Palmitoleic acid, or (Z)-9-hexadecenoic acid, is an omega-7 monounsaturated fatty acid with the formula CH3(CH2)5CH=CH(CH2)7COOH that is a common constituent of the glycerides of human adipose tissue. It is present in all tissues, but generally found in higher concentrations in the liver. It is biosynthesized from palmitic acid by the action of the enzyme delta-9 desaturase.
Dietary sources of palmitoleic acid include a variety of animal oils, vegetable oils, and marine oils. Macadamia Nuts, Macadamia oil (Macadamia integrifolia) and sea buckthorn oil (Hippophae rhamnoides) are botanical sources with high concentrations, containing 17% and 40% of palmitoleic acid, respectively.
A 2001 study proposed that omega-7 unsaturated fatty acids, such as palmitoleic acid and vaccenic acid found on the skin surface, were oxidatively decomposed to 2-nonenal, which may be the cause of the phenomenon commonly known as 'old person smell', an odor apparently similar to the smell of old books.
Potential dietary and biological effects
In a study examining the effects of diets high in various fatty acids, total cholesterol and low density lipoprotein (LDL, "bad cholesterol") concentrations were similar with palmitoleic and palmitic acids and significantly higher than with oleic acid. High density lipoprotein (HDL, "good cholesterol") was significantly lower with palmitoleic than with palmitic acid. The study provides evidence that, at least in males with high blood cholesterol, a modest increase in palmitic acid raises LDL cholesterol relative to oleic acid, even when dietary cholesterol is low. Palmitoleic acid behaves like a saturated and not a monounsaturated fatty acid in its effect on LDL cholesterol.
Other preliminary research indicated that palmitoleic acid could have a role as a signaling molecule affecting body weight. This work is consistent with previous observations that palmitoleic acid, among other fatty acids available in the diet, may be used by enzymes affecting fat oxidation. This work led to the possibility that oil types manufactured with high palmitoleic acid content may be useful in combating obesity, a report that received national media attention in Australia in 1995.
Update on Research
Python hearts use the circulating lipids to fuel an increase in performance. The research, conducted in collaboration with multiple researchers at the University of Colorado working in the lab of Dr. Leslie Leinwand, identified three fatty acids, myristic acid, palmitic acid and palmitoleic acid, for their roles in the snakes' healthy heart growths following a meal.
- "Nuts, macadamia nuts, raw". http://www.nutritiondata.com/facts/nut-and-seed-products/3123/2.
- Li, Thomas S. C.; Thomas H. J. Beveridge (2003). Sea Buckthorn (Hippophae rhamnoides L.) : Production and Utilization. Ottawa, Ontario: NRC Research Press. pp. 54–55. ISBN 0-660-19007-9. http://www.ovid.com/site/catalog/Book/2738.jsp?top=2&mid=3&bottom=7&subsection=11.
- S. Haze, Y. Gozu, S. Nakamura, Y. Kohno, K. Sawano, H. Ohta and K. Yamazaki (2001). "2-Nonenal Newly Found in Human Body Odor Tends to Increase with Aging". Journal of Investigative Dermatology 116 (4): 520–524. doi:10.1046/j.0022-202x.2001.01287.x. PMID 11286617.
- "Smelling Old? Remedies for "Aging Odor" Are Developed". 09-28-2009. http://web-japan.org/trends00/honbun/tj990921.html.
- Nestel P, Clifton P, Noakes M. (1994). "Effects of increasing dietary palmitoleic acid compared with palmitic and oleic acids on plasma lipids of hypercholesterolemic men". Journal of Lipid Research 35 (4): 656–662. PMID 8006520.
- Zelkowitz R (9-19-2008). "Fat molecule fights weight gain". http://sciencenow.sciencemag.org/cgi/content/full/2008/919/3?etoc.
- Power, G.W., Cake, M.H. & Newsholme E.A. (1997) The influence of diet on the activity of carnitine palmitoyltransferase 1 toward a range of acyl CoA esters. Lipids 32: 31-37
- "Fat and Slimy" 7.30 Report, Australian Broadcasting Commission November 1995