Skin Ageing

Changes in the skin are one the most visible indicators of ageing. Studies suggest that up to 60% of the skin ageing process is due to genetic factors [1] Jump to reference section: [1] . 

How does the skin age?

We all want to keep our skin looking healthy, but that depends on our ability to maintain the three properties that determine the skin ageing process; hydration, elasticity and antioxidant ability.

• Hydration relates to your skin-water content and is the ability of your skin to absorb moisture and nutrients from the environment and infuse them into the cells.

• Elasticity is the ability of the skin to regain and maintain its original form following deformation or injuries. The skin tissue responsible for this property is collagen, and it is always broken down as more is produced.

• Antioxidant ability is a mechanism the skin uses to protect itself against damage by harmful radiations, such as exposure to the sun, and toxins.

How does ageing affect skin functions?

As the skin ages, it gradually loses its mechanical and biological properties, a process that may affect its functions. Changes in the genes that initiate and control these properties may cause variations in the skin ageing process between individuals. While some people’s genetics ensure slow skin ageing, others experience it more rapidly.

Externally, skin ageing is characterised by paleness, thinness, and translucent appearance. Depending on an individual’s genetics, their skin may appear dry, wrinkled, loose and inelastic. These outcomes are due to the loss of skin elasticity, hydration and antioxidant properties. Internally, the ageing skin loses melanocytes (which are cells that contain pigments) resulting in pigmented spots in skin regions exposed to the sun. The connective tissue (made of collagen) around the skin also loses its elasticity and strength causing wrinkles and sagging [2] Jump to reference section: [2] . Additionally, the skin produces less oil and its fat glands decrease in size, affecting mechanisms for cooling such as insulation and sweating. 

The genetics of skin ageing

Being a major influence on the nature and composition of the skin, genetic variants play a big role in affecting its elasticity, hydration and antioxidant functions. Twin studies suggest that the effects of skin ageing are heritable among family members. For instance, a study on heritability of skin properties indicates that children of individuals whose skin have pigmented spots, sun damage and wrinkles have 41%, 60% and 55% respective chances of inheriting these skin ageing traits.

In addition, dermatological research claims that there is up-to a 57% chance of an individual inheriting wrinkle depth from their parents [3] Jump to reference section: [3] .

Genetic changes in skin elasticity and antioxidant property are well determined, with hydration thought to be affected by the impact of these two characteristics.

Antioxidant functions

Research links the process of skin ageing with variants of the MC1R gene, which provides instructions for the production of melanocortin-1 receptors in skin cells [4] Jump to reference section: [4] , which controls how these cells produce melanin. Melanin is an important pigment which determines skin color tone and also protects it from UV light and reactive substances. Therefore, variation in the expression of the MCR1 gene is likely to change the formation and transportation of melanin to the skin, and subsequently how the skin carries out its antioxidant functions.

Sensitivity to sun

Variants in the IRF4 gene have also been associated with increased sensitivity of the skin to sunlight exposure. This gene controls how cells specialise in their roles and adapt to the environment. The IRF4 gene variant rs12203592 affects how skin cells protect themselves from sunlight and reactive substances [5] Jump to reference section: [5] . Photoageing, where the sun damages skin cells leaving coloured spots and lesions, increases with such variations.

Developing wrinkles

Skin wrinkling results from changes in skin elasticity and is associated with the SHC4 gene, which is involved in production of skin cells and tissues and their functions. An example is collagen, an important building block of the skin that prevents it from sagging. Variants in SHC4 may result in improper production of vital skin components such as collagen. The formation of wrinkles around the eyes (known as crow’s feet) is one of the effects of skin ageing associated with SHC4 variant rs2839284 [5] Jump to reference section: [5] .

How is the environment involved?

Skin ageing does not begin and end with genetics, as non-genetic factors such as sun exposure, ethnicity and gender account for the other 40% of factors which impact this trait [6] Jump to reference section: [6] .

These factors may lead to variations in the skin ageing process causing the physical and functional changes described above. Prolonged exposure to UV rays and heat from the sun may directly damage the skin’s hydration and antioxidant properties, a process known as photoageing.

On the other hand, individuals with more darkly pigmented skin tones are more likely to retain younger skin properties. More dark pigment denotes more melanin production and increased insulation against damage by UV light. Some dermatological research also suggests that men are more susceptible to skin damage caused by stress from the environment, than compared to women [6] Jump to reference section: [6] . As a result, the likelihood of experiencing rapid or slow skin ageing depends on both genetic and non-genetic factors.
 

What can you do about skin ageing?

Skin ageing is a normal process that is mostly related to changes in your chronological age. While your genetics play an important role in that, you can still do a  lot to determine your skin ageing outcomes. Going forward, it is important to engage in deliberate skin care practices that help you avoid exposure to non-genetic factors that may damage your skin. Whether working, walking or enjoying yourself in the sun, wearing protective clothing and applying sunscreen is important.

Secondly, consuming a diet rich in vitamins and minerals that can replenish the protective qualities of the skin is important. Last but not least, drinking adequate water helps ensure that our skin hydration and detoxification mechanisms can work efficiently.