You might like the sunshine, but it can be a harsh environment for your hair and scalp.
Your scalp microbiome is your ally in the heat so it’s worth doing a deep dive to understand how to protect it, in turn allowing it to protect your scalp and hair.
Firstly a bit about sunshine
The human skin is constantly exposed to various environmental factors, with ultraviolet radiation (UVR) sunshine to you and me - being a major influence on skin health and disease. UVR is divided into UVA, UVB, and UVC.
Sunlight primarily consists of UVA (90–95%) and a smaller portion of UVB (5–10%), while UVC is almost entirely absorbed by the ozone layer and does not reach the Earth's surface . Both UVB and UVA can lead to DNA damage, oxidative stress, premature ageing, and an increased risk of skin cancer. Additionally, UVR has been linked to immune suppression and may significantly affect the skin’s microbiome. Hence, photo-protective measures are important to consider in order to protect the skin against the harmful effects of UVR
Is UVR good or bad?
UVR has several positive effects, including the activation of anti-inflammatory and immunosuppressive pathways, which benefit various skin conditions like psoriasis, atopic dermatitis, vitiligo and graft-versus-host disease, it can also influence certain infections and enhance immune responses, which aid in combating infections.
Beyond skin diseases, UVR also plays a beneficial role in systemic conditions such as asthma, multiple sclerosis, schizophrenia, type 1 diabetes, autism, and cardiovascular diseases.
Emerging research reveals that exposure to sunlight promotes the growth of beneficial microbes across body sites like the gut and skin. Sunlight triggers vitamin D production in the skin, and vitamin D then stimulates the release of antimicrobial peptides – small proteins that alter the microbiome. By avoiding the sun you’re depriving your scalp of vitamin D, allowing unfavourable growth of otherwise healthy microbes like Propionibacterium which can trigger scalp acne.
So UVR in moderation is good for us and in excess can be the opposite.
What is the relationship between the scalp microbiome and sunlight?
As a unique ecosystem, human skin and its microbial inhabitants are also influenced by external environmental stressors, including UVR . UVR can directly or indirectly affect the skin microbiome. Studies have shown changes in the composition of the skin microbiome, with different bacteria responding differently to UVA and UVB radiation
A study published in 2023 found significant changes in microbial diversity after four weeks of extensive sunlight exposure on the forearms of participants, compared to baseline measurements. Prior to taking a holiday in a sunny destination (minimum of 7 days duration), volunteers had skin swabs taken from their extensor forearm , and upon their return, skin swabs were repeated . This suggests that sun exposure influences the diversity and composition of the skin microbiota . Additionally, the overall composition of the skin microbiome may be altered long-term following exposure to UVA and UVB radiation on the backs of the volunteers. Notable increases were observed in Cyanobacteria spp., Fusobacteria spp., Verrucomicrobia spp., and Oxalobacteraceae spp. In contrast, Lactobacillaceae spp. decreased, with a more pronounced decline following UVA exposure.
It's a bit of an over simplification but in general terms this is a decrease in the 'good' bacteria and increase in the 'bad' bacteria on exposure to UVA and UVB radiation.
What the scalp microbiome does to protect scalp and hair in the summer heat?
Protection:
Although invisible to the naked eye, the scalp’s microbiome plays a key role in keeping your hair and scalp healthy by providing protection from UVR .[1]
Defence:
The microbiome defends against pathogens and harmful environmental factors like UV radiation.[2]
It has been shown that Microbiota produce compounds that absorb or deflect UV rays, thus minimising UV induced damage to hair and scalp. [3]
Biofilm protection:
The microbes can also form a protective layer known as a Biofilm, think of it as your own personal home-made sun cream. This shields the hair from external aggressors including UV light. [4]
This barrier function of the scalp also helps protect against environmental pollutants.[5]
Helps modulate sweat glands which in turn helps modulate scalp hydration:
In the extreme heat of a continental holiday – or now with global warming – the extreme heat of some places in the UK in the summer, your scalp sweats more. Sweat can dry out your scalp leading to more oil production which along with environmental pollution can lead to blocking of the pores on your scalp predisposing you to scalp disorders such as dandruff. A healthy scalp microbiome helps modulate sweat production in high temperature helping regulation scalp hydration.[6]
Fights against oxidative stress.:
Our scalp is exposed to oxidative stress on a daily basis. Sources of oxidative stress include UVR as well as chemical insults from oxidizing hair colourants and pollutants – found in all environments when doing something as simple as walking down the high street.[7] Oxidative stress is involved in ageing our hair prematurely and ultimately hair loss. Our scalp microbiome helps protect against oxidative stress [8]
Ultimately, we have our own army on our scalp, holiday ready, to protect our scalp and hair at a moment’s notice. It’s the same as having your own natural protective layer just sitting there waiting to help.
So how do you nurture and protect your scalp microbiome during these summer months?
How can you get this wonderful collection of microbes to work for you not against you?
Our link here to our blog shows how to naturally reset your scalp microbiome making sure that your scalp microbiome is in optimal health. If you don’t wish to click through to the blog here are the essentials:
1. Protect from Heat and Stay Hydrated
Excessive heat from styling tools can dry out your scalp, disrupting its natural balance. Minimize heat styling and allow your hair to air dry whenever possible. On hot days, wear a hat to protect your scalp from UV radiation. Don’t forget to hydrate your body by drinking enough water—around 6 glasses or 2 litres a day. Use moisturising hair products or oils (like coconut oil) to keep your scalp nourished
2. Avoid Harsh Products
Certain products can throw off your scalp’s pH balance. Avoid shampoos with sulphates, which can irritate the skin, dry out your scalp, and harm protective bacteria . Look for gentle, sulphate-free products to maintain a healthy scalp microbiome.
3. Nourish from the Inside
What you eat can impact your scalp health. A diet rich in fruits, vegetables, lean proteins, and whole grains helps nourish the scalp and promote healthy hair growth. Omega-3 fatty acids from fish such as salmon and sardines help reduce inflammation and support scalp circulation. Oxidative stress can contribute to aging so antioidants from food such as green tea and fresh produce can help.
Probiotics, prebiotics, and postbiotics support your gut microbiome and may positively influence the scalp microbiome through a process known as the gut-skin axis. Managing stress and getting enough sleep also play a big role in maintaining overall health.
4. Balance Sebum Production
Sebum, the oil produced by your scalp, is necessary to protect your hair and skin. However, too much oil can cause a build-up which in turn disrupts the microbiome. Wash your hair regularly when it gets oily, but don’t overdo it. Over-washing can strip the scalp of its natural oils. Some people find washing every other day works best, while others can go longer between washes.
5. Maintain the Scalp’s Natural pH
Your scalp’s pH is naturally acidic, typically around 5.5, while the pH of a hair fibre is more acidic still – around 3.67 This acidity helps protect the scalp from infection, keeps the hair cuticle flat and healthy and is the optimal pH for your scalp microbiome to thrive. When the pH is disrupted, such as during chemical treatments like hair colouring, the hair cuticle lifts and can be damaged by pollutants.
To help maintain a balanced pH, rinse your hair with a mixture of diluted apple cider vinegar (1 part vinegar to 5 parts water) or use a spritz of aloe vera juice. Always choose hair products that are pH-balanced to avoid disrupting your scalp’s natural state.
6. Choosing a shampoo with added microbiome friendly ingredients.
There are many naturally derived ingredients that have been found to have beneficial cleansing effects on the scalp, for example a biosurfactant that is yeast fermented produces a very gentle cleanser containing post biotics – which in turn are recognized to be good for scalp microbiome
Why does your shampoo matter?
All An’du products contain microbiome friendly ingredients called post-biotics which are known to help support the scalp microbiome. They also contain nourishing grape seed oil designed to nourish and replenish dry hair.
We contain not one, but two, bio fermented products in all our bars :
Firstly a cleanser (surfactant) again made via fermentation of plant products and containing post-biotics which are certified microbiome friendly.
Secondly, an antistatic agent Brassicyl Isoleucinate Esylate & Brassica Alcohol which is made solely from fermentation and plant materials using sustainable green chemistry principles and is a certified natural ingredient as well as being very gentle on the scalp.
We are free from harsh chemicals, sulphate, parabens, petrochemicals and silicone free – there is nothing nasty in our bars to disrupt your scalp's microbiome.
We are also pH balanced – an important aspect to help keep your microbiome happy!
So when you go on holiday this year, as well as remembering your protective sun cream, don’t forget to bring a good shampoo which will help support your scalp microbiome – the microbiome which in turn will help support your scalp against the onslaught of those hot summer days.
Enjoy your holidays!
1 https://onlinelibrary.wiley.com/doi/10.1111/exd.13935- microbiome and its defence against pathogens and UV radiation.
2 Santos Nogueira and Joekes, 2004 (microbiota produce compounds that absorb and reflect UV rays).
3 https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00928/full
4 https://www.scirp.org/journal/paperinformation?paperid=111264 – helping against environmental pollutants.
6 https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1467-2494.2007.00387.x?getft_integrator=sciencedirect_contenthosting&src=getftr&utm_source=sciencedirect_contenthosting
7 https://journals.lww.com/ijot/fulltext/2018/10060/scalp_condition_impacts_hair_growth_and_retention.3.aspx%20- %20sources%20of%20oxidative%20stress%20to%20the%20scalp
9 https://www.sciencedirect.com/science/article/pii/S2950194625001219 ( function of hair microbiome)