We know that they’re good for our gut health, but working out which probiotic strains do what and whether you need a supplement can be confusing. Know your lactobacillus from your bifidobacterium with this handy guide…

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We’ve got startling news for you: you’re only 43 per cent human. That’s because, as Professor Rob Knight of the University of California San Diego told the  BBC , human cells aside, the rest of you is made up of microbes, residing in your gut and known collectively as your microbiome. Far from being malicious gatecrashers, these microbes can boost everything from mental health  to digestion , but, as in all walks of life, the greater diversity, the better. Hence why hunter-gatherer diets such as  the Hadza diet  are thought to be so key for fostering healthy gut flora: a varied, seasonal style of eating  and high intake of fibre-rich foods  are just a few of the reasons that communities such as the Hadza tribe posses an abundance of gut bacteria compared to the average Westerner, which it’s thought contributes to their low rates of disease.

If hunter-gatherer style eating habits are proving hard to replicate in a trolley dash through Tesco, what can you actually do to encourage your gut microbes to blossom? Probiotics  are one of the quickest routes to starting a friendly bacteria party, but working out how to get them, which ones to go for and whether you really need to shell out on a supplement are just some of the probiotic perplexities we face. Also, the names of different strains are normally quite a mouthful before you even work out what they do. As such, here’s your main strain A-Z, as explained by Registered Nutritionist Daniel O'Shaughnessy .

The Lactobacillus family

Lactobacillus is the largest and most diverse group among the lactic acid-producing bacteria, and they’re naturally abundant in both plant and animal environments- you’ll find them in yogurt and cheese, for example. They’re also commonly used as part of the fermentation process in cider, wine, sauerkraut , pickles and other fermented foods (also, some kinds of chocolate). Let’s break down the strains:

Lactobacillus acidophilus: This is known to improve bowel function in particular- it’s been linked to improvements in cases of diarrhoea, constipation, ulcerative colitis and lactose intolerance. That one might seem odd, but the lactic acid bacteria helps to break down the lactose, which is one reason why lactic acid bacteria-rich kefir is well tolerated by those with lactose intolerances. L.acidophilus is also associated with enhanced immunity and thought to improve the prevention and prognosis of type 2 diabetes , but more research is required in this area.

Lactobacillus casei: This is the big hitter if you’ve got a case of diarrhoea, plus it’s thought to support healthy digestion in general. Nutritional therapist Kerry Beeson  highlights that it’s particularly effective for reducing bloating .

Lactobacillus plantarum: This probiotic is known to soothe symptoms of  IBS  and IBD, and it also aids iron absorption , which is particularly crucial for women of childbearing age.

Lactobacillus rhamnosus: Doses of this are associated with better health across the board during and after a course of antibiotics, with evidence showing that the bacteria can help in the prevention of diarrhoea during and post antibiotics in particular. It’s thought that lactobacillus rhamnosus can help to kill off harmful bacteria such as C.difficile , preventing it from colonising and causing potentially life-threatening illnesses. This one’s also performed well in trials investigating the positive impact of probiotics on allergies  and eczema .

Lactobacillus reuteri: This probiotic can be helpful in the treatment of infants with colic , and it’s known to relieve digestive disorders in infants too.

The Bifidobacterium family

Bifidobacterium are the most common group of bacteria found in the intestines of healthy infants. Otherwise bifidobacterium are found mainly in animals and humans.

Bifidobacterium infantis: This is unique to breast milk and it’ suggested that it’s beneficial for babies to help their microbiome. In studies it tends to be lower in bottle-fed infants, which is possibly why bottle-fed children occasionally have a high number of allergies. It can also help to reduce inflammation in the gut.

Bifidobacterium lactis: Kerry comments that this one is linked to a reduction in incidences of constipation, while Daniel reports that it can be helpful in the metabolisation of gluten, and reducing the immune response in cases of gluten sensitivity. Probiotics aren’t medicine, however, so don’t go chowing down on the bread rolls if you’re coeliac on account of this particular bacteria.

The Saccharomyces

The probiotic species known as saccharomyces boulardii are derived from yeast and fungi and help to suppress pathogenic (harmful) bacteria, while cultivating the good guys. If you’ve had a  parasitic infection , this probiotic could help to reduce symptoms such as fever and abdominal pain, and they’re also another SOS diarrhoea aid. Pilot studies  also indicate positive results where the remission of Crohn's disease and IBS is concerned.

The supplement shopping list

It’s best to play pick and mix with your probiotics according to Daniel:

“If you are using a probiotic then look for one with the mentioned strains above. A good generic probiotic will have a multiple strain count and usually have around 5 billion ‘colony forming units’- this should be stated on the label.”

Our microbiome is as unique as our fingerprint- everything from our environment to our diet and upbringing affects our individual blend of gut flora, and as such Kerry indicates that there’s no “one probiotic fits all” solution or supplement:

“Price is always a consideration, but I would say that using well-researched probiotics is better value, as you know that these strains are going to reach the gut alive. It’s also important to use products that guarantee that the number of billions on the pack will still be present at the date of expiry.”

Kerry rates Optibac Probiotics , while nutritional therapist Eve Kalinik  favours  Symprove , a water-based probiotic that’s been clinically proven to survive the acidic environment of the stomach, keeping bacteria active and helping them to multiply in the intestine. Independent clinical trials look promising too: studies conducted by scientists at King’s College London concluded that taking Symprove for four weeks resulted in a reduction in constipation and diarrhoea in IBS sufferers. Another independent King’s College study showed a 76 per cent decrease in intestinal inflammation among ulcerative colitis patients after taking Symprove, while an independent 2016 study found that Symprove significantly reduced the frequency of constipation, diarrhoea and back pain in those suffering with diverticular disease. All in all, Symprove’s live and active blend of bacteria strains (which major on L. acidophilus, L. plantarum and L rhamnosus) looks to be a goer for gut health, but at £21.95 a bottle it doesn’t come cheap, which leads us to…

Getting probiotics from your diet

If there’s not yet a fermented food aisle in your local supermarket, Kerry reckons that prospect won’t be far off, particularly seeing as gut health is so high on our current wellbeing agenda ( Pinterest  reports a +251 per cent rise in saves for “gut health”):

“Most cultures across the globe will have their own staple fermented foods, and these can be a rich source of probiotic bacteria in the diet. These days, it’s easy to buy these foods from health shops or even in your local supermarket, and you can choose from a huge variety of foods that are naturally high in probiotics, including yoghurt, kimchi , sauerkraut , kombucha , tempeh, kefir  and natto.”

If money’s tight, Daniel recommends on loading up on probiotics from food sources- lactobacillus can be found in yogurt and bifidobacterium is also present in lots of dairy products. He also notes that sauerkraut is a particularly rich source of probiotics and lactic-acid bacteria. In addition he emphasises that including lots of prebiotics  in your diet is vital for helping those health-giving probiotics to grow (that friendly bacteria needs feeding). Fill your basket with prebiotic heavy leeks, onions, artichokes, oats and garlic, and up your fibre intake. Incidentally, dentist Dr Steven Lin highlights that consuming abundant probiotics and prebiotics in your diet  is essential for maintaining good dental health and promoting the growth of good bacteria in the mouth.

So do I really need a probiotic supplement?

Given that all of our microbiomes are so varied, there’s no definitive answer to that one, but Daniel thinks that eating a healthy, balanced diet, including plenty of fermented, probiotic and prebiotic rich foods, will suffice if you’re fit and well. Where a probiotic particularly comes in handy is if you’ve been on courses of antibiotics or have digestive or bowel issues. Given the link between our gut health and overall wellbeing, Kerry thinks that the scope of probiotics for general health could be even more expansive:

“Mounting evidence suggests that gut health may be linked to a variety of other health conditions and there is growing interest in their use for all sorts of health issues, from skin problems to women’s intimate health. For this reason, many people are choosing to take a daily probiotic just to ensure a regular intake of friendly microflora. Everybody’s probiotic needs will differ, but what I find so exciting is that research is allowing us to choose specific strains to suit our own individual needs.”

If you do choose to take a supplement, Kerry suggests there’s an optimum time to do so too:

“Evidence from some of the world’s most highly-regarded probiotic laboratories and research centres suggests that taking your probiotics with your breakfast is best. It’s at this time of day that the stomach is the least acidic, and the food helps to further assist the passage of the probiotics through to the intestines where they can start to colonise.”

Just, whatever you do, don’t chase the probiotic supplement you’ve forked out for with steaming hot coffee, or wine for that matter (a glass of Sauv with your cornflakes generally isn’t recommended anyway). You could slay the bacteria you’re trying to cultivate in the process.

Four probiotic supplements to try

The following come expert-approved or have produced positive results for our contributors.

OptiBac Probiotics ‘For every day MAX’, £35.99 for 30 capsules

Pricey, but it could prove its worth it if you’re an IBS sufferer according to Kerry:

“This contains 50 billion high-quality live micro organism per capsule with a combination of three strains that have been shown to reach the gut alive. One of the strains, L. acidophilus, has been shown in multiple studies to help relieve the symptoms of pain and discomfort that are so typical in IBS sufferers.”

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Symprove £21.95

Professor Ingvar Bjarnason of King’s College London declares this to be a “breakthrough product”, while everyone from nutritional therapists to skincare experts (Meghan Markle’s facialist Nichola Joss has been taking it for years) swear by this water-based probiotic supplement.

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Alflorex, £19.99 for 30 capsules

With a 35624 culture count, this is the number one recommended probiotic by US gastroenterologists.

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Bio-Kult, £9.49 for 30 capsules

This more purse friendly probiotic option contains 14 live bacterial strains and was found to reduce abdominal pain in 69 per cent of IBS patients after 16 weeks, as reported in the journal BMC Gastroenterology

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Are you taking probiotics all wrong?

Follow Daniel on Instagram  @thenakednutritonist  and Anna  @annyhunter