If you’ve got dry skin, you probably use a range of products that are said to be specifically suited to your skin type, and not oily skin. You’ve also probably wondered what makes your skin dry in the first place. Today, we’re about to break it down for you.
Our skin gets dry when the skin’s outermost layer has reduced water content– and there are many reasons this could happen.
Before getting into those reasons, we’re going to take a quick look at what goes on in this layer.
The Stratum Corneum:
The outermost layer of our skin is made up of dead skin cells and is called the stratum corneum. Its main function is to retain the water content in our skin.1
This water content, held inside the stratum corneum with the help of various proteins (like keratin and a few others), has many functions:
- It maintains the skin’s flexibility.
- It circulates enzymes that are vital for the skin’s turnover cycle.
- It extracts water from the environment (which it can do even at very low levels of humidity), because of the proteins and salts it contains.2
- It protects the skin from the UV rays of the sun as it contains urocanic acid, which is a natural UV absorber.3
The spaces between the dead cells are filled with an oily, waxy substance made of cholesterol, fatty acids and lipids called ceramides. The water content in the stratum corneum in sealed in by them.
Every 30-45 days, the stratum corneum is replaced by a new layer, as the dead skin cells keep shedding. This is called the skin’s turnover cycle. Because of this, our body must keep producing this waxy substance to maintain the water content of our skin. We normally lose around 300-400 mL of water per day through our skin, called trans-epidermal water loss (TEWL). Excess TEWL causes skin to dry out.
A lot goes into ensuring a smooth turnover. Disruptions within this cycle could lead to the loss of water in the layer that finally becomes part of the stratum corneum. Alternatively, some factors can even rob the stratum corneum of whatever moisture it does contain.
Here are some of the ‘disruptions’ and factors that would lead to increased TEWL:
A] UV rays of the sun:
Excess exposure to the sun’s UV can damage the proteins in the stratum corneum. This would, as you can imagine, also reduce the water content that they hold.
B] Skin Disorders:
Water can also be lost because of underlying skin disorders like eczema and psoriasis.
C] Nutritional deficiencies:
Omega-3 and omega-6 fatty acids can alter the waxy substance in skin that prevents water from evaporating. If you aren’t getting the right amount in your diet, that would lead to the loss of water.1
Deficiencies in certain nutrients, such as sodium, potassium, calcium and magnesium, can also lead to dry skin.
D] Weather conditions:
We all know that low humidity and extreme temperatures dry the water in the skin. This also, interestingly, disrupts the skin’s turnover cycle, because some proteins require water to carry out their functions.5
So, what can we do about all of this?
A] Apply moisturisers –
Emolients are non-cosmetic moisturisers available over-the-counter, with ingredients (like plant extracts, fats, salts and many more) that relieve dry skin.
B] Use mild skincare products –
Soap can strip away the ceramides and other lipids of the skin. Avoiding the excessive use of soap or using soap-free products, as well as using lukewarm water, can help prevent skin from drying out.
C] Focus on nutrition –
Eating foods that support skin health can help manage dry skin. For example:
- Omega-3 and omega-6 fatty acids can be obtained from food like nuts, avocados, flaxseed, fish, tofu and olives. Supplementation with safflower or evening primrose have also shown to help with dry skin.
- Eating plenty of leafy greens and dairy will increase our calcium and vitamin K levels, which helps regulate the salt content in the skin’s water.
- Vitamin C helps maintain our skin’s structure by aiding the production of collagen. Citrus fruits, berries, broccoli, kale and papaya are all rich in vitamin C.
- Antioxidants: several natural antioxidants found in fruits and vegetables can help manage conditions like eczema and psoriasis that are characterized by dry skin and inflammation. They do so by neutralizing the free radicals that aggravate the inflammation and breakdown of proteins. Eating fruits and vegetables in a wide range of colours is an easy way to ensure we get these antioxidants.
- Harding CR, et al. Int J Cosmet Sci 2000, 22(1): 21-52.
- Blank IH. J Invest Dermatol 1952, 18(6): 433-440.
- Angelin J. Cosmetics Toiletries 1976, 19: 47-49. ‘
- Rawlings AV, et al. Dermatologic therapy 2004, 17 Suppl 1: 43-48.
- Vyumvuhore R, et al. The Analyst 2013, 138(14): 4103-4111.
- Proksch E, et al. J Dtsch Dermatol JDDG 2005, 3(10): 768-774.
- Ziboh VA and Chapkin RS. Arch Dermatol 1987; 123: 1686a-1690a.
- De Spirt S, et al. Br J Nutr 2009; 101(3): 440-445.