Did you know that, because of the similarity of the components of vegetable oils and the building blocks of skin, these oils can be metabolised into the skin?
Essential fatty acids (EFA’s or omega-3, -6, or -9 acids) are known for their healing and soothing properties on skin.
Human skin has two ways of protecting itself. Firstly, with sebum which consists of triglycerides, fatty acids, waxes, squalene, cholesterol and cholesterol esters. Sebum triglycerides resemble that of those found in vegetable oils although the latter contain more unsaturated acids like oleic acid, linoleic acid, alpha and gamma linolenic acid in bonded form. The natural skin flora can enzymatically break down the triglycerides in the skin into free fatty acids to create a natural protective acid barrier which protects the body against external infections caused by pathogenic microbes. Linoleic acid, an omega-6 acid, is a natural component of sebum and in people with acne skin, the linoleic acid content in the sebum has been observed to be less than in normal skin. Treatments containing linoleic acid seem to improve the performance of sebaceous glands and hence normalise skin.
Secondly, the skin protects itself with its lipid barrier layer that forms at the interface between the stratum granulosum and the stratum corneum and which consists of ceramides, fatty acids and cholesterol.
When this protective lipid barrier is damaged, or if transepidermal water loss (TEWL) increases, the epidermis produces more lipids in the lamellar granules of the stratum granulosum. The granules aggregate, the membranes fuse and the contents of the granules are released in the form of discs and lamellae. It takes a year for this barrier to reach optimum thickness in a new-born baby’s skin. With ageing, the reproduction of the lamellar granules slows down. It has been shown that a mixture of cholesterol, fatty acids and ceramides in the ratio of 3:1:1 can accelerate the regeneration of the lipid barrier. Linoleic acid plays a significant role in skin in that it indirectly strengthens the skin barrier by being integrated in ceramide I (there are 7 different types of ceramides in the skin).
Though vegetable oils are not as cost-effective or inert as silicone or petroleum-derived oils such as mineral oil and petroleum jelly which are excellent trans-epidermal water loss (TEWL) reducers, they cannot, like vegetable oils, repair any barrier layer disruptions or skin susceptible to cornification disorders such as acne in the long run. Polygreen Sensolive from Aqia is a natural silicone alternative.
The linolenic acids, alpha linolenic acid (omega-3) and gamma linolenic acid (omega-6), are components of the cell and mitochondrial membranes and are involved in inner and outer cell transport. When applied topically, alpha linolenic acid (omega-3) and gamma linolenic acid (omega-6) produce strong anti-inflammatory degradation products which will alleviate the effect of sunburn, stimulate healing processes and soothe irritations. The Viamerine® range from Aldivia (INCI oleic/linoleic/linolenic triglycerides) is a patented multifunctional anti-ageing active which soothes, hydrates and plumps the skin.
Oat Lipid-e oil from Oat Cosmetics is one of the few vegetable oils that contain ceramides and has been shown to stimulate ceramide synthesis in the stratum corneum. The newly launched AvenaPLex (Avena sativa (Oat) Kernel Extract) is a 40% polar lipid fraction rich in skin identical and skin equivalent ceramides, sphingolipids and phospholipids.
- Alexandra Zielinska et. al. “Fatty acids in vegetable oils and their importance in the cosmetic industry”, CHEMIK 2014, 68, 2, 103 – 110.
- SH Chon et. al. “Keratinocyte differentiation and upregulation of ceramide synthesis induced by an oat lipid extract via the activation of PPAR pathways.”, Exp Dermatol., 2015, Apr; 24(4): 290 - 5.
- Lauten Schläger “Fats and oils in cosmetics – Mother Nature versus petrochemicals”, Kosmetische Medizin, 2008(2), 76-80.