probiotics benefits for health.
For example, the NIH’s paper, based on analysis of numerous research papers on probiotics and gastroenterology, states that while many fermented foods are rich sources of live and potentially beneficial microbes, some fermented products (such as sourdough bread and commercial pickles) are processed after fermentation so they do not contain live cultures. Live microorganisms in “live” fermented foods, including yogurt, typically survive in the product throughout its shelf life but they usually do not survive transit through the stomach and “might not resist degradation in the small intestine by hydrolytic enzymes and bile salts and, therefore, might not reach the distal gut”. That is to say, there is no guarantee of benefit to the health of the consumer.
As far as definitions of what kind of live organisms can be regarded as probiotics, they also acknowledged that “evidence supports the beneficial relationship between some foods containing live microbes, especially fermented dairy products, and reduced risk of certain diseases”.
The paper further states other foods that are often used as examples of probiotics, have yet to be proven to contain the right kind of organisms to qualify as probiotics: “Fermented foods that contain live cultures but do not typically contain proven probiotic microorganisms include many cheeses, kimchi, kombucha, sauerkraut, miso, pickles, and raw unfiltered apple cider vinegar made from fermented apple sugars. Certain unfermented foods, such as milks, juices, smoothies, cereals, nutrition bars, and infant and toddler formulas, have added microorganisms. Whether these foods are truly probiotics depends on the microorganism levels they contain when they are eaten, whether they survive intestinal transit, and whether their specific species and strains have health effects.” To be clear, although some of the live cultures and microorganisms found in some of the foods may not strictly qualify as probiotics, they are still potentially beneficial to human health.
Then there’s the supplement industry. With the current research into probiotics still very much an ongoing field, and as stated above, experts make no recommendation for or against, however, they repeatedly advise consulting a health professional before embarking on a probiotic supplement. As stated by the probiotic and prebiotic association’s consumer video, How to Choose a Probiotic, “Not all probiotics are the same, they contain different strains which may be backed by different levels of evidence for health benefits, they can provide different doses, and they come in different types of products.” Hence they recommend that when choosing a probiotic type, it’s most important to choose one backed by evidence of the health benefits you want.
Should you take probiotic supplements, there are few things to consider when looking at the label on the bottle. Some supplements will highlight the number of different strains they contain, and while it may be tempting to assume that the higher the variety of strains, the better the product, that is not necessarily so, as it is possible none of those may affect the condition you are trying to address. This is yet another reason the association and the NIH recommend choosing supplements under the guidance of a health professional, as they would be better informed about the right strain for specific conditions.
The number of probiotics in supplements are measured in CFUs, which stands for colony forming units, which can sound impressive especially as they typically number in the billions. However, as the NIH’s fact sheet on probiotics reminds, the “higher CFU counts do not necessarily improve the product’s health effects. Current labelling regulations only require manufacturers to list the total weight of the microorganisms on probiotic products’ ‘supplement facts’ labels; this cellular mass can consist of both live and dead microorganisms and, therefore, has no relationship with the number of viable microorganisms in the product… Because probiotics must be consumed alive to have health benefits and they can die during their shelf life, users should look for products labelled with the number of CFU at the end of the product’s shelf life, not at the time of manufacture”.
With the jury still out about the most potentially beneficial way of incorporating probiotics into your diet through either food or supplements, there is still a lot of ongoing research into the medical use of probiotics to target specific conditions. The NIH’s paper looks at six conditions for which a significant body of research was conducted, namely atopic dermatitis (which is the most common form of eczema), paediatric acute infectious diarrhoea, antibiotic-associated diarrhoea, irritable bowel syndrome (IBS), high cholesterol, and obesity.
Starting with the eczema, the available research seems to yield mixed results, with some showing that a specific probiotic strain can reduce severe eczema in toddlers and can have protective effects in children aged one to 18, leading the NIH scientists to conclude that “the effects of probiotics vary by the strain used, the timing of administration, and the patient’s age, so it is difficult to make recommendations”. The results for probiotic effects on diarrhoea are similarly mixed, and dependent on age, dosage, and strain.
As for IBS: the results were much more promising, showing a wide variety of strains helped relieve flatulence and pain symptoms associated with the condition. The effects of probiotic supplementation in obesity are similarly promising. In their review of 14 clinical trials, the scientists found that “probiotics [mostly Lactobacillus administered at various doses for three weeks to six months] significantly decreased body weight and/or body fat in nine trials”.
While the research into probiotics as medicine is still ongoing, there is no doubt about the importance of probiotics in helping to maintain a healthy system as part of one’s diet. On 23 October 2013, some 12 years after association was first formed, it convened a panel of experts to “re-examine the concept of probiotics”. Participants included members of the original expert panel, members of the working group and other internationally recognised experts.
Reviewing data, the panel came to a few conclusions, later published in a paper in 2014. Among those conclusions, they acknowledged the various health benefits of probiotics as found in foods, and voiced their support for the position that “the general benefit of supporting a healthy gut microbiota [is] a core benefit of probiotics”, adding that, “the general benefit of probiotics on gut microbiota derives from creating a more favourable gut environment, through mechanisms shared by most probiotics. The panel further considered two common general benefits often associated with probiotics: supporting a healthy digestive tract and a healthy immune system. The panel concluded that the general benefit of supporting a healthy digestive tract was reinforced by evidence gathered on a large number of different probiotic strains representing commonly studied species”.
As far as definitions of what kind of live organisms can be regarded as probiotics, they also acknowledged that “evidence supports the beneficial relationship between some foods containing live microbes, especially fermented dairy products, and reduced risk of certain diseases”. However, “in the panel’s judgement, it is not always possible to clearly distinguish the contribution of the live microbes from that of the food matrix in such studies. Furthermore, potentially beneficial microbes might often represent a diverse community that is not well-defined in terms of strain composition and stability. As a result, the live microbes in such foods fall short of the criteria needed to be considered ‘probiotics’.”
With that in mind, as often seen on yoghurt on supermarket shelves, “It was recommended that such foods are best described as ‘containing live and active cultures’, but should not be called probiotic.”
Be they live organisms, active cultures or prebiotics, for many of us not in the field of gastroenterology, the jargon might not mean much, and our ignorance might make us more vulnerable to unscrupulous marketing promises. To that end, some experts such as pioneering nutritional psychiatrist Dr Uma Naidoo, recently interviewed by Maverick Life, encourage a more common sense approach to achieving a healthy gut.
“We don’t just eat one ingredient, right? We usually eat several things on a plate of food. And each of those foods contain multiple ingredients and nutrients. Nutritional psychiatry informs us on how to eat them together for better mental health, versus just taking one supplement or a probiotic or an Omega-3 tablet,” says Dr Naidoo.
Although her practice, nutritional psychiatry, largely focuses on the relationship between the gut and mental health, she is adamant that as a foundation for one’s diet, prior to treatment and dietary amendments to address specific issues, we need to eat a varied diet of whole foods, that also incorporates fermented foods, “The gut microbiome basically contains about 39 trillion or more microbes of different kinds that live there to help take care of us. But we have to take care of those microbes to help our health, mental and physical. These microbes need to be fed good foods, and good foods are usually the healthy foods that we know. Eat lots of colourful vegetables and fruits. ‘Eat whole and be whole’, is the expression I like to use. By taking care of those gut microbes, you are taking care of your physical and mental health.” ML/DM