Plants and the chemicals they make. Fatty Acids
What is a fatty acid?
A fatty acid (example: palmitic acid) has a carboxylic acid attached to a long hydrocarbon chain.
Why are fatty acids so important?
Fatty acids are used as a major source of energy during metabolism and as a starting point for the synthesis of phospholipids, the main category of lipid molecules used to construct biological membranes (generally composed of two fatty acids linked through glycerol phosphate to one of a variety of polar groups).
Why are the differences in chemical structure so important?
The chemical structure makes the function possible. Stearic acid cannot do what linoleic acid can.
Fatty acids can differ in
- number of carbon in the chain,
- number and carbon position of the double (unsaturated) bond (the ω refers to the position of the double bond relative to the #1 carbon in the chain)
- configuration of the unsaturated bond (cis vs. trans). A “cis” bond bends the chain in space and is very important for the fluidity of cell membranes.
Note: “trans” bonds are not usually found in nature but in synthetic, hydrogenated fats. (whose idea was to hydrogenate vegetable oils to make margarine? And who decided that they were healthier than butter?)
What is an essential fatty acid?
It is a fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. Why not? We don’t have the enzymes (desaturases 12 and 15) required to synthesize them from the saturated fatty acid stearic acid.
Only two fatty acids are known to be essential for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid).
Some other fatty acids are sometimes classified as “conditionally essential,” meaning that they can become essential under some developmental or disease conditions; examples include docosahexaenoic acid (an omega-3 fatty acid) and gamma-linolenic acid (an omega-6 fatty acid). At SAS we use a variety of plant and algae fatty acids to ensure that our skin has a good supply of both essential and conditional essential fatty acids.
Figure: linoleic acid, an essential fatty acid abundant in pitaya oil. Note the position of the double bonds relative to the omega Carbon 1 in red).
What is the role of fatty acids in our skin?
Cell membranes are crucial to health. Deficiency in essential fatty acids shows as dermatitis.
Fatty acids in general are central to the use of energy in the skin, required to make new skin and maintain function and health.