Capitalising on ‘foods with a function’ and the role of probiotics

The primary role of the diet is the supply of nutrients and energy to meet the needs of the body. In recent years, however, consumers have looked beyond the basic role of food with the expectation that it should have a greater functional purpose in health and wellbeing. Perhaps, not surprisingly, the industry has been quick to respond and in the past three decades a proliferation of foods, purporting to offer a beneficial ‘functional’ role, have come to market. 

Among the excessive number of brands striving to capitalise on the craze for ‘foods with a function’ are probiotics. The World Health Organization (WHO) defines them as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”¹, which sounds straightforward, but in reality, probiotics are quite complicated.

We view probiotics as ‘new’ but they are not. Louis Pasteur first identified the bacteria and yeasts responsible for fermentation, but it was Elie Metchnikoff in 1905 who linked the longevity among Bulgarians to the lactobacilli in the yoghurt they ate and the presence of the same lactobacilli in their colons². This light bulb moment set in motion a new area of research into the benefits of probiotic bacteria, which continues to this day.

As scientific research has progressed, we have learned more about the complexities of probiotics, not least that their benefits are genus, species, strain and dose-dependent; the benefit offered by one probiotic cannot automatically be extrapolated to another. Several of the fundamental mechanisms of probiotics are, however, thought to be shared, such as their improvement of the gut’s epithelial barrier function, their immunomodulatory effects and their degradation of toxin receptors. Competition for nutrients, production of inhibitory substances, antiproliferative effects, blocking of adhesion sites and the ability to modulate the gut’s microbiota³ are also proposed ‘shared’ benefits.

What made probiotics popular?

But why are we, the consumer, so fascinated with probiotics? In the first instance, shiny marketing campaigns taught us about the billions of ‘good’ or ‘friendly’ bacteria in our guts and how essential they were for optimum health. We were urged to take a dose with the same regularity that we brush our teeth while simultaneously being seduced with compelling stories about how they would take care of our gut. Gut health may never have been part of the consumers’ consciousness but probiotics changed that. 

All about the gut!

We have all become obsessed with our gut and the bacteria within it, and rightfully trust the big dairy brands that have been subjected to rigorous research, such as Yakult. However, it is now surprising to see probiotics popping-up in the most unlikely, and largely unproven, products.  From gummy bears to chocolate, coffee to alcoholic beverages, there are even probiotic waters that come with a billion Bacillus coagulans and promise to be ‘crazy good for the gut’! 

Hot on their heels, and somewhat piggybacking the reputation and benefits of probiotics, is a whole new category of ‘good bacteria’ filled fermented foods, including the drinks Kefir and Kombucha. Kombucha, a tea-based, slightly sour, slightly fizzy and sometimes slightly alcoholic drink, has a number of popular brands like KeVita and Kombucha Kat, but they are yet to achieve the cut-through of the more popular fermented drink, Kefir. Daylsford Organics, Biotiful Organic and The Collective all have Kefir ranges and vegan, non-GMO Rhythm Kefir Cultures promises to ‘rebalance your microflora’; they even offer a microbiome testing service, presumably to prove their bacteria survive the passage to the gut!

Proven probiotics or fashion for ferments?

The fashion for ferments may continue to flourish, but beyond the anecdotal, evidence for any benefit is lacking. Conversely, big brand probiotic dairy drinks have ‘scientifically proven’ that they are not just a flash-in-the-pan; they have scientific staying power and, thanks to the endorsement of medical experts, their role in improving our health remains strong. In further support of their cause, the benefits attributed to some probiotics also tap into health issue sweet spots, such as the global use/misuse of antibiotics, obesity and mental health; the associated research – past and present – is extremely compelling. 

The role probiotics play in reducing the incidence of antibiotic-associated diarrhoea (AAD) – a common consequence of antibiotic use – is particularly well documented and continues to underpin probiotic efficacy.

AAD in the hospital setting is particularly troublesome, but the administration of probiotics has been shown to yield positive results. In spinal patients, the administration of a commercial product (Yakult) containing Lactobacillus casei Shirota (LcS) significantly reduced the incidence of AAD compared to patients who received a placebo (17.1 vs 54.9 percent).⁴   

Tackling superbugs

Similarly, probiotics have played a valuable role in reducing the incidence of AAD caused by the superbug Clostridium difficile (CD). CD associated-diarrhoea (CDAD) is particularly virulent among hospital-based elderly patients and large outbreaks are a significant cause of morbidity and mortality. Relapse of disease is also common and it is these patients who are of interest to researchers. In one study, patients with CDAD were given either LcS and antibiotics or antibiotics alone. Results showed that the LcS group were significantly less likely (3.2 vs 20 percent) to have a recurrence of the infection than those getting antibiotics alone, results which could have a strong clinical benefit in the hospital setting.⁵   

In a similarly compelling trial, a supermarket bought product (Actimel) containing Lactobacillus casei, L bulgaricus and Streptococcus thermophilus was consumed twice daily during and for one week after a course of antibiotics; a placebo group received a long-life, sterile milkshake, of similar appearance. Only 12 percent of the probiotic group went on to develop AAD compared with 34 percent in the placebo group; nobody in the probiotic group and 17 percent in the placebo group had diarrhoea caused by CD⁶, which is exciting news in the fight against superbugs. 

These studies illustrate the strain-specific benefits of widely available probiotic drinks, in reducing the incidence of AAD and CDAD with the additional potential of decreasing morbidity, mortality and healthcare costs. A recent Cochrane review shared these conclusions; after studying 8,672 participants in 31 studies, results suggest that when probiotics are given with antibiotics, the risk of developing CDAD is reduced by 60 percent and in high-risk patients, the potential benefit is even more pronounced, with an average 70 percent reduction in risk.⁷

Probiotic possibilities beyond the gut

Probiotics might be the obvious choice for a happy gut, but they are now being positively implicated in therapeutic areas beyond the gut. The role probiotics may play in reducing the incidence or duration of some common infectious diseases – acute respiratory tract infections (RTIs) and gastrointestinal infections – has been investigated, potentially negating the need for antibiotics in the first place, which is firmly in line with global public health goals of cutting antibiotic prescribing. For instance, some research shows that probiotics reduce the risk of infants and children developing the aforementioned common acute infections and, subsequently, they are less likely to be prescribed antibiotics.⁸

Researchers in the US have explored this suggestion further by comparing probiotics vs placebo in reducing incidence and duration of RTIs, cutting the number of prescribed antibiotics and lessening the health economic burden associated with workplace absenteeism. Two large meta-analyses were carried out; the York Health Economics Consortium (YHEC) – a systematic review and meta-analysis – and a Cochrane collaboration. The analysis indicated that if the general population had taken a probiotic during 2017–2018, cost savings would have been achieved for the health care payer of $4.6 million based on the YHEC scenario and $373 million based on the Cochrane scenario, by averting 19 million and 54.5 million RTI sick days, respectively. When calculating productivity losses, total savings for society were estimated to be $784 million (based on YHEC) or $1.4 billion (based on Cochrane).⁹

Food for thought

The power of probiotics is thought to help improve health in other ways too. The recent emphasis on mental health has focused research on a potential brain-gut-microbiota axis as a new paradigm in neuroscience, but the current mechanisms are fraught with complexities and research possibilities are limited. Regardless, a cocktail of probiotics has been shown to alter brain activity (through MRI), and Bifidobacterium longum has reportedly altered the brain’s electrical activity.¹⁰ However, a convincing, positive psychobiotic benefit in humans is yet to be found. 

Overconsumption or obesity is also a major issue in western societies and probiotics are being investigated for their role in terms of causality and/or prevention. Diet is known to influence the microbiota but evidence identifying which specific microbes contribute to or predict obesity is not completely consistent across studies.¹¹

Don’t mention the P word!

Despite the wealth of positive research, some factions still question the efficacy and benefits linked to probiotics. Academics are undeterred by sceptical regulators and researchers continue to publish more and more convincing findings; even Microsoft supremo Bill Gates recently prophesised that personalised probiotics could eventually help to end global malnutrition. 

But, despite the scientific good news on probiotics, strict guidelines from the European Food Safety Authority (EFSA) have stymied probiotic consumer communications, a move that has almost certainly tarnished the reputation of probiotics and is likely to be responsible for a recent, small drop in sales. The International Probiotics Association (IPA) for Europe estimate that since the inception of the Nutrition and Health Claim Regulation (NHCR), for the period 2009-2017, the loss in sales for probiotic yoghurt and fermented milk equates to a 19.3 percent reduction in value, estimated by Euromonitor to be around £1 billion less in sales.¹² Europe has also slipped from the top of the probiotic league table and now sits in third place behind China and the US. 

Regardless of punitive regulations – whereby even the word ‘probiotic’ is banned – it is the scientific substantiation, plaudits by clinicians and the ever-present consumer demand that have all made probiotics big business. Reuters estimates the Global Probiotics Market in 2017 to be valued at $42.55 billion, a figure which is projected to reach $74.69 billion by the end of 2025.¹³ In Europe alone, despite the limiting legislation, the probiotic market is still predicted to grow to $15.62 billion by 2023 from $11.85 billion in 2018.¹⁴

Despite the regulatory radio silence and a slight dip in sales, probiotics and other fermented foods are increasing in global popularity and, while this is the case, researchers will continue to build on the body of evidence and consumers will continue to benefit from their use.    

References

1. Food and Agriculture Organization and World Health Organization Expert Consultation. Evaluation of health and nutritional properties of powder milk and live lactic acid bacteria. Córdoba, Argentina: Food and Agriculture Organization of the United Nations and World Health Organization; 2001.
2. McFarland L. From Yaks to Yogurt: The History, Development, and Current Use of Probiotics. Clinical Infectious Diseases. 2015;60(suppl 2):S85-S90.
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4. Wong S, Jamous A, O’Driscoll J, Sekhar R, Weldon M, Yau C et al. A Lactobacillus casei Shirota probiotic drink reduces antibiotic-associated diarrhoea in patients with spinal cord injuries: a randomised controlled trial. British Journal of Nutrition. 2013;111(4):672-678.
5. Lee L, Golmohamad R, Macfaul G. PTH-004 Prevention of Relapse following Clostridium Difficile Infection using Probiotics: A Retrospective Case-Control study. Gut. 2013;62(Suppl 1):A213.2-A214.
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8. King S, Tancredi D, Lenoir-Wijnkoop I, Gould K, Vann H, Connors G et al. Does probiotic consumption reduce antibiotic utilization for common acute infections? A systematic review and meta-analysis. European Journal of Public Health. 2018;29(3):494-499.
9. Lenoir-Wijnkoop I, Merenstein D, Korchagina D, Broholm C, Sanders M, Tancredi D. Probiotics Reduce Health Care Cost and Societal Impact of Flu-Like Respiratory Tract Infections in the USA: An Economic Modeling Study. Frontiers in Pharmacology. 2019;10.
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11. Sanz Y, Rastmanesh R, Agostonic C. Understanding the role of gut microbes and probiotics in obesity: How far are we?. Pharmacological Research. 2013;69(1):144-155.
12. [email protected] D. Ipa Europe – International Probiotics Association Europe [Internet]. Ipaeurope.org. Available from: http://ipaeurope.org/market.php
13. Probiotics Market 2019 Global Share, Growth, Size, Opportunities, Trends, Regional Overview, Leading Company Analysis, And Key Country Forecast to 2025 – Reuters [Internet]. Reuters.com. Available from: https://www.reuters.com/brandfeatures/venture-capital/article?id=124703
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