The skin is the human body’s largest organ, covering an area of nearly 1.8 m2. It functions as a metabolically active biological barrier by separating internal homeostasis from the external environment. Aside from providing cover, the skin also prevents water loss, regulates the body’s temperature, absorbs mechanical energy, protects against UV light and acts as an antimicrobial defense system. Therefore, maintenance of the skin is critical for normal homeostasis.
A series of publications in the 1920s and 30s discussed a new disease caused by the prolonged exclusion of fat from the diet, which resulted in epidermal hyperplasia, scaly skin and an increase in transepidermal water loss (TEWL).1 Interestingly, upon consumption of linoleic acid (LA), all the characteristics of this deficiency could be alleviated.2, 3 It was therefore recognized that LA was an essential fatty acid (EFA) required for normal bodily function. In addition, a pioneering link was made between the importance of EFAs and cutaneous skin biology.