The Role of Ethnicity in Skin Health and Aging

Intrinsic aging is the “normal” decay of skin caused by the cruel hands of time that results in thinner skin, wrinkle formation, hyperpigmentation and the general signs of bygone years that we are trying to delay by coating our skin in anti-aging products. The way in which this aging occurs tends to vary between individuals and is strongly associated with ethnicities and genetics. Here we will just outline some of the general differences. However, do note that these are generalities and there are always exceptions, especially by those of mixed ethnicities.

Skin Structure:

Genetics plays an important role in the differences of visible aging between individuals. People of different genetic ethnicities often have some visible skin differences that have been shown to have some overall correlations with skin aging. For instance, you may have noticed and/or heard quite a bit about the relative resistance of more pigmented skin types to aging, particularly wrinkles, compared to those of lighter complexions.  Research into the differences in skin structure between ethnicities and skin tones has found that individuals with highly pigmented skin generally have larger fibroblasts (3). Fibroblasts are the cells in our connective tissues that synthesize the all-important collagen and elastin proteins that maintain the structural framework of skin and sustain its firmness and elasticity. Additionally, darker skinned individuals have been shown to have thicker and more compact dermis with a stratum corneum (this is the protective outer layer of dead skin cells - please stop scrubbing them off) that is higher in lipid content and protective cells (3). Simply put, darker skin is structurally better suited for maintaining its strength, firmness and elasticity, leading to less wrinkles.

Melanin, the Dark Knight of the Skin:

Another genetic factor that must be considered when discussing skincare is the presence of the molecule that gives skin its characteristic pigmentation: melanin. Melanin is the protein that gives skin its color, and higher levels of melanin, such as those found in darker skinned individuals, have been shown to provide stronger protection against the damaging effects of UV rays. For instance, Asian skin, which is high in Pheomelanin content (pheomelanin is a type of melanin that is more reddish/yellowish in color, versus eumelanin which is black/brown) also has high levels of UV ray protection and shows delayed appearance of wrinkles. In contrast, Caucasian skin, with its much lower levels of melanin, is more prone to UV damage and photo-aging which manifests as wrinkles and loss of skin firmness (1).

So, yes, high melanin in skin is a gift. However, this does not mean that these individuals get to skip their SPF. Melanin is a bit of a double-edged sword. It is a dark knight that works silently to provide wonderful benefits for skin protection; however, it is also a fickle and prideful molecule that is not the friendliest kid in the playground. Melanin has been shown to be easily irritated through various sources such as sunlight, heat, acne picking, or overly strong exfoliating ingredients. When irritated, melanin will avenge itself by responding with hyperpigmentation, causing uneven skin tone in its host. This is why the idea that dark-skinned and Asian individuals “do not age” is not exactly correct. Intrinsic aging is inevitable and will happen to everyone, but it is the signs or manifestations of aging that are different among ethnicities. While Caucasian skin normally shows its age through wrinkles and loss of firmness due to its lower levels of melanin and fibroblasts and a thinner stratum corneum, dark-skinned and Asian individuals will normally experience hyper and hypopigmentation as their main signs of intrinsic aging. Furthermore, dark skin has been shown to be more prone to Trans-epidermal water loss than their Caucasian or Asian counterparts, making them more prone to dry skin (4).

Sensitivity to Ingredients:

Ethnic and individual diversity in skin structure and physiology could also be responsible for different reactivity levels to chemical ingredients. For instance, consider Glycolic Acid. A Rock Star of the skincare world, this type of Alpha-Hydroxy acid is normally used for its exfoliating property to treat acne and hyperpigmentation. On paper, this would make it an ideal ingredient for those with dark skin that struggle with uneven skin tone; however, we once again must consider the batman-esque hero of dark skin that just wants to be left alone, Melanin. You see, Glycolic Acid is the smallest of all the AHA’s, meaning it can penetrate faster and deeper than any other member of its family. This deep penetration means that Glycolic acid can easily reach and negatively stimulate the melanin molecules in skin. For dark skin, rich in melanin content, this normally translates to high levels of irritation, inflammation, and even more hyperpigmentation. The same deep penetrative property that makes Glycolic Acid such a beloved ingredient for the exfoliation of light skin, can make it irritating for those with dark skin, due to the genetic and structural differences in skin composition (5,6).

In Summary: Your Genetics Matter!

Putting these observations together, it becomes evident that our genetics play a major role in determining our main skincare concerns that we wish to rectify. Asian skin has been shown to have small pores and be resilient to wrinkles, but it is also prone to hyperpigmentation (2). This makes ingredients that support exfoliation and brightening the main interest of this population. Caucasian skin is less prone to dryness and hyperpigmentation, but it is more prone to UV damage that compromises the health of collagen and elastin proteins and causes wrinkles and sagging skin (4). This makes antioxidants and ingredients that promote collagen production to be the main products that would benefit them. Dark skin has been shown to be resilient to wrinkles and loss of firmness but prone to uneven skin tone and dry skin. Products that support skin barrier renewal, enhance the natural moisturizing factor, and prevent trans epidermal water loss could be particularly beneficial for dark skin (4).

Resources:

1. Markiewicz, E., & Idowu, O. C. (2018). Personalized skincare: from molecular basis to clinical and commercial applications. Clinical, cosmetic and investigational dermatology, 11, 161–171. https://doi.org/10.2147/CCID.S163799

2. Sugiyama-Nakagiri, Y., Sugata, K., Hachiya, A., Osanai, O., Ohuchi, A., & Kitahara, T. (2009). Ethnic differences in the structural properties of facial skin. Journal of dermatological science, 53(2), 135–139. https://doi.org/10.1016/j.jdermsci.2008.08.008

3. Montagna, W., & Carlisle, K. (1991). The architecture of black and white facial skin. Journal of the American Academy of Dermatology, 24(6 Pt 1), 929–937. https://doi.org/10.1016/0190-9622(91)70148-u

4. Wesley, N. O., & Maibach, H. I. (2003). Racial (ethnic) differences in skin properties: the objective data. American journal of clinical dermatology, 4(12), 843–860. https://doi.org/10.2165/00128071-200304120-00004

5. Khunger, N., Sarkar, R., & Jain, R. K. (2004). Tretinoin peels versus glycolic acid peels in the treatment of Melasma in dark-skinned patients. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.], 30(5), 756–760. https://doi.org/10.1111/j.1524-4725.2004.30212.x

6. Khunger, N., & IADVL Task Force (2008). Standard guidelines of care for chemical peels. Indian journal of dermatology, venereology and leprology, 74 Suppl, S5–S12.

Article By: Nazli Azodi