Skin deep: Healthy skin comes from the inside out

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Your skin is the largest and one of the most important organs in your body in terms of size, function and sheer versatility. It can act as a window into your overall health as good skin is built from within more than the products you use on it.

Skin cells are in a state of constant growth, in order to replenish dead skin.

It takes around 45-56 days for your innermost, living skin layers to work themselves outwards and, in doing so, they mature and die. Your outermost protective skin layers are actually made of flattened dead skin cells, bound with fatty compounds known as lipids, which rub off as dead skin flakes. Over the course of a year, that amounts to around a pound or half a kilo of dead skin, which we see in dust around our homes.

Skin also holds pools of stem cells that have enormous potential for growth and self-renewal. Stem cells haven’t yet decided what they want to be when they grow up but are assigned a role according to what’s needed. For example, hair follicle stem cells can form oil (sebum) producing cells, new hair follicle cells or new skin cells in the event of damage.

Your skin is the interface between the world outside and the world inside your body. There’s a continuous dialogue between what’s happening outside and what’s happening under your skin.

What does our skin do?

• Synthesises vitamin D.

• Protects against excessive UV radiation from sunlight.

• Provides a barrier function – keeping the outside out and the inside in. It’s not only a formidable mechanical barrier, but also the front line of our immune surveillance system, keeping harmful bacteria out, whilst providing a diverse microbial habitat of approximately 25m².

• Repairs itself, serving a wound healing purpose.

• Shreds and sweats skin cells, meaning it’s the largest organ of detoxification in our body. Poor skin can be a sign that the liver is challenged.

• Synchronises our inner biological clocks by pigments in our skin absorbing light.

• Shields us against harmful chemicals.

• Safeguards against water loss/maintains fluid balance.

• Sensory perception – our skin allows us to feel pleasure, warmth, pain, itch. Responding to vibration, pressure, and touch, our skin has many thousands of receptors that notice and signal what’s happening in our environment.

• Social communication – our skin is involved in communication between people; the way in which we see and are seen in the world and, when it’s less than healthy, it can impact our quality of life, self-esteem, and our happiness.

• Regulates our body temperature.

• Stores energy in its adipose layer.

What influences our skin health?

Vitamin D skin benefits

Vitamin D is made in the outer layers of your skin when UVB in sunlight is absorbed by a waxy cholesterol derivative (7-DHC). Technically speaking, “vitamin D” is a pro hormone, which needs to be transformed by your body into its active form to carry out its essential hormonal functions. Activated vitamin D regulates some 2000 genes, including genes involved in cell growth, immunity, metabolism and DNA regulation.

The prohormoneis vital for healthy bones, teeth and muscles. It’s also important for immune, metabolic and heart health, and possibly protects against certain types of cancer.

Our skin not only makes vitamin D, but uniquely is also able to activate it to its hormonal form, where it acts directly in multiple ways to support our skin’s barrier and immune function. These protective vitamin D skin benefits include the secretion of antimicrobial compounds, the regulation of tight junctions (or gaps) between cells that control what can pass in and out through our skin, as well as regulating our skin’s healing response and hair follicle cycling. Activated vitamin D is important for timely skin cell maturation and shedding.

Overall, the activated vitamin D promotes the skin’s barrier, wound healing, and hair growth, whilst limiting cancer development.

Sunlight exposure

The dangers of high energy ultraviolet (UV) from sunlight are well understood, causing skin ageing, sunburn and skin cancer. In the UK during the winter and autumn months, (beginning of October until the end of March) there isn’t much UV in sunlight and not enough UVB to make vitamin D in our skin. It’s why people living in the UK are advised to take a supplement during this period.

The most concerning skin cancer, malignant melanoma, is linked especially to short-term intense UV exposure, particularly burns acquired in childhood, and protection against UV radiation is an integral part of skin cancer prevention.

What is less well known is that sunlight contains a rainbow palette of light frequencies not just high energy ultraviolet (UV), but also coloured (visible light) and infrared. Radiation from the sun reaching the earth is approximately 53% infrared, 44% visible light, and 3% ultraviolet. We’re just beginning to understand how important these other frequencies are to our health and which can’t be found indoors.

When light is absorbed in our skin and eyes by pigments, such as melanin or vitamin A, it has downstream biological effects. An obvious example would be changes in skin colouration and freckles, which provide protection against the harmful effects of too much sun. Melanin absorbs light across a broad spectrum of frequencies ranging from UV, visible (coloured light) to infrared. Frequencies of blue in natural light provide the primary signal to synchronise our circadian rhythms.

UV is known to be beneficial for certain skin conditions like eczema and psoriasis and may have benefits for cardiovascular health and longevity.

How much sunshine do I need for enough vitamin D and to avoid skin cancer?

How much sunshine you need to produce enough vitamin D, but to do so safely, is a common question. Unfortunately, there’s no straight answer. It’s generally agreed that sunlight provides the appropriate frequency of UVB to encourage vitamin D production between 11am-3pm, and a duration of around 30 minutes minimum is often advocated, although opinions vary. This is also a time when we’re encouraged to take care of excessive UV exposure for fear of sunburn risk, and thus skin cancer risk. Different skin types will need to take varying levels of additional precaution, particularly when the UV Index is high.

The bottom line is people respond to sunlight differently, sometimes dramatically, differently. It’s unsurprising given the variation in human skin tones, migration, weather conditions and degree of skin exposure, air pollution etc.

According to Nina Jablonsky of Penn State University, a biological anthropologist and paleobiologist studying human evolutionary adaptations, skin colour is the product of natural selection acting to regulate levels of melanin pigment in the skin relative to levels of ultraviolet radiation (UVR) in the environment. Melanin is a natural sunscreen that prevents the breakdown of certain essential biomolecules (in particular, the B vitamin folate, and DNA), while allowing enough UVR to enter the skin to encourage the production of essential vitamin D.

There are online calculators that can provide more personal guidance. There’s one linked in the references section. In the meantime, our ‘Sunshine calendar’ may provide some guidance. What we do know is low vitamin D is common. Here in the UK, over 50% of white Europeans (lower risk) had insufficient levels below 50 nmol/L in winter/spring and even higher amongst non-white ethnic backgrounds. The only way to know if you’re in that category is to take a blood test. It’s also recommended to take a supplement during the winter and autumn months (beginning of October until the end of March).

Microbiome skincare

The outer layers of our skin are home to billions of bacteria, viruses, fungi and other micro-organisms. We live in happy co-existence with them most of the time and they help maintain a healthy barrier.

That’s roughly 10 billion microbial cells on each of us, not to mention those living deeper inside and in our gut. These organisms communicate with our skin cells and our immune system to signal how to protect us from pathogens, as well as how to heal from injury. Microbes can alter the amount of oil our skin secretes which, in turn, protects, lubricates and provides an antibacterial shield.

Strangely, and most surprisingly, many microbial substances produced in our skin are completely unknown – we have no idea what they do, there’s a world of discovery ahead of us.

Co-operation between human skin cells, skin microbes and the immune system is important for skin health. Any upset in this delicate balance, such as by pathogen invasion or a breach in the skin barrier, can lead to impaired skin function, delayed wound healing and disrupted overall health. Skin disorders like psoriasis, atopic dermatitis, and acne are all linked with disruptions to the skin microbiome (dysbiosis).

When it comes to microbiome skincare, it’s important to remember that hand sanitisers, antimicrobial skin products and frequent washing can disturb our skin barrier, resulting in skin irritation and changes to our microbiome. These changes can upset the delicate balance in our microbial ecosystem, stripping our skin of beneficial microbes and can lead to resistance.

If you need to use antimicrobial products for your job, your hands might need special attention to make sure they don’t become chapped and sore, such as using a moisturiser. If you develop sensitivity, your workplace might have an occupational therapist who could signpost you to professional help.

Be aware, most skin products contain preservatives which have antimicrobial properties included to prevent them from going off.

Skin and stress

Stress, especially chronic stress, affects every area of health, which often appears visibly on our skin. This means stress can cause skin problems.

Your skin has its own fully functional stress response system (HPA axis) and the release of stress hormones initiates a cascade of diverse events depending on skin cell-type.

Stress is linked with skin conditions, such as psoriasis and atopic dermatitis, making flare ups more likely. Chronic stress may even accelerate skin ageing.

The stress-related corticotrophin releasing hormone (CRH) increases oil production, perhaps to protect the body from possible infection. Acne breakouts are often accompanied by:

1. an increased colonisation by the bacteria Propionibacterium acnes (P. acnes)
2. an increased production of sebum
3. an overproduction of the protein keratin

CRH activates a type of white blood cell called mast cells which release histamine – a complex chemical best known for its role in allergies and pain.

People under emotional stress recover more slowly from skin problems and existing skin problems may worsen. Prolonged stress affects our immune systems and causes inflammatory changes via inflammatory chemicals known as cytokines, which can predispose us to inflammatory skin diseases and/or makes them worse.

Consider exploring stress reduction techniques, such as breathwork and mindfulness.

Skin and detoxification

Our skin plays an under-appreciated role in detoxification. For instance, if your liver is compromised your skin has to do more to clear toxins, which can lead to skin issues, such as yellowing, reddening of your palms, nose and cheeks, thinning, and spidery veins, to name a few. Liver issues can cause bile flow to become sluggish. It’s thought that the deposition of toxins and bile salts in our skin can cause irritation and itching.

It’s worth mentioning that almost anything can be toxic in excess – even good things like water, oxygen, and glucose. Damage occurs if the build-up exceeds capacity to deal with the overload. Often, it can be a build-up of nitrogenous and other metabolic waste products, such as bile acids, or an overgrowth of a certain bacteria or too much alcohol.

The skin is able to degrade, inactivate, and eliminate numerous foreign substances and toxic compounds produced internally through its metabolising enzymes, antioxidant scavenging system, and sweat glands.

Non-alcoholic fatty liver disease may occur in up to 50% of patients with psoriasis. The turnover time for skin cell production is also much shorter in people with psoriasis, around 6-8 days, compared to people with healthy skin (45-56 days).

Gentle dry brushing with a natural-fibre brush or facial exfoliation can help remove dead skin, unblocking pores and making it easier to sweat out toxins. Whilst there’s little published evidence to support the benefits of dry brushing, there is, however, anecdotal evidence and no indication that is does any harm. Possible benefits include: improvement to the skin’s ability to eliminate toxins and increased blood circulation in the skin and lymphatic flow. Take care not to brush too hard as doing so can be damaging.

Alternatively, saunas have been used for their multitude of health benefits going back thousands of years. Saunas promote sweating and sweat contains toxins. They have been used successfully to help people exposed to toxic weapons whilst serving in the military, as just one part of a detox programme that included niacin (vitamin B₃ – see below for food sources) and exercise. A similar programme has been used by people withdrawing from drugs.

The effects of smoking on your skin

The negative effects of smoking on skin include how quickly skin appears to age. It disrupts collagen production, which supports skin strength and elasticity (so one answer to the question ‘how to improve your skin’s elasticity’ would be to stop smoking). Then there’s the effects of the toxic chemicals contained in inhaled smoke on your skin.

Smoking also reduces reduces blood flow to your skin, so it gets fewer nutrients, less oxygen and often looks dull and grey as a result. Having more than 25 cigarettes per day is linked with double the risk of developing psoriasis. Finally, it’s thought smoking can impair skin wound healing. The skin benefits of quitting smoking include skin colour lightening with less redness upon quitting – even more reasons to try to give up.

Our article on smoking includes some links to services that can support you in quitting.

Chemical, environmental and food sensitivities

Our skin can absorb many substances directly. This also means that the things we put on our skin can easily be absorbed into our bodies including chemicals and foreign substances that can be harmful.

A simple demonstration of this that you might like to try is to cut a clove of garlic in half and rub and it on your skin without inhaling. Within a few short minutes, the smell can be detected on your breath. It’s the reason why many drugs can be given as patches since they’re able to cross the skin e.g. nicotine replacement.

There are thousands of foreign chemicals in our industrialised world; substances that our bodies haven’t evolved to deal with. Contact with such agents can give rise to skin reactions and uncovering what those might be requires a certain amount of detective work and sometimes professional help. Repeated contact with chemicals can cause irritation. The damage done to the exposed skin goes unnoticed at first but accumulates to a degree where it develops into a skin condition such as dermatitis/eczema.

One healthy skin tip would be to pay attention to the list of ingredients on any product you apply to your skin, such as make-up and skincare items and avoid those with a long and complicated list. Better still, make your own from ingredients that you know and recognise or use products that are also edible, such as coconut oil, which can be used for dry skin.

The same strategy can be applied to the components of the food we eat and the additives, preservatives and flavourings and the pesticides, herbicides and fungicides used to grow them. You may wish to avoid long ingredient lists and choose those grown with less pesticides. Similarly, detective work and sometimes professional help might be needed.

Common food sensitivities include: gluten, lactose, eggs, and vegetables from the nightshade family, such as tomatoes and bell peppers. Consider keeping a diary to notice and record what you’ve been eating and any symptoms in order to identify patterns.

How to keep skin hydrated

For your skin to function properly as a barrier it needs adequate hydration – we lose water continuously through our skin. This isn’t sweat from our pores, but losses through our skin itself, all over our bodies. If your skin is damaged in any way, water losses increase. Skin water losses are sometimes measured to monitor the integrity of the skin barrier function and its ability to retain water.

Whilst drinking plenty of water is very important to maintain hydration, it’s more complicated if your skin’s barrier/ability to retain water is suboptimal.

Loss of skin moisture is also seen with ageing. A key molecule involved in our skin’s moisture is hyaluronic acid (HA), a type of glycosaminoglycan (GAG). Hyaluronic acid and other GAGs, such as chondroitin, have a unique ability to bind and retain water up to a thousand times their weight in water. GAGs, and the proteins collagen and elastin, are major components of our skin and are responsible its outward appearance. A good dietary source of these ingredients is bone broth.

How to strengthen your skin barrier

Strategies to strengthen the skin’s barrier include:

1. Eating more dietary fibre, (e.g. vegetables) which, in turn, feeds beneficial short-chain fatty acid (SCFA) producing bacteria in your gut and skin. SCFAs (butyrate, acetate and propionate) are created from the microbial fermentation of dietary fibre in your large intestine. It’s recognised that children with atopic dermatitis have lower SCFA levels, especially butyrate.
2. Your upper layer of skin cells and its lipids (ceramides, cholesterol, and free fatty acids) are the cornerstone of your skin’s barrier function and there’s an overall trend of decreased lipid content in skin diseases. So, you may like to include healthy fats in your dietary choices (please see table below). Omega-3 fatty acids reduce inflammation in various ways, which includes changes to the lipid make-up of cell membranes.
3. Magnesium and dead sea salt therapy are two of the oldest forms of treatment for skin disease. If your skin is dry, try a good quality magnesium lotion or cream or add magnesium salts to hot baths. Alternatively, you can use dead sea salts, which can help inflammation and dryness, hydration and barrier function.
4. For really dry skin, lanolin is a natural by-product from wool production which has been used for centuries. It’s used extensively in personal care items such as, nappy creams, baby oil, lip balms, skin cream, lotions, cosmetics (lipstick, powder, foundation), nipple creams for breastfeeding mothers, and shaving creams. It’s worth noting that some people can be allergic to it.
5. If your skin is sore, chapped or inflamed, zinc as a cream or ointment can help. Use of zinc for skin issues has a long history and the skin is the third most zinc-rich organ. If it helps, it could mean you need more zinc in the diet.

Skin nutrition

Your skin requires essentials, such as vitamins, minerals, amino acids (from protein) and fatty acids (from fats) which, if lacking, in your diet, or occasionally if present in excess, can impact skin health. Without these necessary nutrients, your skin can develop a variety of responses including rashes, itching, acne, pimples, infection or eczema.

Try making homemade bone broth e.g. fish, chicken, beef. Boiling bones for a long time e.g. a leftover chicken carcass is an excellent source of nutrients.

Example of nutrients known to be essential for good skin health	Sources
Ceramides	Soy beans, eggs, sweet potatoes, wheat germ, brown rice, soy, meat, and dairy.
Co-enzyme Q10 (ubiquinone)	Rich sources of CoQ10 are organ meats, such as heart, liver and kidney, fatty fish, olive oil and, to a lesser extent, nuts, and seeds.
Collagen, elastin, hyaluronic acid support	Broth made of bones and skin; fish, chicken, meat, when cooked for a long time, provides basic building blocks needed to make these essentials. Vegetarian sources of glycine; sesame seeds, spirulina, sunflower seeds, pumpkin seeds, nori, watercress, beans, and spinach. More information on vegetarian support for collagen production can be found here.
Healthy fats	Coconut oil, avocado oil, extra virgin olive oil, oily fish, fish and krill oil, and seafood.
Magnesium	Dark green leafy vegetables, nuts, yeast extract, seeds and wholegrains, magnesium lotion or cream or magnesium bath salts.
Omega-3 fatty acids	Oily fish like trout, salmon, mackerel, anchovies, herring and sardines, seafood, and algae/seaweed.
Prebiotics	Onions, garlic, leeks, asparagus, apple cider vinegar, pickles, inulin, and resistant potato starch.
Probiotics	Kefir, yoghurt, sauerkraut, kimchi, miso, kombucha, and raw apple cider vinegar.
Selenium	Brazil nuts (best bought in shell as prone to mould and limit to 1 or 2 nuts per day), seafood, offal, eggs, fish, and meat.
Silica	Certain mineral waters, dark leafy greens, horsetail, oats, brown rice, seafood, and alfalfa.
Sulphur	Asparagus, kale, spinach, broccoli, mushrooms, cabbage, garlic, and onions.
Vitamin A family	Liver and cod liver oil, kidney, cream, cheese and butter from pastured cows, egg yolks from pastured chickens, sweet potatoes, algae like chlorella and spirulina, oily fish, spinach, carrots, red peppers, apricots, mangos, and papayas (fruits and vegetables often red, orange, yellow and green in colour).
Vitamin B family: B1 (thiamine) B2 (riboflavin) B3 (niacin) B5 (pantothenic acid) B6 (pyridoxine) B7 (biotin) B9 (folate, methylfolate, folinic acid, folic acid is a synthetic version) B12 (cobalamin, methylcobalamin)	Red meat (B1,B3,B5,B6,B7,B9,B12 ), liver (B1,B2,B5,B6,B7,B9B12), kidney (B1,B2,B5,B6,B7,B9), poultry (B6,B9, fish (B6,B3,B12), dairy (all), eggs (B3,B5,B6,B7,B9), yeast extract (B1,B2, B3,B5,B9,B12), mushrooms (B2,B3), seaweed (B1), leafy green vegetables (B1,B2,B7,B5,B9), wholegrains (B1,B3,B6,B9), nuts (B3,B6,,B9), legumes (B1,B2,B5,B6B9,), potatoes (B1,B3,B6,B9), All flours in UK are fortified by regulation in the UK to meet minimum requirements for B1, and B3.
Vitamin C	Bell peppers, oranges, blackcurrants, broccoli, Brussels sprouts, dark leafy greens, kale, kiwi, strawberries, tomatoes.
Vitamin D	The sun, oily fish, cod liver, eggs, mushrooms.
Vitamin E	Nuts, olive oil, butter, seeds, and wheatgerm.
Vitamin K2	Kefir, natto, sauerkraut, meat, egg yolk, butter, and cheeses. It’s not easy to get enough of this vitamin.
Zinc	Shellfish e.g. oysters, organ meats, liver pâté, beef, lamb, diary products, sprouted beans, wheatgerm, nuts, legumes, tofu, and wholegrains.

If you are unable to include these dietary sources in your diet, or are concerned you’re not getting sufficient quantities, you may wish to consider high quality supplements, preferably from food grown sources, as an alternative.

Retinoids (vitamin A family)

Your skin’s immune defence against microbes includes nutrients that influence the gene expression of antimicrobial proteins and other molecules that enhance skin immunity. Of particular importance is the vitamin A family. Vitamin A also works together with vitamin D to regulate thousands of genes. It’s also used on the skin for anti-ageing to reduce wrinkles. Dermatologists commonly use a pharmaceutical vitamin A derivative to treat skin conditions, such as acne.

Collagen

Collagen is the most common protein in the human body. It’s responsible for structure, stability and strength within the layers of our skin. As we age, collagen and elastin decrease, a process that’s accelerated by overexposure to the sun. Collagen is a common ingredient in nutritional supplements and products marketed for skincare, and there are studies in literature of its effectiveness in improving skin health.

The protein is made up of thousands of amino acids. The most common amino acids found in collagen are glycine, proline and hydroxyproline. Collagen production needs sufficient vitamin C and iron. Without enough collagen, blood vessels, tendons, and skin become fragile. Certain drugs, such as glucocorticoids, stop collagen formation.

Vitamin C

This vitamin is the most important water-soluble vitamin not just a vitamin for healthy skin. Unlike other animals, humans can’t make vitamin C and, therefore it must be obtained from our diet every day.

Vitamin C is essential for collagen maturation, which is vital for the growth and maintenance of healthy skin, bones, teeth, gums, ligaments, and blood vessels.

The vitamin counters the damaging effects of reactive free radicals by neutralising them. Unchecked, they lead to inflammation, cell damage and skin ageing, including sun damage. Skin flaccidity and other signs of degenerative skin conditions, such as wrinkles and age spots, are mainly due to an excess of these oxidising substances. One of the roles of vitamin C is to act as a powerful antioxidant.

Vitamin C is needed to support the collagen structure of the skin, and iron and selenium absorption. Deficiency commonly shows up as skin rashes or gum bleeding, or as poor bone growth under x-ray, particularly the ends of long bones, especially at the knee.

Signs of vitamin C deficiency include: weakness, irritability, aches and pains, and later coiled hair and skin rashes, swollen and bleeding gums, loose teeth, poor wound healing, and bleeding. Whilst true deficiency might be uncommon, suboptimal levels are possible.

The need for vitamin C is increased by: fever, smoking, diarrhoea, inflammation, iron deficiency, cold or heat stress, surgery, burns and protein deficiency. Cooking can destroy some of the vitamin C content in food.

Ceramides

Ceramides are a type of lipid or fat which act like mortar between the bricks of skin cells, helping to retain moisture in skin and protect against UV rays. Over 340 different types of ceramides have been found in human skin, and decreased levels of ceramide have been implicated in atopic dermatitis. Ceramides are used in commercial skincare products.

Co-enzyme Q10

Co-enzyme Q10 is essential for energy production and as an antioxidant. Our ability to make CoQ10 declines after age 25 and by age 60, production in the heart is half that of a 25 year old. CoQ10 levels may be lower in people with certain conditions, such as heart disease, or if they take statin cholesterol-lowering drugs. Supplementation with CoQ10 may limit deterioration of skin viscoelasticity and decrease some visible signs of ageing, such as wrinkles, micro-relief lines and improved skin smoothness.

Genetics

Whilst our genes influence our skin, such as skin type (whether it’s oily, dry or normal), skin colour, skin elasticity, skin ageing and some skin conditions, we’re still learning about how genetics influence outcomes. Data from Evergreen Life users is helping to shed more light on the matter. What’s known though, is that your genes don’t determine your skin’s destiny, simply your predisposition. You can make improvements by focusing on other more controllable things that influence skin health like a good diet, exercise, good hydration, avoiding sunburn, smoking and alcohol.

Good to know! An Evergreen Life DNA test could help you understand the genetic profile of your skin.

Takeaway tips

To discover what your body’s largest organ is trying to tell you, look out for your notification to take our Skin Health Check in your Evergreen Life app to learn about your skin and what affects it.

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