A gut feeling

1 December 2022

From fighting inflammation to boosting mental health, gut health has long been a staple part of our medical folklore. If nothing else, that’s reflected in the numbers, with probiotics wildly popular from Italy to China. But beyond the hype, how do the claims around these supplements actually hold up? And whatever their efficacy, could punters do better by taking a more holistic approach to their health? Andrea Valentino talks to Dr Alexandra Shustina, founder of Whole Gut Health, to learn more.

Humans have long understood the importance of gut health. Even in Ancient Greece, Hippocrates declared that “death sits in the bowels”, while Chinese physicians have long made similar claims. By the eve of the First World War, Élie Metchnikoff was arguing that inflammation could be linked to the gut. A Franco- Russian zoologist, Metchnikoff suggested that health could be bolstered, and old age delayed, by investing the intestinal microbiome with so-called friendly bacteria – like the type found in yoghurt. From there, Metchnikoff’s theories became a sensation across Europe. It’s no coincidence that Danone, now one of the world’s biggest dairy companies, was founded just 12 years after Metchnikoff first advanced his theories.

From those humble beginnings, the friendly bacteria, known as probiotics when packaged into supplements, have gone on to claim a hallowed place in medical folklore. If nothing else, that’s clear from the statistics. According to work by Grand View Research, the global probiotics market is already worth around $58bn and is expected to enjoy a CAGR of 7.5% until the end of this decade. That buoyancy is shadowed by the figures in particular markets: five million Americans took probiotics in 2019, a figure bound to increase in the wake of Covid-19. Past the raw numbers, indeed, probiotics are everywhere, from healthcare websites to the press, from the Guardian to Oprah.

Despite this wild popularity, however, challenges remain. Though their efficacy has sometimes been proven in scientific settings, the probiotic pills that many consumers take are on wobblier ground. That speaks to wider problems. Imagining probiotics as a kind of silver bullet, some people risk ignoring the broader life decisions that can lead to a happy gut, from diet to exercise. Not that the situation is hopeless. From stricter regulations to closer consultation with doctors, probiotic enthusiasts may yet develop a system that keeps them genuinely healthy. Given all the potential benefits of probiotics, that’s undoubtedly good news.

Listen to your gut

It’s hard to overstate the popularity of probiotics across today’s West. That’s long been true of the US, but other countries have recently begun down the same path. In 2020, to take one example, Italy witnessed an 188% increase in probiotics users. At the same time, developing countries are quickly catching up. As so often in the supplements space, China is a major area of growth, with the People’s Republic registering a 108% increase in probiotic users in May 2020 compared with the previous six months. To fill this rise in demand, meanwhile, manufacturers have rushed to adopt. China is once again a leader here, with the government recently approving three new probiotics strains as novel food ingredients.

For Dr Alexandra Shustina, all this frantic activity can be understood in a number of ways. Perhaps most obvious, she argues, are the benefits probiotics offer the body. Typically found in the lower intestine, these bacteria, which in truth also encompass a range of fungi and viruses, can produce a range of “medically studied benefits”. And as Shustina, founder of Whole Gut Health, explains, this is clear across a range of health areas. “That’s in terms of different kinds of diarrheal illnesses, whether it’s infectious diarrhoea or irritable bowel syndrome,” she says. “There’s also been some pretty decent data to show that it’s helpful in specific situations too: ulcerative colitis, which is a chronic inflammatory disease of the colon, and Crohn’s disease.”

Fermentation nation

Shustina’s focus on the bowel and intestines makes sense. Helping to restore the natural bacterial balance in the gut – which can be disrupted by poor diets and antibiotics – probiotics keep harmful germs at bay. Apart from their value below the stomach, moreover, researchers have found probiotics could be useful across a number of other health areas. From mental health conditions like anxiety to keeping heart-busting cholesterol low, probiotics have long been fated as a kind of miracle.

“The microbiome is a very complex thing. That means a probiotic is, in some ways, just a drop in the bucket compared to what the microbiome really is.”


The amount the global probiotics market is worth and is expected to enjoy a CAGR of 7.5% until the end of the decade.

Grand View Research

And, in fact, Shustina argues this fact goes a long way towards explaining their popularity. At a time where wellness is a $1.5trn industry, according to McKinsey and Company, and where consumers are empowered to understand their bodies in all their bewildering complexity, Shustina says that people want to get “the root cause of their health under control”.

Yet if probiotics can certainly do plenty of good, evidence for them as a cure-all is less convincing. In large part, this is a question of research. While scientists have shown probiotics can effectively battle a number of specific gastrointestinal illnesses, any benefits in people who are already healthy are far from clear. This is reflected in the way that probiotics are marketed. Because they’re not defined as a regulatory product by the FDA, it can sometimes be hard for consumers to understand exactly what probiotics can do or what they contain, not least when packaging doesn’t spell it out explicitly. As Shustina puts it: “The main issue with probiotics is the lack of transparency.” It doesn’t help, she adds, that many doctors promote probiotics ‘off label’, meaning for a different purpose than what they were originally intended for. That in itself isn’t unusual or dangerous, she stresses, especially when coming from experienced physicians. But in a sphere like probiotics – where the gap between a genuinely useful product and a waste of time is so vast – off-labelling can be hazardous.

Beyond the limitations of probiotics in themselves, meanwhile, Shustina highlights the challenges of getting consumers to see them holistically, as merely one spoke in a wider wheel of health. “The microbiome is a very complex thing,” she emphasises of the system where gut health happens. “That means a probiotic is, in some ways, just a drop in the bucket compared to what the microbiome really is.”

“We want to make sure that we’re taking exactly what we need, and we need to have the right education and experience to do that.”


The estimated value of the wellness industry.

McKinsey and Company

The solution, of course, is to dovetail probiotics with other measures. Perhaps the most obvious is to consume healthy bacteria through a balanced diet, notably fermented foods like sauerkraut or kimchi. Another approach is to exercise regularly. According to one study, after all, just six weeks of exercise can have an impact on the microbiome. But in a country like the US, where less than a quarter of citizens get enough exercise, all the probiotics in the world risk doing little.


It goes without saying that turning a society of couch potatoes into exercise fanatics is beyond the remit of experts like Shustina. But that hardly means she has no advice for probiotic enthusiasts. In particular, she says prospective users should carefully consult with their doctor before popping pills. “Anything you take in a pill can have a positive or negative effect,” she warns. “I’ve personally seen people who’ve had allergic reactions and adverse effects to supplements, and I think there’s a misconception that more is better. Therefore, we want to make sure that we’re taking exactly what we need, and we need to have the right education and experience to do that.”

Fortunately, there are signs that doctors are taking probiotics more seriously. In Britain, for instance, the NHS now recommends probiotics for mental health. Across the North Sea, the Swedish public health agency now advocates probiotics as a weapon in the fight against certain colon infections. And while medical professionals on the far side of the Atlantic have typically been less comfortable prescribing probiotics and other natural products, Shustina says that in the US, too, change is coming. “I’m assuming there’s going to be general growth for the US,” she says, adding that she expects medical professionals in the US to ultimately embrace the probiotics attitudes of their European colleagues.

Of course, with greater oversight from physicians comes greater regulation. In a sense, that can only be hailed as a positive, especially considering the somewhat muddled situation that’s existed up to now. But as Shustina says, tougher rules also risk dampening the red-hot global market for probiotics. Certainly, her point is reflected in pronouncements by the FDA, which in 2019 began developing a method to test the purity of probiotic products, and more recently said it was seeking to improve guidance on dietary supplements.

“How’s that going to translate?” asks Shustina rhetorically of the regulatory impact on the probiotics market. She argues it’s impossible to know. But even as questions over regulation wobble uneasily in the distance, probiotics themselves continue to soar. From supporting the development of babies to easing Parkinson’s disease in the elderly, studies into their usefulness continue to be published. And from Taiwan to Singapore, new production facilities continue to be built. If only Élie Metchnikoff could come back and see all he’d spawned.

One way to dovetail probiotics is to consume healthy bacteria through a balanced diet, notably fermented foods like sauerkraut or kimchi.
The Whole Gut Health founder says the main issue with probiotics is the lack of transparency.

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