Taking probiotics? Experts say they won't work unless you do this

If you have high cholesterol you wouldn’t try to treat it with a blood thinner. Someone living with Crohn’s disease wouldn’t assume their symptoms could be managed with statins, but when it comes to supplements, knowing what to choose from the health store’s shelves can be less clear cut.

This is particularly true of probiotics. Most of us know that taking them can bring benefits. If you've had a stomach upset, taken antibiotics or want to improve your digestive health, they can help to repopulate and rebalance good bacteria in the gut. Most of us will admit we are unsure what the difference really is between one lengthily-named strain and the next, tending to choose products from brands friends have recommended, or that have the jazziest ad campaigns. But according to research published in the journal Frontiers, when it comes to picking probiotics we should be choosing strains based on the exact condition you are trying to treat.

“I always tell people to treat probiotics as they would other medications,” says registered dietitian Megan Hilbert, who specialises in gut health nutrition. “You wouldn’t expect someone to take heart medication if they were experiencing back pain. Research suggests that general probiotic use isn’t always helpful and that taking specific strains for specific conditions can be more effective.”

So, how do you know which strains are most beneficial? Here’s our expert guide to the best probiotic strains to invest in.

GUT HEALTH: “A balanced microbiome in the gut helps to break down food and aids in the absorption of nutrients and production of postbiotics, including nutrients such as vitamins B and K that have a positive impact on our health,” says Megan.

“Beneficial gut bacteria also produce short-chain fatty acids (SCFAs), which have anti-inflammatory properties. Imbalances in the microbiome can lead to many common gut and digestive issues such as bloating, acid reflux and irregular bowel movements.”

To maintain a healthy gut Lactobacillus and bifidobacterium strains have been shown to help improve gut health. Probiotic foods such as live yogurt, sauerkraut, kefir, kimchi, tempeh and kombucha contain these strains while prebiotic foods, such as oats, garlic, bananas and onions, help feed these healthy microbes.

Try: Healthspan Triple Action Biotic  (£24.99 for 60)

Irritable Bowel Syndrome (IBS) This affects around 12 million people in the UK. Symptoms may include stomach cramps, bloating, diarrhoea and constipation. “Research shows that people who have imbalances in gut bacteria (dysbiosis) are more prone to get IBS,” says Megan. “Latest evidence shows that treating dysbiosis with nutritional therapy and probiotics can be helpful in treating symptoms.”

The report, published in Gastroenterology and Endoscopy in January showed that bacillus coagulans (BC) was effective in reducing the severity of IBS symptoms and abdominal pain. Another, published in Current Microbiology in 2020, found that S. boulardi CNCMI – 745 can help reduce symptoms of IBS, while lactobacillus plantarum 299v ­normalises the stool and alleviates abdominal pain. S. boulardi can also reduce the incidence of traveller’s diarrhoea.

Try: Thorn Bacillus Coagulans (£22.19 for 60) or Optibac Travel Abroad (£14.99 for 20)

Bloating: “Dysbiosis can lead to slower transit time and excess bloating, due to increased fermentation in the gut,” says  Megan. “Studies have shown that ­ bifidobacterium animalis ssp lactis, lactobacillus rhamnosus, and­ saccharomyces boulardii may help.”

Try: Optibac Saccharomyces Boulardii (£8.99 for 16)

PSYCHOBIOTICS AND MENTAL HEALTH: Psychobiotics describes the use of probiotics to benefit and improve mental health. “The gut and brain are in direct contact with each other via the enteric nervous system,” says Megan. “By improving the gut ­microbiome,  this can help to reduce inflammation, including­ neuroinflammation, which may cause cognitive and mood disorders.”

In a meta-analysis published in Microorganisms this February, it was shown that specific strains of probiotics can reduce depressive symptoms and anxiety. The research suggests that probiotics could provide a non-drug based approach in the treatment of mood disorders.

In another study, reported in the journal Nutrients, the strain lactobacillus plantarum PS128 was shown to reduce anxiety, depressive symptoms and fatigue and led to better sleep. Meanwhile, a study on stressed students in the International Journal of Microbiology showed that lactobacillus plantarum 299v reduced the stress and anxiety by inhibiting lowering ­cortisol  levels.

Other beneficial strains for stress and anxiety include: bifidobacterium longum, lactobacillus acidophilus, lactobacillus casei shirota.

Try: VSL#3 Concentrated Probiotic (£55.99 for 30 sachets)

SKIN HEALTH: “Skin problems are often related to gut and digestive issues,” says Megan. “Poor gut health also affects hormones, which can lead to skin problems. By improving the balance of gut bacteria, this will lead to healthier skin.”

To improve skin health, choose probiotics that contain lactobacillus rhamnosus GG, which helps to reduce inflammation and has also been shown to be beneficial in managing eczema and atopic dermatitis. Meanwhile, lactobacillus casei supports the skin barrier and helps to reduce the risk of infection and inflammation. It’s beneficial for dry and acne-prone skin.

Finally, bifidobacterium breve supports skin hydration. Studies show this strain can also help reduce the severity of atopic dermatitis and improve skin texture.

Try: Symprove Daily Essential Supplement (£49.99 for one month’s supply)

ORAL HEALTH: Several probiotic strains are beneficial for oral health. In a 2023 meta-analysis in the journal Frontiers, it was shown probiotics can significantly reduce abnormalities such as tooth decay, oral cavity fungus, infection, and swelling of the gums and palate.

“Certain probiotic strains can inhibit the growth of cariogenic bacteria, such as streptococcus mutans, which is a primary contributor to tooth decay,” says dentist Dr Jasmine Piran. “So, using products that contain specific strains can be effective in promoting oral health and preventing various oral health issues. But do ask your dentist for advice.”

So far, there are 10 key strains to look for with each one doing a specific job. To reduce tooth decay, try lactobacillus reuteri. This reduces levels of streptococcus mutans, which can cause dental cavities. This strain is also beneficial in helping to manage gingivitis and periodontitis by reducing inflammation and harmful bacteria.

Lactobacillus rhamnosus inhibits the growth of pathogens associated with tooth decay and periodontal disease, and bifidobacterium lactis supports gum health by reducing inflammation and pathogenic bacteria.

For fresh breath, look for lactobacillus salivarius and streptococcus salivarius strains. These can reduce bad breath (halitosis) by decreasing the levels of odour-causing bacteria. Bifidobacterium bifidum, lactobacillus johnsonii, lactobacillus crispatus, and lactobacillus jensenii all produce hydrogen peroxide. This has antibacterial effects, kills pathogenic bacteria and helps to break down plaque, which causes gum inflammation leading to gum disease.

Streptococcus oralis and uberis (which occur naturally in the mouth) help to maintain a healthy balance of oral flora.

Try: ProDentim Advanced Oral Probiotics (£24.99 for 60)

IMMUNE BOOSTING: Some 70 per cent of your immunity lies within the digestive tract. So by maintaining a healthy microbiome this leads to improved immunity and helps to protect against infection.

To boost immune health, choose probiotics that contain: lactobacillus rhamnosus GG. “Research shows that this strain can enhance the body’s immune response by increasing the activity of natural killer cells and T lymphocytes, which are critical components of the immune system,” says Immunologist Dr Jenna Macciochi. “Studies also demonstrate that lactobacillus rhamnosus GG can reduce the duration and severity of respiratory infections.”

Bifidobacterium infantis 35624 has been shown to help regulate the immune system, making it less likely to overreact to harmless substances and this can help to reduce the occurrence of allergies. “Research suggests that  lactobacillus  reuteri can help mitigate the symptoms of autoimmune diseases like rheumatoid arthritis by modulating the gut microbiota and reducing systemic inflammation.”

Try: The Naked Pharmacy’s Gut Love (£37)

GYNAECOLOGICAL HEALTH: Urinary tract infections (UTIs), which include cystitis, are caused by bad bacteria getting into the urinary tract and causing an infection. “The most common bacteria causing UTIs is E. coli,” says Consultant Gynaecologist, Dr Jo Bailey. E.coli generally travels from the gut via the rectum, which is close to the urethra.

You’re more likely to get a UTI if you’re sexually active. “Also, during menopause, the decrease in oestrogen can cause the lining of the urethra and bladder to become thinner and produce less lubrication. This may lead to changes in the microbiome, so it becomes more susceptible to bad bacteria.

“Certain probiotic strains can inhibit the growth of bad bacteria commonly leading to UTIs.”

To improve urinary and vaginal health, choose probiotics that contain lactobacillus crispatus, lactobacillus gasseri, lactobacillus jensenii and lactobacillus rhamnosus. Research shows the vaginal microbiome only needs three or four of these essential lactobacillus species to keep it healthy. These bacterial strains help maintain an ideal vaginal acidic pH and a range of antimicrobial compounds. which protect the vagina from infection. 

Try: VJJ Ultimate UT (£26 for one month’s supply)