Probiotics: Why They’re Not a One-Size-Fits-All Fix
Probiotics represent one of the most promising intersections of nutrition and microbiology. They’re everywhere - in supplements, drinks, powders, yoghurts and even skincare. Often marketed as the answer to bloating, gut issues, immunity, mood, skin problems and energy.
Unlike many fads, probiotics have accumulating clinical evidence. But the evidence is strain-specific and context-dependent. Generic muylti-strain probiotic supplementation is far less effective than targeted strains selected based on symptoms.
It’s easy to see why they’re appealing. When you’re uncomfortable, bloated, struggling with digestion or dealing with breakouts, the idea of a simple daily capsule that 'fixes your gut' sounds incredibly attractive. But probiotics are far more complex than most marketing suggests.
This guide breaks down what probiotics can (and can’t) do, where the hype comes from, what the science actually says, and what you may want to explore before trying them.
What are probiotics said to do?
Probiotics are often claimed to be the go-to supplement for bloating or IBS and for improving gut health. Alongside this they've also been touted for boosting immunity, clearing acne, eczema and psoriasis, balancing mood, helping with weight loss, repairing the gut lining and solving conditions like SIBO.
Companies promote generic multi-strain probiotics as cure-alls, leveraging the compelling research on specific strains (Lactobacillus and Bifidobacterium species have the most evidence). Marketing often conflates CFU (colonuy forming units) count with efficacy - higher CFU counts are assumed to be better, though evidence does not support this.
The concept of 'rebalancing' the microbiome appeals intuitively but obscures the complexity of dysbiosis patterns and strain specificity.
Where do these claims come from?
The legitimate science around probiotics and the gut-brain-skin axis has been oversimplified into marketing messaging. The claims stem from :
early research on specific strains
studies done in test tubes, not humans
small clinical trials on very specific conditions
general interest in gut health
the idea that more good bacteria equates to better health
anecdotal stories shared on social media
the growth of the wellness supplements industry
A key issue is that the word 'probiotic' describes thousands of different strains, each with different actions. So a study on one strain gets used to market a completely different product. This creates confusion and unrealistic expectations.
What's the evidence behind probiotics?
The connection between gut microbiota, systemic inflammation and skin health is scientifically robust. Dysbiosis (an imbalance of good vs bad bacteria) is associated with intestintal permeability ('leaky gut') and systemic inflammation. In acne specifically, dysbiosis can increase insulin-like growth factor 1 (IGF-1) which increases oil production. Low levels of beneficial bacteria (particularly Akkermansia muciniphilia and Lactobacillus and Bifidobacterium species) are associated with acne severity.
Research has also shown that probiotics can help restore gut balance after antibiotic use, support irregular bowel movements (whether diarrhoea or constipation) and reducing symptoms in specific gut conditions.
But these are all strain-specific effects. Lactobacillus acidophilus for example has clinical evidence for acne improvement. But a product containing 10 strains may have minimal evidence for any of the individual strains contained within it.
Critically, probiotics do not permently alter microbiota composition. Most probiotics pass through the digestive system and do not permanently stay in the microbiome. They provide temporary colonisation and generate metabolites that support gut health. When probiotic consumption stops the bacteria composition typically reverts within weeks to months. This points to probiotics not being a 'cure', but a supportive tool requiring sustained use alongside dietary changes that support beneficial bacteria.
When choosing a probiotic it's important to consider that many products lose viability during storage, or have lower CFU counts than what the packaging claims. Enteric-coated capsules improve survival, but many budget products lack this protection.
When to consider probiotics
Where stool or SIBO testing has taken place and appropriate dietary changes have taken place to reduce the drivers of any imbalances (reducing processed foods, dietary triggers and excess sugar and increasing fibre, and fermented foods) then targeted probiotics can be introduced. Strains should be chosen based on the dysbiosis pattern. For example, Lactobacillus acidophilus for general dysbiosis or acne support and Bifidobacterium bifidum for dysbiosis with inflammation. Ensure the product has had third-party testing and be consistent for 12 weeks before assessing the efficacy.
If you have been on a course of antibiotics, then once the course has finished probiotics can support the re-establishment of beneficial bacteria, alongside an increased focus on fibre and fermented foods.
When caution may be helpful
There are a few cases when probiotics should not be used without professional guideance:
Histamine intolerance - fermented foods and some probiotic strains generate histamine. If you have histamine intolerance or mast cell activation syndrome then your symptoms may worsen with probiotics. Strain selection is important here. For example Lactobacillus brevis and Lactobacillys plantarum are high histamine producers, whereas Lactobacillus acidophilus and Bifidobacterium bifidum are not.
FODMAP sensitivity - some probiotic formulations contain FODMAP ingredients, or substrates that trigger symptoms in sensitive individuals
Immunocompromised individuals - whilst rare, immunocompromised people (such as those with severe illness or on immunosuppressive medication) may experience infection from probiotic supplementation
Dysbiosis paradox - in severely dysbiotic states (particularly SIBO), introducing probiotics can initially worsen symptoms as bacterial due-off generates endotoxins. This is often misinterpreted as probiotics being harmful, when it actually reflects a need to reduce pathogens first before taking probiotics.
What should I do before taking probiotics?
Most people reach for probiotics to help tackle their bloating, constipation, loose stools, nausea, reflux, skin flare-ups, fatigue or low immunity. But these symptoms often stem from underlying issues such as:
low stomach acid
digestive enzyme insufficiency
stress-related motility changes
poor gut motility
low fibre diversity
inadequate hydration
hormonal shifts
food timing
sleep quality
microbiome imbalance (not always fixed by probiotics)
Therefore, before reaching for probiotics it's important to:
Address dysbiosis patterns with the help of a qualified professional to identify whether your symptoms are consistent with dysbiosis, food sensitivities or low stomach acid.
Support beneficial bacteria through diet through adequate fibre (at least 30g daily) from diverse whole vegetables, fruits, legumes and seeds.
Reduce the drivers of gut imbalances by removing excess sugar and refined carbohydrates, processed foods, additives and alcohol and prioritising stress management techniques, sleep and movement.
Only then should you introduce evidence-based probiotics
The narrative around probiotics often positions them as sufficient intervention by themselves, when really they are a supporting layer atop more foundational dietary and lifestyle work.
Will probiotics help me?
If you want to chat about whether probiotics would be right for you and your symptoms then book in for a free call with me. We can discuss what's going on, what you've tried so far and explore the options together.
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