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Why that probiotic supplement you're taking may not be working

By Geraldine Georgeou 3 min read
Wednesday, May 06, 2020

How are you meant to know if you even need a probiotic? Or which one is right for you? Or if they are really going to improve your general health?

Probiotics are live bacteria taken as an oral supplement to provide a beneficial effect on your gut microbiome by increasing the number and variety of good bacteria. We are starting to learn that your gut bacteria rule your world; when they change or are out of balance, they affect the ability of the lining of the gut to absorb nutrients, which in turn affects your weight, your mental health, your energy and your skin. So it’s no wonder that we have put so much hope in probiotics. Manufacturers promise that these magical pills are the key to health and vitality. But if we put everything else aside, do they deliver when it comes to skin?

Unfortunately, one bug does not fit all. There are different bacterial strains, different "strengths" and different dosage recommendations, variations in quality and an overwhelmingly increasing number of products to choose from on the probiotic market. And how are you meant to know if you even need a probiotic? Or which one is right for you? Or whether these probiotics are really going to improve your general health or skin concerns?

Everyone’s gut and skin microbiome is individual, and we all have unique needs. We already know the ways in which healthy bacteria could have been starved; similarly, if someone has a parasite, a fungal infection or harmful bacterial overgrowth in their gut, this too will need to be considered when selecting the right probiotic and eating plan.

There is no blanket rule or single product that is "best". People should approach probiotics in the same way they would approach rehabilitation after a sporting injury, for example. You would get an assessment from a physiotherapist to identify the problem that is causing you pain, and then they’d recommend particular exercises to fix your specific problem. You wouldn’t go off and just make up your own rehab plan, right? Arguably, probiotics require the same expert input and guidance to ensure that you are taking the right product for your needs. It’s about the ratios of various species rather than the number of bacteria in our gut (so more does not equal better).

Some people could do more harm than good by buying a random probiotic off the shelf, or adding a whole lot of fermented prebiotic foods to their diet all at once. This could only worsen the problem, causing more bloating, gas, diarrhoea and skin problems and so on: all the things they were trying to fix in the first place. Having said that, different strains of bacteria do appear to have benefits for different conditions. Some studies have found probiotics to have beneficial effects on psoriasis, dermatitis and acne, thanks to their anti-inflammatory, antimicrobial and immune system–modulating effects.

Lactobacillus and Bifidobacterium strains of bacteria appear to have a beneficial anti-inflammatory effect on skin cells. They also play a role in leaky gut syndrome by reducing inflammation and strengthening the mucosal barrier. There is even some limited research to suggest that applying Lactobacillus in topical formulations directly onto the skin might help restore a healthy skin microbiome.

These are two very common strains of gut-friendly bacteria used in commercial products. Dosage recommendations vary, but 5 to 10 million "colony-forming units" (CFUs) in children and 10 to 20 million CFUs in adults is an adequate dose to support general health in most people.

Different strains of probiotic can be used to target different skin conditions; L. acidophilus and bulgaricus are recommended for acne; rhamnosus for UV skin damage; reuteri, delbrueckii and salivarius for atopic dermatitis. However, it is best to consult a healthcare professional to devise a plan for your personal needs before you start taking regular probiotics.

Fermented foods

While we’re on the subject of probiotics, we must talk about the buzzword on every modern menu. Fermented foods have become the secret elixir to fix all ailments according to #instafood #happytummies #guthealth. But are they just #expensivemould?

Fermented foods have gained traction in recent years as a natural source of probiotics, which have been shown to help improve certain skin conditions. But this isn’t a green light to eat all the fermented foods you can get your hands on. For a few reasons: Just as with probiotic supplements, different skin conditions might benefit from different strains of bacteria and there is no such thing as a one-bug-fits-all approach.

Secondly, somewhere along the way we’ve forgotten that, like any other therapeutic treatment, fermented foods should be eaten in medicinal, therapeutic amounts. It can be a fun weekend project to try your hand at fermenting your own vegetables, but you need to be very careful that jars are thoroughly sterilised and you follow all instructions in the recipes. There are plenty of cookbooks and internet instructions available.


Text from The Australian Healthy Skin Diet by Geraldine Georgeou, photography by Chris Chen. Murdoch Books RRP $35.00

The Australian Healthy Skin Diet book cover

Geraldine Georgeou is an accredited practising dietitian and director of Designer Diets private clinics in Sydney. As well as treating hormone and skin conditions with nutritional advice, she specialises in metabolic health and gastrointestinal health.