When we talk about “the gut”, we’re actually referring to several organs inside the body. These organs play host to trillions of microbes that all function symbiotically to keep us healthy – among these are probiotics.
The gastrointestinal tract comprises the mouth, oesophagus, stomach, small intestine and large intestine, and probiotics in these organs help maintain functions such as digestion, immunity and even mental health. If you struggle with bloating, stomach issues, low mood or chronic infections, you could be dealing with a microbial imbalance and inflammation in your gut.
“Our gut microbiome has been linked to the health of pretty much every organ in our body. So gut hormone connection, gut skin connection, gut metabolism connection, all of these different connections,” explains Dr Megan Rossi, a gut health expert with a PhD in probiotics. “Technology has allowed us to understand exactly how powerful our gut microbes are […] our gut health uncovers how we can look better, feel better and live longer, happier lives,” she adds.
There’s a reason scientists refer to the gut as a second brain – a disrupted gut also has the power to affect our mood. The gut-brain axis is the direct link between your gut and your brain, so any issues with your gut flora can also affect your mental wellbeing. Gut microbiota – the hundreds of species of bacteria living in our guts – have been shown to influence our physical and mental health.
Research from one study has found that people who struggled with low mood tended to have a less diverse gut microbiome compared with other participants in the study, and that certain species of bacteria have been linked with experiencing more negative emotions.
In a separate study, researchers found that probiotic, prebiotic and synbiotic supplements (those that combine both probiotics and prebiotics) could help reduce the effects of some mental health problems such as anxiety and depression, as well as stress, sleep and even Alzheimer’s disease.
Probiotics have also been shown to have a positive influence on the intestinal microbiota, with different strains displaying different effects on the human body. In short, these bacteria are powerful, and if you’re not getting enough of them through your diet, it might be time to consider taking a supplement.
Do you need a probiotic?
Of course, a diet that’s rich in probiotic cultures is easy to follow. Yoghurt is the most popular choice for most people, but other sources of natural probiotics are fermented foods like kimchi, pickles and sauerkraut and fermented drinks such as kombucha and kefir. Sourdough bread and cottage cheese are other gut-friendly foods.
If these foods aren’t things you eat on a regular basis, you might want to consider giving your gut a little help by way of a supplement. Supplements that contain probiotic bacteria vary – some contain a range of bacterial strains, others also contain prebiotic fibre, and others offer additional nutrients like vitamin D.
“We’re at a stage now with probiotics where you can select specific probiotic products for specific purposes,” explains Sophie Medlin, consultant dietitian and director at CityDietitians and one of the UK’s leading experts in gut health. “For example, there are strains that are great for constipation, strains that are great for bloating, but also strains that are good for your mental health, immunity and for reducing inflammation,” adds Medlin.
The potential benefit of probiotics is exciting, especially with consumer products at clinical grade now readily available. Medlin recommends speaking to a registered dietician if you’re looking to take gut health supplements to manage specific conditions. You might also want to test your gut health before taking a specific type of supplement.
How I tested
I consulted expert Sophie Medlin and Dr Megan Rossi to discern what probiotics are, their role within the body, the different strains of bacteria to look out for and the doses that are most beneficial. I searched for a range of gut health supplements for various needs and tested each of them for at least a month and up to three months. I noted any changes to skin health and any stomach issues, and judged each supplement based on its compatibility with a balanced diet. I considered the following when finding the best probiotics:
- Soothing stomach issues: I assessed whether each probiotic helped with stomach issues, such as bloating and wind, cramps and stomach aches or infrequent or too frequent bowel movements.
- Skin health: I noted skin health after a month of taking each supplement, for example, whether breakouts and dryness were replaced by a glowier complexion.
- Immunity: I considered how energised or run down I felt while taking the probiotics and whether I caught colds or fell ill.
- Variety of strains: Different brands offer varying types and levels of bacteria, so I assessed each on this.
- Easy to take: I also judged each probiotic on how easy it is to take and store.
- Cost: The price and whether the product was suited to a range of budgets were also considered.
Meet the experts
Sophie Medlin is a consultant dietitian. She started her career working in hospitals where she specialised in gastrointestinal diseases. She now lectures at King’s College London and is the chair of the British Dietetic Association for London.
Dr Megan Rossi is one of the world’s leading experts on gut health and probiotics. Known as The Gut Health Doctor, she is an award-winning scientist and registered dietitian.
Why you can trust IndyBest reviews
Emilie Lavinia is The Independent’s fitness and wellbeing editor. Having reported on health and wellness for more than a decade, Emilie tests products with the help of experts like Medlin and Dr Rossi and helps the public discern between useful, quality supplements and overpriced products propped up by marketing jargon.
The best probiotics for 2025 are:
- Best overall – Nutravita 60 billion CFU pro bio cultures complex: £19.99, Amazon.co.uk
- Best budget buy – Bio-Kult everyday gut, 60 capsules: £13.95, Amazon.co.uk
- Best for women – Vida Glow gut pro: £30, Spacenk.com
- Best duo cap – Epetome: £54.99, Epetome.com
- Best multivit with a probiotic – You’re looking well day pill: £48, Ylwclub.com
