There’s ‘no real proof’ that probiotics in pills and yoghurt drinks can ease irritable bowel syndrome, says study

Probiotics are unlikely to relieve gut problems such as bloating and other digestive complaints, according to a comprehensive review of the evidence.

The supplements—often described as “good” or “friendly” bacteria—contain live microorganisms that come in pill form or yogurt drinks, and have received strong medical backing that they improve digestion.

Both the NHS and the British Society of Gastroenterology recommend probiotics to patients suffering from irritable bowel syndrome (IBS), a condition that can cause stomach cramps, bloating, diarrhea and constipation. Still, an analysis of 82 previous studies, involving more than 10,000 volunteers, found no good evidence that taking it provides relief.

“People with IBS are often willing to spend their own money on treatments that might work,” says Professor Alexander Ford, gastroenterologist consultant at the Leeds Teaching Hospitals NHS Trust and co-author of the new study. “Because they are looking for a cure, they may be misled that probiotics are a panacea, when they are not.”

With the supplements available in most supermarkets, the UK probiotic market is now worth around £1.4 billion a year and is set to grow by a fifth over the next five years, according to market research firm Mordor Intelligence.

Proponents say taking the supplements supports the immune system, aids weight loss and prevents infections, and previous studies have shown that taking some strains of probiotics can improve symptoms of IBS, which affects around 13 million Britons.

Probiotics contain live microorganisms that are said to improve the balance of bacteria in the gut, which play a critical role in nutrient absorption. The microorganisms also occur naturally in fermented foods such as yoghurt, sourdough bread and sauerkraut.

Having a wide variety of healthy bacteria in the gut has been associated with a host of benefits. Research has shown that some combinations of gut bacteria can send strong signals of fullness to the brain — reducing hunger pangs — and can also increase mood-boosting hormones.

Presumed improvements in IBS symptoms would be due to a number of factors. Animal studies have shown that an increase in some gut bacteria can reduce the pain signals sent from the gut to the brain, and have also suggested that probiotics may prevent the immune system from releasing proteins that cause intestinal inflammation.

However, the new review — the first of its kind, published in the journal Gastroenterology — casts doubt on these links.

Researchers conducted a mix of international studies testing a total of 60 products – potions and pills – some of which are available in stores. They also analyzed studies with unbranded capsules of strains of bacteria commonly used in probiotics, such as Lactobacillus and Bifidobacterium.

Gastroenterologists at the Leeds Gastroenterology Institute at St. James’s University Hospital dug into specific IBS symptoms, such as pain, bloating, constipation and diarrhea, and found that the evidence for relief was unreliable.

“Most products are tested on too few participants, leaving room for error,” says Prof. Ford.

‘Probiotics are often classified as dietary supplements and are therefore not subject to the rigorous testing that is the case with medicines. Because these products are already on the market and generate money, there is no incentive to carry out high-quality tests, which would be expensive.’

Dietitian Dr Duane Mellor said: ‘In IBS, simple changes such as eating more slowly and sitting up straight, and managing stress are more likely to relieve symptoms than probiotics – and they’re free.’

But Professor Glenn Gibson, a food microbiology researcher at the University of Reading, is more optimistic. “There are good studies showing that Bifidobacterium (found in many UK products) can relieve IBS symptoms,” he says. “Gastroenterologists are used to seeing great benefits from drugs, so their expectations may be too high.”

Catherine Harland, from Newcastle, has suffered from IBS since her early twenties. “I’ve had accidents in malls because I couldn’t get to the bathroom in time,” says the 53-year-old. “I don’t have any underlying issues, so I’ve had to do my own research into what might help.”

In 2021, her daughter recommended trying probiotics after reading about the benefits online. But after taking them for a month, Catherine saw no difference.

After a serious flare-up in April last year, she tried probiotics again and spent £65 on a month’s supply.

“I saw a slight improvement, but I think it’s because I cut trigger foods from my diet,” says Catherine.

By February, her intestinal problems had returned with a vengeance. “I ran to the bathroom about five times a day,” she says. “I realized that the probiotics were literally just wasted money.”

Over the past six months, Catherine has changed her daily routine, which has provided some relief.

‘I’ve tried to de-stress with lots of country walks. I eat healthier and I stopped drinking alcohol like a fish on weekends,” she says.

“It’s not exactly where I want to be, but it seems a lot better.”