We’ve all been there – a hot date coming up and right on cue, the spots have erupted. But for many people, it’s not just a couple of short-term blemishes that are ruining their day; acne is a whole other ballgame. It can bring misery and heart-ache just at the time when people are most concerned about how they look.
But things are looking up for the millions of people who struggle with acne, as we learn more about what triggers this chronic condition and how it might be overcome. Not only is new research unravelling the complex processes underlying acne but it is also revealing a promising role for probiotics in its treatment. And this research could help explain why acne is associated with drinking milk but not with yogurt – which contains probiotic bacteria.
Acne can affect adults too
Acne mainly arises when the sebaceous glands in our skin produce too much sebum, which then blocks the skin follicles – a situation most likely to happen during puberty.
The chances are that most of us develop acne at some point. It affects 50-95% of teenagers aged 12-18 years. But it’s not just a blight for young folk – adults can get it too. Research has shown that up to 43% of people who had acne in adolescence still have it when they’re 30–40 years old.
Acne is closely linked to the westernised lifestyle and in particular the finger of suspicion points towards the western diet, characterised by processed foods, saturated fats, and refined sugars.
Investigating the link between dairy products and acne
Dairy products, another popular part of the diet, have also come under the spotlight but previous studies on their possible role in the development of acne have led to conflicting results (3,4,5).
So to get a clearer picture, researchers reviewed these studies, analysing data from 14 studies that met their criteria and comparing findings from people who had the highest intake of various dairy products with those who had the lowest intake. The age of participants in these studies ranged from 9 to 30 years (1).
Acne is associated with consuming milk but not yogurt or cheese
Results showed that consuming dairy, total milk, whole fat milk, low-fat milk and skimmed milk were all associated with the presence of acne. The more milk people drank, the greater their risk of acne. Each additional serving of dairy, whole milk and skimmed milk increased the risk of acne by 83%, 13% and 26%, respectively.
But it was a different story when it came to yogurt and cheese. The four studies that looked specifically at yogurt and cheese intake all consistently found that these products were not associated with acne.
The authors suggested that the lack of a relationship between yogurt/cheese and acne may be due to the fermentation process involved in making them. This process, requiring a starter culture of bacteria, may modify the components of milk that are associated with acne development.
‘Results of the present meta-analysis recommend the consumption of yogurt/cheese to avoid acne creation.’ – Aghasi M, et al, 2019
The gut-skin axis plays a key role in acne development
Separate research may shed light on these findings. It has sought to uncover the processes underlying the development of acne, and the role of the human microbiota – the trillions of microorganisms that live on and in us.
In particular, our gut microbiota constantly interacts with our immune system and helps to shape our inflammatory response – this may explain findings suggesting a role for the gut microbiota in several inflammatory skin conditions, including acne.
Our community of gut microbiota is profoundly influenced by what we eat. While fruit and vegetables in the diet promote a healthy mix of gut microorganisms, fatty foods and foods with a high glycaemic index are associated with less diverse gut microbiota and an increase in inflammatory triggers. Hence it comes as no surprise that our western diet may aggravate the development of acne.
In light of these findings, researchers reason that modulating the gut microbiota could potentially influence the appearance and progression of acne. And a good way to achieve this would be through probiotics, used together with, or instead of existing therapies for acne (2).
Probiotics show promise against acne
A review of research to date has indeed suggested that, according to laboratory tests, probiotics may help against acne, and the few studies carried out so far in people have shown promising results for probiotics applied to the skin and especially probiotics taken orally.
Probiotics may exert their beneficial effects through several ways, say the researchers. For example, probiotics taken by mouth may modulate the gut microbiota, generating an anti-inflammatory response and improving the barrier function of the gut. Or they may affect insulin-like growth factor I (IGF-1), a hormone that has been implicated in the development of acne.
Several probiotic strains, including Lactobacillus strains, have been shown in lab tests to produce anti-microbial substances that inhibit the growth of acne bacteria, Cutibacterium acnes.
Trials in people have included:
- An early study found that adding a probiotic mix containing Lactobacillus and Bifidobacterium strains to antibiotic treatment increased the anti-inflammatory effects and reduced potential adverse effects of prolonged antibiotic therapy (6).
- In another study, an oral Lactobacillus probiotic taken for 12 weeks was associated with improvement in acne compared with placebo, also reducing IGF-1 expression (7).
- An increase in levels of the anti-inflammatory interleukin-10 was seen in a trial following treatment with a probiotic mixture containing Lactobacillus and Bifidobacterium strains given orally for 30 days (8].
- A recent study evaluated a mixture of probiotic strains of Bifidobacterium, Lacticaseibacillus, and Ligilactobacillus plus extract of aubergine (Solanum melongena) and Echinacea taken orally in 114 people with mild to moderate acne for 8 weeks (9). Compared with placebo, acne symptoms improved and the rate of sebum secretion fell, as did presence of C. acnes in patients who were treated with the probiotic mixture and the botanical extract, especially when taken together.
‘Given the aggressiveness of some standard acne treatment, probiotics should continue to be investigated as an alternative or adjuvant therapy.’ – Sánchez-Pellicer P, et al, 2022