Light skin

Ethnic groups such as Norwegians (top left), Russians (top right), and Koreans (bottom), are examples of people around the world who have light skin

Light skin is a human skin color that has a low level of eumelanin pigmentation as an adaptation to environments of low UV radiation.[1][2] Due to migrations of people in recent centuries, light-skinned populations today are found all over the world.[2][3] Light skin is most commonly found amongst the native populations of Europe, East Asia,[4][5][6] West Asia, Central Asia, Siberia, and North Africa as measured through skin reflectance.[7] People with light skin pigmentation are often referred to as "white"[8][9] although these usages can be ambiguous in some countries where they are used to refer specifically to certain ethnic groups or populations.[10]

Humans with light skin pigmentation have skin with low amounts of eumelanin, and possess fewer melanosomes than humans with dark skin pigmentation. Light skin provides better absorption qualities of ultraviolet radiation, which helps the body to synthesize higher amounts of vitamin D for bodily processes such as calcium development.[2][11] On the other hand, light-skinned people who live near the equator, where there is abundant sunlight, are at an increased risk of folate depletion. As a consequence of folate depletion, they are at a higher risk of DNA damage, birth defects, and numerous types of cancers, especially skin cancer.[12] Humans with darker skin who live further from the tropics may have lower vitamin D levels, which can also lead to health complications, both physical and mental, including a greater risk of developing schizophrenia.[13] These two observations form the "vitamin D–folate hypothesis", which attempts to explain why populations that migrated away from the tropics into areas of low UV radiation[14] evolved to have light skin pigmentation.[2][15][16]

The distribution of light-skinned populations is highly correlated with the low ultraviolet radiation levels of the regions inhabited by them. Historically, light-skinned populations almost exclusively lived far from the equator, in high latitude areas with low sunlight intensity.[17]

  1. ^ "Light-skinned". thefreedictionary.com. Retrieved 24 January 2017.
  2. ^ a b c d Jablonski, Nina G. (29 July 2010), Muehlenbein, Michael P. (ed.), "Skin Coloration", Human Evolutionary Biology (1 ed.), Cambridge University Press, pp. 192–213, doi:10.1017/cbo9780511781193.016, ISBN 978-0-521-70510-3, retrieved 1 June 2024
  3. ^ O'Neil, Dennis. "Skin Color Adaptation". Human Biological Adaptability: Skin Color as an Adaptation. Palomar. Archived from the original on 18 December 2012. Retrieved 10 December 2012.
  4. ^ Hou, Sen (March 2024). "Skin color of Chinese women across different regions of China: An analysis based on both individual typology angle and hue angle". Journal of Dermatologic Science and Cosmetic Technology. 1 (1). doi:10.1016/j.jdsct.2024.100003.
  5. ^ Cho, Changhui (January 2015). "Comparison of skin color between two Asian populations: according to latitude and UV exposure". Journal of Cosmetic Dermatology. 14 (1): 22–26. doi:10.1111/jocd.12130. PMID 25573440.
  6. ^ Wu, Yue (July 2020). "Objective measurement and comparison of human facial skin color in East Asian females". Skin Research and Technology. 26 (4): 584–590. doi:10.1111/srt.12838. PMID 31943387.
  7. ^ Relethford, John (1997). Fundamentals of Biological Anthropology. Mayfield Publishing Company. p. 270. ISBN 978-1559346672.
  8. ^ Oxford Dictionaries. April 2010. Oxford University Press. "belonging to or denoting a human group having light-coloured skin" "white" (accessed 6 August 2012).
  9. ^ Dictionary.com: white 3.a "marked by slight pigmentation of the skin"
  10. ^ "Global Census". American Anthropological Association. Archived from the original on 14 September 2018. Retrieved 10 December 2012.
  11. ^ Kirchweger, Gina. "The Biology of Skin Color: Black and White". Evolution Library. PBS. Retrieved 22 September 2018.
  12. ^ Wolf, S. Tony; Kenney, W. Larry (1 September 2019). "The vitamin D-folate hypothesis in human vascular health". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology. 317 (3). American Physiological Society: R491–R501. doi:10.1152/ajpregu.00136.2019. ISSN 0363-6119. PMC 6766707. PMID 31314544.
  13. ^ Cui, Xiaoying; J. McGrath, John; H. J. Burne, Thomas (26 January 2021). "Vitamin D and schizophrenia: 20 years on". Nature. 26 (7): 2708–2720. doi:10.1038/s41380-021-01025-0. PMC 8505257. PMID 33500553.
  14. ^ Appenzeller, Tim (2012). "Human migrations: Eastern odyssey". Nature. 485 (7396): 24–26. Bibcode:2012Natur.485...24A. doi:10.1038/485024a. PMID 22552074.
  15. ^ Relethford, JH (2000). "Human skin color diversity is highest in sub-Saharan African populations". Human Biology; an International Record of Research. 72 (5): 773–80. PMID 11126724.
  16. ^ Jones, P.; Lucock, M.; Veysey, M.; Beckett, E. (2018). "The Vitamin D⁻Folate Hypothesis as an Evolutionary Model for Skin Pigmentation: An Update and Integration of Current Ideas". Nutrients. 10 (5): 554. doi:10.3390/nu10050554. PMC 5986434. PMID 29710859.
  17. ^ "Modern human variation: overview". Archived from the original on 5 November 2012.