Sunburns are burns that can cause pain and itching. They make the skin sensitive and can be a nuisance for those who suffer from them. The use of shea butter could be a solution to alleviate sunburns. But how?
Sunburn: Causes of Occurrence and Consequences.
The sunburns fall under the category of first-degree burns. These are superficial burns that affect the top layer of the skin.
Sunburns are caused by prolonged exposure to UV radiation. The sun emits 3 types of UV rays: UVA, UVB, and UVC, which generate intense heat. The UVC, the most harmful UV rays, are completely filtered by the ozone layer and do not reach the Earth. The UVB rays have a low penetration into the dermis. They are responsible for tanning but also for sunburns.
A sunburn is characterised by redness in the affected area. It typically appears 8 to 24 hours after exposure and is caused by a dilation of the superficial skin vessels. The skin becomes sensitive and a light touch can cause mild to moderate pain.
The mechanism behind the occurrence of sunburn was analysed in a study conducted in 2012 on human skin cells and mice. This study demonstrated that UVB radiation damages the cellular microRNA These damaged molecules are then released into the extracellular environment and come into contact with neighbouring cells. These cells then trigger an inflammatory response, which is the cause of the sunburn.
However, there are instances where sunburn can worsen, leading to swelling, the emergence of blisters or bullae filled with clear fluid, as well as heightened pain. In advanced cases, a sunburn can trigger the onset of cancerous melanomas.
Shea Butter: A solution for relieving sunburn?
The shea butter provides a natural solution for relieving sunburn due to its properties:
Sunburn destroys thousands of epidermal cells. The UV radiation emitted by the sun breaks down elastin and collagen fibres. Shea butter helps to soothe the skin and has regenerative properties.
Shea butter aids in promoting collagen production. Collagen and elastin are two essential proteins for skin elasticity, firmness, and resilience. α-amyrin and lupeol are triterpenes found in the unsaponifiable fraction of shea butter. They deactivate proteases such as collagenase, a metalloprotease, and elastase, a serine protease. Thus, shea butter enables the skin to regenerate following sunburn.
Rich in fatty acids, shea butter helps to maintain skin hydration. It strengthens the skin barrier, thereby reducing noticeable water loss and maintaining hydration.
A study conducted by a Swedish company in 2009 highlighted the moisturising power of shea butter. Skin moisture levels were measured using a corneometer. The application of shea butter resulted in a steady increase in moisture levels over a four-hour period. The use of shea butter on the skin provides an alternative against transepidermal water loss.
Lupeol is a terpenic alcohol found in shea butter, possessing anti-inflammatory properties. The anti-inflammatory properties of shea butter are due to the inhibitory action of lupeol on the mRNA expressions of iNOS, COX-2, TNF-α, IL-1β, and IL-12 induced by lipopolysaccharides (LPS).
Our skin is naturally equipped to defend against UV radiation thanks to melanin. This biological pigment, responsible for our tanning, also serves to protect us from the intensity of light radiation. When the body is overly exposed to the sun, melanin no longer effectively filters UV rays. Certain compounds lose one or more electrons and transform into free radicals.
Vitamin E, or tocopherol, found in shea butter, protects against external aggressions such as UV radiation and chemical pollution. Vitamin E is capable of donating an electron to a free radical without becoming unstable. The free radical is stabilised, less reactive, and the oxidation cascade of molecules is halted.
Thanks to its regenerative, moisturising, anti-inflammatory and antioxidant properties, shea butter provides a natural solution for relieving sunburn.
ANDERSSON A. C. &al. Effect of topically applied lipids on surfactant-irritated skin. The British Journal of Dermatology (1996).
GAUTAM H. K. &al. Anti-Inflammatory Effects of Shea Butter through Inhibition of Inos, Cox-2, and Cytokines via the Nf-Kb Pathway in Lps-Activated J774 Macrophage Cells. Journal of Complementary and Integrative Medicine (2012).