The gut-skin connection

Your gut has a big influence on your immune system and salute generale. There's lots of evidence that a healthy gut can ward off many health problems, from digestive issues to poor moods and brain health. According to Dr Rekha Singh, dermatologist at Clinica Oliva per Pelle e Capelli, there is also a connection between your gut, skin and hair - known as the gut-skin axis:

"The gut hosts trillions of bacteria, both good and bad, and this is known as the gut microbiome. When the balance between these two types of bacteria is disrupted, it can lead to various health issues, including hair problems like hair loss, dandruff and diseases related to scalp inflammation," she says.

• Hair loss (alopecia areata) - an imbalance of gut bacteria can trigger inflammation in hair follicles, and research suggests this is linked to hair loss¹.

• Scalp inflammation - as well as a gut microbiome we also have a scalp microbiome. An imbalance in bacteria here may also contribute to inflammation, as well as related scalp diseases².

• Forfora (seborrhoeic dermatitis) - is one inflammatory scalp-related problem. People with dandruff often have an excess of certain yeasts on their scalp³.

This is where probiotics come into play. Probiotics are live microorganisms, also known as good (or beneficial) bacteria, that we can consume to improve the balance of good and bad (unbeneficial) bacteria in the gut. You can get probiotics from:

• Fermented foods: for example, natural yoghurt, kefir, kombucha, kimchi e crauti.

• Probiotic dietary supplements: also exist in the form of capsules, powders, or liquids. Find out how to shop for the best quality ones in our latest feature, Cosa sono i probiotici?

"I'm often asked for advice on hair growth and supplements that claim to promote healthy, fuller or longer hair. Probiotics has got a lot of attention in recent years," says Dr Singh.

However, whether probiotics for hair are worth this attention is another matter.

How do probiotics for hair work?

The use of probiotics for promoting healthy hair is a relatively new concept, and the truth is there is limited evidence available. This said, some studies suggest that probiotics could be beneficial.

Dr Singh says: "some studies have shown that certain strains of probiotics can improve hair growth by reducing inflammation, balancing the gut microbiome, and increasing nutrient absorption."

However, many of these studies are of poor quality, and there's little to no evidence that probiotics can lead to fuller and thicker hair in people who don't have hair loss.

Other studies suggest that certain probiotics may help other conditions related to scalp inflammation, including dandruff⁴.

It's early days for probiotics and hair. As promising as these small studies are, we simply don't know enough yet to say that probiotic supplements are worth spending your money on - especially if you aren't trying to deal with an existing hair-related problem.

"I always recommend my patients rely on evidence-based treatments rather than fads or marketing gimmicks," says Dr Singh. "Currently, there is not enough scientific evidence to support the use of probiotic supplements for hair growth. More research is needed before any conclusions can be drawn."

We may not know enough to make investing in supplements worthwhile, but Dr Singh believes probiotic foods are the way to go. It's all about thinking of healthy hair as a possible added benefit:

"For now, I do not recommend any specific probiotic supplements for hair growth. Instead, I advise my patients to focus on maintaining a healthy gut microbiome through a balanced and varied diet that includes fermented foods. This can benefit their overall health but may also have positive effects on their hair."

Remember, if you have a hair concern, speak to your GP or visit a dermatologist to get the best advice on how to treat and manage.

1. Pessemier et al: Gut–skin axis: current knowledge of the interrelationship between microbial sysbiosis and skin conditions.

2. Polak-Witka et al: The role of the microbiome in scalp hair follicle biology and disease.

3. Dawson Jr: Malassezia globosa and restricta: breakthrough understanding of the etiology and treatment of dandruff and seborrheic dermatitis through whole-genome analysis.

4. Reygagne et al: The positive benefit of Lactobacillus paracasei NCC2461 ST11 in healthy volunteers with moderate to severe dandruff.