Do Probiotics really work?

Michael MosleyGlobally, each year we spend more than $39 billion on probiotics.

But is popping pills and powders or eating yoghurt really going to help with weight control, mood and digestion, or treating your allergies?

All promise to help balance your gut health.

And just what are probiotics, anyway?

If you’ve ever been on a course of antibiotics, or been unwell for a period of time, you may have been advised to take probiotics. These, along with prebiotics, are added – and promoted – in many everyday foods, such as yoghurt or fermented dairy drinks, and other products such as kimchi and kombucha, and are also available as a tablet, capsule or powder.

Around the world, more than US$30 billion (A$39 billion) is spent on probiotics every year, even though there’s still not extensive research to support the health benefit claims. While an increasing number of studies are examining how our gut bacteria influences every aspect of our health, there is still so much we don’t know about our inner eco-system. However, research during the past few years suggests that probiotics may lower blood pressure, help children suffering from stomach bugs, boost immunity, promote mental wellbeing, aid weight loss, reduce side effects caused by antibiotics (such as diarrhoea), treat allergies, and even clear acne.

What are probiotics (and prebiotics)

“Probiotics are live organisms that have been proven by research to have a health benefit,” Accredited Practising Dietitian Charlene Grosse tells SBS. “And a prebiotic is a food substance that specifically promotes the growth of good bacteria in our bowel.”

While we’re conditioned to think of bacteria as negative or harmful, and something to banish from our body, good bacteria and other microorganisms help our bodies function properly. The microorganisms in probiotics products are the same as, or quite similar to, the microorganisms that normally live in our bodies (of which there are 100 trillion).

“Probiotics are essentially supposed to work in the opposite way to antibiotics,” says Dr Saleyha Ahsan, one of the hosts of Trust Me I’m a Doctor, which takes a look at probiotics in the show’s latest episodes (Monday nights 7.30pm on SBS and then on SBS On Demand). “Instead of killing harmful bacteria, it’s claimed they add new beneficial bacteria to the complex swamp of microbes that already live in our intestines.”

An expensive waste of money?

The question researchers, and the Food Standards Australia and New Zealand (FSANZ) has, is whether taking a supplement of probiotics, or eating a food which boasts it as an ingredient, can do our bodies any good. After all, before the bacteria in a probiotic product can change our gut for the better, ”they have to survive the perilous journey through the acid bath that is our stomach and set up home in the intestines”, Ahsan explains.

But not all probiotics are created equal, nor does everybody respond in the same way to probiotics. “While one type of probiotic, such as Lactobacillus, may help prevent ill health, another type of the same probiotic may be useless or may do more harm than good,” Victoria University’s Dr Michelle Ball tells SBS. “A generic probiotic is not suitable for everyone, because the reasons for imbalance are highly individual,” she says. “Ultimately, people need to gain understanding of their own gut health and this can be achieved by working their doctor and providing a simple stool sample.”

Ball’s research paper also found that probiotics act differently between men and women, which means it’s not as simple as taking one-size-fits-all supplement to restore your gut health.

Dr Margaret Morris, Professor and Head of Pharmacology at the School of Medical Sciences, University of New South Wales, who is currently working on the link between gut and cognitive health, agrees that more research needs to be done. Morris’ findings, which indicate that eating an unhealthy diet leads to poor gut bacteria, which can be linked to changes in cognitive ability (or function) may go a long way to exploring some of the effects of gut microbiota on the brain. “What we do know, is that if you have been eating poorly, drinking excessive levels of alcohol, or taking antibiotics, you’ll have a disruption of the balance of good and bad bacteria in your gut,” she says. “When your bacteria is in balance, your body is healthy and your immune system is strong. If it’s lacking, you’re more likely to have poor memory recall, disrupted sleep patterns, low mood and other health issues.”

Another reason to ensure your bacteria is balanced is the effect it has on your weight. “When an obese person diets, the balance of their gut organisms shift towards that of a lean person,” she says of her recent studies. “Some obese people try to redress their bacterial imbalance by consuming probiotics, but unless you know which bacteria you’re lacking, they may not do much good.”

Real food may be the best bet

“Our gut make up is determined to some extent by genes, lifestyle, history of disease and current diet,” says Dr Morris. “Based on recent laboratory research, it seems that eating prebiotic-rich and high fibre foods and cutting out sugar, saturated fats and alcohol for at least 20 consecutive weeks is, right now, a good way to properly balance your gut bacteria. It was also found that enriching the diet with flavones was effective.”

Dietitian Charlene Grosse recommends including prebiotic foods in your diet – to provide fuel for the good bacteria in your bowel – that also happen to include flavones. “These include onion, garlic, inulin, wheat, Jerusalem artichoke, chicory and bananas.” And if you want to add fermented foods to help encourage good bacteria, add, “yoghurt, kefir, kumbucha, miso soup, saukraut and tempeh,” she says.

All of these, when made using traditional methods, can be rich in helpful bacteria.

Do believe the hype: kombucha is a good thing! Healthy, delicious and beloved by some of our best chefs, kombucha is gaining ground not just as an alternative to soft drink and water – but as a sub for wine and beer, too.

In the first episode of Trust Me, I’m a Doctor season 6 (watch it below), Dr Michael Mosley and Dr Saleyha Ahsan examine whether eating taking a supplement, consuming a fermented dairy drink or eating foods high in inulin is better at encouraging a healthier gut flora, and  whether  commercially-produced or alternative probiotics are better.

Dr Saleyha Ahsan with volunteers from an experiment on probiotics.

As Mosley explains, we’re all familiar with the idea of fermentation being used to make products such as beer, but before the invention of refrigeration, it was also widely used to preserve food. Today, it’s becoming more popular again as people embrace making their own fermented foods, such as sauerkraut (fermented cabbage), kim chi (Korean fermented vegetables), kefir (a fermented dairy drink) and kombucha (fermented tea).

The experiment found that homemade fermented foods have higher levels of probiotics than commercial varieties. This is because, the  experiment concluded, some commercial varieties are subjected to pasteurisation after preparation to ensure their safety and extend their shelf life, which can kill off the bacteria, whereas that wouldn’t be the case for the homemade varieties.

“For general good gut health, and to acquire a range of helpful bacteria, fermented foods are an excellent way forward, “ Mosley concludes. “And our tests suggest you’ll find more of these helpful bacteria in traditionally made fermented foods.”

If you do want to make your own probiotics, follow a recipe (fermentation and storage times and temperatures are important), and ensure that your hands and cooking utensils are clean.

Trust Me I’m A Doctor starts Monday 27 February 7.30pm on SBS, then watch it on SBS On Demand. Watch episode one, including the team’s investigations of probiotics, whether bad sleep makes you hungrier and decaf coffee, here: