Vaccenic acid

Vaccenic acid is a trans fat found in the fat of ruminants and in dairy products. Its IUPAC name is trans-7-octadecenoic acid, and its lipid shorthand name is 18:1 trans-11. The name was derived from the Latin vacca (cow).

Vaccenic acid was discovered in 1928 in animal fats and butter. It is the main trans fatty acid isomer present in milk fat. Mammals convert it into rumenic acid, a conjugated linoleic acid, where it shows anticarcinogenic properties.

Its stereoisomer, Cis-Vaccenic acid is an Omega-7 fatty acid found in Sea Buckthorn (Hippophae rhamnoides) oil. Its IUPAC name is cis-7-octadecenoic acid, and its lipid shorthand name is 18:1 cis-11.

Old Person Smell
In the April 2001 issue of THE JOURNAL OF INVESTIGATIVE DERMATOLOGY, Shinichiro Haze et al published an article entitled: "2-Nonenal, Newly Found in Human Body Odor Tends to Increase with Aging".

In this article it was suggested that omega-7 unsaturated fatty acids, such as palmitoleic acid and vaccenic acid, found on the skin surface may be the cause of the phenomenon commonly known as "old person smell".